Study suggests link between air pollution and heightened Covid risk

The risk of getting the virus could be heightened by where you live, according to a new study based on a city of tens of thousands of residents.

Long term exposure to air pollution can heighten the risk of getting Covid, a new study suggests.

Researchers based their findings on a study of polluted northern Italian city, Varese in the Lombardy region, which was hit hard by the Covid wave.

They found an average annual rise of 1 one-millionth of a gram of particle pollution was linked to a five per cent jump in infection rates.

This equalled an extra 294 Covid cases per 100,000 people a year, according to findings published in the journal Occupational & Environmental Medicine.

A map showing levels of air pollution in Sydney.

The researchers studied 62,848 Varese residents who generated 4408 Covid cases from the start of the pandemic to March 2021.

The Lombardy region was Italy’s worst affected region in terms of Covid cases and deaths, representing 21 per cent and 28 per cent, respectively.

Estimates from the European Union Environmental Agency show most of the 3.9 million Europeans living in areas where air pollution exceeds European limits reside there, in northern Italy.

Exposure to air pollutants and Covid cases were analysed. Picture: Emanuele Cremaschi/Getty Images

While recent research has linked airborne pollution as a risk factor for getting Covid, flaws in study design and data only up to mid-2020 have limited the findings.

To overcome these issues, the researchers looked at long term exposure to airborne pollutants and patterns of Covid from the start of the pandemic to March 2021, among Varese residents.

By the end of the observation period, 3.5 per cent of the population in the entire region was fully vaccinated.

After taking into account age, gender, home care residency and concurrent long term conditions, the study found fine inhalable particles and inhalable particles “were significantly associated with an increased Covid-19 infection rate”.

This was even more noticeable among older age groups, showing a stronger effect of pollutants on infection rates among 55–64 and 65–74 year olds.

Researchers studied a highly polluted Italian city hit hard by Covid. Picture: Miguel Medina / AFP

The researchers said long term exposure to air pollution heightened the risk of respiratory and cardiovascular diseases through persistent inflammation and compromised immunity.

They said they believed these same pathways could be involved in the link between air pollution and higher Covid infection rates.

However, more research was needed to confirm cause and effect, they added.

“The causality warrants confirmation in future studies; meanwhile, government efforts to further reduce air pollution should continue,” the authors said.

Although the researchers considered various potentially influential factors in their study, they weren’t able to account for mobility, social interaction, humidity, temperature and certain underlying conditions such as mental ill health and kidney disease.