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

Unusually sensitive people should consider reducing prolonged or heavy exertion.

Unhealthy for Sensitive Groups (101-150)

75 - 115

35.5 - 55.4

People with heart or lung disease, older adults, children, and people of lower socioeconomic status should reduce prolonged or heavy exertion.

Unhealthy (151-200)

115 - 150

55.5 - 150.4

People with heart or lung disease, older adults, children, and people of lower socioeconomic status should avoid prolonged or heavy exertion; everyone else should reduce prolonged or heavy exertion.

Very unhealthy (201-300)

150 - 250

150.5 - 250.4

People with heart or lung disease, older adults, children, and people of lower socioeconomic status should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.

Hazardous (301-500+)

250 – 500

250.5 - 500.4

Everyone should avoid all physical activity outdoors; people with heart or lung disease, older adults, children, and people of lower socioeconomic status should remain indoors and keep activity levels low

 

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

Unusually sensitive people should consider reducing prolonged or heavy exertion

Unhealthy for Sensitive Groups (101-150)

150 - 250

155 - 254

People with heart or lung disease, older adults, children, and people of lower socioeconomic status should reduce prolonged or heavy exertion.

Unhealthy (151-200)

250 - 350

255 - 354

People with heart or lung disease, older adults, children, and people of lower socioeconomic status should avoid prolonged or heavy exertion; everyone else should reduce prolonged or heavy exertion.

Very unhealthy (201-300)

350 - 420

355 - 424

People with heart or lung disease, older adults, children, and people of lower socioeconomic status should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion.

Hazardous (301-500+)

420 - 600

425 - 604

Everyone should avoid all physical activity outdoors; people with heart or lung disease, older adults, children, and people of lower socioeconomic status should remain indoors and keep activity levels low.


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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