Standards for Air Quality Indices in Different Countries (AQI)

There are several AQI systems across different countries and regions. Each system uses its own hazard index, contamination concentration, and data measurement time. In this regard, it is quite difficult for an ordinary user to navigate between the systems of different countries. This article explains the Air Quality Score you see on Atmotube portable air quality monitor app and other Air Quality Indices in different countries.

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United States (AQI)

The United States Environmental Protection Agency (EPA) has developed theAir Quality Index, or AQI that ranges from 0 to 500. The AQI is divided into six categories varying by severity of health concern. An AQI value over 300 represents hazardous air quality and below 50 the air quality is good. The American system is based on the measurement of five major pollutants:

• ground-level ozone (O3)
• particle pollution (PM2.5, PM10)
• carbon monoxide (CO)
• sulfur dioxide (SO2)
• nitrogen dioxide (NO2)

– and converts their concentrations into a separate AQI for each pollutant. The highest AQI is reported as a common AQI for this area. More detailed information on how AQI is calculated can be found in the Technical Assistance Document at AirNow.

Canada (AQHI)

The Air Quality Health Index (AQHI) is an aggregated measurement system used in Canada to define air quality based on its impact on people’s health. The AQHI ranged between 1 to 10+. The AQHI index values are grouped into health risk categories as shown below.

The AQHI is based on scientific research conducted by Health Canada to identify major pollutants harming people’s health. These pollutants are:

• ground-level ozone (O3)
• PM2.5
• PM10
• nitrogen dioxide (NO2).

Europe (EAQI)

European Environment Agency devised the European Air Quality Index (EAQI).

Five major air pollutants are measured:

• PM10
• PM2.5
• ground-level ozone (O3)
• nitrogen dioxide (NO2)
• sulphur dioxide (SO2)

The index ranges from "Good" to "Extremely poor" for each pollutant category, offering health advice based on the index level.

Atmotube Air Quality Score (AQS)

Atmotube Air Quality Score (AQS) is the index used within the Atmotube app that complements Atmotube air quality monitors.

Atmotube PRO, the latest generation in this product line, is a wearable, portable air quality tracker and weather station. It allows you to analyze personal exposure to air pollution with real-time data, both indoors and outdoors, and create a personal air quality map.

Since there is no unified air quality measurement system for the whole world, the ATMO team has developed their own Air Quality Score based on academic research, National Air Quality Indexes (AQIs), and WHO recommendations. AQS ranges on a scale from 0 (severely polluted air) to 100 (very clean).

Atmotube’s AQS is calculated based on:

• PM1, PM2.5 and PM10
• VOCs (volatile organic compounds) such as formaldehyde, tetrachloroethylene, acetone, propylene, etc.

United Kingdom (DAQI)

In the UK most air pollution information services use the Daily Air Quality Index (DAQI) and a four-band system approved by the Committee on Medical Effects of Air Pollutants (COMEAP) The system uses a scale from 1 to 10 and measures:

• nitrogen dioxide (NO2)
• sulphur dioxide (SO2)
• O3
• PM2.5
• PM10

Air pollution is divided into four bands: Low, Medium, High and Very High.

Australia (AQI)

Each of the states and territories of Australia is responsible for monitoring air quality and publishing data in accordance with the national NEPM standards.

The following pollutants are monitored:

• carbon monoxide (CO)
• nitrogen dioxide (NO2)
• ozone (O3)
• sulfur dioxide (SO2)
• PM10
• PM2.5

South Korea (CAI)

The CAI (Comprehensive Air-quality Index) is a scale measuring ambient air quality in South Korea.

The CAI is based on measurements of the following air pollutants:

• carbon monoxide (CO)
• nitrogen dioxide (NO2)
• ozone (O3)
• sulfur dioxide (SO2)
• PM10
• PM2.5

The CAI uses a scale of 0 to 500. The higher the CAI value, the more severe the air pollution.

Singapore (PSI)

The PSI (Pollutant Standards Index) is based on six pollutants:

• particulate matter (PM10)
• fine particulate matter (PM2.5)
• sulphur dioxide (SO2)
• carbon monoxide (CO)
• ozone (O3)
• nitrogen dioxide (NO2)

For each pollutant, a sub-index is calculated, and the highest sub-index is taken as the PSI value. In most cases, it’s a PM2.5 concentration.

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Hong Kong (AQHI)

From 1995 to 2013, Hong Kong used the Air Pollution Index (API), which was replaced by the AQHI system in 2013.

The Air Quality Health Index (AQHI) is a health risk-based air pollution index based on tracking the following air pollutants:

• particulate matter (PM10)
• fine particulate matter (PM2.5)
• sulphur dioxide (SO2)
• ozone (O3)
• nitrogen dioxide (NO2)

The AQHI is reported on a scale from 1 to 10 and 10+, and is divided into five categories: low, moderate, high, very high, and serious.

Mainland China (AQI)

China’s AQI level is based on the level of six pollutants:

• sulfur dioxide (SO2)
• nitrogen dioxide (NO2)
• PM10
• PM2.5
• carbon monoxide (CO)
• ozone (O3)

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India (AQI)

Air Quality Index (AQI) is a tool to showcase air quality status. It converts the complex air quality data of various pollutants into a single number and colour. AQI has six categories of air quality. These are: Good, Satisfactory, Moderate, Poor, Very Poor, and Severe. Each of these categories is decided based on ambient concentration values of air pollutants and their likely health impact. As the AQI increases, an increasingly large percentage of the population is likely to experience health effects.