Effects of short-term ambient particulate matter exposure on the risk of severe COVID-19

Abstract

Objectives : Previous studies have suggested a relationship between outdoor air pollution and the risk of coronavirus disease 2019 (COVID-19). However, there is a lack of data related to the severity of disease, especially in China. This study aimed to explore the association between short-term exposure to outdoor particulate matter (PM) and the risk of severe COVID-19. Methods : We recruited patients diagnosed with COVID-19 during a recent large-scale outbreak in eastern China caused by the Delta variant. We collected data on meteorological factors and ambient air pollution during the same time period and in the same region where the cases occurred and applied a generalized additive model (GAM) to analyze the effects of short-term ambient PM exposure on the risk of severe COVID-19. Results : A total of 476 adult patients with confirmed COVID-19 were recruited, of which 42 (8.82%) had severe disease. With a unit increase in PM 10 , the risk of severe COVID-19 increased by 81.70% (95% confidence interval [CI]: 35.45, 143.76) at a lag of 0-7 days, 86.04% (95% CI: 38.71, 149.53) at a lag of 0-14 days, 76.26% (95% CI: 33.68, 132.42) at a lag of 0-21 days, and 72.15% (95% CI: 21.02, 144.88) at a lag of 0-28 days. The associations remained significant at lags of 0-7 days, 0-14 days, and 0-28 days in the multipollutant models. With a unit increase in PM 2.5 , the risk of severe COVID-19 increased by 299.08% (95% CI: 92.94, 725.46) at a lag of 0-7 days, 289.23% (95% CI: 85.62, 716.20) at a lag of 0-14 days, 234.34% (95% CI: 63.81, 582.40) at a lag of 0-21 days, and 204.04% (95% CI: 39.28, 563.71) at a lag of 0-28 days. The associations were still significant at lags of 0-7 days, 0-14 days, and 0-28 days in the multipollutant models. Conclusions : Our results indicated that short-term exposure to outdoor PM was positively related to the risk of severe COVID-19, and that reducing air pollution may contribute to the control of COVID-19.

Particulate matter air pollution and COVID-19 infection, severity, and mortality: A systematic review

“…This study also found that the association remained when controlling for another air pollutant, NO2. Similarly, Li et al (29) found a positive association between PM2.5 and clinically-defined severe COVID-19 across four different lag periods (0-7 days to 0-28 days), which attenuated but remained mostly significant when adjusting for other air pollutants.…”

“…Three of the seven infection studies only included participants with a COVID-19 test (24,31,33), while the remainder either used entire cohorts regardless of whether there was a record of a COVID-19 test (32,34) or conducted analyses of the entire cohort as well as just those tested (16,28). Similarly, all but one study examining severity (28) and mortality (27) were limited to cohorts who were diagnosed with COVID-19, while three were restricted to patients hospitalised with COVID-19 (17,23,29). Restricted cohorts present a risk of collider bias, as PM 2.5 exposure could influence both whether an individual sought testing for COVID-19 or was COVID-19 positive, resulting in distorted associations (35).…”

“…Most studies used single-pollutant models, i.e., PM2.5 without any other air pollutants (N = 12). The remainder were evenly split between only multi-pollutant models (16,24,27) and both single and multi-pollutant models (29,34,37) 18) also used the maximum.…”

“…As these are not designed to account for how independent variables may interact (e.g., as mediators or colliders), the statistical associations are less reliable (36). Some studies reported resolutions up to 100m 2 (28,31), others used entire cities (29) or monitoring stations spaced tens of kilometres apart (32,37). Several did not specify PM2.5 resolution.…”

Impact of short-term ambient air pollution exposure on the risk of severe COVID-19

“… ( Chen et al., 2022a ) Jiangsu province, China PM 2.5 , PM 10 Increased risk of severe COVID-19 with OR of 3.99 (1.93-8.25) and 1.82 (1.35-2.44) was associated with a unit increase in PM 2.5 and PM 10 . ( Li et al., 2022 ) Varese, Italy PM 2.5 , PM 10 , NO 2 , NO A unit increase in PM 2.5 was associated with a 5.1% (2.7%-7.5%) increase in COVID-19 cases. Similar findings were observed for PM 10 , NO 2 and NO.…”