The role of air pollution (PM and NO2) in COVID-19 spread and lethality: A systematic review

Abstract

A new coronavirus (SARS-CoV-2) has determined a pneumonia outbreak in China (Wuhan, Hubei Province) in December 2019, called COVID-19 disease. In addition to the person-to person transmission dynamic of the novel respiratory virus, it has been recently studied the role of environmental factors in accelerate SARS-CoV-2 spread and its lethality. The time being, air pollution has been identified as the largest environmental cause of disease and premature death in the world. It affects body's immunity, making people more vulnerable to pathogens. The hypothesis that air pollution, resulting from a combination of factors such as meteorological data, level of industrialization as well as regional topography, can acts both as a carrier of the infection and as a worsening factor of the health impact of COVID-19 disease, has been raised recently. With this review, we want to provide an update state of art relating the role of air pollution, in particular PM 2.5 , PM 10 and NO 2 , in COVID-19 spread and lethality. The Authors, who first investigated this association, often used different research methods or not all include confounding factors whenever possible. In addition, to date incidence data are underestimated in all countries and to a lesser extent also mortality data. For this reason, the cases included in the reviewed studies cannot be considered conclusive. Although it determines important limitations for direct comparison of results, and more studies are needed to strengthen scientific evidences and support firm conclusions, major findings are consistent, highlighting the important contribution of PM 2.5 and NO 2 as triggering of the COVID-19 spread and lethality, and with a less extent also PM 10 , although the potential effect of airborne virus exposure it has not been still demonstrated.

Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2020

“…7.4 ). The correlation between air quality and health outcomes is consistent with the notion of respiratory damage from both COVID-19 and air pollution, but the methods used in these studies have weaknesses [ 559 , 564 ], which prevent a quantitative assessment of the link between air pollution and mortality from COVID-19.…”

“…Meteorological factors associated with the spread and severity of COVID-19 have been investigated [ 556 – 558 ] and it appears that poor air quality is associated with worsened health outcomes [ 559 – 563 ]. Air quality can also be related to changes in UV radiation resulting from the pandemic (Sect.…”

Associations between mortality from COVID-19 in two Italian regions and outdoor air pollution as assessed through tropospheric nitrogen dioxide

“…These factors included medical history, life-style factors, and environmental risk factors such as climate indicators and air pollutants. Some studies suggested a possible relation of virus outbreak with high levels of environmental air pollution (Barcelo, 2020;Bashir et al, 2020;Copat et al, 2020;Filippini et al, 2020;Li et al, 2020;Ogen, 2020;Pequeno et al, 2020;Setti et al, 2020b;Tsatsakis et al, 2020;Wu et al, 2020;Zhu et al, 2020). Putative mechanisms included enhanced susceptibility to respiratory viral infections through damage and inflammation of lung cells, immune dysregulation, and hyperactivation of inflammatory cytokines and chemokines (Chen et al, 2010;Comunian et al, 2020;Conticini et al, 2020;Peng et al, 2020), upregulation of viral receptor ACE-2 (Borro et al, 2020;Tung et al, 2020), or air pathogen transportation by particulate matter suitable as virus carrier (Comunian et al, 2020;Manoj et al, 2020).…”

Macrolevel association of COVID-19 with non-communicable disease risk factors in India

“…Multiple studies from across the globe have reported that individuals with established coronary heart disease, heart failure, chronic respiratory, renal or liver disease and cancers or their risk factors such as diabetes, hypertension, obesity, and other vascular risk factors are at greater risk of acquiring infection and developing complications and deaths from COVID-19 [ [2] , [3] , [4] , [5] , [6] , [7] , [8] , [9] , [10] ]. Environmental factors such as urbanization, crowding, ambient and indoor air pollution, poor sanitation and low socioeconomic status are also important in increasing the risk of disease incidence and deaths [ 5 , [11] , [12] , [13] ].…”