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DAILY SIMULATION OF OZONE AND FINE PARTICULATES OVER NEW YORK STATE: FINDINGS AND CHALLENGES
Citation:
HOGREFE, C., W. HAO, K. CIVEROLO, J. Y. KU, G. SISTLA, R. S. GAZA, L. SEDEFIAN, K. L. SCHERE, A. GILLILAND, AND R. MATHUR. DAILY SIMULATION OF OZONE AND FINE PARTICULATES OVER NEW YORK STATE: FINDINGS AND CHALLENGES. JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY. American Meteorological Society, Boston, MA, 46(7):961-979, (2007).
Impact/Purpose:
The objectives of this task include: (1) to continuously evaluate and analyze the forecast results to provide diagnostic information on model performance and inadequacies to guide further evolution and refinements to the CMAQ model, and (2) extending the utility of the daily air quality forecast model data being produced by NOAA's National Weather Service (NWS) as part of a NOAA/EPA collaboration in air quality forecasting, to EPA mission-oriented activities. These objectives include developing and maintaining a long-term database of air quality modeling results (ozone and PM2.5), performing periodic analysis and assessments using the data, and making the air quality database available and accessible to States, Regions, RPO's and others to use as input data for regional/local scale air quality modeling for policy/regulatory purposes.
Description:
This study investigates the potential utility of the application of a photochemical modeling system in providing simultaneous forecasts of ozone (O3) and fine particulate matter (PM2.5) over New York State. To this end, daily simulations from the Community Multiscale Air Quality (CMAQ) model for three extended time periods during 2004 and 2005 have been performed and predictions were compared to observations of ozone and total and speciated PM2.5. Model performance for 8-hr daily maximum O3 was found to be similar to other forecasting systems and to be better than that for 24-hr average total PM2.5. Both pollutants exhibited no seasonal differences in model performance. CMAQ simulations successfully captured the urban/rural and seasonal differences evident in observed total and speciated PM2.5 concentrations. However, total PM2.5 mass was strongly overestimated in the New York City metropolitan area, and further analysis of speciated observations and model predictions showed that most of this overprediction stems from organic aerosols and crustal material. An analysis of hourly speciated data measured in Bronx County, New York, suggests that a combination of uncertainties in vertical mixing, magnitude and temporal allocation of emissions, and deposition processes are all possible contributors to this overprediction in the complex urban area.