Not just resigned to the laboratory, researchers at the Center for Atmospheric Particle Studies are often collecting measurements in the field to better understand atmospheric phenomena. Day or night, rain or shine, CAPS researchers work to collect important measurements from the Pittsburgh region and around the world. These are their stories.
Over the past year, residents of Allegheny County, Pennsylvania may have noticed a unique vehicle driving on local roadways or parked in their neighborhoods. With several metal tubes extending upwards from the roof, this vehicle can be (and has been) mistaken for some type of surveillance vehicle. While this is partially true, the vehicle in question – Carnegie Mellon University’s Center for Atmospheric Particle Studies (CAPS) mobile laboratory – is not being used to intercept communications. Rather, CAPS researchers are using the mobile lab for an altogether different type of investigation – a surveillance of air quality. Equipped with a wide variety of instrumentation capable of measuring concentrations of particles and gases in the atmosphere, the mobile lab provides a specialized platform for use in air pollution research projects. We are currently using the CAPS mobile lab to study the spatial variability of air pollution in Allegheny County.
Quantifying human exposure to harmful air pollutants is a complex problem. Exposure is directly related to the concentration of air pollutants in the air that people breathe. Concentrations of these species are in turn dependent on many factors and are subject to spatial and temporal variability. For example, concentrations of pollutants emitted by motor vehicles are typically elevated downwind of roadways, particularly during rush hour. The Allegheny County Health Department (ACHD) operates a network of stationary air monitors to measure concentrations of a number of air pollutants throughout the county (http://www.achd.net/air/monitor-data.html). This network provides a robust picture of air quality and is necessary for the measurement of nationally regulated air pollutants. However, due to the limited number of monitoring sites in the network, important small scale variations in air pollutant concentrations may be overlooked. For instance, pollution “hot spots” near roadways or industrial sources of emissions are not fully characterized by the stationary monitoring network.
With our mobile sampling project, we aim to supplement the existing ACHD monitoring network by utilizing the unique capabilities of the CAPS mobile lab. The mobile lab enables us to make measurements at a large number of sites with varying degrees of influence from air pollution sources such as traffic or industrial facilities. We are also able to investigate the impacts of altitude on air quality by comparing measurements made at river valley sites with upland sites at higher elevations. Our measurements will help us to develop a better understanding of how these factors influence concentrations of harmful air pollutants and to determine whether certain subgroups and communities are experiencing high exposure conditions. To date, we have conducted hundreds of hours of measurements at sites across the county. Our goal is to use this data to develop county level maps showing concentrations of air pollutants, including criteria pollutants such as ozone and particulate matter, as well as other pollutants of concern such as metallic species. These maps will support future investigations into the public health impacts of air pollution in the county and will provide regulators and decision makers with more detailed information on important emission sources.
Written by Tim Dallmann, Photos by Peter Leeman