It analysed more than 46,000 coronavirus deaths in England and showed that a small, single-unit increase in people’s exposure to small-particle pollution over the previous decade may increase the death rate by up to 6%. A single-unit increase in nitrogen dioxide, which is at illegal levels in most urban areas, was linked to a 2% increase in death rates.
These increases are smaller than found in other research; a US study found an 8% increase and an analysis of the Netherlands found a 15% rise. This may be because those studies assessed earlier stages of the pandemic when the virus was mostly spreading in cities.
Data is so far only available as averages for groups of people and the ONS said this meant no definitive conclusion on the link between dirty air and the worst impacts of Covid-19 could yet be made. Instead, individual-level data would have to be examined to rule out other possible factors. The ONS has begun this work for patients in London.
The ONS also found that air pollution could be a factor in explaining why people from BAME backgrounds suffer more from coronavirus.
“The effects of long-term exposure to air pollution as a factor that increases coronavirus mortality appear smaller than those reported in previous studies, though our upper estimates are similar in magnitude to some,” the ONS report said. “[But] it must be accepted that the true picture will likely only emerge once data are available for highly detailed individual-based modelling.”
There are good reasons to suspect that air pollution worsens Covid-19. “Consistent exposure to air pollution is a known cause of breathing difficulties and other long-term conditions in the lungs and heart,” the ONS report said.
“Our data show that 35% of deaths involving Covid-19 had a respiratory or cardiovascular disease as the main pre-existing health condition.”