National Air Quality Forecast Capability: Nationwide Prediction and Partnerships
Ozone predictions and developmental testing of fine particulate matter (PM2.5) predictions combine the NOAA National Centers for Environmental Prediction (NCEP) operational North American Mesoscale (NAM) weather predictions with inventory based emission estimates from the EPA and chemical processes within the Community Multiscale Air Quality (CMAQ) model. Emissions data were updated using the projections of mobile sources for 2012. Predictions of smoke and dust from dust storms, both of which have highly variable intermittent sources, use the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Routine verification of ozone and developmental aerosol predictions relies on AIRNow compilation of observations from surface monitors, whereas verification of smoke and dust predictions relies on satellite retrievals of smoke and dust column integrals.
Recent testing of PM2.5 predictions is relying on emissions inventories augmented by real time sources from wildfires and dust storms. Testing of PM2.5 predictions continues to exhibit seasonal biases – overprediction in the winter and underprediction in the summer. The current efforts focus on bias correction and development of linkages with global atmospheric composition predictions.
Air quality forecasting in the U.S. relies on a partnership among NOAA, EPA, state and local agencies. Emission and monitoring data are provided by state and local agencies and compiled and maintained by the EPA. NOAA uses these national emissions and monitoring data to develop and evaluate the air quality prediction models and produce operational air quality predictions nationwide. State and local agencies use available data, including NOAA's predictions to issue local forecasts in the form of the Air Quality Index (AQI) for their areas. The EPA sets the AQI scale based on health impact of poor air quality. The EPA facilitates dissemination of AQI forecasts to the public. State and local agencies continue to provide feedback on NOAA air quality predictions. NOAA is developing additional partnership with health agencies and considering ways of evaluating the impact of air quality predictions on public health.