Seasonal modelling assessment of ozone sensitivity to precursors in northern Italy

One of the major thrusts of model application is to assess the relative importance of NOx and VOC controls in reducing ozone levels; in this paper, the long-term assessment of ozone exposure and sensitivity to NOx and VOC emissions, in terms of mean values and seasonal indicators, has been investigated over a complex domain in northern Italy, including Milan metropolitan area. The analysis has been carried out comparing eight seasonal simulations performed by the Gas Aerosol Modelling Evaluation System (GAMES): the summer season 1996, selected as reference case, and seven simulations obtained feeding the modelling system with increasing or decreasing precursor emissions. The study allowed to: (1) recognize the photochemical regimes of the domain, (2) investigate the influence of Milan plume in ozone production and accumulation processes over neighbouring suburban and rural areas, (3) identify parts of the domain where local emission reduction strategies are not effective, (4) provide a support system for local Air Quality Authorities in selecting effective emission reduction strategies.