Learn — AirCheck

Air quality describes how clean or polluted the air is, and what that means for your health. The single number you usually see is the Air Quality Index (AQI) — a 0–500 scale that converts the measured concentration of several pollutants into one easy-to-read value with a color, from green “Good” to maroon “Hazardous”.

• 🎚️How the Air Quality Index worksWhy one pollutant’s concentration becomes a 0–500 number, the six categories, and how the reported AQI is the worst pollutant, not an average.
• 🧪The pollutants that drive the indexPM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide — what each is, where it comes from, and why it matters.
• 🫁What polluted air does to the bodyShort- and long-term effects, and why children, older adults, pregnant people and those with heart or lung conditions are most at risk.
• 😷Protecting yourself on bad-air daysPractical steps by AQI category — timing outdoor activity, filtering indoor air, masks that actually work, and when smoke changes the rules.
• 📡Where the numbers come fromReference-grade monitors vs. low-cost sensors, why two nearby readings can differ, and how AirCheck normalizes them.