The need to determine whether VOC or NOx control strategies are more effective for attaining ozone (O3) air quality standards has led to a search for observational based methods (OBMs) that uniquely characterize VOC sensitive versus NOx sensitive conditions. Although the OBM concept is very promising, it has not yet been evaluated in experimental studies under controlled conditions. In this project, we are to carry out a series of chamber experiments using a wide range of VOC and NOx levels, and measure the concentrations of each of the species required to evaluate the proposed OBMs in the newly finished EPA chamber facility located at University of California at Riverside. The use of such a state-of-the-art chamber facility provides for reproducible, well-controlled experiments in an analytical laboratory setting in which instrumentation can be carefully controlled and calibrated.
The overall goal of this project is to experimentally validate the OBM concept so that it will provide a direct method for using ambient data to determine the sensitivity of O3 to its precursors in ambient air. In addition, this project will provide an extremely promising approach for performing a rigorous model evaluation because the model must correctly simulate both the O3 concentration and the O3 sensitivity.