« Previous AbstractOccurrence of priority pollutants in WWTP effluents and Mediterranean coastal waters of Spain    Next AbstractAdjoint sensitivity analysis for a three-dimensional photochemical model: implementation and method comparison »

Environ Sci Technol

Title:		Evaluation of incremental reactivity and its uncertainty in Southern California
Author(s):		Martien PT; Harley RA; Milford JB; Russell AG;
Address:		"Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720-1710, USA"
Journal Title:		Environ Sci Technol
Year:		2003
Volume:		37
Issue:		8
Page Number:		1598 - 1608
DOI:		10.1021/es026174t
ISSN/ISBN:		0013-936X (Print) 0013-936X (Linking)
Abstract:		"The incremental reactivity (IR) and relative incremental reactivity (RIR) of carbon monoxide and 30 individual volatile organic compounds (VOC) were estimated for the South Coast Air Basin using two photochemical air quality models: a 3-D, grid-based model and a vertically resolved trajectory model. Both models include an extended version of the SAPRC99 chemical mechanism. For the 3-D modeling, the decoupled direct method (DDM-3D) was used to assess reactivities. The trajectory model was applied to estimate uncertainties in reactivities due to uncertainties in chemical rate parameters, deposition parameters, and emission rates using Monte Carlo analysis with Latin hypercube sampling. For most VOC, RIRs were found to be consistent in rankings with those produced by Carter using a box model. However, 3-D simulations show that coastal regions, upwind of most of the emissions, have comparatively low IR but higher RIR than predicted by box models for C4-C5 alkenes and carbonyls that initiate the production of HOx radicals. Biogenic VOC emissions were found to have a lower RIR than predicted by box model estimates, because emissions of these VOC were mostly downwind of the areas of primary ozone production. Uncertainties in RIR of individual VOC were found to be dominated by uncertainties in the rate parameters of their primary oxidation reactions. The coefficient of variation (COV) of most RIR values ranged from 20% to 30%, whereas the COV of absolute incremental reactivity ranged from about 30% to 40%. In general, uncertainty and variability both decreased when relative rather than absolute reactivity metrics were used"
Keywords:		Air Pollutants/*analysis California Carbon Monoxide/analysis/*chemistry Forecasting Hydrocarbons/analysis/*chemistry Monte Carlo Method Organic Chemicals/analysis Photochemistry Volatilization;
Notes:		"MedlineMartien, Philip T Harley, Robert A Milford, Jana B Russell, Armistead G eng Evaluation Study Research Support, Non-U.S. Gov't 2003/05/07 Environ Sci Technol. 2003 Apr 15; 37(8):1598-608. doi: 10.1021/es026174t"