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ABSTRACT The primary emission source contributions to fine organic carbon (OC) and fine particulate matter ([PM.sub.2.5]) mass concentrations on a daily basis in Atlanta, GA, are quantified for a summer [...]

Over the period July 1996 April-1998, airborne particle concentrations and chemical composition were measured both inside and outside the new J. Paul Getty Museum outside Los Angeles. The purpose of these experiments was to determine the relationship between the stages of construction and operation of the building and the soiling hazard to the collections. Particular attention was paid to tracking the concentrations of fine black soot particles and mineral dust particles. The time needed to 'air out' the building following construction can be seen from the data collected, as well as the inherent particle removal efficiency of the filters within the building ventilation system, and the effect of entry of the general public into the building. During the period of observation when the building was under construction, weekday coarse dust particle concentrations on occasion reached very high levels (600-1,100 [micro]g [m.sup.-3]; 24 h average), falling to relatively low values averaging 26 [micro]g [m.sup.-3] over weekend periods when construction activity subsided. In March, 1997, with construction largely completed and with the heating, ventilation, and air conditioning (HVAC) system in full operation, indoor coarse dust concentrations fell to 1.7% of those outdoors. Beginning at this time, indoor fine particle concentrations relative to those outdoors declined steadily over a period of about one to two months, reaching levels of 3.9% of those outdoors during the period June 3-December 6, 1997 when construction was completed but before entry of the general public into the building. Thus, the coarse and fine particle removal efficiencies of the building HVAC system absent major indoor sources are at least 98 and 96%, respectively. Following the opening of the museum to the public, indoor particle concentrations increased by approximately 1 [micro]g [m.sup.-3] in each of the coarse dust and fine smoke-size particle size ranges indicating that there is a small but measurable effect due to increased air infiltration as doors are opened and closed more frequently and due to particles shed by the visitors. Indoor particle concentrations inside the new Getty Museum in the presence of the general public are only 3.2 [micro]g [m.sup.-3] of coarse dust and 1.8 [micro]g [m.sup.-3] of fine particles on average over the period January-April, 1998. DOI: 10.1061/(ASCE)0733-9372(2005)131:10(1453) CE Database subject headings: Particles; Facilities; Indoor air pollution; California; Buildings, public.

ABSTRACT Using organic compounds as tracers, a chemical mass balance model was employed to investigate the relationship between the mutagenicity of the urban organic aerosol sources and the mutagenicity of [...]

ABSTRACT Atmospheric particulate matter (PM) samples from 12 sites in southern California, collected as part of the Southern California Children's Health Study (SCCHS), were analyzed using gas chromatography/mass spectrometry (GC/MS) [...]

Six species of trees grown in the northeastern United States, including northern red oak, eastern white pine, paper birch, eastern hemlock, red maple, and balsalm fir are burned to study the particle-phase organic compounds emitted from different types of wood. Detailed speciation of the compounds emitted from the trees is charted.

Aerosol trajectory models for particulate emissions are constructed by researchers at the California Institute of Technology, Pasadena, using mass spectrometry measurements and neural network algorithms. The article details the model-building procedures and illustrates the result with multiple charts, graphs and statistics.

The study measures the pollution emission rates from residential fireplace combustion of wood. The firewood used in the study were from a conifer tree (pine) and oak and eucalyptus trees.

Researchers from the California Institute of Technology used a photochemical airshed model to measure the frequency of exceedence of ozone concentration standards set by the U.S. federal government in the Los Angeles area and how the area will respond to greater emission control.

Using gas chromatography and mass spectrometry, researchers at the California Institute of Technology have worked to identify polar organic compounds in both wood smoke and the ambient atmosphere. Sugar anhydrides mannosan, galactosan and levoglucosan were detected and measured. Multiple charts and diagrams show the concentrations and structure of lignins and sugars found in wood smoke in the San Joaquin Valley in California.

California researchers used human subjects to visually test the presence of black carbon soot deposition on specially prepared samples. The experiment was conducted to find a solution as to how to address the problem of the darkening of valuable art pieces in museums and galleries.

Researchers from the California Institute of Technology developed a dilution source sampling system to measure the chemical distribution of fine particle emissions from motor vehicles.

The chemical composition of particle emissions from cigarettes, meat charbroiling, and wood combustion are examined using cascade impactors and electronic instruments.

Measurements of chemical composition and single particle size are compared with conventional air sampling instruments at a network of monitoring sites in southern California.

Meat cooking is shown to produce a significant percentage of the fine aerosol released into the atmosphere in urban areas.

Particulate matter was studied when paraffin and beeswax candles are burned in a closed chamber. Fine particle samples were collected on both Teflon and quartz fiber filters. An optical particle counter and differential mobility analyser were used to determine particle size. The majority of emissions consist of organic compounds including alkanes alkenes, alkanoic acids, wax esters, cyclohexylalkanes and alkanals.

A two-stage dilution source sampling system was used to quantify gas- and particle-phase tailpipe emissions from late-model medium duty diesel trucks. Emission rates of 52 gas-phase volatile hydrocarbons, 67 semivolatile and 28 particle-phase organic compounds and 26 carbonyls are determined along with fine particle mass and chemical composition.

Unsubstituted polycyclic aromatic compounds (PAC) are the main sources of human cell mutagenicity within airborne fine particulate matter found in Los Angeles, CA. The main types of PACs found in the airborne matter are benzo[a]pyrene, benzo[b]fluoranthene, benzo[ghi]perylene, indeno[1,2,3-cd]pyrene, cyclopental[cd]pyrene, and benzo[k]flouranthene. Other mutagens present in the airborne particulate matter include 6H-benzo[cd]pyren-6-one and 2-nitrofluoranthene.

A Los Angeles roadway tunnel yielded carbon monoxide emissions rates of 130 g L-1 of gasoline-equivalent fuel burned and volatile organic compound (VOC) emissions of 9.1 gL-1. The concentration of organic compounds in the tunnel is consistent with a linear combination of the pollutants over a fairly wide range of about 74-97% vehicle exhaust when VOC emissions composition in the tunnel compared to that of tailpipe emissions source test date and to the composition of additional unburned whole gasoline. The fine particulate emissions within the tunnel are made up mostly of carbonaceous material and ammonium nitrate.

Air sampling studies were conducted on a particularly severe Los Angeles photochemical smog episode to determine the air transport characteristics of 86 non-polar and semipolar aromatic compounds. Data showed a relationship that showed the concentration of the polyaromatic hydrocarbons (PAH) decreasing as the number of aromatic rings increases. Primary aromatics were found to decrease in concentration as sampling proceeds downwind, while nitro-PAH and oxy-PAH followed a reverse trend. The trends are governed by the subsititution in the PAHs during their downwind transport.

An estimation of the emission rate for ammonia from in-use vehicles yielded an average ammonia emission rate of 72 mg/km for vehicles using the three-way catalyst or the three-way catalyst plus oxidizing catalyst equipment. This figure results in an increase in the ammonia emissions from vehicles in the Los Angeles area from 2% prior to the introduction of catalyst-equipped automobiles, to 15%.

The fine particle organic carbon (OC) emmisions to the Los Angeles urban atmosphere appear to have come mostly from the combustion of wood. The fine organic aerosol from wood combustion accounts for 14% of the total OC emissions annually and 30% on winter days. Pine and oak logs are found to produce smoke rich with lignin decomposition products. Resin acids and their thermal alteration products mostly constitute pine smoke. Synthetic log combustion, meanwhile, yields major components of petroleum products combined with traces of sawdust components from which it is made.

The formic (HNO3) and acetic acid (HCl) concentrations obtained in the Southern California atmosphere in 1986 yielded an average of 2.7 to 5.8 ppb and 2.9 to 4.2 ppb, respectively. The concentrations are far above the accepted level of HNO3 and HCL concentrations. Changes in HNCL and HCL concentrations, especially near the coast, depend upon the changes in atmospheric dilution potential which could happen if HNO3 and HCL were produced primarily by major sources of pollution such as motor vehicle traffic.

N-alkanes appear to be the most abundant among the 143 non-aromatic hydrocarbons measured in 36 samples collected during a severe photochemical smog occurrence in Los Angeles, CA. The concentrations of individual low moleculer weight alkenes is reduced during transport across the city in the expected order as they react with the hydroxyl radicals. A substantial decrease in the concentration of petroleum biomarkers, which serve as tracers for particulate organics emitted from vehicle exhaust, was observed between 1982 and 1993.

An eight-month long air monitoring experiment to measure atmospheric hydrofluoric acid in Southern California yielded a long-term average HF concentration between 0.13 microgram/cu.m to 0.22 microgram/cu.m. Of the nine air monotoring sites, two showed significant abrupt rises in HF concentrations, which was surmised to come from an accidental discharge of HF by industrial sources. HF concentration was collected through the tandem filter method.

A comprehensive study aimed at measuring the human cell mutagenicity of particulate air pollution samples gathered in Southern California is presented. The experiment utilized a human cell mutation assay which tested mutagenic activity at the thymidine kinase locus in h1A1v2 cells using a 72-h exposure. The experiment was randomly conducted in 1993 and no seasonal pattern of the mutagenic potency is followed. It is found out that Los Angeles urban air has high concentrations of human cell mutagens.

The dynamic of air circulation in the Yungang Grottoes at Yungang, China was analyzed to determine the effects of air-borne pollutants and particle deposition due to extensive coal mining near the surrounding areas. The 12-month monitoring program indicated the presence of high concentrations of airborne particles. Furthermore, the pollutants are composed mainly of soil dust and carbon-containing particles that are deposited by natural convection inside the caves.

Ambient concentrations of peroxyacetyl nitrate (PAN) and peroxypropionyl nitrate (PPN) in the atmosphere were measured at four urban locations in Los Angeles, CA. Average PAN and PPN concentrations were above the detection limits of 0.010 ppb and 0.016 ppb, respectively. The highest concentration for PAN was 9.9 ppb and 1.5 ppb for PPN. Diurnal and spatial variations in ambient PAN and PPN levels were consistent with those measured previously at other locations.

Ambient concentrations of carbonyls in the range C1-C14 were measured at different locations in Los Angeles, CA, during the 1993 smog season. A total of 23 carbonyls were positively identified and 19 were tentatively identified. The average ambient carbonyl concentration was 22 ppb, with the highest concentration at Azusa, CA, at 29 ppb. The most abundant carbonyls were formaldehyde, acetaldehyde and acetone, which accounted for 24%, 18% and 7% of total carbonyl concentrations, respectively.

The identity and concentration of the individual organic compounds present in both the gas and particle phases during the worst photochemical smog episode in the South Coast Air Basin surrounding Los Angeles, CA, from Sep. 8-9, 1993, were obtained. The data will be useful in future tests of air quality models for the study of organic air pollutant transport and reaction. High concentrations of ozone and nitrogen were observed during the field measurements conducted at a five-station air monitoring network.

A study was conducted on air pollutant transport into the Wielickza Salt Mine World Cultural Heritage Site. Filter-based air sampling techniques were used the concentration and chemical composition of airborne particles. Pollutant gases including SO2 and HNO3 existing in outdoor air are easily and quickly removed from air within the site through deposition to the surfaces.

A model for illustrating the impact of atmospheric aerosols and gases on visibility is presented. The model uses simulated photographs and is driven by data on landscape images generated by artificial satellites as well as digital terrain elevation data. It is shown that the model is suitable for evaluating visibility-related phenomena in rural settings and it has potential for use in treating ground reflectance on a pixel-by-pixel basis in future models.

The bacterial mutagenicity of 15 contributors to organic aerosol emissions in the Los Angeles, CA, area is investigated. To determine the mutant fraction per microgram of organic carbon, the Salmonella typhimurium forward mutation assay is employed. The results, which show all combustion source samples to be mutagenic, are then compared to the mutagenicity of ambient aerosol samples collected in southern California.

The 12C and 14C content of carbonaceous aerosol emmissions collected from major sources in the Los Angelese basin atmosphere is measured. Meanwhile, an emission inventory is developed to predict the concentrations of fine contemporary vs fossil carbon at two ambient sites. Predictions are compared with ambient sample analyses results. The major sources of primary fossil and contemporary carbonaceous aerosol are described.

Gas chromatography and mass spectrometry were used to identify molecular market compounds which indicate the cigarette smoke particles. The experiment, which was conducted in Los Angeles, CA, was able to trace iso- and anteisoalkanes. These alkanes, when compared to n-alkanes found in leaf surface waxes from plants, show a huge jump in concentration when found in tobacco smoke particles. With the data collected, it was estimated that fine cigarette smoke particles make up 1.0% to 1.3% of the fine particle mass concentration.

A study was conducted to obtain baseline air quality data inside and outside the Buddhist cave temples at the Yungang Grottoes in China. The cave temples do not have air purification systems and thus experience rapid soil deposition from airborne air particles. The chemical composition of fine and coarse particles and the concentrations of SO2, NO2, HCl, HNO3 and NH3 were measured to aid future remediation efforts.

The Eulerian photochemical model was used as basis for developing a model on the atmospheric transport and formation of gas-phase toxic organic contaminants. Primary hazardous organic and inorganic pollutants were chosen and analyzed by using an airshed model. A statistical study showed concentrations that were relatively lower than the predicted values. The data also indicated that a mobile source was responsible for the toxic emissions, consisting of aromatic hydrocarbons, aldehydes and 1,3-butadiene.

The dry flux of nitrogen-containing air pollutants such as nitrogen dioxide, nitric acid, peroxyacetyl nitrate and aerosol nitrates is the largest contributor to the deposition of inorganic acids in the Los Angeles area. A mathematical model of the dry deposition flux of these air pollutants is presented using a modified version of the grid-based Caltech airshed model. In addition, the effect of various emission control measures for pollutant dry flux is studied.

The source profile of leaf surfaces of plants needs to be characterized to determine if they are important sources of fine organic aerosol in an urban environment. Green and dead leaves from 62 plant species growing in the Los Angeles area were gathered using the area's actual leaf mass distribution to characterize the source profile of plant leaf surfaces. Gas chromatography and mas spectrometry were used in analyzing the fine particles from the leaf surfaces. Results indicate that higher molecular weight n-alkanes can be use in tracing vegetative detritus in an urban environment.