key: cord-0961546-vif25x2d
authors: Xu, Lei; Taylor, John E.; Kaiser, Jennifer
title: Short-term air pollution exposure and COVID-19 infection in the United States()
date: 2021-11-02
journal: Environ Pollut
DOI: 10.1016/j.envpol.2021.118369
sha: d929aa151cf42ee72614d6567d4ec363a3139a98
doc_id: 961546
cord_uid: vif25x2d

The Sars-CoV-2 disease (known as COVID-19) has become a global public health emergency. Researchers have been unveiling the transmission mechanisms and disclosing possible contributing factors. Studies have theorized plausible linkage mechanisms between air pollution exposure and COVID-19 infection and have divided the air pollution exposure into two types: long-term exposure and short-term exposure. However, present studies on impacts of short-term exposure have not reached a conclusive result and are mostly focusing on Asian and European countries. In this study, we conduct a nationwide analysis to examine the association between short-term air pollution exposure and COVID-19 infection in the United States. Daily confirmed cases, air pollution information, and meteorological factors at the county level were collected between March 1st and June 30th, 2020. A total of 806 (out of 3143) counties were included in this study, with 554 counties for PM(2.5), 670 counties for ozone (O(3)), and 418 counties for both, accounting for around 2.1 million cumulative confirmed cases. This accounts for about 80% of all confirmed cases in the U.S. over the study period. A generalized additive model was applied to investigate the relationship between short-term exposure to PM(2.5)/O(3) and COVID-19 confirmed cases. The statistically significant results indicate that, with every 10 [Formula: see text] increase in mean pollutant concentration, the number of daily confirmed cases increases by 9.41% (CI: 8.77%–10.04%) for PM(2.5) and by 2.42% (CI: 1.56%–3.28%) for O(3). The relative risks associated with short-term PM(2.5) exposure remain positive after isolating the impacts of long-term exposure. The findings of this study suggest that short-term exposure to air pollution, especially to PM(2.5), is likely contributing to the spread and course of the pandemic. This finding has important implications for policymakers and the public to take preventive measures such as staying at home on polluted days while improving ventilation indoors to lower the probability of infection.

Coronavirus disease , caused by severe acute respiratory syndrome-42 coronavirus 2 (SARS-CoV-2), has swept the world as a pandemic. As of July 30 th , 2021, there 43 have been over 196 million confirmed cases and over 4.2 million deaths globally (WHO, 2021) . 44 Air transmission has been recognized as a primary way for the virus to spread (The Lancet matter and O3 are the two pollutants of major concern. Particulate matter was found to increase the missing data. Counties with more than 25% missing data were removed from future analysis. 

After merging the above-mentioned datasets, counties without comprehensive 140 information (i.e., missing meteorological data, or both type of air pollutants data) or no 141 confirmed cases within the study period were excluded from further analysis. The geographical 142 distribution of counties with PM2.5 and O3 data is provided in Figure 1 

Where, reported as the results for every 10 / 3 increase for concentration of selected pollutants.

The two metrics are calculated as follow:

Where 1 is the estimate values for moving-average concentration of pollutants and 178 is the corresponding standard error of the estimate.

Following the main analysis, a sensitivity analysis was conducted to ensure the 180 robustness of this study. Firstly, correlation between short-term exposure and confirmed 

Ozone Pollution: A Major Health Hazard 504

Associations between air pollution and COVID-19 epidemic during quarantine

Association between short-term exposure to air 509 pollution and COVID-19 infection: Evidence from China