空气质量指数计算器 — 公式

How to Calculate Air Quality Index

The AQI converts pollutant concentrations into a standardized scale.

Simplified PM2.5 to AQI

AQI (approx) = PM2.5 * 4.167 (for values up to ~100 AQI)

AQI Categories

  • 0-50: Good (green)
  • 51-100: Moderate (yellow)
  • 101-150: Unhealthy for sensitive groups (orange)
  • 151-200: Unhealthy (red)
  • 201-300: Very unhealthy (purple)
  • 301+: Hazardous (maroon)

    • The WHO guideline for annual PM2.5 is 5 ug/m3.

    计算示例

    PM2.5 of 35 ug/m3, spending 2 hours outdoors daily for 250 days/year.

    1. AQI: 35 * 4.167 = 146 (Unhealthy for sensitive groups)
    2. Annual exposure: 35 * 2 * 250 = 17,500 ug*hr/m3
    3. vs WHO: 35 / 5 * 100 = 700% above guideline
    4. Reduction needed: 35 - 5 = 30 ug/m3