Beginner Topic 1053 of 1102 Biochemistry, Environment & Industry

Air Quality Index

A scale reporting how polluted the air is.

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In-depth explanation of Air Quality Index

The Air Quality Index, AQI, converts measured concentrations of key pollutants into a single number on a scale from 0 to 500. The pollutants included are PM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide, and the sub-index for the worst pollutant determines the overall value. The scale is divided into categories such as good, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy and hazardous, each with associated health advice. Each category corresponds to concentration breakpoints that differ between countries. The index helps the public and authorities decide when to limit outdoor activity.

Going deeper: Air Quality Index

Key ideas: Converts pollutant concentrations (PM2.5, PM10, O3, NO2, SO2, CO) to a 0 to 500 scale; the highest sub-index among pollutants sets the AQI. Typical bands: 0 to 50 good, 51 to 100 moderate, 101 to 150 sensitive groups, 151 to 200 unhealthy, 201 to 300 very unhealthy, over 300 hazardous. Indian scale uses similar colors.

Common mistakes and connections: Mistake: averaging pollutants; it uses the worst one. Scales vary between countries, so numbers are not directly comparable. Index is piecewise linear between breakpoints and uses averaged times (24-hour PM, 8-hour O3). Links to particulate matter and smog.

Visualization of Air Quality Index

AQI categories from 0 to 500. Above 150 the air is unhealthy, and sensitive groups should limit outdoor exertion. The interactive lesson shows this as a live animation or chart.

Worked example and use case

An AQI above 150 is in the unhealthy range, so sensitive groups should limit outdoor exertion.

Frequently asked questions about Air Quality Index

What is Air Quality Index?

A scale reporting how polluted the air is.

Is Air Quality Index a beginner, intermediate or advanced topic?

Air Quality Index is a beginner topic in Biochemistry, Environment & Industry. It needs no earlier chemistry lessons and is a good starting point.

What should I learn before Air Quality Index?

Study these earlier topics in Biochemistry, Environment & Industry first: CFCs, Smog, Particulate Matter.

What comes after Air Quality Index?

The next topics in Biochemistry, Environment & Industry are Water Pollution and Eutrophication.

Can I practise Air Quality Index with quizzes?

Yes. The interactive lesson includes a self-check question on Air Quality Index, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.

Where Air Quality Index fits in Biochemistry, Environment & Industry

Air Quality Index is topic 78 of 127 in Biochemistry, Environment & Industry.