World air quality map (PM2.5)
PM2.5 means particles smaller than 2.5 micrometres, small enough to be breathed deep into the lungs. This layer shows their concentration near the surface in micrograms per cubic metre, forecast by the NOAA GEFS-Aerosols model, which simulates how particles are emitted, carried and removed.
Colours begin to appear above a few micrograms and climb to deep tones for very polluted air. As a rough reference, the World Health Organization recommends an annual average below 5 micrograms per cubic metre. Hover or tap to read the value at one point.
The map covers all sources the model includes, such as smoke from fires, dust, sea salt and the emissions of cities and industry. Expect hot spots over densely populated and industrial regions, plumes of smoke downwind of large fires, and haze that follows the wind for hundreds of kilometres.
This is a model forecast on a coarse grid, not a measurement from a sensor, so it describes regional patterns rather than a particular street. The forecast runs four times a day, and each run reaches 48 hours in 3-hour steps.