Air quality predictions of the urban airshed model containing improved advection and chemistry algorithms

Article Abstract:

Air quality should be modeled using the best available numerical methods to be able to identify potential hidden errors and develop a more reliable air quality control design. The use of more accurate algorithms in place of advection and chemistry algorithms in the Urban Airshed Model was tested using the Southern California Air Quality Study episode of Aug. 26-28, 1987 and input data from the California Air Resources Board. Using the implicit-explicit hybrid solver results in somewhat lower afternoon ozone concentrations, noticeably lower afternoon PAN concentrations and significantly lower H2O2 concentrations.

Usage, Forecasts and trends, Algorithms

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Human lymphoblast mutagens in urban airborne particles

Article Abstract:

A bioassay-directed fractionation method proved useful in describing the analysis of an organic extract of Washington, DC airborne particle sample for human cell mutagens. The method allowed the separation of mutagenic constituents into chemically simplified fractions. Less than 20% of the total mutagenicity of the extract was obtained in two fourth-order fractions that contained less than 3% of the total extract mass. Thirteen polycyclic aromatic hydrocarbons were identified that accounted for less than 15% of the mutagenicity of the extract.

Waste Management and Remediation Services, Particulate Pollutants, Washington, D.C., Atmospheric research, Mutagens

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Air quality predictions using a fixed layer-depth vertical structure in the urban airshed model

Article Abstract:

A study aimed at determining air quality through the utilization of a fixed layer-depth vertical structure in the urban airshed model (UAM) is presented. The UAM, which is the only photochemical grid model accepted by the Environmental Protection Agency (EPA) for ozone-related government studies, normally uses a varying layer-depth structure. The results of the experiment show that a fixed layer-depth approach gives a higher hourly concentrations of NO, CO, and VOC in the early morning air than the varying layer-depth approach.

Measuring & controlling devices, not elsewhere classified, Other Measuring and Controlling Device Manufacturing, Services, not elsewhere classified, Other Nonscheduled Air Transportation, Air Gauges, Air Geophysical Services, Models, Aviation, Measuring instruments, Photochemical research, Geophysical surveying

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