Last reviewed 10 September 2021

Commissioned by Mayor Sadiq Khan, a new report by researchers from Imperial College London has found a link between a person’s exposure to air pollution and the severity with which they will experience the effects of Covid-19.

The report also highlights air pollution’s role in increasing hospital admissions for other lung infections, which had been previously overlooked.

Available at, the 80-page report emphasises that, as the pandemic is so recent, research into air pollution and Covid-19 is not as mature as other research areas, and further research will be necessary to confirm these emerging findings.

The publication of the report follows research by scientists in the USA linking smoke from the recent devastating wildfires with an increase in hospital admissions and deaths from Covid-19.

Main findings

The review confirmed the following.

  • Exposure to air pollution before the pandemic increased the risk of hospital admissions if a person became infected with Covid-19 in a small number of good quality studies. This is most likely because air pollution contributes to people having heart or lung disease and they then become sicker from Covid-19 if they catch it.

  • Exposure to air pollution might increase the likelihood of contracting Covid-19 if someone is exposed to the coronavirus. This finding comes from a few studies that found that pollutants, once inhaled into the lungs of animals, increase the amounts of the protein that allows the coronavirus to attach to the lung cells.   However, human population studies of air pollution and new cases were poor quality and inconclusive.

  • More widely, there is pre-existing evidence that exposure to air pollution increases susceptibility to, and worsens the outcome from, a range of infectious lung diseases, such as pneumonia and bronchitis.    

Professor Ally Lewis, Chairman of the Government’s Air Quality Expert Group, said: “The exact mechanisms are still not yet fully resolved, but sufficient evidence has been reviewed to be confident that long-term exposure to air pollution both increases risk of respiratory diseases and is responsible for causing many other health conditions that make Covid-19 more severe”.