Blog: Let's clear the air

28 May 2020

Brabant and Northern Italy were not only hot spots for the corona virus, the air quality in both areas is also relatively poor. A connection between the two is easily made. In the Dutch newspaper NRC, professor Roel Vermeulen wonders whether that is justified. 

This blog was published on 28 May 2020 on the climate blog of the NRC.

The similarity between Northern Italy and Brabant is not just that they are both hotspots for the coronavirus, but the air quality in both areas is also relatively poor. A link between polluted air and the coronavirus is therefore established quickly. Is that justified? Professor Roel Vermeulen has no doubts about the impact of air quality on general health, but also thinks it’s premature to establish a connection between the quality of air and the rate of the spread of the coronavirus.

In Brabant, just like in the North of Italy, the air quality is relatively poor

Dutch air quality has repeatedly been a topic of discussion during the corona pandemic, both positively and negatively. For example, based on recent satellite images, the media wrote that our skies appear much cleaner (bluer) than this time last year. At the same time, there is unrest because the coronavirus would strike harder because of polluted air. But is there proof for a relationship between air pollution and the coronavirus? And how clean are the Dutch cloudy skies in the first place?

Air pollution is a major problem. According to the Dutch National Institute for Public Health and the Environment (RIVM), before the pandemic hit, we could attribute an estimate of 3 to 5 percent of the disease burden to chronic exposure to fine dust. This amounts to an annual loss of no less than 135.000 healthy life years. Worldwide, the annual number of deaths from poor air quality is even estimated at 4 to 6 million.

Less emissions

But do clean(er) skies also have a positive health effect? According to KNMI satellite images, the drastic decrease of current economic activity in the Netherlands, with the associated reduction in industrial emissions and (air)traffic, is leading to a decrease in air pollution of somewhere between 20 to 60 percent. However, this estimate seems somewhat optimistic. Ground-level measurements, where people live and breathe, show that air quality only improved by 10 to 20 percent. Although such an improvement will yield health benefits in the long run, it is highly questionable whether this also applies to this relatively short period. But the feeling remains that if we want to comply with the current air quality guidelines of the World Health Organization, we need to see the same or even greater reduction in air pollution then we are experiencing now, during the corona crisis.

In Brabant, just like in the North of Italy, the air quality is relatively poor. And both Brabant and Northern Italy have been hit hard by the pandemic. The connection between air quality and the virus is therefore quickly established. Is there a coincidence, or might people who live here actually be at greater risk? It is too early to make such statements. The main cause of the outbreak in these areas was that it was not clear yet what was going on, so there were no measures like social distancing in place. Also, a mass gathering such as the Carnival ensures that a rapid spread of the virus is possible. This does not alter the fact that there is sufficient reason to investigate whether air quality plays a role in the coronavirus outbreak. Other research shows that respiratory infections and lung diseases are more prevalent in areas where air pollution is high, both after years of exposure and in the very short term.

Ecological studies

Several recent studies from the US and Europe show a possible statistical relationship between coronavirus deaths and poor air quality. Unfortunately, we cannot draw any conclusions from this yet. These so-called ‘ecological studies’ link the average health statistics (and therefore corona mortality) in a municipality or region to the average air quality. But more factors could influence the number of deaths in an area and that may vary by region. For example, the number of inhabitants can differ greatly, and so the chance of human-to-human contact and thus the chance of infections, or the population is much older and therefore sensitive.

An additional challenge is that the course of the pandemic is very dynamic. Initially, one patient infects several people, but the introduction of restrictive measures means that the number of infections is greatly reduced. So, it matters where the pandemic starts and where you see the most patients. You can imagine that regions closer to the hotbed are hit harder. And if these regions happen to have a lot of polluting industries, then the association may not be justified. You would therefore only want to do such analyses in periods of time where the spread is fairly stable, or only among people who have proven contamination to see if poorer air quality leads to more complaints and more serious illness.

In short, it will not be easy to investigate whether there is a connection between air quality and the coronavirus. It calls for research at the national and European level, in both severely and mildly affected areas. In addition, we want to take into account the impact of the measures that have been taken, long-term research is required. The impact of today’s measures will have an effect far beyond tomorrow. Access to individual health data is still an obstacle. Strict privacy laws make it difficult to quickly share health data. Solutions in which the data is not shared but securely ‘visited’ digitally have already been developed. This accelerated introduction of this technology may offer a solution.

Scientists from Utrecht University are reporting in the climate blog of the NRC on their research in the field of sustainability. They are united around the strategic theme of 'Pathways to Sustainability'.


Areas of Expertise

Air quality

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