John S. Kinsey

Polycyclic aromatic hydrocarbon size distributions in aerosols from appliances of residential wood combustion as determined by direct thermal desorption—GC/MS

In this work, a direct thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) method is implemented to determine the polycyclic aromatic hydrocarbon (PAH) composition in size-segregated aerosols from residential wood combustion. Six combustion tests are performed with two commonly burned wood fuel species, Douglas-fir (Pseudotsuga sp.) and white oak (Quercus sp.). Atmospheric dilution and cooling of the aerosol plume are simulated in a newly designed wind tunnel, and the resulting aerosols are size classified with an electrical low-pressure impactor (ELPI). ELPI stage data speciated by TD/GC/MS were inverted and modeled using a log normal distribution function. Gravimetrically determined PM2.5 (fine particles with aerodynamic diameters ) emission rates (2.3–) corroborate to matrix-corrected ELPI mass measurements of stages 1–8 (2.7–). Fuel moisture content linearly correlates (r2=0.986) to the PM2.5 mass geometric mean diameter (dg). Combustion efficiency (CO2/CO) and temperature, O2 levels, and gas dilution temperature affect particle size distributions; dg ranges from 313 to , indicating an accumulation mode. Reconstruction and summation of inverted ELPI data allow for the quantification of 27 individual PAHs (and clusters of structural PAH isomers); PAHs characterize between 0.01 and of the PM2.5 mass. Benzo[a]pyrene predominates the PAH emissions. PAH size allocations (dg are out of phase with PM2.5 mass ones and shifted to finer da. Higher and lower MW PAHs preferentially segregate to fine and coarse da in that order. The ultrafine mode contains on average greater than 80% of the total measured particle number concentration. Values of dg for particulate matter surface area distributions are between 120 and . For these tests, PAH mass and PM surface area linearly correlate (r2⩾0.913). Application of a simple function to consider adsorption and absorption mechanisms makes apparent that (a) surface and core compositions of PAH of identical MW groups vary with combustion and (b) preferential surface adsorption of lower MW PAH is possible.

Traffic and Meteorological Impacts on Near-Road Air Quality: Summary of Methods and Trends from the Raleigh Near- Road Study

Abstract A growing number of epidemiological studies conducted worldwide suggest an increase in the occurrence of adverse health effects in populations living, working, or going to school near major roadways. A study was designed to assess traffic emissions impacts on air quality and particle toxicity near a heavily traveled highway. In an attempt to describe the complex mixture of pollutants and atmospheric transport mechanisms affecting pollutant dispersion in this near-highway environment, several real-time and time-integrated sampling devices measured air quality concentrations at multiple distances and heights from the road. Pollutants analyzed included U.S. Environmental Protection Agency (EPA)-regulated gases, particulate matter (coarse, fine, and ultrafine), and air toxics. Pollutant measurements were synchronized with real-time traffic and meteorological monitoring devices to provide continuous and integrated assessments of the variation of near-road air pollutant concentrations and particle toxicity with changing traffic and environmental conditions, as well as distance from the road. Measurement results demonstrated the temporal and spatial impact of traffic emissions on near-road air quality. The distribution of mobile source emitted gas and particulate pollutants under all wind and traffic conditions indicated a higher proportion of elevated concentrations near the road, suggesting elevated exposures for populations spending significant amounts of time in this microenvironment. Diurnal variations in pollutant concentrations also demonstrated the impact of traffic activity and meteorology on near-road air quality. Time-resolved measurements of multiple pollutants demonstrated that traffic emissions produced a complex mixture of criteria and air toxic pollutants in this microenvironment. These results provide a foundation for future assessments of these data to identify the relationship of traffic activity and meteorology on air quality concentrations and population exposures.

Particulate Emissions from Construction Activities

Abstract Although it has long been recognized that road and building construction activity constitutes an important source of particulate matter (PM) emissions throughout the United States, until recently only limited research has been directed to its characterization. This paper presents the results of PM10 and PM2.5 (particles ≤10 μm and ≤2.5 μm in aerodynamic diameter, respectively) emission factor development from the onsite testing of component operations at actual construction sites during the period 1998 –2001. Much of the testing effort was directed at earthmoving operations with scrapers, because earthmoving is the most important contributor of PM emissions across the construction industry. Other sources tested were truck loading and dumping of crushed rock and mud and dirt carryout from construction site access points onto adjacent public paved roads. Also tested were the effects of watering for control of scraper travel routes and the use of paved and graveled aprons at construction site access points for reducing mud and dirt carryout. The PM10 emissions from earthmoving were found to be up to an order of magnitude greater than predicted by AP-42 emission factors drawn from other industries. As expected, the observed PM2.5:PM10 emission factor ratios reflected the relative importance of the vehicle exhaust and the resuspended dust components of each type of construction activity. An unexpected finding was that PM2.5 emissions from mud and dirt carryout were much less than anticipated. Finally, the control efficiency of watering of scraper travel routes was found to closely follow a bilinear moisture model.

Determination of the emissions from an aircraft auxiliary power unit (APU) during the Alternative Aviation Fuel Experiment (AAFEX)

The emissions from a Garrett-AiResearch (now Honeywell) Model GTCP85–98CK auxiliary power unit (APU) were determined as part of the National Aeronautics and Space Administrations (NASAs) Alternative Aviation Fuel Experiment (AAFEX) using both JP-8 and a coal-derived Fischer Tropsch fuel (FT-2). Measurements were conducted by multiple research organizations for sulfur dioxide (SO2), total hydrocarbons (THC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), speciated gas-phase emissions, particulate matter (PM) mass and number, black carbon, and speciated PM. In addition, particle size distribution (PSD), number-based geometric mean particle diameter (GMD), and smoke number were also determined from the data collected. The results of the research showed PM mass emission indices (EIs) in the range of 20 to 700 mg/kg fuel and PM number EIs ranging from 0.5 × 1015 to 5 × 1015 particles/kg fuel depending on engine load and fuel type. In addition, significant reductions in both the SO2 and PM EIs were observed for the use of the FT fuel. These reductions were on the order of ∼90% for SO2 and particle mass EIs and ∼60% for the particle number EI, with similar decreases observed for black carbon. Also, the size of the particles generated by JP-8 combustion are noticeably larger than those emitted by the APU burning the FT fuel with the geometric mean diameters ranging from 20 to 50 nm depending on engine load and fuel type. Finally, both particle-bound sulfate and organics were reduced during FT-2 combustion. The PM sulfate was reduced by nearly 100% due to lack of sulfur in the fuel, with the PM organics reduced by a factor of ∼5 as compared with JP-8. Implications: The results of this research show that APUs can be, depending on the level of fuel usage, an important source of air pollutant emissions at major airports in urban areas. Substantial decreases in emissions can also be achieved through the use of Fischer Tropsch (FT) fuel. Based on these results, the use of FT fuel could be a viable future control strategy for both gas- and particle-phase air pollutants. Supplemental Data: Supplemental data is available for this article. Go to the publishers online edition of the Journal of the Air & Waste Management Association for information on the test participants, description of the APU, fuel composition, sampling probes and instrumentation, test matrix, benzene to formaldehyde ratios, and speciated emissions by particle size.

On-Road Facility to Measure and Characterize Emissions from Heavy-Duty Diesel Vehicles

Abstract In response to lingering concerns about the utility of dynamometer data for mobile source emissions modeling, the U.S. Environmental Protection Agency (EPA) has constructed an on-road test facility to characterize the real-world emissions of heavy-duty trucks. The facility was designed to effectively demonstrate the full range of vehicle operation and to measure the emissions produced. Since it began operation, the facility has been continuously upgraded to incorporate state-of-the-art technology. Its potential uses include collecting modal emissions data, validating dynamometer test parameters and results, and demonstrating new emission control technologies.

Characterization of the fugitive particulate emissions from construction mud/dirt carryout

Abstract Although the fugitive dust associated with construction mud/dirt carryout can represent a substantial portion of the particulate matter (PM) emissions inventory in non-attainment areas, it has not been well characterized by direct sampling methods. In this paper, a research program is described that directly determined both PM10 and PM2.5 (particles ≤10 and 2.5 μm in classical aerodynamic diameter, respectively) emission factors for mud/dirt carryout from a major construction project located in metropolitan Kansas City, MO. The program also assessed the contribution of automotive emissions to the total PM2.5 burden and determined the baseline emissions from the test road. As part of the study, both time-integrated and continuous exposure-profiling methods were used to assess the PM emissions, including particle size and elemental composition. This research resulted in overall PM10 and PM2.5 emission factors of 6 and 0.2 g/vehicle, respectively. Although PM10 is within the range of prior U.S. Environmental Protection Agency (EPA) guidance, the PM2.5 emission factor is far lower than previous estimates published by EPA. In addition, based on both the particle size and chemical data obtained in the study, a major portion of the PM2.5 emissions appears to be attributable to automotive exhaust from light-duty, gasoline-powered vehicles and not to the fugitive dust associated with re-entrained mud/dirt carryout.