A near carless Hewletts Rd on the first day of the level 4 lockdown. Photo / File
A near carless Hewletts Rd on the first day of the level 4 lockdown. Photo / File
There aren't many upsides to a global pandemic that forced people to stay home and ground economies to a halt, but improvements to air quality are one silver lining recorded in cities all over the world, including Wellington and Auckland. But did anything change in Tauranga?
Fewer cars on theroad, a slowed industrial sector and a four-week lockdown have made no difference to particle pollution in Tauranga, raw data shows.
Data from four Bay of Plenty Regional monitoring sites around the region showed little change in levels from PM10 - tiny particles that can be inhaled - compared to previous years.
And while Auckland and Wellington have reported significant decreases in pollution from vehicle exhausts, comparable data is not available for the Bay of Plenty.
Bay of Plenty Regional Council coastal land and air science team leader Shane Iremonger said PM10 was the focus of the council's air quality monitoring.
Iremonger said the lockdown results - taken from March 26 to April 22 - were similar to those of previous years.
"[This suggests] there has not been any significant reductions in PM10 as a result of alert level 4 restrictions."
Levels of PM10 in industrial area Totara St, Tauranga over the first four weeks of lockdown, compared to an average of previous years (grey bar). Graphic / Bay of Plenty Regional Council
He said the lockdown data had not been through the usual quality assurances yet, so caution should be applied to any conclusions.
Asked what might be behind the lack of impact from the lockdown, he said more information was needed to draw conclusions about PM10 sources during the period.
"Further analysis is planned to correlate our air quality information with other meteorological or activity data such as roadway traffic counts, Port activity, industrial site (essential business) operations or domestic heating."
He said the council's monitoring focused on fine particles and a range of other air contaminants related to odour, fumigation, shipping, Port activities and industrial processes, as those were the main issues and activities for the council and its communities.
"Historically we have measured nitrogen oxides but the values were low so discontinued. We have the capability to measure nitrogen oxides at some time in the future should the focus of our investigations change for any reason."
Bay of Plenty Regional Council coastal land and air science team leader Shane Iremonger. Photo / Supplied
Dr Ian Longley, an air quality researcher with the National Institute of Water and Atmosphere (Niwa), said most councils did not measure nitrogen oxides.
He analysed monitoring of nitrogen oxides in Auckland and Wellington and found levels had dropped to between 83 and 91 per cent of normal at most sites by the third week of lockdown.
Levels of PM10 at most sites in Auckland rose between the first and third weeks of lockdown, but remained below normal.
He attributed the change over lockdown to stronger winds and the normal expectation of a rise in April due to the start of home heating season.
He said the Bay of Plenty's lockdown PM10 results were "consistent with what we're seeing all over the country".
Like Auckland, most emissions of PM in Tauranga and Rotorua were not from traffic, so were "not expected to be affected much or at all by lockdown".
Levels of PM10 in Otumoetai Rd over the first four weeks of lockdown, compared to an average of previous years (grey bar). Graphic / Bay of Plenty Regional Council
Experts only expected the traffic portion to fall significantly, leading to an overall drop in PM10 of about 10 per cent.
"That's exactly what we've seen in Auckland."
It was not possible to verify such a small change in the Bay of Plenty data provided by the council due to the formatting, he said.
The data for Tauranga showed a rise in PM10 over the four-week period, while remaining in the normal range.
An image Colin Alexander took of dust near Tauranga Airport during the lockdown. Photo / File
Colin Alexander, who lives in the middle of the Mount Maunganui industrial area and has ongoing health issues associated with PM10, said from his perspective on the ground, levels had been worse than usual during the lockdown.
He believed it was due to industrial business not following protocols to contain dust.
One of the data collection points was Totara St in the industrial area. Emission sources monitored included traffic, industrial, Port of Tauranga and shipping activities.
Residential data was collected in Otumoetai Rd in Tauranga, Edmund Rd in Rotorua and Kopeopeo in Whakatāne. All monitored for domestic emissions such as woodsmoke, with Tauranga and Rotorua also monitoring minor urban traffic emissions.
Levels of PM10 in Edmund Rd, Rotorua, over the first four weeks of lockdown, compared to an average of previous years (grey bar). Graphic / Bay of Plenty Regional Council
The daily limit for PM10 is 50μg/m3 over a 24-hour average. This national environmental standard sets a guaranteed level of health protection, and the regional council must take action if it is exceeded.
