key: cord-0986707-wcrzxp3f
authors: Marwah, Harleen; Rosseau, Natalie; Mangipudi, Sowmya; Ward, Caitlin; Keswani, Anjeni
title: Investigating Air Pollution as a Contributor to Health Disparities During the COVID-19 Pandemic
date: 2021-05-07
journal: Ann Allergy Asthma Immunol
DOI: 10.1016/j.anai.2021.04.030
sha: d42c535fb09f0017732f9daf32975af7a41844ba
doc_id: 986707
cord_uid: wcrzxp3f

nan

The high rates of morbidity and mortality from COVID-19 among Black patients has been a ubiquitous component of media coverage of the global pandemic. 1 While the association between race and COVID-19 is likely multifactorial due to household crowding, socioeconomic status and percentage of essential workers, 2 the association between air pollution, and the disproportionate exposure of COVID-19 for minority communities, has not been adequately explored. Emerging evidence has shown there is a relationship between exposure to increased levels of air pollution and adverse COVID-19 outcomes, and displayed that race is a significant predictor of living in a polluted area within the United States. 1 Prolonged exposure to air pollution leads to chronic inflammatory stimulation with a link between race, pollution, and respiratory conditions in vulnerable populations. 3 Though race is often cited as an independent risk factor for poor outcomes in respiratory diseases such as asthma, environmental factors that disproportionately impact communities of color play a significant role in health disparities across the U.S. As such, the higher rates of pollution in areas with a greater proportion of Black residents may also contribute to the data indicating poor COVID-19 outcomes among Black patients. 1 A nationwide crosssectional study showed that a 1μg/m 3 increase in PM 2.5 was significantly correlated with an 11% increase in the COVID-19 death rate. 4 Regional percentage of Black residents was an additional predictor of COVID-19 mortality. 4 Populations exposed to increased air pollution levels in China and Italy were shown to have a higher COVID-19 incidence and mortality. 3, 5 Evidence regarding COVID-19 suggests that a severe inflammatory response syndrome, marked by fever, hypoxia, and increased serum inflammatory markers, is a significant factor in morbidity and mortality related to the virus. 6 Therefore, racial minorities with an increased risk of inflammatory stimulation due to air pollution exposure may be at greatest risk for severe consequences of COVID-19. Few studies to date, however, have investigated the possible biological mechanisms behind such disparities. 4 This letter reviews the relationship between COVID-19, racial health disparities, and atmospheric pollutants, including: fine matter particulate (PM 2.5 ), particulate matter-10 (PM 10 ), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), and ground level ozone (O 3 ). We then summarize implications for future research to investigate such links.

COVID-19 morbidity and mortality has been correlated with physiologic factors that may be influenced by air pollution. High levels of air pollutants have been shown to impair the function of cilia in airway host defense leaving individuals more susceptible to viral respiratory infections. 7 Exposure to sustained elevations in air pollution have been associated with an increase in Type 1 inflammatory cytokines 3 (Table 1 ) which suggests that air pollution can drive a Type 1 inflammatory state. The severity of COVID-19 infection has also been associated with a heightened Type 1 inflammatory response with elevated serum levels of Interleukin (IL)-1, IL-6 and TNF-alpha in COVID-19 patients requiring hospitalization and ICU level care as well as those with Acute Respiratory Distress Syndrome. 6 Additionally, as endothelial damage appears to be a distinguishing feature of COVID-19 infection compared to other viral infections, it is worth noting that PM 2.5 and PM 10 have been associated with overexpression of platelet-derived growth factor and vascular endothelial growth factor, two potential contributors to cardiovascular disease. 3 Thus, air pollution may contribute to the underlying health conditions which make individuals more susceptible to severe COVID-19 infections, thus conferring an additional stressor on minority communities.

Several study models to determine the relationship between inflammatory markers and COVID-19 are promising. A prospective cohort model could follow patients after measuring a series of baseline inflammatory markers, and assess changes in such markers among those in the cohort infected with COVID-19. This model would allow for consideration of simultaneous comorbidities among patients that involve systemic inflammation, such as atherosclerosis or Type II Diabetes Mellitus. A larger population study might compare inflammatory markers in demographically similar populations differentiated by air pollution exposure, and track incidence and prevalence of respiratory conditions, including COVID-19 and subsequent respiratory impairment, over a lifetime. This may also help understand whether continued type 1 inflammation from air pollution influences the incidence of COVID-19 "long haulers". Studies of inflammatory biomarkers may provide more targeted anti-inflammatory medications to populations. In addition, investigating biological mechanisms may change the discourse around race alone as a risk factor, in favor of understanding the additional underlying environmental factors disproportionately affecting specific communities.

As air pollution drives environmental factors that may create a heightened risk for severe disease and mortality from COVID-19 in Black communities, it is crucial that future research addresses the role of pollutants in driving healthcare outcomes in these communities. We must find a meaningful way to consider environmental influences on our epidemiological findings, health equity data and clinical samples. Air pollution exposure should be factored into respiratory health studies, particularly in mechanistic studies involving airway epithelium as the local inflammatory milieu may be differentially influenced by air pollution exposure. A national research initiative into the health disparities in COVID-19 severity is needed to compare community results across different geographic regions with differing baseline air pollution levels. As air pollutants vary in sources and seasonality, each may be differentially relevant across communities. Additionally, it will be important to understand the short-term and longterm exposure impact of air pollution on COVID-19. Evaluating the short-term impact may include assessing trends in COVID-19 cases with short-term changes in air pollution, secondary to stay-at-home orders. Communities of color make up a higher number of essential workers who have been unable to shelter-in-place during the pandemic. 8 Therefore, these communities may not see as dramatic a change in air pollution levels compared to other settings. The long-term impact of adjustments to public policy, transportation, and city planning on air pollution and disease severity must also be evaluated. Research should examine national trends in air pollution over time in relation to COVID-19 outcomes and compare community results across regions implementing different lockdown or social distancing policies. As the Table 1 : Atmospheric pollutants and sources with associated over-expressed inflammatory markers.

there is a need to understand how air pollution may drive severe COVID-19 outcomes, especially in vulnerable populations. References: 1

Ethnic and racial disparities in COVID-19-related deaths: counting the trees, hiding the forest

Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?

Air pollution and COVID-19 mortality in the United States: Strengths and limitations of an ecological regression analysis

Initial evidence of higher morbidity and mortality due to SARS-CoV-2 in regions with lower air quality. medRxiv: the preprint server for health sciences

Interleukin 6-blockade treatment for severe COVID-19 in two patients with multiple myeloma

Environmental pollutants damage airway epithelial cell cilia: Implications for the prevention of obstructive lung diseases

COVID-19 exacerbating inequalities in the US

Ambient air pollution and its influence on human health and welfare: an overview

The authors would like to acknowledge and thank Drs. Hana Akselrod, Rachel Harold, Neelima Tummala and Susan Anenberg for their review of this manuscript..