Michael W. Holdren

INTER-URBAN COMPARISON OF AMBIENT VOLATILE ORGANIC COMPOUND CONCENTRATIONS IN U.S. CITIES

Comparison of data from various cities in the United States concerning the levels of volatile organic compounds in the air and which ones perpetuate a significant health risk are given. It is noted that there are no federal standards for many of the compounds listed and that interpretation of findings can create problems and should be used with caution. It is also noted that while automobile exhaust emissions are not the only source of these compounds, they are the dominant source.

Applicability of canisters for sample storage in the determination of hazardous air pollutants

This paper evaluates the applicability of canisters for storage of air samples containing volatile organic compounds listed among the 189 hazardous air pollutants (HAPs) in the 1990 U.S. Clean Air Act Amendments. Nearly 100 HAPs have sufficient vapor pressure to be considered volatile compounds. Of those volatile organic HAPs, 52 have been tested previously for stability during storage in canisters. The published HAP stability studies are reviewed, illustrating that for most of the 52 HAPs tested, canisters are an effective sample storage approach. However, the published stability studies used a variety of canister types and test procedures, and generally considered only a few compounds in a very small set of canisters. A comparison of chemical and physical properties of the HAPs has also been conducted, to evaluate the applicability of canister sampling for other HAPs, for which canister stability testing has never been conducted. Of 45 volatile HAPs never tested in canisters, this comparison identifies nine for which canisters should be effective, and 17 for which canisters are not likely to be effective. For the other 19 HAPs, no clear decision can be reached on the likely applicability of air sample storage in canisters.

Peroxyacetyl nitrate solubility and decomposition rate in acidic water

Abstract Recent investigations have shown that peroxyacetyl nitrate (PAN) is soluble in acidic water samples. A Henrys law constant of 5 ± 1 M atm −1 has been determined. PAN decays in a first order manner in these solutions, with k = 7.0 ± 0.3 × 10 −3 min −1 at 5°C. The principal anionic product was nitrate ion.

The ubiquity of peroxyacetyl nitrate in the continental boundary layer

Abstract Although peroxyacetyl nitrate (PAN) is generally considered to be an urban pollutant of relatively short lifetime, it has been measured at significant concentrations (> 0.1 ppb) in rural and remote locations and during all seasons. This communication reports the results of several recent measurement programs and speculates on the importance of these observations.

Field-compatible calibration procedure for peroxyacetyl nitrate.

A field compatible calibration procedure for generating ppb levels of peroxyacetyl nitrate is presented. The procedure is based upon the condensed-phase synthesis of peroxyacetyl nitrate (PAN) in octane solution. These solutions show PAN loss of <4% month/sup -1/ when stored at -20/sup 0/C. The dilute PAN solutions are injected directly into known volumes of air in Tedlar bags to obtain ppb gas-phase concentrations. The addition of low levels of NO/sub 2/ into the bags stabilizes PAN in the gas phase.

Variability of hazardous air pollutants in an urban area

Abstract The variability of hazardous air pollutants (HAPs) is an important factor in determining human exposure to such chemicals, and in designing HAP measurement programs. This study has investigated the factors which contribute to HAP variability in an urban area. Six measurement sites separated by up to 12 km collected data with 3 h time resolution to examine spatial variability within neighborhoods and between neighborhoods. The measurements were made in Columbus, OH. The 3 h results also were used to study temporal variability, and duplicate samples collected at each site were used to determine the component of variability attributable to the measurement process. Hourly samples collected over 10 days at one site provided further insight into the temporal resolution needed to capture short-term peak concentrations. Measurements at the 6 spatial sites focused on 78 chemicals. Twenty-three of these species were found in at least 95% of the 3 h samples, and 39 chemicals were present at least 60% of the time. The relative standard deviations for most of these 39 frequently detected chemicals was 1.0 or lower. Variability was segmented into temporal, spatial, and measurement components. Temporal variation was the major contributor to HAP variability for 19 of the 39 frequently detected compounds, based on the 3 h data. Measurement imprecision contributed less than 25% for most of the volatile organic species, but 30% or more of the variability for carbonyl compounds, trace elements, and particle-bound extractable organic mass. Interestingly, the spatial component contributed less than 20% of the total variability for all the chemicals except sulfur. Based on the data with hourly resolution, peak to median ratios (hourly peak to 24 h median) averaged between 2 and 4 for most of the volatile organic compounds, but there were two species with peak to median ratios of about 10.

Development of emission factors for polypropylene processing

Emission factors for selected volatile organic and particulate emissions were developed over a range of temperatures during extrusion of polyethylene resins. A pilot scale extruder was used. Polymer melt temperatures ranged from 500 °F to 600 °F for low density polyethylene (LDPE), 355 °F to 500 °F for linear low density polyethylene (LLDPE), and 380 °F to 430 °F for high density polyethylene (HOPE). An emission factor was calculated for each substance measured and reported as pounds released to the atmosphere per million pounds of polymer processed (ppm[wt/wt]). Based on production volumes, these emission factors can be used by processors to estimate emissions from polyethylene extrusion operations that are similar to the conditions used in this study.

Probing emissions of military cargo aircraft: description of a joint field measurement Strategic Environmental Research and Development Program.

Abstract To develop effective air quality control strategies for military air bases, there is a need to accurately quantify these emissions. In support of the Strategic Environmental Research and Development Program project, the particulate matter (PM) and gaseous emissions from two T56 engines on a parked C-130 aircraft were characterized at the Kentucky Air National Guard base in Louisville, KY. Conventional and research-grade instrumentation and methodology were used in the field campaign during the first week of October 2005. Particulate emissions were sampled at the engine exit plane and at 15 m downstream. In addition, remote sensing of the gaseous species was performed via spectroscopic techniques at 5 and 15 m downstream of the engine exit. It was found that PM mass and number concentrations measured at 15-m downstream locations, after dilution-correction generally agreed well with those measured at the engine exhaust plane; however, higher variations were observed in the far-field after natural dilution of the downstream measurements was accounted for. Using carbon dioxide-normalized data we demonstrated that gas species measurements by extractive and remote sensing techniques agreed reasonably well.

Sampling and Analysis of Volatile Organic Compounds Evolved During Thermal Processing of Acrylonitrile Butadiene Styrene Composite Resins

Abstract The evaluation of emissions of volatile organic compounds (VOCs) during processing of resins is of interest to resin manufacturers and resin processors. An accurate estimate of the VOCs emitted from resin processing has been difficult due to the wide variation in processing facilities. This study was designed to estimate the emissions in terms of mass of emitted VOC per mass of resin processed. A collection and analysis method was developed and validated for the determination of VOCs present in the emissions of thermally processed acrylonitrile butadiene styrene (ABS) resins. Four composite resins were blended from automotive, general molding, pipe, and refrigeration grade ABS resins obtained from the manufacturers. Emission samples were collected in evacuated 6-L Summa canisters and then analyzed using gas chromatography/flame ionization detection/mass selective detection (GC/FID/MSD). Levels were determined for nine target analytes detected in canister samples, and for total VOCs detected by an...

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