Guidance for Conducting Air Quality Monitoring Studies in Local Airsheds

The Lane Regional Air Pollution Authority (LRAPA, Springfield, OR) and the Environmental Protection Agency jointly developed a compact, portable, battery operated, air sampler for characterizing respirable dust (PM[10]) , lead or carbon monoxide (CO) in an airshed. The sampler (LRAPA Portable Sampler, Model 3.1) can monitor in airsheds where permanent sites are not practical in order to estimate the community pollutant exposure and to determine the spatial and temporal variation of pollutant levels. The decision regarding where to locate these samplers in an airshed is often based on subjective considerations. Nontechnical factors, such as convenience and accessibility, may dominate the selection of a specific monitor site within a study area. A guidance protocol was developed which quantitatively establishes the portable monitor locations based on dispersion modeling and statistical analysis. A field study performed in Weehawken, NJ characterized the ambient PM[10] concentrations in the vicinity of the Lincoln Tunnel entrance using the LRAPA sampler. Monitors were located based on the guidance protocol at twelve separate locations within a 2 km X 2 km square grid surrounding the tunnel entrance. Three of these sites contained collocated samplers. Results indicate the siting model performed well, yielding a positive correlation between the model's predicted concentration rank at each site and the actual rank experienced in the field. A calculation of Kendall's correlation coefficient yielded a positive value of 0.253. The model performed best on clear, moderately windy days while less accurate results appeared on days with large fluctuations in wind direction. In addition, the model tended to underpredict the effects of auto emissions on the urban area's total aerosol concentration. The information obtained from the samplers provided a complete depiction of the PM,o concentration distribution throughout the study area. Monitor collocation data demonstrates that the LRAPA samplers provided consistent pollutant concentration measurements with over 90% of the concentration readings yielding differences of less than 5 μ/m^3.Master of Science in Environmental Engineerin