Long term exposure to ambient air pollution may heighten the risk of Covid-19 infection, suggests recent research. The findings were published in the journal 'Occupational and Environmental Medicine'. The association was strongest for particulate matter, with an average annual raise of 1 ug/m3 linked to a 5 per cent increase in the infection rate.

Northern Italy has been hit hard by the coronavirus pandemic, with Lombardy the worst affected region in terms of both cases and deaths. Several reasons have been suggested for this, including different testing strategies and demographics. But estimates from the European Union Environmental Agency show that most of the 3.9 million Europeans residing in areas where air pollution exceeds European limits live in Northern Italy. Recent research has implicated airborne pollution as a risk factor for Covid-19 infection, but study design flaws and data capture only up to mid-2020 have limited the findings, say the researchers.

The observed associations were even more noticeable among older age groups, indicating a stronger effect of pollutants on the Covid-19 infection rate among 55-64 and 65-74-year-olds, suggest the researchers.