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The chemical composition and emission strength of fine particle emissions from the combined exhaust of a vented natural gas-fired residential space heater and a water heater are studied using gas chromatogrpahy and mass spectrometry techniques. Results indicate that exhaust emissions from the combined heaters contain such organic compounds as n-alkanes, n-alkanoic acids, PAH, oxy-PAH, aza arenes and thia arenes and that the amounts of PAH and oxy-PAH released into the atmosphere are comparable to those emitted by diesel and other automobiles.

High resolution gas chromatography was used to measure the properties of urban organic aerosols. Mathematical models were constructed using the data garnered through this method. Results indicate that there is substantial agreement between nonpolar organics but ambient concentrations of fine acidic organic aerosols were grossly underpredicted. The models indicate that 18 to 27% of the organic aerosols in the Los Angeles region may be secondary.

The organic constituents of fine particulate matter such as road dust, brake lining wear and tire attrition particles were investigated utilizing gas chromatography/mass spectrometry. Molecular tracer methods were used to determine the composition of paved road dust. Results showed that paved road dust is a combination of particles from urban sources like vehicle exhaust and garden soil. Moreover, the sample was found to be chemically similar to atmospheric aerosol.

The transport and reactions of organic gas emissions in the atmosphere was modeled using a Eulerian photochemical approach. The model was used to predict the Los Angeles, CA, emissions for the period of Aug 27-29, 1987. The results showed that the model could accurately predict the observed concentrations of ethene, monalkylbenzenes and formaldehyde, while other organic species were underpredicted. However, model performance could be improved by scaling up on-road vehicle hot exhaust emissions of organic gases and by revising some chemical composition profiles for the organic gas emissions.

The determination of tracer compounds by investigating the effect of fine organic particulate exhaust emissions to the Los Angeles atmosphere is discussed. Gas chromatography/mass spectrometry were used in the analysis of the chemical composition of gasoline and diesel powered vehicle exhaust aerosol samples. It was found that fossil petroleum markers, readily identified in the emissions, can be used as suitable tracer compounds.

The development of an improved image processing based visibility model and its application to regional haze conditions are discussed. Sky color and its intensity were theoretically calculated and related by photographic data. Comparison against radiometer measurements and point by point comparison of actual photographs and synthetic images were used to validate the model. The utility of the model for providing visibiity to pollutant loadings was demonstrated.

The application of an updated CIT photochemical airshed model to a Southern California Air Quality Study intensive monitoring period is discussed. Ozone concentrations were predicted using measured meteorological parameters, measured initial and boundary conditions and the government-prepared official emission imventory. Results indicate that in recent years, the estimation of organic gas emissions in Los Angeles have been understated.

The utilization of new and updated information to improve the accuracy and level of chemical detail of a review of speciation profiles for organic gas emissions is discussed. The photochemical reactivity of the revised speciation profiles are compared with the corresponding speciation profiles in the official emission inventory. The organic gas emission inventory for the Los Angeles area is recomputed with this information. It was found that the emissions of unburned gasoline relative to combustion-derived hydrocarbons are understated in the Los Angeles area.

Particulate nitrate and nitric acid deposition in the Los Angeles, CA, area were studied for temporal and spatial trends. Nitric acid concentrations averaged only 0.3 micrograms per cubic meter in the San Nicolas Island air basin. Inorganic nitrate deposition exceeded 109 micrograms per cubic meter in Rubidoux, CA. Additional observations of this study agreed with previous air quality models, and the methodology of the study is discussed.

A study was conducted to identify the reaction products that form when artists' colorants are exposed to gas-phase nitric acid. The reaction products of nine colorants were studied by using chemical ionization mass spectrometry. The chloride cationic dye basic fuchsin and the carbinol pararosaniline were the most nitric acid-fugitive colorants. Both of these were derivatives of triphenylmethane. The remaining colorants produced small amounts of oxidation. These results can be applied to the analysis of the effect of atmospheric nitric acid on museum collections.

Aerosol time-of-flight mass spectrometry (ATOFMS) is capable of measuring the sizes and chemical compositions of individual polydisperse aerosol particles in real time. A qualitative estimate of the particle composition is acquired in the form of a mass spectrum that must be subsequently interpreted in order to draw conclusions regarding atmospheric, relevance. The actual problem involves developing a calibration that allows the mass spectral data to be transformed into estimates of the composition of the atmospheric aerosol. A properly calibrated ATOFMS system should be able to quantitatively determine atmospheric concentrations of various species. Ideally, it would be able to accomplish this more rapidly, accurately, with higher size and time resolution, and at a far lower marginal cost than the manual sampling methods that are currently employed. Attempts have already been made at using ATOFMS and similar techniques to extract the bulk chemical species concentration present in an ensemble of particles. This study represents the use of a multivariate calibration method, two-dimensional partial least-squares analysis, for calibrating single-particle mass spectral data. The method presented here is far less labor-intensive than the univariate methods attempted to date and allows for less observer bias. Because of the labor savings, this is also the most comprehensive calibration performed to date, resulting in the quantification of 44 different chemical species.