The coupled chemistry-meteorology model BOLCHEM: An application to air pollution in the Po Valley (Italy) hot spot

We present the model performance of the online air quality model BOLCHEM on seasonal period (year 2010) in an air pollution hot spot located in Northern Italy. Simulated surface concentrations of pollutants are compared with those measured at background AirBase stations. Particulate matter (PM10 and PM2.5) is investigated for winter and summer period. The correlation coefficient R is 0.6 for both pollutants and in both seasons. In the winter period, the PM2.5 ground concentration is underestimated by 6.5% on average, the PM10 ground concentration is underestimated by 7.8% on average. In the summer period, the PM2.5 average ground concentration is underestimated by 0.7% on average, while the PM10 average ground concentration is underestimated by 20% on average. The last result suggests that PM10 from Saharan dust storms is underestimated. Ozone (O) ground concentration is considered only in summer period. It is well reproduced, the correlation coefficient R is 0.7.