Ultrafine Particles, or UFPs, are tiny air particles with big health consequences. The EPA regulates air particulate matter (PM) by mass. Because UFPs are tiny and take up very little mass, they are effectively unregulated by the EPA. But studies show that UFPs are more dangerous than other forms of air pollution. Their small size allows them to cross into the bloodstream more easily than larger particles.

High UFP exposure is linked to increased instances of asthma, cardiovascular disease, and chronic obstructive pulmonary disease (COPD). 

A major source of UFPs is traffic from airports. UFP concentrations are 100x higher than baseline by busy roadways, and 1000x higher than baseline beneath landing planes.

The best way to protect yourself from the harmful effects of UFPs is to install HEPA air purifiers indoors, keep your windows closed, and avoid going outside when the ambient air quality is at its worst.