The Air District uses Health Risk Assessments (HRAs) to model health risk from new and existing sources of toxic air contaminants that require a permit. The modeling results are used to determine whether the project risk meets requirements in Air District regulations. The Air District also uses computer modeling to assess potential health impacts and health benefits as part of the rule development process for new and revised rules and in community health protection programs such as AB617.
The Air District does not evaluate the presence or buildup of pollutants within individual people. We refer these requests to colleagues with this expertise at
Biomonitoring California, a collaborative effort between the California Department of Public Health (CDPH), the Office of Environmental Health Hazzard Assessment (OEHHA), and the Department of Toxic Substances Control (DTSC).
While we do not measure buildup of pollutants in people or other biological effects of air pollution exposure, we do measure the levels of many air pollutants in the air that have health effects, and much of this data on environmental exposure to air pollution is used by OEHHA and other health researchers. These measurements are conducted at a network of 31 long-term air monitoring stations throughout the Bay Area. A complete list of what monitors are located at each air monitoring station is in the district’s
Annual Air Monitoring Network Plan; examples include:
• 20 stations measuring ozone
• 18 stations measuring nitrogen dioxide
• 17 stations measuring PM2.5
• 7 stations measuring black and brown carbon, which are markers for diesel particulate matter and woodsmoke
• 21 stations measuring daily average levels of 22 VOCs, many of which are toxic
• 1 station measuring concentrations of compounds that are toxic or form ozone, including hourly concentrations of 56 VOCs (including benzene) and 8-hour concentrations of four carbonyls (including formaldehyde)
• 2 stations that are part of CARB’s statewide air toxics monitoring network, which in addition to the VOCs measured at other sites, measure formaldehyde and acetaldehyde.
• 4 stations that measure the composition of PM2.5, including toxic metals
• One station at Reid Hillview Airport measuring TSP-lead
We are expanding measurements in the refinery corridor to include real-time hourly measurements of benzene, ethylbenzene, toluene, and xylene, or BTEX, four more common toxic air contaminants that have serious health effects.