As Auckland traffic volumes plummeted during New Zealand’s strictest lockdown, so did air pollution levels but a detailed analysis shows a more complex picture than might be expected.
Worldwide, the WHO estimates that air pollution kills around seven million people a year and in the world’s big cities, road traffic emissions have the biggest impact on air quality. But scientists have struggled to establish causal links between air pollution and vehicle emissions because things like weather, woodburners and sea salt also play a role.
New Zealand’s Level 4 lockdown, from 27 March to 26 April, provided a golden opportunity for scientists to test air pollution models and historic baseline data against a period of almost no traffic.
In a University of Auckland study on how lockdown impacted air quality in Auckland, Associate Professor Jenny Salmond and PhD candidate Hamesh Patel measured the top five pollutants associated with air quality: fine and coarse particulate (PM2.5 and PM10), black carbon (BC), ozone (O3) and nitrogen dioxide (NO2). Measurements were from three sites: central Auckland (Queen St and Customs St), a suburban area at Henderson and a rural background site at Patumahoe.
Continue reading at University of Auckland.
Image via University of Auckland.