Impacts of the 2020 COVID-19 Shutdown Measures on Ozone Production in the Los Angeles Basin

Abstract

In March and April 2020, the South Coast Air Basin of California (USA) experienced noticeable declines in on-road activity and primary traffic-related pollutant emissions. However, secondary ozone concentration trends were not consistent across the basin. This research letter explores the impact of meteorology and emissions during this time period. The study elucidates the potential impacts on ozone nonattainment status for the region.

Societal shifts due to COVID-19 reveal large-scale complexities and feedbacks between atmospheric chemistry and climate change

“…When temperatures rose above average during an unusual heat wave in late April and May of 2020, ozone DM rose above the range seen in 2015–2019, despite the fact that NO 2 remained similar to 2015–2019 concentrations. An increase in ozone during April and May was also seen in a previous study ( 50 ). The response of ozone per degree increase in temperature is shown in SI Appendix , Fig.…”

Performance of machine learning for ozone modeling in Southern California during the COVID-19 shutdown

“…The reduction in traffic volumes during the lockdown from March to May led to a decrease in observed CO and NO X . 3,16 As a result, we expected an overall reduction in ozone levels over the SoCAB region. The average diurnal ozone concentrations before the lockdown (Jan–Feb) in 2020 were noticeably greater than the average from 2016–2019 for all 15 building sites.…”

“…2 The COVID-19 shutdown also provided an estimation of the impacts of future large-scale emission reduction strategies on ozone concentrations in SoCAB. 3…”