The U.S. Embassy in Madagascar uses an air quality monitor on its grounds to measure PM 2.5 particulates as an indication of air quality on the embassy’s compound located in Antananarivo’s Andranomena district. The AQI readings from this monitor can be accessed on Twitter @AntananarivoAir. Note this data is local and is not a representation of air quality throughout the entire city of Antananarivo.
PM 2.5 particulates – that is particulates less than 2.5 micrometers in diameter – are referred to as “fine” particulates. Because they are small enough to directly enter the lungs and bloodstream, PM 2.5 particulates are believed to pose the greatest health risks for sensitive populations, including those with heart or lung disease, children, and older adults. The PM 2.5 standard is recognized by the U.S. Environmental Protection Agency (EPA) as an effective means to determine air quality levels worldwide. For more information about particulate matter pollution and its health effects, visit the EPA’s website.
The EPA has developed a formula to convert PM 2.5 particulate readings into an air quality index (AQI) value that can help inform health-related decisions. For example, an AQI value of 50 represents good air quality with little potential to affect public health, while an AQI value more than 300 indicates hazardous air quality. The chart below is a useful guide to air quality readings you may see from the embassy’s air quality monitor. To learn more about AQI, visit the U.S. government’s AirNow page.
| Concern Level | AQI | PM 2.5 µg/m3 | Description of Air Quality |
| Good | 0 to 50 | 0 – 12 | Air quality is satisfactory, and air pollution poses little or no risk |
| Moderate | 51 to 100 | 12 – 35 | Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution. |
| Unhealthy for Sensitive Groups | 101 to 150 | 35 – 55 | Members of sensitive groups may experience health effects. The general public is less likely to be affected. |
| Unhealthy | 151 to 200 | 55 – 150 | Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects. |
| Very Unhealthy | 201 to 300 | 150 – 250 | Health alert: The risk of health effects is increased for everyone. |
| Hazardous | 301 to 500 | >250 | Health warning of emergency conditions: everyone is more likely to be effected. |