Air monitoring for polycyclic aromatic hydrocarbons (PAHs)

Polycyclic aromatic hydrocarbons (PAHs) are a class of over 1,000 different chemicals that contribute to air pollution. However, these chemicals have few regulations for outdoor air. The MPCA uses a variety of methods to monitor the levels of PAHs in the environment. 

Why study PAHs?

  • Elevated exposures to PAHs are linked with respiratory health effects including irritation and lung cancer.
  • PAHs come from sources like tobacco smoke, wood smoke, vehicles, asphalt roads, or smoke from prescribed burning. They are products of incomplete combustion.
  • There are many types of PAHs. They have different sizes, shapes, compositions, and health effects. More information on PAHs: Oregon State University Superfund Research Center website

Where are PAHs being monitored in Minnesota?

PAH monitoring at urban and rural locations

From 2013 – 2015 the MPCA monitored PAHs in Mille Lacs and South Minneapolis through a grant-funded project. More information about this project including the data and the sampling methodologies can be found using this interactive tool.

Findings:

  • All measured PAHs were found below available inhalation health benchmarks, which suggests that PAHs in the study do not exceed risk guidelines
  • The highest measured concentrations were associated with events that included air pollution sources such as an apartment fire, campfires, fireworks, and a large influx of vehicles to the sampling site
  • PAH concentrations in the study area varied by season and location

Facility fenceline PAH monitoring 

After monitoring PAHs in rural and urban locations, the MPCA determined that it would be important to monitor these pollutants at facilities with higher estimated PAH emissions. The two priority facility types were shingle manufacturers and petroleum refineries. This monitoring began in July 2016 and utilizes similar methodologies as the EPA Grant Funded PAH Monitoring; data and monitoring locations can be found using this interactive tool. 

Findings:

  • All measured PAHs were found below available inhalation health benchmarks, which suggests that PAHs in the study do not exceed risk guidelines.
  • The highest concentrations were found at the Lowry Avenue site which is surrounded by a shingle manufacturer, highways, and diesel truck activity. Based on wind direction analysis, all of these sources contributed to the air concentrations measured at the monitor.
  • The air concentrations of the PAH Benzo[c]fluorene were closest to its health benchmark. This suggest that Benzo[c]fluorene should be included in PAH air monitoring studies in order to provide a complete look at potential risks from PAHs.