Positive association between outdoor air pollution and the incidence and severity of COVID-19. A review of the recent scientific evidences

Abstract

In June 2020, we published a review focused on assessing the influence of various air pollutants on the transmission of SARS-CoV-2, and the severity of COVID-19 in patients infected by the coronavirus. The results of most of those reviewed studies suggested that chronic exposure to certain air pollutants might lead to more severe and lethal forms of COVID-19, as well as delays/complications in the recovery of the patients. Since then, a notable number of studies on this topic have been published, including also various reviews. Given the importance of this issue, we have updated the information published since our previous review. Taking together the previous results and those of most investigations now reviewed, we have concluded that there is a significant association between chronic exposure to various outdoor air pollutants: PM 2.5 , PM 10 , O 3 , NO 2 , SO 2 and CO, and the incidence/risk of COVID-19 cases, as well as the severity/mortality of the disease. Unfortunately, studies on the potential influence of other important air pollutants such as VOCs, dioxins and furans, or metals, are not available in the scientific literature. In relation to the influence of outdoor air pollutants on the transmission of SARS-CoV-2, although the scientific evidence is much more limited, some studies point to PM 2.5 and PM 10 as potential airborne transmitters of the virus. Anyhow, it is clear that environmental air pollution plays an important negative role in COVID-19, increasing its incidence and mortality.

Temporal air quality (NO2, O3, and PM10) changes in urban and rural stations in Catalonia during COVID-19 lockdown: an association with human mobility and satellite data

“…This situation gives a unique opportunity to evaluate the impact of these restricted anthropogenic emissions on air quality. Moreover, air quality assessment might be very useful to better understand the incidence of COVID-19, according to recent studies that report a positive relation between air pollution and SARS-CoV-2 severity (Domingo et al 2020 ; Marquès and Domingo 2022 ). Various studies that evaluate the effects of COVID-19 lockdown on air contamination have already been performed in different parts of the world (Delhi (Srivastava et al 2020 ): London (Kumari and Toshniwal 2020 ), Milan (Altuwayjiri et al 2020 ), Lima (Kumari and Toshniwal 2020 ), Ghaziabad (Lokhandwala and Gautam 2020 ), Nigeria (Zabbey et al 2020 ), Tunisia (Chekir and Ben Salem 2021 ), Baghdad (Hashim et al 2021 ), and Spain (Tobías et al 2020 ; Briz-Redón et al 2021 )).…”

Global COVID-19 pandemic trends and their relationship with meteorological variables, air pollutants and socioeconomic aspects

“…As atmospheric oxidants, O 3 can efficiently promote SO 2 oxidation in aerosol media and result in a high level of particulate sulfate formation particle contaminant in the air ( Wang et al, 2016 ). Particle contaminants can promote the spread of the SARS-CoV-2 virus and reducing human immunity ( Bontempi et al, 2020b ; Marquès and Domingo, 2022 ). The interaction between SO 2 and RH also significantly affected COVID-19 transmission.…”

“…RH affected heterogeneous reactions of SO 2 with soot particles. The reaction progress generated by the ketone and sulfate species can lead to inflammation and cellular damage ( He et al, 2017 ) and thus increased human susceptibility to COVID-19 ( Cole et al, 2020 ; Marquès and Domingo, 2022 ). The interaction of O 3 and T also affect COVID-19 transmission.…”

“…The temperature may interact with air pollutants to affect human susceptibility to the virus ( Sillman and Samson, 1995 ; Domingo and Rovira, 2020 ). Air pollutants affect not only human susceptibility to the SARS-CoV-2 virus ( Brandt et al, 2020 ; Conticini et al, 2020 ; Frontera et al, 2020a ; Marquès and Domingo, 2022 ), but also affects regional meteorological conditions and human activity intensity ( Fenger, 2009 ). Moreover, socioeconomic factors are closely related to regional environmental conditions and medical levels ( Copiello and Grillenzoni, 2020 ).…”

Impact of COVID-19 on Extremely Polluted Air Quality and Trend Forecast in Seven Provinces and Three Cities of China

“…Because of severe air pollution in winter, humans are at higher risk of contracting the new crown (Naqvi et al, 2021). Therefore, more scholars have focused their research on the impact of air and climate on COVID-19 (Linares et al, 2021), NO 2 , PM 2.5 , PM10, O 3 are directly proportional to the incidence and mortality of COVID-19 (Montse and Domingo José, 2022). Weather has become an important factor in determining the disease (Khurram et al, 2002).…”