Wildfire Smoke Exposure: Covid19 Comorbidity?

Abstract

Air pollution, particularly fine and ultrafine particulate matter aerosols, underlies a wide range of communicable and non-communicable disease affecting many systems including the cardiopulmonary and immune systems, and arises primarily from transportation and industry. A number of air pollution driven diseases also are Covid19 comorbidities. Thus, a number of studies on air pollution exposure, particularly particulate matter, strongly indicate air pollution is an important underlying factor in Covid19 transmission, severity, and mortality. This suggests that air pollution from natural sources, particularly wildfires, could play a role in the Covid19 pandemic. We tested this hypothesis on three wildfire smoke events in Orange County, CA, each of which was followed by Covid19 case increases after an approximately one-week lag. This lag was consistent with combined incubation time and testing/reporting times. Moreover, the three events suggest a dose dependency. The wildfire comorbidity hypothesis implies that at-risk-populations should reduce smoke exposure from wildfires, as well as indoors from biomass burning for heating, cooking, and aesthetic purposes.

Long-term exposure to fine particulate matter air pollution: An ecological study of its effect on COVID-19 cases and fatality in Germany

“…The first is that particulate matter might carry the airborne virus, transmitting it into the human respiratory system ( Copat et al, 2020 ; Martelletti and Martelletti, 2020 ; Di Girolamo, 2021 ; Nor et al, 2021 ). The second is that fine particulate matter could increase the severity of the Covid-19 disease by delaying or complicating recovering ( Domingo and Rovira, 2020 ; Leifer et al, 2021 ). However, it is difficult to distinguish between these two mechanisms, due to a lack of individual-related longitudinal data that are not available in the midst of a pandemic ( Villeneuve and Goldberg, 2020 ).…”

SARS-CoV-2 test positivity rate in Reno, Nevada: association with PM2.5 during the 2020 wildfire smoke events in the western United States

“…Another study by Leifer et al observed increased numbers of COVID-19 cases following wildfire smoke events in Orange County, California (ref. [ 31 ]). However, our study significantly improved on these studies by controlling for additional covariates: the general prevalence of the virus, which increased over time (not included in Meo et al); and temperature and the number of tests administered (not included in Meo et al or Leifer et al).…”

Elucidating the role of environmental management of forests, air quality, solid waste and wastewater on the dissemination of SARS-CoV-2

“…In another study, Laudares and Gagliardi (2020) analyzed the potential of deforestation and spread of COVID-19 affecting indigenous people and found that deforestation of 1 km 2 area resulted in 9.5% new COVID-19 cases. Association between wildfire incidences with COVID-19 cases and severity has been reported even though the number of these correlation studies were observed to be less compared to wider literature on ambient air pollution and COVID-19 ( Meo et al, 2020 ; Firebaugh et al, 2021 ; Kiser et al, 2021 ; Leifer et al, 2021 ; Zhou et al, 2021 a). Of this, Meo et al (2020) found that wildfire allied pollutants, particulate matter PM 2.5 and CO is associated positively with COVID-19 daily cases and cumulative deaths.…”

“…Secondary transmission routes are also plausible. For example, air quality can be reduced due to higher levels of pollutants from wildfires and other activities, which have shown to lead to strong impacts upon contracting COVID-19 ( Liu et al, 2020a ; Meo et al, 2020 ; Middleton, 2020 ; Curtis, 2021 ; Dragone et al, 2021 ; Kiser et al, 2021 ; Leifer et al, 2021 ; Setti et al, 2020 b; Zhou et al, 2021 a). Furthermore, natural ventilation for optimal indoor air quality is not sufficient to control the potential spread of SARS-CoV-2 ( Li et al, 2004 ; Meiss et al, 2021a ; WHO, 2021a).…”

“…These conditions for zoonotic disease emergence are of general nature and can be applied to COVID-19, also due to involvement of plausible mediators such as bats ( Platto et al, 2021a ). Current literature that directly associates COVID-19 and deforestation is the evidence for SARS-CoV-2 like viruses in zoonotic wild hosts, along with few studies analyzing loss of ecosystem services from deforestation and COVID-19 severity ( Meo et al, 2020 ; Murakami et al, 2020 ; Roviello and Roviello, 2020 ; Zhou et al, 2020 ; Firebaugh et al, 2021 ; Kiser et al, 2021 ; Leifer et al, 2021 ; Roviello and Roviello, 2021 ; Wacharapluesadee et al, 2021 ; Zhou et al, 2021 a; Zhou et al, 2021 b).…”