Soot arising from chimneys in residential area

How black carbon can increase the risk for respiratory diseases

25 May 2020
Interview with Dr Ragnhildur Finnbjörnsdóttir, Iceland’s Head of Delegation for the Arctic Council’s Expert Group on Black Carbon and Methane

How is air pollution – caused by particles such as black carbon – affecting human health?

Black carbon is part of what we call particulate matter (PM), fine particles in the air, such as dust, dirt, soot, or smoke. It is accepted within the scientific community that exposure to particulate matter adversely affects human health in various ways: it can increase symptoms of respiratory- and cardiovascular diseases, it can increase the susceptibility towards different respiratory diseases, and scientists have also found an association between particulate matter and respiratory- and cardiovascular mortality.

Especially people with underlying diseases, as well as children and older people, are vulnerable towards particulate matter exposure. In addition to the above, particulate matter exposure can also increase the likelihood that someone develops respiratory diseases. Thus, long-term exposure can lead to more people getting affected by lung- and cardiovascular conditions.

Black carbon is amongst the smallest particles of particulate matter – and these are usually of the highest concern. Generally speaking: The smaller the particles, the more adverse the health effects, but studies have shown that it is difficult to distinguish the different effects of particulate matter whose individual particles are smaller than 2.5 micrometers (PM2.5) and black carbon. Some studies have shown that black carbon – the smallest particulate matter particles – can pass the blood brain barrier, and they have also been found in the fetal side of the placenta, where they can affect the development of a fetus.

While there is still research needed on the adverse health effects of different particle sizes, the scientific community agrees that that overall particulate matter exposure is bad for you – just as everybody knows that smoking is bad for you.

To say it in very simple terms: Covid-19 is bad, air pollution is bad, combining both should, according to existing literature on increased susceptibility to lung disease following air pollution exposure, be extremely bad.Dr Ragnhildur Finnbjörnsdóttir

Where does the pollution originate from?

The main sources for black carbon emissions in the Arctic is transport – both on and off road. So, vehicles that burn fossil fuels either on Arctic transport routes or heavy machinery on building sites and agricultural lands. Another main source for black carbon emissions in the Arctic – although not such a big problem in Iceland – is residential combustion; small stoves and fireplaces.


Could exposure to increased air pollution levels enhance the susceptibility towards respiratory diseases such as Covid-19?

If you are scientist, you are not going to answer this questions with a straight ‘yes’. We need epidemiologic research to analyze the linkage between air pollution and the susceptibility towards Covid-19. But in general, air pollution exposure increases the susceptibility to respiratory diseases. When you breath in particulate matter, you get an inflammatory reaction in your lungs and respiratory airway, which decreases the lungs ability to tackle other bacteria and viruses. To say it in very simple terms: Covid-19 is bad, air pollution is bad, combining both should, according to existing literature on increased susceptibility to lung disease following air pollution exposure, be extremely bad. But only time and further studies on the effects of Covid-19 will reveal the definite answer.


How can we tackle air pollution caused by black carbon and other particles efficiently?

We need to focus on the main sources that cause air pollution. One of the first things we can do is to shift from diesel and fossil fuel burning vehicles to more environmentally friendly alternatives, such as electric vehicles. The same applies to residential combustion burning: more environmentally friendly stoves can reduce the emissions. These are also recommendations that the Arctic Council’s Expert Group on Black Carbon and Methane outlined in its Summary of Progress and Recommendations 2019, which was presented to the Arctic ministers last year.