Research Projects

Project at a Glance

Project Status: complete

Report Published July 1975:

Title: Chemical consequences of air quality standards and of control implementation programs: roles of hydrocarbons, oxides of nitrogen and aged smog in the production of photochemical oxidant

Principal Investigator / Author(s): Pitts, James N., Jr.

Contractor: University of California Statewide Air Pollution Research Center

Contract Number: 3-017


Research Program Area: Atmospheric Processes


Abstract:

Construction, testing and validation has been completed of the environmental chamber facility originally conceived and established at the Statewide Air Pollution Research Center, U. C. Riverside, under a joint Air Resources Board-University of California (Project Clean Air) program. Subsequently, this facility which consists of two 6000 liter smog chambers, a 25,000 watt solar simulator, a special high capacity air purification system and a comprehensive array of supporting analytical instrumentation was employed to generate an experimental data base:

* For evaluating te effectiveness of various technical approaches to oxidant control in the California South Coast Air Basin (SCAB), and
* For assessing the impact of incremental control strategies such as new car emission controls, vehicle inspection and maintenance programs, etc.

Development and validation of a "surrogate" mixture of hydrocarbons (HC), carbon monoxide and oxides of nitrogen (NOx) representative of the pollutant mix in the greater Los Angeles area was followed by more than 60 irradiation experiments of 2, 6 or 9-hour duration. These were conducted at concentration levels ranging from those presently observed in the SCAB down to those predicted from the implementation of emission control strategies aimed at meeting State and Federal ambient air quality standards fro non-methane hydrocarbons, NO2 and oxidant.

By combining results from these experiments with approriate analyses of available ambient air quality data, initial assessments have been made of:

* The degree of HC and NOx control required to meet the California Air Quality standard for oxidant in the SCAB, and
* The possible effects on oxidant levels in the SCAB due to various incremental reductions in HC and NOx.

Additional achievements include the discovery that commercial chemi-luminescent NO-NO2 analyzers respond essentially quantitatively in the NO2 mode to a host of nitrogen containing compounds including peroxyacetyl nitrate (PAN) and organic nitrates and nitrites, and the determination of the reactivities of selected aromatic hydrocarbons with the hydroxyl radical, a key intermediate species in photochemical smog.

This report was submitted in fulfillment of Contract No. 3-017 by the Statewide Air Pollution Research Center, University of California, Riverside, under the partial sponsorship of the California Air Resources Board. Work was completed as of June 30, 1974.


 

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