PM 2.5 decadal data in cold vs. mild climate airports: COVID-19 era and a call for sustainable air quality policy.

Airports are identified hotspots for air pollution, notably for fine particles (PM _2.5 ) that are pivotal in aerosol-cloud interaction processes of climate change and human health. We herein studied the field observation and statistical analysis of 10-year data of PM _2.5 and selected emitted co-pollutants (CO, NO _x , and O ₃ ), in the vicinity of three major Canadian airports, with moderate to cold climates. The decadal data analysis indicated that in colder climate airports, pollutants like PM _2.5 and CO accumulate disproportionally to their emissions in fall and winter, in comparison to airports in milder climates. Decadal daily averages and standard errors of PM _2.5 concentrations were as follows: Vancouver, 5.31 ± 0.017; Toronto, 6.71 ± 0.199; and Montreal, 7.52 ± 0.023 μg/m ³ . The smallest and the coldest airport with the least flights/passengers had the highest PM _2.5 concentration. QQQ-ICP-MS/MS and HR-S/TEM analysis of aerosols near Montreal Airport indicated a wide range of emerging contaminants (Cd, Mo, Co, As, Ni, Cr, and Pb) ranging from 0.90 to 622 μg/L, which were also observed in the atmosphere. During the lockdown, a pronounced decrease in the concentrations of PM _2.5 and submicron particles, including nanoparticles _, in residential areas close to airports was observed, conforming with the recommended workplace health thresholds (~ 2 × 10 ⁴  cm ^-3 ), while before the lockdown, condensable particles were up to ~ 1 × 10 ⁵  cm ^-3 . Targeted reduction of PM _2.5 emission is recommended for cold climate regions.
(© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)