Main pollutant thresholds for US and China Air Quality Indexes (AQI)

On the AirVisual app and monitor, you can choose to display either US or China AQI. The tables below help you to understand how pollutant concentrations are different when China AQI and US AQI indexes are showing the same value range. 

Particulate Matter PM2.5 

AQI

China standard concentration (μg/m³) [24-hour average]

US standard concentration (μg/m³) [24-hour average]

Recommendations

Good (0-50)

0 - 35

0 - 12.0

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended. 

Moderate (51-100)

35 - 75

12.1 - 35.4

Sensitive individuals should avoid outdoor activity as they may experience respiratory symptoms. 

Unhealthy for Sensitive Groups (101-150)

75 - 115

35.5 - 55.4

The general public and sensitive individuals in particular are at risk to experience irritation and respiratory problems. 

Unhealthy (151-200)

115 - 150

55.5 - 150.4

Increased likelihood of adverse effects  and aggravation to the heart and lungs among the general public - particularly for sensitive groups. Everyone is advised to limit outdoor activities. 

Very unhealthy (201-300)

150 - 250

150.5 - 250.4

General public will be noticeably affected. Sensitive groups will experience reduced endurance in activities, and should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.

Hazardous (301-500+)

250 – 500

250.5 - 500.4

General public and sensitive groups are at high risk to experience strong irritations and adverse health effects that could trigger other illnesses. Everyone should avoid exercise and remain indoors. 

 

Particulate Matter PM10

AQI

China standard concentration (μg/m³) [24-hour average]

US standard concentration (μg/m³) [24-hour average]

Recommendations

Good (0-50)

0 - 50

0 - 54

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended.

Moderate (51-100)

50 - 150

55 - 154

Sensitive individuals should avoid outdoor activity as they may experience respiratory symptoms.   

Unhealthy for Sensitive Groups (101-150)

150 - 250

155 - 254

The general public and sensitive individuals in particular are at risk to experience irritation and respiratory problems.   

Unhealthy (151-200)

250 - 350

255 - 354

Increased likelihood of adverse effects and aggravation to the heart and lungs among the general public - particularly for sensitive groups. Everyone is advised to limit outdoor activities.  

Very unhealthy (201-300)

350 - 420

355 - 424

General public will be noticeably affected. Sensitive groups will experience reduced endurance in activities, and should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.  

Hazardous (301-500+)

420 - 600

425 - 604

  General public and sensitive groups are at high risk to experience strong irritations and adverse health effects that could trigger other illnesses. Everyone should avoid exercise and remain indoors.   


Carbon monoxide (CO)

AQI

China standard concentration (μg/m³) [1-hour average]

US standard concentration (ppm) [8-hour average]

Recommendations

Good (0-50)

0 - 5

0 - 12.0

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended.

Moderate (51-100)

5 - 10

12.1 - 35.4

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended.   

Unhealthy for Sensitive Groups (101-150)

10 - 35

35.5 - 55.4

People with heart disease, such as angina, should limit heavy exertion and avoid sources of CO, such as heavy traffic.

Unhealthy (151-200)

35 - 60

55.5 - 150.4

People with heart disease, such as angina, should limit moderate exertion and avoid sources of CO, such as heavy traffic.

Very unhealthy (201-300)

60 - 90

150.5 - 250.4

People with heart disease, such as angina, should avoid exertion and sources of CO, such as heavy traffic.

Hazardous (301-500+)

90 - 150

250.5 - 500.4

People with heart disease, such as angina, should avoid exertion and sources of CO, such as heavy traffic; everyone else should limit heavy exertion.

 

Sulfur dioxide (SO2)

AQI

China standard concentration (μg/m³) [1-hour average]

US standard concentration (ppb) [1-hour average]

Recommendations

Good (0-50)

0 - 150

0 - 12.0

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended.   

Moderate (51-100)

150 - 500

12.1 - 35.4

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended.   

Unhealthy for Sensitive Groups (101-150)

500 - 650

35.5 - 55.4

People with asthma should consider limiting outdoor exertion.

Unhealthy (151-200)

650 - 800

55.5 - 150.4

Children, people with asthma, or other lung diseases, should limit outdoor exertion.

Very unhealthy (201-300)

800 - 1600

150.5 - 250.4

Children, people with asthma, or other lung diseases should avoid outdoor exertion; everyone else should reduce outdoor exertion. People with asthma, children and older adults should avoid all outdoor exertion; everyone else should avoid prolonged exertion. 

Hazardous (301-500+)

1600 - 2620

250.5 - 500.4

Children, people with asthma, or other lung diseases, should remain indoors; everyone else should avoid outdoor exertion.

 

Nitrogen Dioxide (NO2) 

AQI

China standard concentration (μg/m³) [1-hour average]

US standard concentration (ppb) [1-hour average]

Recommendations

Good (0-50)

0 - 100

0 - 12.0

Air quality is satisfactory and poses little or no risk. Ventilating your home is recommended.   

Moderate (51-100)

100 - 200

12.1 - 35.4

Unusually sensitive individuals should consider limiting prolonged exertion especially near busy roads.

Unhealthy for Sensitive Groups (101-150)

200 - 700

35.5 - 55.4

People with asthma, children and older adults should limit prolonged exertion especially near busy roads.

Unhealthy (151-200)

700 - 1200

55.5 - 150.4

People with asthma, children and older adults should avoid prolonged exertion near roadways; everyone else should limit prolonged exertion especially near busy roads.

Very unhealthy (201-300)

1200 - 2340

150.5 - 250.4

People with asthma, children and older adults should avoid all outdoor exertion; everyone else should avoid prolonged exertion especially near busy roads.

Hazardous (301-500+)

2340 - 3840

250.5 - 500.4

People with asthma, children and older adults should remain indoors; everyone else should avoid all outdoor exertion.

 

 

 

Reference:

US standard: https://www3.epa.gov/airnow/aqi-technical-assistance-document-sept2018.pdf

China standard: http://210.72.1.216:8080/gzaqi/Document/aqijsgd.pdf

 

 

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