Study by the Office for National Statistics finds that a single-unit increase in exposure to air pollution in the long term can increase the death rate by up to 6%
Long-term exposure to air pollution can increase the risk of death from Covid-19, according to a large study from the Office for National Statistics.
It analyzed 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 past decade can increase the death rate by as much as 6%. A single unit increase in nitrogen dioxide, found at illegal levels in most urban areas, was linked to a 2% increase in death rates.
These increases are less than those found in other investigations; a US study found an 8% increase and an analysis from the Netherlands found a 15% increase. This may be because those studies looked at the early stages of the pandemic when the virus was mainly spreading in cities.
So far, the data is only available as averages for groups of people and the ONS said this meant that a definitive conclusion could not yet be reached on the link between dirty air and the worst impacts of Covid-19. Instead, the data at the individual level should be examined to rule out other possible factors. ONS has started this work for patients in London.
The ONS also found that air pollution could be a factor in explaining why people from Black, Asian and Ethnic Minority Communities (BAME) suffer more from coronavirus.
"The effects of long-term exposure to air pollution as a factor in increasing mortality from coronavirus appear smaller than those reported in previous studies, although our upper estimates are similar in magnitude to some," the ONS report said. "But it must be accepted that the real picture will likely only emerge once the data is available for highly detailed individual modeling."
There are good reasons to suspect that air pollution worsens Covid-19. "Constant 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 Covid-19 related deaths had respiratory or cardiovascular disease as the main pre-existing health condition."
However, towns and cities have high air pollution and also high rates of coronavirus infections, deprivation, poor health, and a dense population. The ONS report was able to take these factors into account, but determining the impact of each factor alone is a difficult statistical challenge.
This is particularly true for ethnic minority populations, as they are exposed to higher levels of dirty air than others. The ONS said it is currently impossible to completely separate the effects of race and pollution. But it said, "If there is a causal link between air pollution and Covid-19-related mortality, it would partially explain the disparities in outcomes for ethnic minority groups."
ONS used a novel approach to help account for the other factors. Rather than using zip codes or other geographic areas for the analysis, he grouped areas across the country that shared socioeconomic and demographic characteristics.
Professor Matthew Cole, from the University of Birmingham, who conducted the analysis from the Netherlands, said: “The ONS study uses a very unconventional way of pooling the data. This is a real shame, as it means that we cannot be sure if the estimated results are based on this unconventional method.
"In the absence of data at the individual level, accurate regional data is the only way to examine these issues," he said. “It is a shame, therefore, that this study uses 175 relatively large regional groupings. This means that the characteristics of each region run the risk of being averaged ”.
Geraint Davies MP, Chairman of the All-Party Parliamentary Group on Air Pollution, said: “The study does not test or disprove the hypothesis that air pollution worsens outcomes in Covid-19. However, we know that air pollution causes 62,000 premature deaths each year and weakens people before contracting the coronavirus. Therefore, the government has a duty to act and this should be a call to action, not an excuse for further inaction.
In July, the detailed and comprehensive analysis of the Netherlands concluded that there was "convincing" evidence that air pollution significantly increases coronavirus infections, hospital admissions and deaths. There is also evidence from Europe, the United States, and China.
UK Government Air Pollution Expert Advisors stated in early July that air pollution is likely increasing the number and severity of Covid-19 infections. They said further investigation of the link between dirty air and the coronavirus pandemic was urgently needed and that it could be relevant to how the pandemic is managed.
Also in July, a study of 400 hospital patients in Birmingham linked the severe impacts of Covid-19 on people from ethnic minorities to air pollution and overcrowded and substandard homes.
Ninety MPs led by Davies have urged the government to back action on air pollution to help prevent a second wave of coronavirus, while an air pollution investigation by a select committee of MPs is examining delays in the deployment of clean air zones in cities as a result of the pandemic.