Smog Calculator

A rough rule equates breathing high-PM2.5 air to the harm of smoking cigarettes.

How the Math Works

The Smog Calculator translates Air Quality Index (AQI) levels into an equivalent number of cigarettes by first converting AQI to PM2.5 concentrations using standardized EPA breakpoints. Once PM2.5 is determined, the formula divides this value by 22 micrograms per cubic meter (ug/m³), the approximate daily PM2.5 exposure from smoking one cigarette. For example, an AQI of 100 corresponds to ~35 ug/m³ PM2.5, equating to ~1.6 cigarettes. This comparison simplifies complex air quality data into a tangible metric, though it is a rough estimate based on averaged exposure levels.

Practical Applications

To use the calculator, input your local AQI reading into the tool, which automatically converts it to PM2.5 using the EPA’s piecewise linear formula. The result is then divided by 22 to determine how many cigarettes’ worth of PM2.5 you’re exposed to in a day. This helps contextualize air quality by linking it to a familiar health risk, making it easier to grasp the severity of pollution levels. Note that the calculation assumes static exposure over 24 hours and does not account for individual health factors or smoking habits.

Day-to-Day Use

The Smog Calculator empowers users to visualize air pollution in relatable terms, aiding daily decision-making. For instance, if your AQI indicates 2 cigarettes worth of PM2.5, you might choose to limit outdoor exertion or use air purifiers. While not a direct health warning, this comparison encourages proactive steps like checking forecasts, wearing masks, or reducing prolonged outdoor activities on high-pollution days. It transforms abstract AQI numbers into actionable insights, fostering greater awareness of environmental health impacts in everyday life.

Worked example

AQI 150 (PM2.5 ~52 ug/m^3) over 2 hours outdoors is like about 0.2 cigarettes.

FAQ