New Approach to Assessing Traffic Related Air Pollution

Drivers and passengers who carry their smartphones while driving could help researchers predict the amount of air pollution along their routes. As the use of GPS-linked smart phones like iPhones continues to increase, researchers at the Mailman School of Public Health are putting this new source of data to work. A recently published study aimed both to assess the validity of crowd-sourced traffic data maps and to develop models that use this traffic data to determine the contributions traffic has to air pollution levels.

Traffic-related air pollution, including black carbon, is associated with several poor health outcomes. These air pollutants are associated with respiratory and cardiovascular diseases, cancer, and together are considered a trigger for ischemic strokes.

In the summer and early fall of 2017, Columbia scientists studied three highly trafficked areas in the South Bronx, NY. At the first site, an exit ramp off of US Interstate 87, the team installed a radar device to monitor the flow of one-way traffic. In the same vicinity, an air monitor was used to determine the levels of black carbon in the air. The same measurements were taken at another location, called site B. The third location, site C, was only monitored for air pollution, and instead of radar data, the researchers used traffic data published by the Department of Transportation.

While collecting data from the radar and air monitors, the researchers also downloaded the crowd-sourced traffic data produced by GPS-enabled cell phones traveling in cars, as well as hourly weather data.

In comparing all of their collected data, the researchers found that levels of primary air pollutants like black carbon can be estimated from models that use radar-calibrated crowd-sourced traffic data from smart phones. The researchers conclude that there is major potential for crowd-sourced traffic data in modeling air pollution. With the magnitude of this information available to all, it is likely that researchers and advocacy groups will use it to reduce trucking routes, etc. that contribute to air pollution and ultimately poor health in the Bronx.

Hilpert M,  Johnson M, Kioumourtzoglou MA, Domingo-Relloso A, Peters A, Adria-Mora B, Hernández D, Ross J, Chillrud SN. A new approach for inferring traffic-related air pollution: Use of radar-calibrated crowd-sourced traffic data. Environment International 2019 Jun;127:142–159. doi: 10.1016/j.envint.2019.03.026.