How to read the map
The map is centred on the place you chose and shows the surrounding area divided into square cells of about 10 km: each cell has a single value, the one forecast for the hour shown at the bottom left (when the map opens, the current hour).
Colours
The colour tells how close the value is to the reference threshold of the selected pollutant:
- cyan and green: good air, well below the threshold;
- yellow: around the threshold;
- orange and red: above the threshold;
- purple: above twice the threshold.
The cells are drawn as dots: the more polluted the air, the bigger the dots, until they merge into a solid colour.
The bar in the top-right panel is the legend: the numbers below it are values in µg/m³ and the white tick marks the threshold. The Intensity slider makes everything stronger or lighter, useful to read the place names underneath. The ▴ button hides the panel (on phones it starts hidden): tap the pollutant name to bring it back.
Other controls
- Arrows next to the date (bottom left): look at earlier or later hours, one hour (‹ ›) or one day (« ») at a time; now takes you back to the current hour.
- 20, 50, 100 (top left): how many cells to show along the long side of the screen, i.e. how wide the area around the centre is. They replace the zoom buttons.
- Tap a cell to read the exact value and how far it is from the threshold.