CHIMERE air quality forecasts : results during Pays de la Loire summer 2004 experiment and end-user point of view ! Arnaud REBOURS - AIR PAYS DE LA LOIRE ! ACRI-ST 1st CHIMERE workshop 21, 22 March Palaiseau France

French air pollution control networks organization Air Pays de la Loire NANTES PARIS Pays de la Loire region : inhab.; km2 ! 2 missions : air quality survey and information

Air Pays de la Loire ! Territorial cover La Roche/Y Cholet Laval St-Nazaire ! 10 survey zones ! 50 survey sites ! continuous control ! 15 minutes time resolution Nantes Le Mans Angers

! Modelisation tools ! Regional scale : Calgrid 10 august 2003 ! Street scale : OSPM NO2 - Nantes 2001 ! Industrial scale : Calpuff 11 feb refinery Scenario mode

CONTEXT ! 18 june 2004 french regulation : during pollution episodes, air quality public information is based on observations or on risk of exceedings of thresholds -> necessity of forecasting development ! Period : 13 july - 12 october 2004 ! Summer 2004 experiment : operation by ACRI-ST of an air quality forecast system based on MM5- CHIMERE over the Pays de la Loire region

LOCAL FORECASTING PLATFORM ! 2 zones : Great West area (15 km) and Pays de la Loire region (5 km) GWEST 15 km APL 5 km ! 2 pollutants : O3 and NO2 ! 4 daily outputs : D-1, D, D+1 and D+2 ! hourly time step

InputsOutputs Emissions inventory : 5km and 50 km Meteorological data : NCEP Continental chemistry : PREV AIR 2D Data Platform publication Maps Forecast computer : MM5-CHIMERE Interface computer Job programmer LOCAL FORECASTING PLATFORM

Meteo- rology pollution zone pollutant 4 days forecasts WEB INTERFACE

FORECAST PRELIMINARY RESULTS ! Observation data : 20 survey sites ! Statistical criteria : BIAS and NMSE

FORECAST PRELIMINARY RESULTS ozone

FORECAST PRELIMINARY RESULTS ozone

FORECAST PRELIMINARY RESULTS ozone

FORECAST PRELIMINARY RESULTS ozone

FORECAST PRELIMINARY RESULTS NO2

FORECAST PRELIMINARY RESULTS NO2

POST-PROCESSING ON FORECASTS ! Vigilance maps improve public information ! 13 alert zones :5 departments (counties), 7 agglomerations, 1 industrial area ! 3 symbolic colours : green, orange, red calculation ! 2 ways : forecasting observation validation

POST-PROCESSING ON FORECASTS ! Vigilance maps improve public information Forecasted exceeding Procedure activating conditions - agglomerations : 2 sites - departments : 2 agglomerations or 30% of the zone

communiqués (fax and ) web site : POST-PROCESSING ON FORECASTS ! Vigilance maps improve public information

POST-PROCESSING ON FORECASTS ! Air quality index prediction,...)= Annual maps ! Exceedings evaluations of limit values, quality objectives and target values

CONCLUSION ! Forecast results are acceptable for ozone and better than continental modeled values for NO2 ! Local platform brings helps to diagnosis : background pollution in the great west of France, influence of Paris pollution, meteorological forecast parameters ! Post processing improve air quality information in connection with alert system or daily pollution

PROSPECTS ! Integration of detailed emission calculations (AIREMIS) ! Integration of meteorological and pollution vertical profiles ! Local platform should be operated by Air Pays de la Loire during summer 2005 ! Statistical adaptation of modeled results with observations for D-1 and D steps

FORECAST PRELIMINARY RESULTS ozone

FORECAST PRELIMINARY RESULTS NO2 ! Emissions inventory comparison