Particulate matter (PM) pollution is the most serious environmental health risk in the world, causing more deaths than poor diet or lack of exercise.

Exposure to fine particles (PM2.5) has been linked to disease and early death through extensive research. Ultrafine particle pollution (UFP), which is smaller than PM2.5, is also a serious health concern. Due to their small size, UFP can easily get into people’s lungs, blood and brain where they have been linked to increased risks for disease and early death.

In Massachusetts, particle pollution arises mostly from combustion-powered transport, such as cars and trucks. While PM2.5 spreads widely, UFPs usually concentrate close to sources. This means that residents living within 500 feet of busy roads breathe more polluted air and face increased health risks.

In Massachusetts, near-roadway PM pollution is an environmental justice concern. Due to racially inequitable transportation and housing policy, more residents of color live close to high-polluting roads and breathe polluted air, indoors and outdoors.