Air quality tools for the decision in front of you
Start with the number or question you already have. Every tool leads to a concrete calculation, comparison, or action plan instead of another generic article.
Convert the reading
Translate AQI and PM2.5 into units that are easier to compare.
AQI to cigarettes calculatorConvert an AQI reading and exposure time into a cigarette-equivalent estimate.Open toolPM2.5 cigarette calculatorEnter a PM2.5 concentration directly when your monitor already shows µg/m³.Open toolPM2.5 ↔ AQI converterConvert in either direction with the current EPA PM2.5 breakpoints.Open toolU.S. multi-pollutant AQI calculatorCalculate AQI sub-indices for ozone, particles, carbon monoxide, sulfur dioxide, and nitrogen dioxide.Open toolPM NowCast calculatorTurn the latest 12 hourly PM2.5 or PM10 readings into an EPA-weighted NowCast and AQI.Open toolPurpleAir EPA correction calculatorCorrect a PurpleAir CF=1 PM2.5 reading for humidity, including extreme-smoke conditions.Open toolCanada AQHI calculatorCalculate the Canadian Air Quality Health Index from three-hour ozone, NO₂, and PM2.5 averages.Open toolCigarette smoke AQI calculatorCompare baseline and measured smoke PM2.5 readings with the U.S. AQI scale.Open tool
Decide what to do
Turn today’s conditions into an activity, smoke-response, or cleaner-air equipment plan.
Indoor PM2.5 calculatorEstimate steady-state indoor PM2.5 from outdoor air, room volume, infiltration, sources, and purifier CADR.Open toolAQI activity decision plannerPlan outdoor activity by AQI, audience, intensity, and duration.Open toolDaily air pollution exposure plannerCombine the places in your day into a time-weighted PM2.5 comparison.Open toolAir purifier size calculatorCalculate smoke CADR, air changes per hour, and purifier count for a room.Open toolAir purifier electricity cost calculatorCalculate electricity, filter, annual, and three-year costs for one or more air purifiers.Open toolDIY air cleaner & Corsi–Rosenthal box calculatorCompare EPA-tested DIY designs by estimated smoke CADR, room ACH, unit count, and material cost.Open toolWildfire smoke plannerBuild a smoke-day plan for exercise, errands, indoor air, and overnight exposure.Open tool
Compare conditions
See how exposure and recommended actions change between readings.
Check local air
Use supported live city readings and forecasts for repeat decisions.
Choose a data source
Find a verified app or map that matches your location and priority.
One calculation framework
Conversion tools share the same AQI, PM2.5, and cigarette-equivalent methodology. Planning tools remain educational aids and do not replace local public-health or emergency guidance.