American Association for Aerosol Research - Abstract Submission

AAAR 38th Annual Conference
October 5 - October 9, 2020

Virtual Conference

Abstract View


Impacts of Modifiable Factors on Ambient Air Pollution: A Case Study of COVID-19 Shutdowns

REBECCA TANZER GRUENER, Jiayu Li, Rose Eilenberg, Allen Robinson, Albert A. Presto, Carnegie Mellon University

     Abstract Number: 134
     Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases

Abstract
Sources of air pollution that are known as modifiable factors such as traffic, cooking, and electricity emissions can be modulated either by changing activity levels or source intensity. Although air pollution regulations typically target reducing emission factors rather than altering activity, the COVID-19 related closures offered a novel opportunity to observe and quantify the impact of activity levels of modifiable factors on ambient air pollution in real-time.

We use data from a network of 27 low-cost Real-time Affordable Multi-Pollutant (RAMP) sensor packages deployed throughout Pittsburgh along with data from EPA regulatory monitors. The RAMP locations were divided into four site groups based on land use (Traffic, Urban, Suburban, and Industrial). Concentration measurements of PM2.5, CO, and NO2 following the COVID-related closures at each site group were compared to measurements from “business as usual” periods in March 2019 and 2020. Overall PM2.5 concentrations decreased across the domain by 3μg/m3. Intra-day variabilities of the pollutants were computed to attribute pollutant enhancements to specific emission sources (i.e. traffic and industrial emissions). The morning rush hour induced CO and NO2 concentrations at the Traffic sites were reduced by 57% and 43%, respectively, which is consistent with the observed reduction in commuter traffic (~50%). There was no significant change in industrial related intra-day variability of PM2.5 and CO at the Industrial sites following the COVID-related closures.

We observe that the morning rush hour enhancement from traffic emissions fell from 1.5μg/m3 to ~0μg/m3 across all site groups. This translates to a reduction of 0.125µg/m3 in the daily average PM2.5 concentration. If National Ambient Air Quality Standards (NAAQS) are tightened these calculations shed light on to what extent reductions in traffic related emissions are able to aid in meeting more stringent NAAQS.