Heavily traveled roads present a unique challenge for air quality. Routine air quality measurement data (either from government sources or networks like Purple Air) can’t tell you if pollution from roadways is elevated at your location. This is because the sensors are mostly blind to the pollutants such as ultrafine particles that are often elevated around roadways. Research led by UCLA researchers as well as other researchers around the world has led to a reasonable understanding of when and where pollution is elevated, how it depends on the design of structures near roadways and traffic control strategies, and how to address it within homes.
For easy to read summaries, see two recent Air Resources Board reports, that bring together much of the UCLA research in one place.