Comprehensive Measurements of Common Air Pollutants from a New England Suburban Background Site During COVID Shutdowns and Re-openings

Abstract:

The pandemic caused by the COVID-19 virus has altered human behavior in many unusual ways, prompting reduced movement and economic activity. Many of these altered behaviors are hypothesized to have large changes on pollutant emissions and thus air quality. Here we describe near-continuous measurements obtained at a ground site in Billerica, MA from early March 2020 through the fall/winter of 2020. The measurements comprise: numerous VOCs, and oVOCs with a Vocus Proton Transfer Reaction Time-of-Flight Mass Spectrometer (Vocus PTR-TOF); trace greenhouse gases such as CO, formaldehyde, ethane, and methane using Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS) instruments; aerosol composition obtained with a Soot Particle Aerosol Mass Spectrometer (SP-AMS) ; other gases including ozone and carbon dioxide; and basic meteorology such as wind velocity, temperature and relative humidity. Long-term time series were analyzed using positive matrix factorization (PMF). The trends in composition and concentrations of the gas phase and particulate phase species show similarities and differences during the Covid-19 pandemic. These observations are compared across the different phases of economic re-opening in MA and also to ambient observations in the region prior to the pandemic.