Association between long-term exposure to ambient air pollution and COVID-19 severity: a prospective cohort study

Abstract

Background: The tremendous global health burden related to COVID-19 means that identifying determinants of COVID-19 severity is important for prevention and intervention. We aimed to explore long-term exposure to ambient air pollution as a potential contributor to COVID-19 severity, given its known impact on the respiratory system. Methods: We used a cohort of all people with confirmed SARS-CoV-2 infection, aged 20 years and older and not residing in a long-term care facility in Ontario, Canada, during 2020. We evaluated the association between long-term exposure to fine particulate matter (PM 2.5 ), nitrogen dioxide (NO 2 ) and ground-level ozone (O 3 ), and risk of COVID-19-related hospital admission, intensive care unit (ICU) admission and death. We ascertained individuals’ long-term exposures to each air pollutant based on their residence from 2015 to 2019. We used logistic regression and adjusted for confounders and selection bias using various individual and contextual covariates obtained through data linkage. Results: Among the 151 105 people with confirmed SARS-CoV-2 infection in Ontario in 2020, we observed 8630 hospital admissions, 1912 ICU admissions and 2137 deaths related to COVID-19. For each interquartile range increase in exposure to PM 2.5 (1.70 μg/m 3 ), we estimated odds ratios of 1.06 (95% confidence interval [CI] 1.01–1.12), 1.09 (95% CI 0.98–1.21) and 1.00 (95% CI 0.90–1.11) for hospital admission, ICU admission and death, respectively. Estimates were smaller for NO 2 . We also estimated odds ratios of 1.15 (95% CI 1.06–1.23), 1.30 (95% CI 1.12–1.50) and 1.18 (95% CI 1.02–1.36) per interquartile range increase of 5.14 ppb in O 3 for hospital admission, ICU admission and death, respectively. Interpretation: Chronic exposure to air pollution may contribute to severe outcomes after SARS-CoV-2 infection, particularly exposure to O 3 .

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

“…Of the remaining studies, all but Chen, Wang et al (26) found a significant positive association between PM 2.5 and COVID-19 mortality. Chen, Sidell et al (37) found that PM 2.5 was consistently associated with higher mortality rates across multiple models, regardless of whether PM 2.5 was measured in the previous month or year and whether the model adjusted for NO 2 .…”

“…There was no evidence of publication bias ( p = 0.100). Trim-and-fill points could not be applied, though leave-one-out sensitivity analysis indicated the results remained positive but only became significant with the exclusion of Chen, Wang et al (26) (OR: 1.66; 95% CI: 1.06 to 2.59). These results are summarised in Supplementary Figures 5 and 6.…”

Air pollution, SARS-CoV-2 incidence and COVID-19 mortality in Rome: a longitudinal study

“…Similarly, no association between air pollutants and SARS-CoV-2 positive testing was detected in the COVICAT cohort of Catalonia, Spain, although a statistically significant association was estimated with severe COVID-19 disease among infected patients [8]. No association between PM 2.5 or NO 2 and mortality was found in a prospective longitudinal study conducted in Ontario, Canada, while significant associations were estimated with hospitalizations and accesses to intensive care units [9]. In contrast, positive associations between PM 2.5 exposure and COVID-19 incidence were estimated in northern Italy [10] and southern California [11].…”

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

“…Estimates were smaller for NO 2 . ( 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.…”