Working together to resolve quarry dust issues

Environment Canterbury, Christchurch City Council and the Canterbury District Health Board are committed to working together to resolve quarry dust issues in the Yaldhurst area.  To ensure the community has access to the most up to date information, the organisations have agreed to provide regular updates here.  

Update 34. 5/12/2018

All of the Yaldhurst-based quarries in Christchurch have upped their game since a report showed nuisance dust was an issue.

In June, a report was released after a four-month air quality monitoring programme in Yaldhurst which showed no serious public health risk from airborne dust, but that nuisance dust could be an issue from time to time.  

The programme, run by Environment Canterbury with the Canterbury District Health Board and Christchurch City Council also involved, led to Environment Canterbury calling for better dust management by quarry operators.

Environment Canterbury chief operating officer Nadeine Dommisse said quarry dust management hadn’t been good enough in the past.

“It is clear more needs to be done by all parties, including the quarry operators themselves to avoid dust nuisance issues,” she said. “Which is why when we released the results we signalled the need for new tougher quarry dust management and monitoring requirements.”

These requirements meant quarries within 500 metres of someone’s home had to install dust monitors on their boundaries by 1 December 2018. If there was no practicable reason why these boundary monitors were not in place by 1 December, Environment Canterbury would take enforcement action.

“Since we announced the boundary monitoring, we’ve been in regular contact with the quarries to assess each one’s requirements and ensure they were taking all practical measures to reduce dust leaving boundaries. It’s great that several quarries have already put the monitoring in place, including Fulton Hogan, Winstone Aggregates Division Limited and Road Metals, with monitoring due to be installed on Frews Quarries Limited site by the end of this week and at KB Contracting and Quarries within the next two weeks,” Dommisse said. “We’ve also assessed Taggart Earthmoving Limited and Christchurch Ready-Mix Concrete Limited who have comprehensive dust mitigation measures in place so we are satisfied that they do not need the monitors based on their individual site specific situations.”

“Meanwhile, as we head into the drier windier time of the year, we’ll have our compliance officers regularly monitoring the quarries to ensure no visible dust is leaving the boundaries.”

Previous updates

Read previous updates

Update 33. 29/11/2018

We have received an addendum to the final report from Mote as a final update on the Yaldhurst Air Quality Monitoring Programme. The overall conclusions have not changed from those given at the time of release to the public.

This was an update from further analysis undertaken due to an airflow issue discovered at the time of releasing the final report, which potentially affected the results for the March and April RCS results.  At the time we took a conservative approach, based on advice from Mote and our scientists, and gave a final figure double what was noted in the Mote report.  What we are providing in this final addendum is clarification from Mote, for the additional RCS monitoring to assess the performance of the RCS airflow equipment. This has advised that the final readings were in fact higher than given in the original report, as was expected. 

The key points of note are:

  • The overall conclusions have not changed, ie the RCS results were all still below the Californian annual guideline, of 3 ug/m3, used for the programme.  Most sites were below the detection limit. 
  • The revised concentration numbers for the March and April RCS findings were all higher than originally detailed in table 14 of the report.  You can see the new figures on pages 3, 4 and 5 of the addendum report.  This was due to the equipment’s flow sensor not working correctly during the colder months. 
  • At Site 3 the average concentration for the three months was measured at 0.8 µg/m³, with the highest single month at 1.68 µg/m³, the site where the highest concentrations were measured.  Based on the revised calculations, the results are still below the Californian guideline annual average of 3 µg/m³.  Our scientist has advised: “Even if every other month had a concentration double the 1.68 now reported for site 3 in March/April, the annual average for site 3 would still be less than 3 ug/m3.”

Update 32. 20/09/2018 

Environment Canterbury has received a few requests for the number of complaints we’ve received about particular quarries. We’ve pulled details of complaints from 1 July 2008 to 30 June 2018 into spreadsheets that can be found below. Please note, in 2014 the way complaints were recorded changed as the system became more advanced which means some of the data prior to this date is incomplete. However, we have provided all complaints that we have about quarries in Canterbury.

Complaint summary

Update 31. 19/07/2018

Response to questions around monitoring

Since the final report was released there have been several questions and statements from the community about it, which has led to some misunderstanding.  We took the questions to the science team at Environment Canterbury and its chief scientist Dr Tim Davie has summarised it in this memo.

Questions around monitoring

1.  What are dust contaminants?

The contaminants are:

  • Total suspended particulate (TSP)
  • PM10
  • PM2.5
  • Inhalable dust
  • Respirable dust
  • Respirable crystalline silica (RCS)

Total suspended particulate includes all the particles that are in the air, regardless of their size.

PM10 means all particles that are in the air and are less than 10 microns in diameter.  It is a subset of TSP.  Note: One micron is one-millionth of a metre which is one-thousandth of a millimetre.  PM2.5 means all particles that are in the air and less than 2.5 microns in diameter.  It is a subset of PM10 and TSP.

These first three terms are used to measure ambient air quality, mainly by environmental agencies.

Inhalable dust means all particles that are in the air and less than around 100 microns in diameter.  It includes all of PM10, plus some larger particles between 10 and 100 microns.

Respirable dust means all particles that are in the air and less than around 4 microns.  It is a subset of PM10 and includes all PM2.5 particles.  When inhalable dust is measured alongside PM10 and PM2.5, we would expect the amount of respirable dust to be less than the amount of PM10, but more than the amount of PM2.5.

‘Inhalable’ and ‘respirable’ are terms that are mainly used by health agencies, and people talking about workplace and personal exposure.

Respirable crystalline silica includes all particles in the air below around 4 microns (i.e. “respirable”) that are made of crystalline silica.

2. What units are used in dust measurement?

The units that are used when measuring the mass of dust are grams, milligrams (mg) and micrograms (µg, or ug).

  • 1 gram = 1000 milligrams (mg) = 1,000,000 micrograms (ug)
  • 1 milligram = 1000 micrograms (ug)

We also use cubic metres (m3) to measure the volume of air.

Concentrations are measured as the amount (mass) of dust in each cubic metre of air.  For dust, they are usually measured in milligrams per cubic metre (mg/m3) or micrograms per cubic metre (ug/m3). And 1 mg/m3 = 1000 ug/m3.

3. What are concentrations, exceedances, and doses?

These three terms are all used when explaining how much dust there is, but they each have different meanings.  It is important to use the correct units for that measure.

Concentrations are defined as the amount of dust in each cubic metre of air.  They are usually measured and reported as mg/m3 or ug/m3.
Air quality standards are usually written as the maximum concentration of dust that is allowed.

Exceedances are days (or hours, or years) when a particular guideline (e.g. a maximum concentration) is exceeded.  They are expressed as a plain number – e.g. the number of days the guideline was exceeded. They don’t have any units.  They are a result of counting the number of days.

Dose means the amount of substance (e.g. PM10) that a person receives – either by breathing it, eating it, or injecting it.  If you are sitting in a room where the concentration of PM10 is 50 ug/m3, then the amount of PM10 you inhale, the dose, will keep increasing, with every breath you take.  Even though the concentration is staying the same, your dose depends on how long you stay in the room, breathing that 50 ug/m3 air.

Note that guidelines and standards are almost always written as concentrations – e.g. the 24-hour average concentrations of PM10 must not exceed 50 ug/m3.  This is a concentration.  At times the standard may also have some exceedances.  For example, you are allowed three exceedances of 50 ug/m3 per year.  But, it always has a concentration as the standard to be exceeded.

Guidelines and standards are very rarely written as doses when setting air quality standards.

4. What is an averaging period?

Some air quality monitoring periods measure the concentration of PM10 in the air every minute.  This produces a lot of data, which can change rapidly, as the dust moves around, and the concentrations vary.

If we take a list of 60 of these one-minute concentrations, taken one after the other, and we calculate the average, we get a 1-hour average.  The 1-hour average will always be lower than the highest 1-minute average, because it will be watered down by all the other, lower 1-minute averages that hour.

If we take 24 of these 1-hour average concentrations, and average them, we get a 24-hour average concentration.  This will always be lower than the highest 1-hour concentrations for that day, because it will be diluted by all the other, lower 1-hour concentrations.

And if we take 365 24-hour concentrations, and average them, we get a 1-year average concentration.  Which, again, must be lower than the highest 24-hour concentration that year.

When governments produce guidelines for different contaminants, such as PM10, they always specify the contaminant the guideline refers to and the averaging period.  A 1-hour guideline for PM10 will always be higher than a 24-hour guideline, this in turn will always be higher than an annual guideline.  Just because we might be able to cope with high concentrations of PM10 for a day doesn’t mean we could cope with that much for a year.

5. What was measured in the Yaldhurst Air Quality Monitoring Programme?

Contaminants – this programme measured four contaminants – PM10, PM2.5, respirable dust, and RCS. They each have separate results, and separate guidelines to compare against.

Units – all contaminant concentrations were reported as micrograms per cubic metre (ug/m3). Some exceedances of the guidelines were also reported. There was no attempt to calculate dose, as there are no guidelines for dose for these contaminants.

Averaging periods

  • to measure nuisance dust, we used a 1-hour averaging period for PM10
  • to measure PM10 health effects, we used a 24-hour averaging period
  • to measure RCS health effects, we used a long term average, which means we took the average concentration over the whole study (four months) and compared it to an annual guideline. It would have been useful to have 12 months of data, to calculate an annual average concentration, but monitoring RCS is expensive, and after four months we had a reasonable idea of what the annual concentration might be.

We used these averaging periods because:

  • the Ministry for the Environment (MfE) guideline for nuisance dust (PM10) is a 1-hour average of 150 ug/m3;
  • the MfE health guideline for PM10 is a 24-hour average of 50 ug/m3; and
  • the Californian ambient guideline for RCS is an annual average of 3 ug/m3.
In other words, we calculated and reported the average concentrations for each contaminant using the same averaging period as the relevant guideline, which is important.

Comparing a 1-hour concentration to an annual guideline doesn’t make sense. Comparing an annual concentration to a 1-hour guideline doesn’t make sense either.  For example, if a town has an annual PM10 concentration of 20 ug/m3, it doesn’t help to compare that to the 1-hour guideline of 150 ug/m3.  The hourly concentration could have gone over 150 ug/m3 many times in a year, and the town could have a real dust problem, even though the annual average was only 20 ug/m3.

As an aside, many countries, when setting PM10 guidelines for air quality in cities, use both a 24-hour guideline and an annual guideline.  One protects against acute, or short-term effects.  The other protects against long-term health effects. 

6. Can we compare this programme to the Hnizdo and Sluis-Cremer (1993) RCS study?

This was a study of the effect of RCS exposure on South African goldminers. It compared the miner’s exposure to RCS and their risk of developing silicosis (and many did develop silicosis).  The exposure was measured as average concentration of respirable dust the miners were exposed to, times the number of years they were exposed.  The RCS concentration was assumed to be 30% of the respirable dust.  The study found that at the highest level of exposure to RCS, 120 ug/m3 every working day for 37 years, the miners had a 77% chance of developing silicosis.  The results of this study were part of the background information that preceded the decision by the Californian EPA to set an ambient guideline for RCS of 3 ug/m3 (annual average).

The Californian EPA guideline for RCS, of 3 ug/m3 (annual average), was the one used for the Yaldhurst air monitoring programme. All measurements of RCS in the Yaldhurst study were below 3 ug/m3.

Reference:

Hnzido, E. and Sluis-Cremer, G.K. (1993) Risk of silicosis in a cohort of white South African gold miners. American Journal of Industrial Medicine. D downloaded from https://onlinelibrary.wiley.com/doi/abs/10.1002/ajim.4700240409

Update 30. 13/07/2018

The results for the additional period of 22 April to 20 May have been received.  Whilst we wanted to collect the additional data for the respirable crystalline silica monitor that was tampered with, to ensure the full three months for all sites, we felt it important to have further data to compare this against, so continued with monitoring at all sites for this additional month.  The following data covers all sites that were included in the full programme, previously noted in the results in ‘Update 29. 22/06/2018’.

Respirable crystalline silica (RCS):

All monitoring of RCS was below the detection limit for all sites during this period.

PM10 and PM2.5:

Mote have advised the following:

“There were a total of 12 instances where the suggested dust nuisance trigger level was exceeded. Four of these exceedances occurred at Site 2 and the remaining 8 exceedances occurred at Site 6. However all 12 of these exceedances occurred as a result of local burning rather than dust nuisance events. Peak hourly dust nuisance concentrations at the remaining sites did not exceed the suggested dust nuisance trigger level during this monitoring period. Burning events were identified either by local land owners in the area or were observed by staff in the area at the time.”

In home monitoring:

The in home monitoring second round was completed in March. The CDHB Medical Officer of Health has advised that the results are personal to those involved and therefore cannot be made public. He did advise that after international peer review, his conclusion was that the results were inconclusive.

Update 29. 22/06/2018

No serious public health risk from quarries

  • Results well below the international guideline for Respirable Crystalline Silica dust
  • Tougher enforcement promised
  • Nuisance dust above short-term guideline for periods of time on nine of the 120 monitored days. On those nine days, there were 13 exceedances spanning from one minute to less than one hour.

An air quality monitoring programme in Yaldhurst shows no serious public health risk to residents from airborne dust.

The results, released today, follow a four-month monitoring programme run by Environment Canterbury, with Canterbury District Health Board and Christchurch City Council also involved.

Environment Canterbury chief operating officer Nadeine Dommisse said in late 2016 some Yaldhurst residents came forward with concerns about the health effects of dust coming from the quarries.

“The joint agencies’ primary concern is the health of the community. We agreed it was important to understand if respirable crystalline silica, a fine dust that can cause serious health problems, was present in airborne dust around the quarries. And, if so, we needed to determine if it is at a level that poses a long-term public health risk to residents.”

“We also wanted to understand how much nuisance dust was in the air, commonly called PM10 due to the size of the dust particles,” she said. “Ultimately, this led to the Yaldhurst Air Quality Monitoring programme.”

Canterbury Medical Officer of Health Dr Ramon Pink reviewed the results.

“Overall, the results show there is no serious public health risk to Yaldhurst residents from airborne dust,” he said.  “Nuisance dust levels will not cause long-term health effects, but we know it can cause irritation and symptoms of concern in some people and we have prepared a factsheet with advice for residents.”

Dommisse said “While the results show there is no serious public health risk, there is a nuisance dust issue from time to time.”

“We appreciate nuisance dust is a concern for some residents, and we want them to know we have, and are, taking this seriously.”

“We agree quarry dust management hasn’t been good enough in the past. It is clear more needs to be done by all parties, including the quarry operators themselves to avoid dust nuisance issues,” she said. “Today, we are signalling new tougher quarry dust management and monitoring requirements.”

“We’re going to require all quarries within 500 metres of someone’s home to install dust monitors on their boundaries by December 1.  If there is no practicable reason why these boundary monitors are not in place by December 1, we will be taking enforcement action.”

An example of how these boundary monitors work is that they run continuously and must be fitted with an alarm system to send the quarry manager a message if it starts getting close to the threshold level for nuisance dust.  If the alarm is triggered the quarry will be expected to take whatever action they need to, such as stopping work or adding more water carts, to ensure the dust doesn’t breach the Ministry for the Environment’s 1-hour nuisance dust guideline level.  If the guideline is breached the quarry will need to cease operations until dust levels have been managed to acceptable levels.

Quarry operators would have to make this data available to Environment Canterbury, and inform the regional council if there was a breach.

“If a quarry breaches the trigger level, we’ll investigate to find out what action they took to stop dust leaving the quarry before deciding what further action we need to take.”

The Yaldhurst Air Quality Monitoring programme was run by an independent company, Mote, and was designed with input from residents, the quarrying industry and the agencies involved.  It was peer reviewed by international experts to ensure it was robust and comprehensive.

Update 28. 27/04/2018

Third report on PM10 and PM2.5

We’ve received the third report on PM10 and PM2.5 across the six ambient air quality monitoring sites.  It shows that between 22 February 2018 and 23 March 2018, there were three exceedances of the hourly guideline (150 μg/m3, MfE 2016).

The details of the three are:

  • Site 2 (North) – 8 March 2018 2-3pm, 183 μg/m3
  • Site 3 (South) – 15 March 2018 7-8am, 167 μg/m3
  • Site 5 (South) – 15 March 2018 7-8am, 197 μg/m3

The exceedance at Site 2 occurred during a north-easterly wind and coincided with a fire on a neighbouring property.  The exceedances at Sites 3 and 5 occurred during light variable winds, which were predominantly from the north-west.

Mote has analysed the data and has advised that it is likely that the source of these events originated to the north-west, but given the variability in wind direction immediately prior to and during the event, it is also possible that the dust could have originated from the north or north-east of Sites 3 and 5.  These exceedances coincided with dust complaints received by Incident Response.

There were no exceedances of the national environmental standard for PM10 as a 24-hour average during this period.

You can find the full report here:

Update 27. 17/04/2018

The third PM10 report was expected to be released this week but Mote’s Auckland offices are still without power due to last week’s storm.  We don’t yet know when they will be able to return to their normal operations.

Update 26. 20/03/2018

Second report on PM10 and PM2.5

We’ve received the second report on PM10 and PM2.5 across the six ambient air quality monitoring sites. It shows that between 22 January  2018 to 21 February  2018, there were 3 exceedances of the hourly guideline (150 μg/m3, MfE 2016), of which all three were on the same day and two were at the same site. These exceedances coincided with a strong north-westerly wind change and dust complaints to Environment Canterbury.

The details of the three are:

  • Site 5 (South) 11am (173 μg/m3)
  • Site 5 (South) 12 pm (205 μg/m3)
  • Site 3 (South) 12pm (284 μg/m3)

There were no exceedances of the national environmental standard for PM10 as a 24-hour average during this period.

You can find the report here:

Update 25. 20/03/2018

Update on RCS monitoring

We will be releasing all results from the RCS monitoring programme in July 2018.  If any immediate health concerns are identified at any time we will take guidance from Canterbury District Health Board (CDHB), who we continue to work with closely.

The RCS monitoring programme measures RCS against the long-term average guideline. We are monitoring for three months over the windiest/driest months (instead of 12 months).  Results from these three months will be averaged across the year and compared against the long-term average guideline.

Accurate data is key to understanding any potential risks and deciding on the next steps. We need results from three months to get an accurate picture, reach conclusions and take actions in response.  We will make all RCS results available at the end of the three-month period.  We expect this will be in July 2018 due to a delay caused by tampering in January 2018 (as per update 20 below), the time it takes for the laboratory in Australia to analyse the results, and the time it takes for Mote to complete its technical reporting.  We appreciate everyone’s patience while we complete the monitoring and draw scientifically robust conclusions.

Next steps for Yaldhurst quarries

Once the Yaldhurst Air Quality Monitoring Programme is completed, Environment Canterbury, Christchurch City Council, CDHB and WorkSafe New Zealand may take further actions. Any actions will depend on the results.

For example, if the results of the three-month programme show RCS and PM10 levels are tracking below the health guideline, Environment Canterbury’s current approach to monitoring and dust mitigation will continue.

If the results show unacceptable levels of RCS or PM10, actions include directing the quarries to cease operations (under the Resource Management Act) until controls are put in place that mitigate the discharge of dust to an appropriate level.

CDHB will undertake any assessment of health effects.

Update 24. 19/03/2018

To help residents better understand the resource consent process, we have explained how we determine if a quarrying consent would be notified or not.

Update 23. 2/03/2018

  • We received 7 complaints to the Pollution Hotline in February

First report on PM10 and PM2.5

We’ve received the first report on PM10 and PM2.5 across the six ambient air quality monitoring sites. It shows that for between December 19 2017 to January 21 2018, there were 3 exceedances of the hourly guideline (150 μg/m3, MfE 2016), of which all three were on the same day and two were at the same site.

The details of the three are:

  • Site 1 (East) 4 pm (185 μg/m3)
  • Site 3 (South) 11 am (225 μg/m3)
  • and midday (182 μg/m3)

There were no exceedances of the national environmental standard for PM10 recorded by the reference method monitors at Site 2 (North rural/residential) or Site 4 (Background rural/residential) during this period.

You can find the report here:

We apologise for the delay in releasing the report.  The report release was delayed due to awaiting an addendum.

Update on funding

The Yaldhurst Air Quality Monitoring Programme has been independently designed and peer-reviewed.  It is Environment Canterbury’s general principle when undertaking monitoring to determine effects, to consider both the wider public benefits arising from monitoring and other organisations and entities who should contribute to the project.  As such we are seeking funding or in-kind contributions from Christchurch City Council, Canterbury District Health Board and from the quarries themselves.  We have now received some funding from the quarries.

We have also added an additional background RCS monitor to add further data to the programme.

Update 22. 12/02/2018

As of this morning, an additional five PM10 monitoring sites have now been added to live data feed.   

The live data can be found here

To login, please use: 

Username: Yaldhurst 

Password: Airquality123 

Update 21. 09/02/2018

In January, there were six complaints to the Pollution Hotline regarding dust in Yaldhurst.

Update 20. 08/02/2018

One of the RCS monitors being used for the long-term Yaldhurst Air Quality Monitoring Programme was tampered with on January 31, 2018.

Mote noticed irregular readings and went to investigate the site. The tamper-proof tape around the monitoring enclosure had been removed and the clips securing the enclosure had been opened. It was not clear who was responsible.  No tampering was evident at any other site.

The owner of the property that the monitor is located on was notified by Mote, and has agreed for a motion-activated camera to be installed before monitoring at this site starts again on February 9, 2018. Additionally, Mote inspected the equipment that had been tampered with to ensure it had not been damaged, then reinstated it in a way that would further reduce the possibility of future tampering.

Environment Canterbury Zone Manager Steve Firth said it was disappointing someone had attempted to interfere with the monitoring programme.

“We are working hard to deliver a robust monitoring programme that everyone can rely on, and this type of interference does nothing but delay results. We are pleased Mote has appropriate measures in place to detect tampering but we hope we will not see a repeat of this,” he said.  

The data collected at this site to date will be disregarded, but the monitoring at the other sites is continuing as planned and we expect to get the first lot of results back in July 2018.

“We will be working with Mote to ensure the overall programme is not affected by this interference so that we can all have full confidence in the overall results,” said Firth.  

Update 19. 23/01/2018

The RCS monitors are now in place. We expect the first results in July.

During December, we had 5 complaints about dust in Yaldhurst.

Update 18. 12/01/2018

The respirable crystalline silica monitoring is expected to be in place by January 19, with the first results available in July.

The delay in installing is due to a stock shortage over the Christmas period.  Mote have now received the shipment and will be in Yaldhurst installing these next week.

PM10 readings to date

Please note, all data visible to the public to date is yet to be verified so is subject to change as anomalies are fixed.

We have been gathering a substantial amount of data since the instruments were installed last month, and expect to have some further reports about the data to date in mid-February.

Update 17. 21/12/2017

An independent specialist air quality monitoring company has started a long-term programme in Yaldhurst amid concerns about the health effects of the dust coming from the quarries.

Mote and Emission Impossible have teamed up to deliver a scientifically robust monitoring programme for the next three months which will monitor PM10, PM 2.5 and Respirable Crystalline Silica (RCS).

The PM10 and PM2.5 monitoring equipment is now in place, while the RCS monitors will be installed next month.

Environment Canterbury regional leader compliance delivery James Tricker said the results would be vital in understanding what, if any, risk there was for the nearby residents.

“Getting this equipment in the ground is a milestone for us as it’s gone through so many checks, including international review, to ensure this is a robust programme,” he said. “Both the quarry operators and residents have had input into this design, however due to privacy reasons we can’t say exactly where all the equipment is located.”

To ensure that the monitoring equipment isn’t tampered with, several cameras have been set up.

“The data for the PM10 will be live so if there is any high activity we will be calling the quarries to find out what is happening and what action they will be taking to lower the dust levels,” he said. “The data for the respirable crystalline silica will be available monthly so won’t be on the live feed.”

Mr Tricker said the programme needed to run for the full length to get meaningful results, especially as while there was live data it still needed to be verified.

Live data information and interpretation

Live data for one PM10 site is available now, with the other sites expected in the new year due to ensure the systems are working properly.

The live data can be found here

To login, please use:

Username: Yaldhurst

Password: Airquality123

Please note this data has not been validated and should be used with caution. The data may be subject to instrumental faults, drift or erroneous values that will be removed during validation. 

PM10 The Yellow line on the graphic is the Ministry for the Environment guideline for PM10.

This covers an hourly average, and a 24 hour average.

RCS This data will be available monthly, due to needing to be analysed in Australia. The first results we expect in mid to late February.

PM2.5 This data will be available in mid-January. 

Who are MOTE and Emission Impossible?

Find out more here.

Update 16. 8/12/2017

Long-term Air Quality Monitoring Programme update:

We expect to have some monitoring on site from today with a staged implementation of the equipment over the next two weeks with the RCS monitors installed by Christmas.  This will allow us to have monitoring up and running over the windier, drier time of the year and some data available in the new year.  

  • There were ten complaints to the Pollution Hotline in November.

Update 15. 1/12/2017

Today Mote presented Environment Canterbury with its final design recommendations for the Yaldhurst Quarry Air Quality Monitoring Programme.  A document outlining the changes in the design since it was last presented to residents at a public meeting can be read here.

To summarise, Mote is proposing to monitor RCS over 12 months (subject to funding being available for more than three months) at five locations around the quarries.

The locations will remain confidential to ensure privacy of the residents who agreed to use their properties.

Mote will also monitor fine and coarse particles around the quarries and weather conditions, and it will conduct background monitoring at a site representative of rural Canterbury. Results will be available publicly.

The final design document will be available via this website when the recommendations have been reviewed by Environment Canterbury, the Christchurch City Council and CDHB.

Updated 14. 9/11/2017

  • There were three complaints to the Pollution Hotline in October

On Wednesday 8th November, a meeting was held to show interested parties the proposed design for the monitoring programme. During it, several residents asked questions. Below is a list of the questions and comments, with answers from the appropriate authority, as well as the presentation given on the Yaldhurst Quarry Air Quality Monitoring Programme.

Questions directed to Mote
Monitoring should be down wind of the crushing and quarries?

We will be monitoring both upwind from quarrying activities and away from quarrying activities.

Why are you (Mote) not covering the eastern side with the programme? 

We will consider this if there is a prevailing wind which would indicate this would be of benefit.

Why did we go to the quarries prior to going to the residents?

This was simply a matter of timing.  The quarries were able to meet with us during the day however many residents were working so we had an evening meeting to allow as many as possible to attend.  Both meetings occurred on the same day and were shown the same presentation. 

Have you (Mote) ever done monitoring for Respirable Crystalline Silica (RCS) before? 

Yes, however not around a quarry like this.  As far as we know this is the first time this long-term monitoring has been done in New Zealand.

What are the guidelines you are going to use for RCS?

We intended to use the Californian guide of 3 micrograms per cubic meter (µg/m3) as an annual average for comparison with long-term average measurements. We should note that, in order to get the monitoring up and running, the current proposal is only for 3 months.

Why is Environment Canterbury (ECan) focusing on the locations of houses around the Old West Coast Road quarries, and not following wind directions?  This is not the only area with residents and the data needs to be transportable.

The programme is still in a draft state, as we are yet to finalise the exact locations however, we are keen to ensure we cover the main wind directions to get the best possible outcomes for the program.  This will be dependent on suitable, and available, sites also.   

Monitoring dust away from quarries is difficult when there are quarries in all directions so a background site in the area may not give a fair reflection of non-quarrying activity background readings.

We are yet to confirm a background site and will take this into consideration when choosing a site to ensure there are no quarrying activities nearby. But we’re not looking for a pristine site – we’re looking for a “typical Canterbury site that doesn’t have quarries close by – if it experiences long-range quarry dust, then we’ll see that in the results. What we’re trying to determine is the local effect of quarrying, compared to the rest of Canterbury.

Can your monitoring confirm which quarry the dust is coming from?

For the purposes of this programme the quarries are being treated as one and not individually. 

Have you worked for Winstones, Road metals, or Fulton Hogan?  Do you have any conflict of interest? 

No, however we have worked for a quarry in the past and currently work with a number of private and public clients.  We are required to sign a disclaimer to ensure we have no conflict of interest in regard to undertaking monitoring activities for any clients we work with. 

What does the Californian measure 3 for?

The Californian guide of 3 micrograms per cubic meter (µg/m3) as an annual average, is used for measuring exposure to respirable crystalline silica (RCS) less than 4 micrometres in diameter over a 12-month period.

Will you have access to the data for the previous 3-6 months for activities at the quarries?

We have asked the quarries to provide us with their own data and activity information and hope to use this to compare our own data with.  The more information we receive the better detailed overall picture we will get.

Is there a Terms of Reference for the programme to understand the required outcomes and how you got to this stage?  If so, do the residents have access to it?

There is a detailed process that the procurement process has gone through to get to this stage, including an extensive request for proposal from which Mote, and Emission Impossible were selected.  We intend to be as transparent as possible and this presentation to deliver the programme is part of this process. 

Does RCS come from extraction and crushing?  Where a site is no longer extracting but still processing, could there still be RCS?

Yes, and yes.

Are you going to look at the weighbridge information from a quarry to check quarry activities during this period, previously and after?

We have asked the quarries to help us share this type of information to help build a better picture as part of the programme.  This request however is a voluntary one for the quarries.  

Can we have monitoring at other areas and not just around the Yaldhurst quarries?

The programme is only covering the Yaldhurst quarries.  There are a range of quarries and activities undertaken in this area and we are confident we can use this data to understand quarrying activities in other areas also. 

What was the meeting with the quarries like?  What was the vibe?

The quarries also had concerns around the wind direction and the sites for the monitors.  They were also given the opportunity, and did, provide valuable feedback which we will be taking into consideration along with the feedback from the residents. 

What’s wrong with putting monitoring all the way around the quarries and then making a decision on where to put them long term once the appropriate wind directions have been found?  We are locating monitors in three locations around the quarries. The exact location is still under consideration and will depend on both practicalities as well as frequent wind directions.

Will you (Mote) give recommendations for what you find?  This is outside the scope of the monitoring study.

We data gather and interpret, the decision making on consents and policies as a result of the programme will need to come from the Councils. 

Will you be using a cyclone for measuring RCS, as this has missed RCS in the past monitoring in this area?

Yes, we will be using a cyclone for monitoring RCS less than 4 micrometres in diameter.  The monitoring is undertaken for a month, rather than short-term monitoring, to gather sufficient data.

You’re not going to come back and say no RCS found because the program wasn’t comprehensive enough, or didn’t have enough funding or?

No.  The programme has been designed, and recommended, to provide data to be sufficient enough to stand up in court.  

Questions directed to the Councils

Are ECan going to give consents for quarrying whilst the programme is going and the outcomes are not known?

ECan must respond to consent requests as they are received, under the Resource Management Act, and will approach each consent based on its own merit.  However, we have made it clear to the quarries the need to ensure dust mitigations are strictly adhered to. 

Is there a TOR for the programme to understand the required outcomes and how you got to this stage?

If so, do the residents have access to it?  There is a detailed process that the procurement process has gone through to get to this stage, including an extensive request for proposal from which Mote, and Emission Impossible were selected. 

Will this affect the RCS future outcome decisions for the Canterbury region?

We are undertaking the programme to help build knowledge to make appropriate decisions and actions. 

How will this affect things like health and consenting moving forward?  What action will you take if the results are not what you like?

Environment Canterbury, Christchurch City Council and the Canterbury District Health Board are going into this with an open mind and will make decisions, as required, by the legislation we are under.  If this legislation advises we must act, based on any outcomes of the programme, then we will act, and are obliged to.

 Update 13. 31/10/2017

We have arranged for a public presentation, with Mote, to discuss the Yaldhurst Air Quality Monitoring Programme and to ask for volunteer property owners if they would be prepared to have some monitoring equipment on their site for the duration of the programme. 

We have booked in the Yaldhurst Hotel, Lounge Bar, Main West Coast Road, Yaldhurst, on Wednesday the 8th November at 6pm and would like to extend a warm welcome to anyone interested in the outcomes of this programme.  

If you have any questions around this please contact us via YAQM@ecan.govt.nz

Update 12. 18/10/2017

  • There were seven dust complaints to the Pollution Hotline in September.

We have completed the initial round of in home monitoring and received the results.  The in home monitoring was undertaken to assess if there was any potential accumulated effect of dust in residents close to quarrying activities in the Yaldhurst area.

It appeared that some residents were still presenting symptoms they believed to be associated with dust even though it was winter and there was minimal dust with the wetter conditions.

Eight residents participated in the in home monitoring, including a ‘control’ resident who was not in the vicinity of any quarrying activity, though still in the area, to gain a comparison.  We will do a further round of in home monitoring in the new year in the driest and windiest time of the year to compare with these initial results.

We have received the following from the Canterbury Medical Officer of Health on the results of the programme:

  • The results have all come back below any level which is remotely likely to cause silicosis.  Most results were undetectable. Two results were above background levels (though still not at a level of health concern).
  • The results were independently reviewed by a respiratory physician, an occupational physician and a public health physician, who have provided a response to the participants.

If any Yaldhurst resident is concerned by dust, public health advice remains to stay indoors with doors and windows closed until the dust dies down.

Please call Environment Canterbury's pollution hotline on 0800 765 588 if you are troubled by dust.

Update 11. 21/09/2017

  • We now have a recommended design from Mote (the supplier) for long-term ambient air quality monitoring that has been peer-reviewed.
  • We are continuing to work with the Canterbury District Health Board on appropriate health guidelines for this monitoring.
  • We are currently progressing discussion with partners to get this monitoring in place, and we are hoping to get this done as soon as practicable.

Update 10. 15/09/2017

  • There were five dust complaints to the Pollution Hotline in August.

On the 20th July 2017, Dr Kelvin Duncan and Dennis Thomson presented a deputation to the Environment Canterbury councillors, on behalf of the Yaldhurst Rural Residents Association, around concerns with dust and water in the Yaldhurst area. 

On the 1st September 2017 the Chair of the Environment Canterbury Council sent an email, and a posted letter, response to this deputation.  Read the letter of response, and associated response memorandum.

Update 9. 29/08/2017

The report for the in home monitoring has been delayed due to the requirement to have a background ‘control’ comparison.  This comparative monitoring will allow us to compare a resident within the area, who is still more than a kilometre from quarrying site activities, to others adjacent to the quarries.

Once all the results have been analysed the participants will receive their specific results and a summary will be published on this site, and made generally available.  We expect the final report by the end of September.

The Yaldhurst Air Quality Programme recommended design is now being peer reviewed by an air quality monitoring specialist in Australia, as well as one here in New Zealand.  Once the design has been reviewed, pending any required changes, we will then be able to present this to residents, the quarrying industry, and the general public for feedback.

Update 8. 18/08/2017

We finished doing the in home monitoring last week, and are now awaiting a final report as to the dust, or total suspended particulate (TSP), and if there is any respirable crystalline silica (RCS) component. We expect this report, which will cover both TSP and RCS, by the end of August.

In the meantime, we’re proceeding with the next part of this monitoring process which is to arrange for industrial cleaning of the participant’s homes, after which we will complete another round of personal monitoring in order to gain a baseline.  In 3-6 months we will monitor again to help understand any possible accumulated effects. We hope to begin the industrial cleaning within the next week or two depending on availability.

Update 7. 1/08/2017

  • There were three complaints to the Pollution Hotline about quarry dust in July.

In home monitoring update

Four residents have started this today, and a further three will take part tomorrow.  The residents are required to wear two small pumps for eight hours within their homes, which draw air up through two separate filters.  It will take approximately four weeks to receive the results. Once these are available, we will give the results to the residents who participated and a summary will be made available on this site. The monitoring will be undertaken for inhalable dust, respirable dust, and respirable silica.  The results will be compared to non-occupational exposure standards.

Long-term Air Quality Monitoring Programme update

We are continuing to work with Mote around the recommendations of the design and are awaiting some further clarity before proceeding to the next stage.  Once the design has been confirmed, we will be in a position to submit for peer review, industry and public feedback.  We hope to have the programme up and running as soon as possible after this, pending availability from peer reviewing specialists, industry, residents, and general public.  

Pollution Events:

We have received three pollution event calls into our Pollution Hotline for the Yaldhurst quarries over the month of July.  

Update 6. 14/07/2017

In home monitoring update

Environment Canterbury have signed a contract with an independent company, ChemSafety, to do this monitoring.  We are meeting with some residents next week to go over the detail of what this will involve.  After this meeting, we’ll confirm how many residents will take part.  We hope to do the monitoring as soon as practicable based on resident’s availability.

The participating residents will wear two small monitors while they go about their day.

Long-term Air Quality Monitoring Programme update

We’ve picked a supplier, Mote, and are working through the details of the design currently. We hope to have it in place within a month.

Update 5. 30/06/2017

  • There were no dust complaints in June

In home monitoring update

Environment Canterbury have asked a handful of residents to be involved in some in home monitoring to understand if there is any potential accumulated dust effects.

The participating residents will wear two small monitors while they go about their day.

As well as some residents along Old West Coast Road, we’re going to take some comparative readings from residents along Conservators Road.

We’re hoping to meet with the residents taking part shortly to explain exactly what this will involve and to show them how the equipment works.

Long-term Air Quality Monitoring Programme update

We’ve gone back to the shortlist of suppliers with a specific scenario in order to ascertain a like for like proposal to evaluate against, as the original proposals supplied were difficult to compare. 

This has meant a delay in making decisions on the final supplier and therefore a delay on getting a design to progress with.  We have now received these comparative proposals and are currently working on the review process for these.  We hope to have another update on this by the end of next week. 

We are continuing to focus on getting the right outcome for all parties and need to ensure the right proposal will meet everyone’s needs.  We will ensure the residents have an opportunity to review and respond to the proposal once the suitable candidates have been reviewed.

Update 4. 9/06/2017

Environment Canterbury, CCC and CDHB met with about 30 residents from the Yaldhurst area to discuss air quality issues on June 7.  Environment Canterbury invited Professor of Toxicology Ian Shaw to give a presentation on dust and health.

Other topics discussed included;

  • Update on monitoring and additional mitigations (view meeting presentation)
  • Update on the monitoring programme and resident participation in this.

ECan is evaluating the air quality monitoring programme proposals received.  We expect to be able to provide a further update on this by the end of the next week.

Update 3. 2/06/2017

  • The second stage of the tender for the air quality monitoring programme, a Request for Proposal from shortlisted suppliers, closed on 1 June.
  • We are evaluating these proposals. We expect to have finished this by the end of next week.
  • There have been no dust complaints to the Pollution Hotline in the last week. In May overall, there were 2.

Additional information

On 10 May 2017 Environment Canterbury and Christchurch City Council were sent a spreadsheet of readings taken from a Laser PM2.5 Particle Meter and calculations to make comparisons between Yaldhurst measurements with permissible exposure limits (PELs) set out by the Occupational Safety and Health Administration (OSHA). The calculations showed an apparent exceedance of the permissible exposure limits.

In addition to science staff at ECan reviewing the spreadsheet, we have also asked two independent scientists to review it. We concluded there was a significant error in the calculations. If we were to accept the accuracy of measurement, using the formula provided by OSHA the worst reading comes out at around 20% of the PEL.

Further details can be found on the memorandum from ECan chief scientist, Tim Davie.

Update 2: 26/5/2017

  • Suppliers have requested an extension on the RFP for the Air Quality Monitoring Programme. We agreed to extend the deadline to allow all respondents sufficient time to compile quality proposals and to confirm the availability of instrumentation and expertise to meet the tight project schedule.  Full proposals are now expected by 1 June.
  • There have been 2 dust complaints in May to date.
  • A residents meeting is being planned for early June.

Update 1: 15/05/2017

  • Tendering for the Air Quality Monitoring Programme: the first stage - Registration of Interest - closed on 5 May.
  • Responses to the tender were evaluated this week.
  • Of the responses, ECan have asked five of the respondents to submit full proposals by 25 May.
  • No tolerance for dust leaving quarry boundaries continuing with staff actively monitoring these boundaries.
  • There have been no dust complaints in the week 1 - 7 May.
  • Residents were sent a letter on 15 May.
  • Residents are asked to please contact the Pollution Hotline 0800 765 588 if they see dust leaving the quarry boundaries.
Why we need a monitoring programme?

Environment Canterbury, Christchurch City Council and the Canterbury District Health Board are working together on a comprehensive air quality monitoring programme in response to concerns about the health effects of dust coming from quarries in the Yaldhurst area.

The intent of the monitoring programme is to gather sufficient data that the Medical Officer of Health can use to determine if levels of dust and respirable crystalline silica from quarrying activities poses a long-term health risk to residents. As dust containing crystalline silica particles can be too small to see special equipment and lab analysis is required to measure airborne concentrations.

Environment Canterbury has gone out to the open market to seek expertise in delivering this programme and is looking for a supplier with proven skills and experience in delivering similar studies for an end-to-end service from design to supply of instruments and analysis of the data.

Registration of interest by suitably qualified specialists closed on Friday 5 May, and Environment Canterbury have now evaluated these. Full proposals from five of the respondents are expected by 25 May.

Further information can be found on our news page.

Further information

Councils and Canterbury District Health Board Questions and Answers

1. What are the councils doing right now about airborne dust as a result of quarrying activity in Yaldhurst?

ECan and CCC staff are monitoring quarrying activity in Yaldhurst daily to ensure airborne dust is not leaving the quarries’ boundaries, and to ensure quarry operators are complying with their resource consent conditions, as well as recent dust mitigation plans put in place. If dust is observed beyond quarrying sites Ecan enforcement officers will require operators to immediately remedy the situation.In addition to these monitoring activities, ECan is tendering for a comprehensive air quality monitoring programme, to gather sufficient data that the Medical Officer of Health can use to determine if levels of dust and respirable crystalline silica from quarrying activities pose a long-term health risk to residents.

2. What are the quarries doing about it?

Winstone Aggregates’ quarry has created a vehicle exit via Miners Road in order to avoid dust transport onto Old West Coast Road. All quarry vehicles are now exiting via Miners Road. Other mitigations under way by Winstones Aggregates include rationalising truck movements, further sealing roads on-site, investigating improvements to parts of the crushing plant’s housing, and investigating the installation of an additional wheel-wash station at the Miners Road exit.

All of the quarries operating in the Yaldhurst area are required to minimise visible dust emissions arising from quarrying activities. The quarry operators in the area are aware of the importance of effectively implementing dust-control measures and the current monitoring and investigation activities being undertaken by the councils.

3. What is silica dust?

Silica is a natural substance found in materials on construction sites, such as concrete, bricks, rocks, stone, sand and clay. Dust containing silica is created when these materials are cut, ground, drilled or otherwise disturbed. If the silica particles in this dust are small enough (known as respirable crystalline silica), they can be breathed deep into the lungs and cause long term health problems such as silicosis or cancer. The silica-containing dust particles that can be breathed in are not always visible to the naked eye. The Canterbury Plains and its riverbeds are mostly made up of greywacke rock, which contains silica. A hard sandstone, greywacke underlies about 70 per cent of the land area of New Zealand. Quartz is the most common form of crystalline silica and is the second most common mineral on the earth’s surface. Since it is so abundant, quartz is present in nearly all mining operations, including quarries.

4. How does silica get released from quarried rock?

A quarry’s crushing facility is the place where extracted rock is crushed into smaller rocks and gravels. During the crushing process, silica particles can be released as the rock (and the quartz within it) is broken up and ground down. Not all of these particles are small enough to potentially become airborne or to be breathed in, so not all are potential health risks. Visible airborne dust some of the time does not necessarily mean that there is enough respirable crystalline silica to cause silicosis in the long term.

5. I live on Old West Coast Road – how close is Winstone Aggregates’ crushing facility to my home?

Although the boundary of the quarry runs along residential boundaries, the closest dwelling (occupied building) to Winstone Aggregates’ crushing facility on Old West Coast Road is 525 metres away.

6. Why is CCC/ECan planning to carry out further monitoring – aren’t the issues and risks for residents obvious?

Getting accurate data is key to understanding the potential risks and determining the next steps for residents and for the councils. The councils need to carry out monitoring in order to gather up-to-date information and establish clear facts about the quarries’ activities. In particular, further information about airborne dust particulates (in terms of size and silica content) is needed before conclusions about any actual and potential health risks can be reached.

7. When will the air quality monitoring programme start, and when will it start providing useful data?

ECan expects that instruments will be in the ground by July 1 2017 and will look for trends in the data and get an understanding of dust exposure as soon as practical. The number of months of data capture before we can have confidence in the information will be confirmed through the design process.

8. What specific information is ECan seeking from the air quality monitoring programme?

ECan is seeking to measure the levels of respirable crystalline silica in the air, to ascertain whether the concentrations at Old West Coast Road – in closest proximity to active quarry operations – are above relevant guidelines, and to measure the levels of dust (total suspended particulate).

9. Why is it taking until July?

ECan has gone out to the open market to seek a supplier with proven skills and experience in delivering similar studies for an end-to-end service, from design to supply of instruments and analysis of the data. ECan is also seeking input from the quarries and residents on the design before it is started. The programme will be independently reviewed by an expert to ensure it is to the highest standard.

ECan is being very careful to ensure that the data gathered is the right data for Environmental Health officers and medical professionals to use in determining whether there is a health risk. This means ECan staff are working closely with the CDHB to understand what guidelines and standards they will use, in order to gather the supporting information they need.

10. What setback distances apply to quarry activities under the District Plan?

The setback distances that apply to quarrying activities depend on the land-use zone where the quarry is located and the type of quarrying activity.

Most of the quarries in the Yaldhurst area are located in the Rural Quarry Zone, where the following setbacks apply:

• Excavation setback from zone boundary – 10 or 20 metres, depending on screening option

• Excavation setback from site boundary within zone – 6 metres

• Crushing and screening plant setback from zone boundary – 100 metres and below original ground level

• Stockpile setback from zone boundary – 50 metres.

In other rural zones, a 250-metre setback is required from a residential- or school-zone boundary (but not from other rural-zone properties). Otherwise, there is no specific setback in the District Plan, requiring a site-specific assessment of the adverse impacts when processing resource consent applications.

11. Are the councils able to modify the Yaldhurst quarries’ resource consents?

The councils cannot overturn a resource consent decision, but they can review the conditions of the consent to change the management of adverse effects if there is a condition of consent that enables reviews. The councils are currently considering this as a possible action, but are also awaiting further dust-monitoring results and investigations. We are aware that a number of dust-related conditions are already in resource consents, in order to manage adverse dust effects beyond the boundaries of a quarry’s site. Therefore, any review of conditions would need to consider whether there are effects that are not adequately managed by existing conditions. A review of consent conditions related to dust would also need to involve both councils as ECan issues air discharge consents and the CCC issues land use consents.

Also, there are a number examples of quarries which do not rely on land-use resource consents. They either existed prior to planning requirements, or were permitted by the planning requirements at the time. Therefore, a review of land use consents could not be carried out in this instance but a review of the air discharge consents may be possible.

12. Will CCC change the District Plan so that it includes a minimum setback distance between a quarry’s boundary and a residential property’s boundary?

Under the Regeneration Act, the Council is currently prevented from changing its District Plan. This restriction is in place until 2021.

13. Is Winstone Aggregates’ quarry going to be allowed to expand its operations in Yaldhurst, as planned?

The two councils are required to process an application under the Resource Management Act. There is no legal basis for us to refuse to process an application unless it is a prohibited activity (which quarries are not). Whether Winstone Aggregates will be allowed to expand further will depend on the assessment of that application when lodged with the Council for processing.

14. Up until recently, why has it been acceptable for visible dust to leave a quarry’s boundary?

Until the Canterbury Medical Officer of Health identified the potential link between the quarry dust and the potential adverse health effects, the threshold of what Ecan considered to be offensive or objectionable was different, as before it included low levels of visible dust.

15. Is CCC/ECan intending to monitor all quarries within the district/region that are near residential areas more regularly?

Yes – both councils are working together to monitor all quarrying activity in relation to consents and Plan provisions (where relevant).

16. Will CCC/ECan put a temporary halt on issuing any further resource consents to quarry operators?

The two councils are required to process an application under the Resource Management Act once lodged and complete. There is no legal mechanism for us to refuse to process an application unless the activity is listed as a prohibited activity in the District Plan.

17. I think the dust from the quarries is affecting my health – what should I do?

It is important you speak with your General Practice team (family doctor) as soon as possible.

18. I want to speak to someone at CCC/ECan about my situation. How should I get in contact?

Environment Canterbury: 353 9007 or 0800 324 636

Christchurch City Council: 03 941 8999 or 0800 800 169