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What is the Air Quality Index?
The Air Quality Index (AQI) is a standardized measurement used worldwide to communicate how polluted the air currently is. The scale runs from 0 to 500, with higher values indicating greater levels of air pollution and increased health risks.
AQI values are calculated based on concentrations of major pollutants including particulate matter (PM2.5 and PM10), ground-level ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide. Each pollutant has its own AQI value, and the overall AQI reflects the highest individual pollutant reading.
Common Air Pollutants
PM2.5
Fine Particulate Matter
Microscopic particles smaller than 2.5 micrometers that can penetrate deep into the lungs and enter the bloodstream. Primary sources include vehicle exhaust, industrial emissions, and wildfires.
PM10
Coarse Particulate Matter
Particles between 2.5 and 10 micrometers in diameter. Common sources include dust, pollen, mold spores, and construction activities.
O₃
Ground-Level Ozone
Formed when pollutants from cars and industrial sources react with sunlight. Most problematic during hot, sunny days. Can trigger respiratory issues and worsen asthma.
NO₂
Nitrogen Dioxide
A reddish-brown gas produced by vehicle engines and power plants. Contributes to smog formation and can irritate airways, particularly in people with asthma.
CO
Carbon Monoxide
A colorless, odorless gas from incomplete combustion. High concentrations reduce oxygen delivery to the body's organs and can be dangerous in enclosed spaces.
SO₂
Sulfur Dioxide
Produced primarily by burning fossil fuels at power plants and industrial facilities. Can cause respiratory problems and contributes to acid rain formation.
Last updated: 15 minutes ago
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