Quito’s coronavirus curfew: Escalating tropospheric ozone pollution

During Quito's COVID-19 curfew, tropospheric ozone (O3) pollution surged by 96% to 109% compared to pre-pandemic levels, primarily due to a sharp drop in NOx emissions. This reduction, while lowering other pollutants like NO2, CO, and PM2.5, paradoxically allowed O3 to accumulate unchecked, reaching midday peaks. Despite these increases, daily O3 concentrations remained below safety limits. The study highlights how strict controls on primary pollutants can inadvertently worsen secondary pollutant levels like O3, offering critical insights for designing more effective urban air quality policies.

Salazar, C., Kurbatova, A. I., & Kupriyanova, M. E. (2020). Quito’s coronavirus curfew: Escalating tropospheric ozone pollution. E3S Web of Conferences, 211, 4008. https://doi.org/10.1051/e3sconf/202021104008