R. Mukund

Source attribution of ambient air toxic and other VOCs in Columbus, Ohio

Abstract Chemical mass balance (CMB) source apportionment modeling was conducted on a data set of 142 3 h integrated air samples collected at 6 different sites in 3 separate campaigns during the summer of 1989 in Columbus, Ohio; source contributions to 19 light hydrocarbon and toxic VOC species, including formaldehyde and acetaldehyde, were modeled. Overall, the results indicated that area sources, and in particular vehicle exhaust and organic solvent usage by small industrial/commercial facilities, are important contributors to the major toxic VOCs measured in urban air. In addition, the temporal resolution of the measurements allowed a number of observations regarding the short-term variability of these area sources, including diurnal trends in vehicle exhaust, gasoline vapor, and natural gas sources. The natural gas source was identified as a significant source of light hydrocarbons in the Columbus area, a finding similar to that of several other recent source apportionment studies of VOCs in urban areas. The temporal and spatial variability in gasoline vapor contributions suggested that the source is associated more with mobile sources (running losses, evaporative emissions from vehicles), rather than with fixed sites such as service stations. Finally, CMB modeled source contributions were coupled with a simple box model of the study area to provide estimates of the emission rates of various area sources. The results of these calculations suggest that there are probably substantial emissions from area sources that are not included in current emissions inventories.

Hazardous Air Pollutant Handbook: Measurements, Properties, and Fate in Ambient Air

Hazardous Air Pollutants: A Brief Introduction Background The List of Hazardous Air Pollutants Impact of the HAPs List Organization of Information in this Book References The Title III Hazardous Air Pollutants: Classification and Basic Properties The 188 Hazardous Air Pollutants: Diversity and Derivation Some Common Features of the Title III HAPs Chemical and Physical Properties of the 188 HAPs Polarizability and Water Solubility as Defining Characteristics of Polar and NonPolar VOCs References Measurement Methods for the 188 Hazardous Air Pollutants in Ambient Air Introduction Background Survey Approach Status of Current Methods HAPs Method Development: Future Directions References Concentrations of the 188 HAPs in Ambient Air Introduction Survey Procedures Ambient Air Concentrations of HAPs Data Gaps Recent Data for High Priority HAPs Summary References Atmospheric Transformation Products of Clean Air Act Title III Hazardous Air Pollutants Introduction Experimental Approaches for the Study of HAP Transformations Hazardous Air Pollutant Transformations Transformations of 33 Urban Air Toxics Transformations of Other Atmospheric Chemicals Summary References Appendix Index

Status of Ambient Measurement Methods for Hazardous Air Pollutants

T he 1990 Clean Air Act Amendments (CAAA) have refocused attention on ambient air toxics. Title III of the CAAA seeks to reduce the public health risks from 189 hazardous air pollutants (HAPs) in ambient air through congressionally mandated riskreduction timetables and goals for HAP emission controls and other requirements (i). Health risk determination and the quantification of reductions in health risks requires knowledge of ambient HAP concentrations and, by extension, the availability of adequate ambient HAP measurement methods. However, a ssessments of the current da tabase of information available on ambient concentrations and transformation products, recently reported in ES&T (2), found a paucity of data needed to conduct adequate health risk assessments for many HAPs (3, 4). For example, the survey showed no ambient data for 74 of the 189 HAPs. The principal reason for the absence of ambient data for many HAPs has been suggested as a lack of suitable ambient air sampling and analysis methods.

Infrared open-path monitoring for studies of atmospheric dispersion of gaseous pollutants

This paper describes an automated FT-IR open path monitoring system that bas been installed at Tinker Air Force Base to monitor volatile organic hydrocarbon (VOC) emissions from the Industrial Waste Treatment Plant. Coordinated FT-IR and gas sampling measurements were performed to provide a basis for the development of plume dispersion calculations to predict emission source strengths and fenceline concentrations. Methods developed to perform this analysis are described.