Substantial Decreases in NO2 Pollution Measured by Ground-Based Monitors in US Cities During COVID-19 Shutdowns from Reduced Transportation Volumes (preprint)

The air pollutant NO2 is derived largely from transportation sources and is known to cause respiratory disease. A substantial reduction in transport and industrial processes around the globe from the novel SARS-CoV-2 coronavirus and subsequent pandemic resulted in sharp declines in emissions, including for NO2. Additionally, the COVID-19 disease that results from the coronavirus may present in its most severe form in those who have been exposed to high levels of air pollution. To explore these links, we compared ground-based NO2 sensor data from 11 US cities from a two-month window (March-April) over the previous five years versus the same window during 2020 shutdowns. NO2 declined roughly 12-41% in the 11 cities. This decreased coincided with a sharp drop in vehicular traffic from shutdown-related travel restrictions. To explore this link more closely, we gathered more detailed traffic count data in one city, Indianapolis, Indiana, and found a strong correlation between traffic counts/classification and vehicle miles travelled, and a moderate correlation between NO2 and traffic related data. This finding indicates that we can use such analysis in targeting reduction in pollutants like NO2 by examining and manipulating traffic patterns, thus potentially leading to more population-level health resilience in the future.

Indoor Exposure to Commonly Used Disinfectants During the COVID-19 Pandemic (preprint)

Staying safe during the COVID-19 pandemic requires frequent disinfecting of the indoor environment. Quaternary ammonium compounds (QACs or “quats”) are the major class of chemicals widely used as disinfectants in consumer products. While disinfection is necessary for a safe environment during the pandemic, the increased use of QACs is concerning as exposure to these compounds has been associated with adverse effects on reproductive and respiratory systems. We have determined the occurrence and distribution of 19 QACs in 46 residential dust collected before and during the outbreak of COVID-19. All QACs were detected in more than 90% of the samples at concentrations ranging from 1.95 to 531 μg/g (median 58.9 μg/g). Higher QAC concentrations were found in dust collected before the COVID-19 pandemic and in homes with higher disinfecting frequencies ( p < 0.05). In addition, 7 products most frequently used in these homes were analyzed, and QACs were detected at concentrations reaching up to 16,600 mg/L. The QAC profiles in dust and in products were similar, suggesting that these products can be a significant source of QACs. Our findings indicate that the indoor exposure to QACs is widespread, raising concerns about increased exposure to these chemicals during the ongoing pandemic.