A source apportionment study was carried out to estimate the contribution of motor vehicles to ambient particulate matter (PM) in selected urban areas in the USA. Measurements were performed at seven locations during the period September 7, 2000 through March 9, 2001. Measurements included integrated PM(2.5) and PM(10) concentrations and polycyclic aromatic hydrocarbons (PAHs). Ambient PM(2.5) and PM(10) were apportioned to their local sources using the chemical mass balance (CMB) receptor model and compared with results obtained using scanning electron microscopy (SEM). Results indicate that PM(2.5) components were mainly from combustion sources, including motor vehicles, and secondary species (nitrates and sulfates). PM(10) consisted mainly of geological material, in addition to emissions from combustion sources. The fractional contributions of motor vehicles to ambient PM were estimated to be in the range from 20 to 76% and from 35 to 92% for PM(2.5) and PM(10), respectively.

Resuspended road dust is an important contributor to ambient particulate matter (PM). In areas with significant snow events, the use of wintertime roadway abrasives for traction control can result in increased PM emissions. An alternative control measure is to use chemical deicers prior to a snow event to minimize ice formation and reduce the need for abrasives. Street sweeping is also commonly used to reduce the impact of re-entrained abrasive material after the snow pack on the road has cleared. In this study, we performed roadside measurements of PM flux and instrumented vehicle PM measurements to evaluate the effectiveness of street sweeping to reduce dust re-entrainment and assess the impact of abrasives and deicers on ambient PM near an alpine lake (Lake Tahoe). The results indicate use of liquid deicers contributes less to road dust emissions than abrasives. Street sweeping was found to increase the PM10 re-entrainment rate of the remaining road dust. Emission factors for roads in the study area (a snowy mountain climate) tend to decrease significantly from late Spring to early Summer by as much as a factor of 4.

This study evaluated the effectiveness of expedient sheltering in place in commercial buildings for protection against airborne hazards, as described in U. S. Government guidance to the public. Expedient sheltering measures (plastic sheeting and duct tape) were applied to four different rooms inside commercial buildings. In two rooms, additional tests were performed with ceilings covered, and one room was tested with persons entering and exiting the shelter. Measured air exchange rates for the shelter rooms and literature values for air exchange rates for large buildings were used to determine protection factors for various scenarios. Protection factors were compared for leaky, typical, and tight buildings and shelters under various occupancy times and plume pass- over times for hazardous airborne contaminants. Protection factors ranged from 1.0 to 3960, depending on the conditions. Results reinforced the importance of timing for effective sheltering in place. Sheltering in place can be most beneficial if people enter shelters before the arrival of a hazardous plume and people exit shelters as soon as the plume passes over. However, sheltering in place can be detrimental if people enter or exit shelters too late. CO2 and O-2 concentrations were calculated for a tight shelter with maximum recommended occupancy.

Intensive mass and chemical measurements were performed at roadside locations in Reno, Nevada, and Durham/Research Triangle Park), North Carolina to derive tailpipe, resuspended road dust, and brake-wear emission factors from in-use vehicles. Continuous particulate matter (PM) data were utilized to derive total emission factors while integrated PM data were used to attribute the calculated emission factors to different mechanisms using chemical mass balance receptor modeling and scanning electron microscopy techniques. Resuspended road dust and tailpipe emissions were found to be the dominant mechanisms that contribute significantly to the total PM10 and PM2.5 emission factors, respectively. Small contributions from brake-wear were observed at locations where strong braking occurs, but no tire-wear was seen at any sampling location. PM10 emission rates from light-duty spark ignition (LDSI) vehicles ranged from 40 to 780mg/km, 10 to 70mg/km, and 0 to 80mg/km per vehicle for road dust, tailpipe, and brake-wear, respectively. PM10 emission rates from heavy-duty vehicles ranged from 230 to 7800mg/km, 60 to 570mg/km, and 0 to 610mg/km per vehicle for road dust, tailpipe, and brake-wear, respectively. PM2.5 emission rates from LDSI vehicles ranged from 2 to 25mg/km, 10 to 50mg/km, and 0 to 5mg/km per vehicle for road dust, tailpipe, and brake-wear, respectively. PM2.5 emission rates from heavy-duty vehicles ranged from 15 to 300mg/km, 60 to 480mg/km, and 0 to 15mg/km per vehicle for road dust, tailpipe, and brake-wear, respectively.

Mobile sources are major contributors to observed ambient PM10 and PM2.5 levels. Most PM emission factors have been developed from engine and chassis dynamometer tests, which may not accurately capture emissions from the in-use fleet. In addition to direct tailpipe emissions, there is a lack of real-world emission factors for tire wear, brake wear, and resuspended road dust. To provide data to aid transportation planners implementing strategies to meet stricter ambient PM standards, we have applied a methodology to determine on-road tailpipe, brake-wear, tire-wear, and resuspended road dust emission factors for different classes of in-use vehicles using road-side measurements coupled with a multi-lag regression analysis. Intensive measurements were performed at roadside locations in Reno, Nevada, and Durham/Research Triangle Park (RE), North Carolina. Measurements included, but were not limited to, continuous PM concentrations (PM2.5 and PM10), wind speed, wind direction, and vehicle number, class, and speed. The results indicated that the observed PM concentration at a given time is a function of PM emissions from vehicles passing the sensors at earlier time intervals. In order to calculate mass emission rates using the continuous data, we applied a multi-lag linear regression approach. The output of the multi-lag regression model, the regression coefficients, along with the vehicle specifications and the wind speed/direction at each site were then used to calculate mass emission factors for passenger cars, light duty trucks, buses, dump trucks, and heavy duty diesel trucks. This paper reports methods used to calculate the mass emission factors and the results of this study. For the covering abstract see ITRD E122175.

Many spray painting facility operators have been under pressure to reduce the discharge of volatile organic compound (VOC) emissions to the atmosphere. Some operators have been able to convert their operations to lower VOC containing paints and coatings such as powder coating, waterborne coating, and radiation cured coatings. However, because of the functional requirements for some painted surfaces, acceptable paints with low VOC content may not be available. Consequently, these manufacturers may require the continued use of the higher VOC content paint formulations.The control of emissions from paint booths has been considered not economically viable due to the cost of treating the high volume of polluted air exhausted from these sources. Studies conducted by EPA with various Department of Defense (DoD) services, however, have demonstrated that the cost associated with typical spray booth control system can be significantly reduce through the use of spray booth recirculation. Reductions of exhaust flow rates of up to 90 percent may be possible when using recirculation in properly designed and operated booths without concern for the industrial hygiene or fire safety issues often mentioned when discussing recirculating booths. This paper presents the results of the design and demonstration program of full scale recirculating spray paint booths installed and operated at the U.S. Marine Corps (USMC), Marine Corp Logistics Bases (MCLB) facility at Barstow, CA. It also summarizes the regulatory and safety design issues of recirculation spray booths.

Abstract : The report describes in detail the source testing, construction, and data reduction/analysis activities that comprise the three phases of a technology demonstration program. Phase I consisted of a detailed baseline evaluation of several paint spray booths operated at the Barstow (California). Marine Corps Logistics Base to establish key operating parameters and air toxic emission profiles. This information was used to design a safe recirculation/flow partitioning system for the paint booths involved in the study to efficiently reduce the overall exhaust flow rate. Under Phase II, the necessary booth construction and retrofit modifications were made, and the air pollution control device was installed. The recirculation/flow partitioning system was tested extensively as part of the Phase III effort to ensure that the booths operated in accordance with health and safety standards mandated by the Occupational Safety and Health Administration (OSHA) and the National Fire Protection Association (NFPA).

: Acurex Environmental was contracted by the U.S. EPA to demonstrate an advanced pollution control cost reduction strategy at a U.S. Marine Corps maintenance facility in Barstow, CA. One booth was modified and two new booths were built and manifolded into a single air pollution control device. This SERDP funded project grew out of previous studies by the EPA and DoD to evaluate and develop economic volatile organic compound (VOC) control technologies for painting facilities. This first application of partitioned recirculating booth in a high volume production environment fulfills a stated SERDP goal of transferring promising design concepts into reliable production applications.

Indoor air quality (IAQ) was assessed in homes in an experimental community of single-family dwellings that had been built with materials chosen for low pollutant emission and other modified design features to provide enhanced residential indoor air quality. The IAQ was measured in six of these experimental homes and also tit three conventionally built homes of similar size and price range. The IAQ was assessed shortly after construction before the houses were occupied and again after each of the houses had been occupied for five months.Before occupancy, there were higher levels of airborne particles and of some volatile organic compounds in the conventional homes than in the experimental homes. During occupancy, benzene, ethylbenzene, m- and p-xylene, and o-xylene were all higher in the conventional homes, but dichloromethane, Freon 11, and trichlorethylene were higher in the experimental homes. In the conventional homes, mean level of benzene and chloroform increased, whereas methylchloroform and toluene levels decreased from preoccupancy to occupancy. In the experimental homes, dichloromethane increased, and m- and p-xylene and o-xylene decreased from preoccupancy to occupancy.The results suggest that attached garages, geographical siting, and occupants' activities substantially influenced the IAQ in these homes. The enhanced indoor air quality homes tested in this study were judged to be at least partially effective, with the most obvious sustained IAQ benefits being related to the lack of an attached garage.