Air pollution can aggravate covid-19 cases, study shows

Prolonged exposure to atmospheric pollution can lead to the worsening of the clinical picture of the covid-19. This is shown by a Spanish study published this month in the scientific journal Environmental Health Perspectives.

Air pollution, especially in large cities, is a problem that can have many adverse effects on human health. This is the first work to carry out a massive study of antibodies against covid-19 and link it to pollution exposure data. The study started from a sample of more than 9,000 adults, of which 4,000 were invited to donate blood for the research.

In total, 1 in 5 participants had positive results in serological tests, which measure the presence of antibodies in the body. Among these, 5% (about 480) had cases of covid-19 confirmed by clinical tests or the onset of symptoms. About 40% of cases identified among study participants were asymptomatic.

The exposure of these people to pollution was estimated from the participants’ addresses for the period 2018 to 2019, before the pandemic.

Professional sanitizes environment during the covid pandemic.19.  People exposed to pollution develop more severe cases of covid-19 (Source: Shutterstock)Professional sanitizes environment during the covid pandemic.19. People exposed to pollution develop more severe cases of covid-19 (Source: Shutterstock)Fonte:  Shutterstock

The pollution assessment was carried out using four different parameters: nitrogen dioxide concentration (NO2), fine particles, ozone gas, and black carbon—the latter, an impure form of carbon produced during the incomplete burning of fossil fuels.

In addition, the work made use of recent, high-quality climate surveillance data in a relatively small geographic area. These characteristics ensure greater accuracy of the observed results and are an advance in the methodology used in the research.

NO concentration2 and dust particles were the factors most associated with the worsening of the disease.

Nitrogen dioxide is released by car exhaust and was one of the pollution indicators in the articleNitrogen dioxide is released by car exhaust and was one of the pollution indicators in the articleFonte:  Shutterstock

Manolis Kogevinas, the first author of the article, says that scientists were suspicious of the relationship between these two factors. However, the phenomenon is difficult to be observed.

“The problem is that the previous studies were based on the reported cases, but left out the asymptomatic or undiagnosed patients”, says the researcher, who is also a member of the Global Health Institute in Barcelona (ISGlobal).

Another advantage pointed out of the study was that the researchers were able to carry out individual follow-up of the participants and collect data before the start of the vaccinations — which would have made the analyzes otherwise difficult.

It is not known what reasons can lead to aggravation of the disease by these factors.

One theory assumes that pollution may increase people’s susceptibility to developing severe respiratory symptoms, including a reduction in the body’s immune response.

Another associates comorbidities resulting from contact with pollution, such as diabetes and cardiorespiratory diseases, with worsening symptoms.

Anna Hansell, a researcher at the University of Leicester, UK, says this study represents a major advance in understanding covid-19.

But she underscores the need for disease containment measures: “From a public health perspective, vaccination and mask use represent more effective and powerful measures to help us out of this pandemic.”

Also surprising, for her, was the discovery that air pollution does not lead to an increase in the number of cases of infection by the disease.

Researches had shown, in animals, that pollution favors the entry of the coronavirus into cells, but the data did not show significant differences in the total number of infected people living in different neighborhoods, with greater or lesser pollution.

ARTICLE Environmental Health Perspectives: doi.org/10.1289/EHP9726

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