Pandemic Ponderings: US study finds Air pollution link to Covid19 deaths

Wednesday, April 8, 2020

Pandemic Ponderings: US study finds Air pollution link to Covid19 deaths

New research from the Harvard School of Public Health highlights a possible causal link between PM2.5 particulate pollution and Covid19 deaths.

That is, areas in the US with higher levels of PM2.5 particulate pollution have statistically significant higher rate of Covid19 deaths.

The aggregated data strongly suggests a link, while the researchers suggest more research is needed down to the individual patient medical data level to positively confirm the link.

The New York Times Lisa Friedman has reported on the study in an article titled New Research Links Air Pollution to Higher Coronavirus Death Rates.

The research is presently undergoing fast tracked peer review for the New England Journal of Medicine.

There was research conducted in Northern Italy recently that also indicated high pollution levels in the Lombardy region contributed to much higher death rates than in other regions of Italy. I prepared this article on that early research: Indications that High levels of Air Pollution exacerbate Covid19 spread

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The Harvard study preprint can be accessed here: https://projects.iq.harvard.edu/covid-pm

COVID-19 PM2.5: A national study on long-term exposure to air pollution and COVID-19 mortality in the United States.

Abstract:

Exposure to air pollution and COVID-19 mortality in the United States (Updated April 5, 2020)

Background: United States government scientists estimate that COVID-19 may kill between 100,000 and 240,000 Americans. The majority of the pre-existing conditions that increase the risk of death for COVID-19 are the same diseases that are affected by long-term exposure to air pollution. We investigate whether long-term average exposure to fine particulate matter (PM2.5) increases the risk of COVID-19 deaths in the United States.

Methods: Data was collected for approximately 3,000 counties in the United States (98% of the population) up to April 04, 2020. We fit zero-inflated negative binomial mixed models using county level COVID-19 deaths as the outcome and county level long-term average of PM2.5 as the exposure. We adjust by population size, hospital beds, number of individuals tested, weather, and socioeconomic and behavioral variables including, but not limited to obesity and smoking. We include a random intercept by state to account for potential correlation in counties within the same state.

Results: We found that an increase of only 1 μg/m3 in PM2.5 is associated with a 15% increase in the COVID-19 death rate, 95% confidence interval (CI) (5%, 25%). Results are statistically significant and robust to secondary and sensitivity analyses.

Conclusions: A small increase in long-term exposure to PM2.5 leads to a large increase in COVID-19 death rate, with the magnitude of increase 20 times that observed for PM2.5 and all-cause mortality. The study results underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis. The data and code are publicly available.

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With evidence mounting of this link between level of air pollution particulates and increased Covid19 deaths, public health authorities need to look carefully and plan public health reponse accordingly. This has health risk implications for areas in Australia with high particulate pollution, whether inner city suburbs, the Hunter Valley and LaTrobe Valley coal mining and power station areas, or for regional towns that might suffer increased smoke PM2.5 particulate pollution from hazard reduction burns.

This comes as the Sydney Morning Herald and The Age report that aging coal fired power stations have been increasing their particulate air pollution, according to Nick O'Malley (April 7, 2020) Deadly pollutant surged by 3000 per cent at coal-fired power plant.

"The amount of dangerous fine particle pollution emitted by the Vales Point coal-fired power station on the NSW Central Coast has increased by 3000 per cent over the past six years and 181 percent last year.

"Last year the Yallourn power station in Victoria increased its emissions of the same pollutant by 82 per cent and the amount from the Gladstone power station in Queensland increased by 23 per cent."

Knowing the link between air pollution and Covid19 severity should allow public health administrators to more fully prepare targeted public health and hospital response. To save lives.

Notes:

Lisa Friedman, New York Times (7 April 2020) New Research Links Air Pollution to Higher Coronavirus Death Rates

Wu, X., Nethery, R.C., Sabath, M.B., Braun, D. and Dominici, F., 2020. Exposure to air pollution and COVID-19 mortality in the United States. medRxiv. https://projects.iq.harvard.edu/covid-pm