Air Quality Monitor

The U.S. Embassy Hanoi air quality monitor was re-installed and re-certified on September 6, 2019, at a new location in the Hoan Kiem district of Hanoi. Current and historical EPA-certified data is also available here:$Hanoi.

The U.S. State Department, in collaboration with the U.S. Environmental Protection Agency (EPA), puts air quality monitors on many of its facilities around the world to provide information to help protect the health of American personnel and citizens overseas. The U.S. Embassy Hanoi has an air quality monitor to measure particulate pollution with a size of 2.5 microns in diameter or smaller, commonly referred to as PM2.5. Please note that citywide analysis cannot be done with data from a single monitor. This data provides an accurate measure of the air quality for PM 2.5 in the section of Hanoi close to the monitor’s location at 19/21 Hai Bà Trưng in Hoan Kiem District, Hanoi.

This factsheet (PDF 870 KB) on air quality provides detailed information on air quality monitoring, why outdoor air quality is important, and Frequently Asked Questions (FAQ). Highlights from the factsheet on air quality:

  • The instrument located at the U.S. Embassy uses a beta attenuation measurement principle to provide hourly PM2.5 concentrations in micrograms per cubic meter.
  • The hourly PM2.5 concentrations are converted into the U.S. EPA’s Air Quality Index (AQI)  made available to the public on the website.
  • The instrument is operated and maintained according to manufacturer specifications, as well as following the U.S. Environmental Protection Agency’s Ambient Air Quality Surveillance requirements.
  • The U.S. EPA has developed a formula to convert PM 2.5 readings into an air quality index (AQI) value that can help inform health-related decisions. Meanings of AQI numerical values can be seen in the chart below. Please note that the U.S. EPA’s AQI includes air pollution in the form of both gases and particles, but U.S. embassies use particle pollution as an overall indicator for air quality. For more information on AQI and how it is calculated, please click here.

Please click here (PDF 418 KB) for the Fact Sheet on Air Quality Monitoring.

Air Quality Index Levels of Health Concern Numerical Value Meaning
Good 0 to 50 Air quality is considered satisfactory, and air pollution poses little or no risk
Moderate 51 to 100 Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
Unhealthy for Sensitive Groups 101 to 150 Members of sensitive groups may experience health effects. The general public is not likely to be affected.
Unhealthy 151 to 200 Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.
Very Unhealthy 201 to 300 Health warnings of emergency conditions. The entire population is more likely to be affected.
Hazardous 301 to 500 Health alert: everyone may experience more serious health effects