Measuring Air Quality
Have you ever been outside and found that it was hard to breathe? You might have seen or even smelled smoke. Air pollution is a serious health risk. The Healthy Air Network collects data and informs the public about the current air quality. With this information, people can take steps to protect their health. Observing patterns over time helps us identify the sources of poor air quality and take action to prevent it.
What We Measure
Each dot on the network map corresponds to an air sensor. Each sensor reports PM2.5 levels together with the air quality index (AQI), developed by the EPA. The AQI is a national index of air pollution and provides information on how to avoid the health effects of poor air quality. AQI values range from 0 to 500 and are divided into six categories (good, moderate, unhealthy for sensitive groups, unhealthy, very unhealthy, and hazardous) with corresponding colors from green to dark purple. The AQI determines the color of the sensor and the actions to take. We use a combination of Purple Air and Air U sensors. Air U sensors also report ozone.
In addition to air quality, each sensor card includes wind, weather and pollen information. For people with respiratory illness, the pollen count and temperature can also impact health. In addition, the changing climate is leading to increasing pollen counts and a longer pollen season as well as more days over 90 degrees.
The Sensor Card also shows PM 2.5 measurements over the last 24 hours. In addition you can click on the “View History” link to find past data for specific timeline. You can also change the dates to find specific time periods for air quality information.
What does it mean if a sensor shows up as gray?
Sensors that are not reporting show up as gray on the map. This can be due to a temporary wifi or power outage, or other maintenance issue. We do our best to maintain sensors with the help of our partners. Please contact us if you have questions about a sensor that is offline.
Air pollution: understanding what's in the air we breathe
Particles of pollution in the air are very small – many times smaller than a human hair.
Sometimes, you can see these small particles – think about smoke from the tailpipe of a car, a burning furnace, a wood fire or haze from wildfire smoke. If we can see them, it means there are high levels of particles. These particles are very small, which allows them to stay in the air for long periods of time, sometimes hours or even weeks. These tiny particles can travel deep into our lungs which can make it difficult to breathe. Exposure can cause health problems like lung disease, heart disease and COPD.
Particulate Matter
Healthy Air Network sensors measure particles that are very small, less than 2.5 micrometers, or microns, in size. (Another name for particulate matter of this size is PM2.5.) Their small size lets these particles stay suspended in the air for an extended period of time, and also makes it more likely that we will breathe them into our lungs. PM2.5 is made up of many different chemicals that may be released from many sources like vehicles, factories, and wildfires. High levels of PM2.5 in the air can reduce visibility and impact our health.
Learn more about particulate pollution:
Ozone or smog
Ozone is a gas that can be good or bad depending on where it is.
- Ozone that is found high in the atmosphere (stratosphere) protects the Earth from the Sun’s harmful UV radiation.
- Ozone at ground level can react with sunlight and other air pollutants to form smog. This is harmful for health. Ozone itself is a strong oxidant which can be harmful to our health.
Learn more about ozone:
- American Lung Association, Ozone
- CDC, Air pollutants
- EPA, Ground level ozone pollution
Air pollution sources
Pollution can come from different sources:
- Transportation: cars, trucks, buses, planes and any other vehicle that burns gas or diesel fuel
- Heating: Furnaces or stoves that burn gas, wood or oil
- Factories and power plants: Gas, coal, and other fuels are burned to create energy and products
- Wildfires: Wildfire smoke can have an impact far from the site of the fires themselves. Wildfires are increasing due to climate change, land use and fire management practices.
Learn more on sources of air pollution:
Healthy Air Network
Healthy Air Network
The Healthy Air Network is a collaboration of organizations and community members who work to improve air quality, increase climate resilience, and advocate for environmental justice in Massachusetts. Convened by the Public Health Institute of Western Massachusetts
