Timaru has recorded three high pollution nights so far this year. (File)
Washdyke has recorded 12 high pollution nights for the year to date and could face air quality monitoring as a result, Environment Canterbury says.
In 2019, there were 12 high pollution nights recorded in Washdyke for the entire year.
ECan Timaru operations manager Judith Earl-Goulet said it was likely some particulate pollution in Washdyke was the result of consented activities.
“We also noted that most of the high particulate occurred on weekdays, suggesting there was some contribution from human activities (industry). This was supported when we observed low concentrations at Washdyke during Alert Level 4,” Earl-Goulet said.
Earl-Goulet said there had been early investigations into the possible source of air pollution at Washdyke, which suggested that there were a number of different causes, from a number of different sources, acting at different times.
These included soil particles during strong north-west winds, road dust and dusty activities near the monitoring site, and dust sources south of the monitoring site during strong southerlies.
”Washdyke’s particulate pollution is mainly made up of coarse particles (between 2.5 and 10 microns), which tend to come mainly from non-combustion (eg, seasalt, dust, and large coal boilers),” Earl-Goulet said.
Earl-Goulet said ECan has a consultant re-analysing all the wind speed and PM10 data, to look for patterns in wind changes (eg, north-westerly followed by southerly), wind speeds and time of day.
It had also asked some of the staff monitoring stormwater to look out for possible sources of coarse particles.
“We will be working with Timaru District Council, and we also know that engaging with the industries and businesses in Washdyke is likely to be a key element of any future work, as is the possibility of additional air quality monitoring.
“Part of the work we are undertaking in the coming months is to determine the nature of these different sources to better engage with industry and potential emitters to improve air quality,” Earl-Goulet said.
She said while ECan could not rule out serving abatement notices or fines to Washdyke businesses which repeatedly breach the rules, the preferred approach in the first instance is to work with those who are having problems complying with the requirements.
“We have found this to be the most effective way to encourage change,” she said.
In contrast, Timaru’s township has recorded just three high pollution nights this year. .
On Saturday, the town recorded its third high pollution night with a 24-hour average concentration of 53 micrograms of suspended particulate per cubic metre of air measured at the monitoring site in Anzac Square.
At the same time last year, there had been four high pollution nights. Each year, since 2015, between two and 17 high pollution nights have been recorded at the Anzac Square site by July 4.
Timaru has, in the past, recorded some of the worst air pollution records in the country. ECan estimates the majority of the town’s particulate pollution comes from poor home heating.
ECan air quality director Tafflyn Bradford-James said this year’s numbers for Timaru were encouraging.
“We are confident in the framework set out under the Canterbury Air Regional Plan and expect to see the trend continue downward as more people upgrade to cleaner forms of home heating,” she said.
“The development of affordable ultra-low emission burners in a range of designs, like insert models, means even more households will be able to reduce their emissions.”