In 2020, Switzerland was ranked 18th out of a 106 nations for the quality of its air, placing it comfortably in the top quintile. However, Swiss air quality depends on where you live.
In 2020, Switzerland ranked 18th with a score of 9.00, up from a rank of 24th with a score of 10.90. The scores refer to average annual concentrations (µg/m³) of PM2.5, airborne fine particulate matter that penetrates into lungs with the potential to pass through the lungs into other organs.
Switzerland has made significant progress on improving air quality since the eighties with more stringent measures and reductions in large scale pollution offenders, said IQAir in its report.
The World Health Organisation has set its healthy PM2.5 target at an annual mean of 10 μg/m3. So in 2020 Switzerland met this target, however in 2019 it didn’t. Any level between 10 – 12 μg/m3 is considered good, but not optimal.
Nations with cleaner air than Switzerland in 2020 include Belgium (8.90), Ireland (8.60), United Kingdom (8.30), Costa Rica (8.20), Ecuador (7.60), Australia (7.60), Andorra (7.40), Canada (7.30), Iceland (7.20), New Zealand (7.00), Estonia (5.90), Norway (5.70), Finland (5.00), Sweden (5.00), U.S. Virgin Islands (3.70), New Caledonia (3.70) and Puerto Rico (3.70).
Bangladesh (77.10), Pakistan (59.00) and India (51.90) had the world’s worst air in 2020. They were the worst in 2019 too. The air in the first two of these countries is classified as unhealthy.
Pollution gets better or worse with magnification. In general, cities are far worse than the countryside and the most polluted cities are not all in the most polluted countries. In 2020, the most polluted city was Hotan in China, with an average annual PM2.5 of 110.2 μg/m3. This is considered unhealthy. However, in March 2020 the average rate in Hotan was 264.4 μg/m3, a level considered hazardous.
Pollution levels in Swiss towns and cities vary too. Switzerland’s most polluted town in 2020 was Rotkreuz in Zug. PM2.5 concentrations there averaged 15.4 μg/m3 and went as high as 22.9 μg/m3 in November 2020. Dubendorf (14.0) and Liestal (13.7) were Switzerland’s second and third most polluted towns.
The most polluted town in French-speaking Switzerland was Ecublen (11.0), in Ticino it was Lugano (11.9) and in German-speaking Switzerland it was Binningen (10.1 μg/m3).
Switzerland’s cleanest town in 2020 was Neuchâtel, with an average PM2.5 concentration of 4.5 μg/m3. Neuchâtel was followed by Kussnacht (5.7) and Illnau (6.2). Bern (9.4), Lausanne (9.8) and Zurich (8.9) were in the middle. There was no data on Geneva.
For much of Switzerland the most polluted months are November, December and January.
Fine particulate matter is only one measure of air pollution. Other important ones include ozone (O3), nitrogen dioxide (NO2) and sulfur dioxide (SO2).
The main drivers of outdoor air pollution in Switzerland are industrial activity and vehicles, in particular 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. Vehicles also produce high levels of nitrogen dioxide (NO2) and sulfur dioxide (SO2).
Those most at risk are people living near areas of dense traffic and road commuters.
In winter, wood burning and extra dirty electricity generation add to Switzerland’s pollution. Nations pushing electric cars will need to work hard to ensure they don’t just shift pollution and emissions from tailpipes to power stations. Switzerland has already exhausted its hydro electric output and risks importing more coal-produced electricity from Germany.
In the end, one of the biggest factors behind pollution levels is weather and topography. Some places, with naturally limited air flow and winter inversion layers are dealt a poor hand.
IQAir report (in English)