Urban Air Pollution May Enhance COVID-19 Case-Fatality and Mortality Rates in the United States

BACKGROUND The novel human coronavirus disease 2019(COVID-19)pandemic has claimed more than 600,000 lives worldwide,causing tremendous public health,social,and economic damages.Although the risk factors of COVID-19 are still under investigation,environmental factors,such as urban air pollution,may play an important role in increasing population susceptibility to COVID-19 pathogenesis.METHODS We conducted a cross-sectional nationwide study using zero-inflated negative binomial models to estimate the association between longterm(2010–2016)county-level exposures to NO2,PM2.5,and O3 and county-level COVID-19 case-fatality and mortality rates in the United States.We used both single-and multi-pollutant models and controlled for spatial trends and a comprehensive set of potential confounders,including state-level test positive rate,county-level health care capacity,phase of epidemic,population mobility,population density,sociodemographics,socioeconomic status,race and ethnicity,behavioral risk factors,and meteorology.RESULTS From January 22,2020,to July 17,2020,3,659,828 COVID-19 cases and 138,552 deaths were reported in 3,076 US counties,with an overall observed case-fatality rate of 3.8%.County-level average NO2 concentrations were positively associated with both COVID-19 case-fatality rate and mortality rate in single-,bi-,and tri-pollutant models.When adjusted for co-pollutants,per interquartile-range(IQR)increase in NO2(4.6 ppb),COVID-19 case-fatality rate and mortality rate were associated with an increase of 11.3%(95%CI 4.9%–18.2%)and 16.2%(95%CI 8.7%–24.0%),respectively.We did not observe significant associations between COVID-19 case-fatality rate and long-term exposure to PM2.5 or O3,although per IQR increase in PM2.5(2.6 mg/m3)was marginally associated,with a 14.9%(95%CI 0.0%–31.9%)increase in COVID-19 mortality rate when adjusted for co-pollutants.DISCUSSION Long-term exposure to NO2,which largely arises from urban combustion sources such as traffic,may enhance susceptibility to severe COVID-19 outcomes,independent of long-termPM2.5 and O3 exposure.The results support targeted public health actions to protect residents from COVID-19 in heavily polluted regions with historically high NO2 levels.Continuation of current efforts to lower traffic emissions and ambient air pollution may be an important component of reducing population-level risk of COVID-19 case fatality and mortality.

Fluctuating temperature modifies heat-mortality association around the globe

Studies have investigated the effects of heat and temperature variability(TV)on mortality.However,few assessed whether TV modifies the heat-mortality association.Data on daily temperature and mortality in the warm season were collected from 717 locations across 36 countries.TV was calculated as the standard deviation of the average of the same and previous days’minimum and maximum temperatures.