Presentation on theme: "An experience on modelling-based assessment of the air quality within the Air Quality Directive framework Ana Isabel Miranda, Isabel Ribeiro, Patrícia."— Presentation transcript:
An experience on modelling-based assessment of the air quality within the Air Quality Directive framework Ana Isabel Miranda, Isabel Ribeiro, Patrícia Fernandes, Alexandra Monteiro, Cristina Monteiro, Carlos Borrego
Concentration Fixed measurements shall be used Combination of fixed measurements and modelling techniques and or indicative measurements may be used Upper assessment threshold Lower assessment threshold Modelling techniques or objective- estimation shall be sufficient SO 2, NO 2, NOx, PM10, PM2,5, Pb, C 6 H 6, CO Those fixed measurements may be supplemented by modelling techniques and/or indicative measurements to provide adequate information on the spatial distribution of the ambient air quality. 2008 Air Quality Directive| air quality assessment Assessment strategy depends on upper and lower assessment thresholds
Exceedances of upper and lower assessment thresholds shall be determined on the basis of concentration during the previous 5 years where sufficient data are available. An assessment threshold shall be deemed to have been exceeded if it has beed exceed during at least 3 separate years out of those previous five years. Assessment for 2010 and 2011 Upper and lower thresholds exceedances for 2006-2010 (5 years period).
Modelling 1. Model application to Portugal (5 km x 5 km), 2010 and 2011 2. Bias correction based on the multiplicative ratio adjustment technique 3. Evaluation (using the DELTA tool when possible) The approach Monitoring 1. Monitoring stations selection and data treatment, for the period 2006-2010 2. Comparison with the upper and lower thresholds, for every pollutant 3. 2010 data treatment for the model evaluation AQ assessment based on a combination of Modelling and Measuring values NO 2, O 3, PM10, PM2.5, SO 2, CO, C 6 H 6.
SUBST an additive correction of the mean bias RAT a multiplicative ratio correction We started to compare… Bias-correction techniques
after BIAS correction, model results have a decrease > 70% on the average systematic error the multiplicative ratio: better correction technique Bias-correction techniques RAT & SUBST synoptic conditions are characterized by a 3-4 day period. (Borrego et al., 2011, Atmospheric Environment) O3O3 PM10
PM10 daily average (2010) Ervedeira monitoring station
NO 2 maximum daily (2010) Ervedeira monitoring station obs RAT04 original
PM10 Annual average 2011 2010 < LAT LAT-UAT > UAT LV
2011 2010 PM10 Daily average < LAT LAT-UAT > UAT LV
Notwithstanding this modelling work no modelling-based report to the Comission was delivered. This work was requested by the Portuguese Agency for the Environment. It was presented to the national agency and to the different regional entities in charge of the air quality assessment in Portugal. Several comments and feedbacks were received. They were very interested and willing to do a cost-benefit analysis of using modelling tools and reducing monitoring stations instead of keeping the maintenance costs they’re facing nowadays. We’re doing 2012 and we’re going to increase spatial resolution. Final comments
But … There is a strong difficulty to trust models and people is afraid of using them, because: they were always working with AQ monitoring networks and that’s what they know they think models are a kind of “monster” and they do not provide a really added value February 2009
Attitude towards models changed and people are much more receptive to their use for air quality assessment. Thanks to FAIRMODE!!!!
www.ua.pt/gemac email@example.com Thank you very much!!!