ActSmall · Air

Air-Quality Map

Tap any monitor — see PM2.5 readings against the WHO 2021 guideline, and the single best thing you can do for that air tonight. Stations from OpenAQ; country shading from population-weighted PM2.5 via Our World in Data. Refreshed once a day.

Opens on a top-3 worst-PM2.5 monitor on the live OpenAQ feed. Search or the worst-list to explore your own region.

Loading live PM2.5 data…

Country averages — population-weighted PM2.5 from Our World in Data.

Act now — what you can do

Curated, link-out-only. Pick a monitor on the map to see actions tailored to its situation; or tonight’s default is the same everywhere: the $30 Corsi-Rosenthal filter.

    Today’s worst monitors

    Top monitors on the active pollutant from the latest OpenAQ pull. Click a row to fly there and see interventions.

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        Browse the open intervention catalogue (12 items)

        Each intervention is household- or community-scale and pairs with at least one freely accessible reference (EPA, WHO, CDC, peer-reviewed evaluations). Click any card for details.

        How this portal works
        • Monitor readings are pulled from OpenAQ — an open archive of measurements from 100+ governmental and research networks. We pull the latest PM2.5, NO₂, and O₃ values once a day.
        • WHO 2021 thresholds colour stations: PM2.5 24-hour mean over 15 µg/m³ is above guideline; over 75 is very unhealthy. NO₂ and O₃ have their own thresholds.
        • Country shading uses population-weighted PM2.5 annual averages from Our World in Data — a fallback when no station is right next to you.
        • The recommender derives need-signals (pollutant level, indoor vs outdoor source, climate band) and ranks the catalog by use-case match plus simplicity.
        • Your pins live in your browser’s local storage. Use Export JSON to back them up or share with someone you trust.
        • No accounts. No tracking. No upload. Outbound calls from the browser: our own server (live data), OpenFreeMap (basemap).

        Sources: country borders — Natural Earth (public domain); basemap — OpenFreeMap & OpenStreetMap contributors (ODbL); air-quality monitors — OpenAQ (CC BY 4.0), refreshed daily; country PM2.5 averages — Our World in Data (CC BY 4.0); thresholds — WHO Global Air Quality Guidelines (2021); rendering — MapLibre GL JS (BSD-3); intervention catalogue assembled from open-access references including US EPA IAQ, WHO, Clean Air Crew, CDC NIOSH.

        Station coverage is uneven: most of Europe, North America and East Asia is dense; sub-Saharan Africa and parts of Central Asia are thinly covered. Where there is no station, country shading is the best signal we have. See methodology.