Smoke from a wildfire hundreds of kilometres away can push a city's air quality into "hazardous" territory within hours. This lab uses a simplified Gaussian plume model — the same family of equations air-quality forecasters use — to estimate how much fine particulate matter (PM2.5) reaches a downwind city, and converts that concentration into the US EPA Air Quality Index (AQI).
During the June 2023 Canadian wildfire smoke event, New York City's PM2.5-based AQI briefly exceeded 400 — worse than many of the world's most polluted megacities — despite the fires burning over 1,000 km away.
A Gaussian-plume model of wildfire smoke drifting toward a city: tune the fire's distance, intensity and wind to watch PM2.5 and AQI shift on live-tinted buildings, then toggle a HEPA-filtered clean-air shelter and see indoor exposure drop far below outdoor levels.
Smoke concentration downwind depends on emission rate, wind speed and distance-driven dispersion — the same Gaussian plume physics used in real air-quality forecasting. PM2.5 is converted to the official EPA AQI scale in real time.
Drag the fire distance, intensity and wind sliders to change the plume, rotate wind direction to send smoke toward or away from the city, and switch the clean-air shelter's HEPA filtration on and off to compare indoor vs. outdoor AQI.
Well-sealed rooms with HEPA filtration can cut indoor PM2.5 by 80–90%, which is why public-health guidance during smoke events centres on "clean air shelters" rather than evacuation alone.