The air right now, where it is measured

What you are looking at

Each dot is a station that has reported in the past six hours, coloured by its PM2.5 level in micrograms per cubic metre. Where there are no dots, nobody is sharing measurements — much of Africa and Central Asia — and the map leaves them empty rather than guessing.

How to read it

• Green is clean air; yellow, orange, red and purple are ever higher PM2.5.
• The World Health Organization's guideline is 5 µg/m³ as a yearly average and 15 µg/m³ over a day.
• A single high dot can be a local source or a faulty sensor; look at its neighbours.

Questions

What is PM2.5?

Particles smaller than 2.5 micrometres — about a thirtieth of a hair's width — from traffic, heating, industry, fires and dust. They reach deep into the lungs and the blood, which is why they are the pollutant most closely watched for health.

Where is the air worst right now?

The highest readings usually come from South Asia, parts of China, the Middle East and West Africa, and from wherever a large fire or a dust storm is blowing smoke over cities.

Why is my country empty on the map?

The map shows only real measurements that are shared openly. Where no station reports, or reports only old readings, nothing is drawn — an honest gap instead of a modelled guess.