Only 13 countries breathe clean air
/In 2025, only 13 countries worldwide met the WHO guideline for fine particulate matter — including just three in Europe. Switzerland wasn't among them: PM2.5 levels rose, driven by wildfire smoke, Saharan dust, and local emissions from traffic and wood burning. Sources: IQAir: Interactive global map of 2025 and Nationalen Beobachtungsnetzes für Luftfremdstoffe (NABEL) report of 2025
At the same time, the world's ability to track air quality is shrinking. When the US State Department shut down its embassy monitoring programme in March 2025, six countries lost their only source of reliable air quality data — and monitoring was weakened in 44 more.
The conclusion is hard to avoid: centralised monitoring alone is no longer enough. Distributed, low-cost sensor networks are becoming critical infrastructure — to close data gaps, validate models, and give communities the information they need to act.
