On 22 September 2021, the World Health Organisation (WHO) adjusted its healthy guidelines for key air pollutants. Switzerland now regularly exceeds maximum guidelines for several pollutants.
According to WHO, exposure to air pollution is estimated to cause 7 million premature deaths a year globally and result in the loss of millions more healthy years of life. The damage includes reduced lung growth and function, respiratory infections and aggravated asthma in children. In adults it mainly causes ischaemic heart disease and strokes. Evidence is also emerging of other effects such as diabetes and neurodegenerative conditions. The burden of disease attributable to air pollution is on par with unhealthy diet and tobacco smoking, said the health agency.
The WHO said that there was a marked increase in evidence that shows how air pollution affects different aspects of health. After a systematic review of the evidence the body decided to adjust almost all of its air quality guideline levels downwards.
The guidelines set out new healthy guideline levels for six pollutants, which include particulate matter (PM2.5 and PM10), ozone (O₃), nitrogen dioxide (NO₂) sulfur dioxide (SO₂) and carbon monoxide (CO).
The annual guideline for PM2.5 was halved from 10µg/m3 to 5µg/m3 – PM2.5 particulate matter penetrates into lungs with the potential to pass through the lungs into other organs. The same annual rates for PM10 were cut from 20µg to 15µg and for NO2 they were cut from 40µg to 10µg.
Much of Switzerland regularly exceeds these new guidelines. In 2019, Bern came in with a PM2.5 reading of 10.9 μg/m³, well in excess of the new guideline of 5µg/m3.
Air pollution in Switzerland is seasonal. In 2019, air quality in Bern declined in November from around 8 μg/m³ of PM2.5 to 11.6μg/m³. This then climbed to 14.7 μg/m³ in January, and then to a yearly high of around 18 μg/m³ in February, the most polluted month.
In winter, burning wood, gas and heating oil add to Switzerland’s pollution. In addition, between 2-3% of the electricity generated in Switzerland is from fossil fuels.
During September 2021, Bern managed PM2.5 levels under 5µg for only 3 out of 30 days, according to IQAir. On the worst day air concentration of PM2.5 rose as high as 14.8µg/m3, close to three times the annual guideline limit. September air in Bern scored better on PM10 concentrations. The new annual WHO guideline is 15µg/m3. Bern had PM10 concentrations above this level for only 17 out of 30 days (57%).
Much of Switzerland’s pollution comes from vehicles and factories. Cars and trucks generate large amounts of NO2 and SO2 in addition to rubber particles from their tyres, which continue to accumulate. 200 tonnes of these particulates have been spread around Switzerland over the last 20 years alone.
Those most at risk from poor air quality are people living near factories and areas of dense traffic. Road commuters are also exposed to road pollution.
WHO announcement (in English)