Air Pollution, Meteorology, and COVID-19

Effects of air pollution reductions on mortality during the COVID-19 lockdown; and role of meteorological factors in the transmission of SARS-CoV-2

In this study funded by the Health Effects Institute, where we analyzed more than 8.9 million deaths in four different countries, we used an interactive fixed-effects model and found that an increase in daily PM2.5 and NO2 concentrations was associated with increases in daily all-cause mortality. The findings of this study add to the growing evidence that increases in short-term exposures to PM2.5 and NO2 may be associated with increases in mortality rates.

Published in JAMA Network Open, 2024

In this study funded by the Health Effects Institute, we estimated air pollution changes due to COVID-19 lockdowns in early 2020 in four regions, using region-specific estimates of the association between air pollution and mortality derived from causal modeling using data from 2015 to 2019. We found that during lockdowns, NO2 reductions avoided 1.41, 0.44, and 4.66 deaths per 100,000 people in Jiangsu, China, California, U.S., and Central-southern Italy, respectively. Mortality benefits due to PM2.5 reductions were smaller but still significant. During the lockdown in Germany, there were no significant mortality benefits due to NO2, and an increase in PM2.5 concentrations was associated with an increase in mortality.

Published in ScienceDirect, Environmental International, 2024

Effect of air pollution reductions on mortality during the COVID-19 lockdown: A natural experiment study

With funding from the Health Effects Institute, we will conduct a multicountry study to evaluate whether changes in mortality are associated with changes in ambient NO2 and PM2.5 levels before, during, and after the lockdown and disentangle the short-term effects of NO2 versus PM2.5 on mortality.

Learn more about AIR-LOCK

While physical distancing and the use of face masks are well-known factors in preventing the spread of COVID-19, our recent research links meteorological variables such as temperature, humidity, and ultraviolet (UV) radiation to the transmission of SARS-CoV-2, the virus that causes COVID-19. found that warmer temperatures (above 20° Celsius), increased humidity, and higher levels of UV radiation were moderately associated with a lower reproductive number (a measurement of how many new infections are caused by a single infected person in a fully susceptible population), meaning that these factors were likewise associated with decreased person-to-person transmission. Of the three factors, absolute humidity played the greatest role.

The study is published in the journal Nature Communications.