Evaluation and application of OSPM for traffic pollution assessment for a large number of street locations

Evaluation of the Operational Street Pollution Model (OSPM) on a large set of NO2 measurements collected in connection with an epidemiological study on traffic pollution and children cancer is presented. These measurements were conducted in the years 1994e1995 using passive samplers placed at 204 street locations in Copenhagen as well as in some smaller towns and the adjacent rural areas. At each location NO2 concentrations were measured during a period of 6 months with a sampling period of 1 month. The temporal and geographical variation of the model results compared with measurements was evaluated. Although the overall performance was satisfactory, the modelled concentrations were on average slightly higher than the measured concentrations. The agreement was better in the rural areas than in densely trafficked urban areas. Two different methods for estimation of the urban background are compared. It is shown that relatively simple methods for modelling traffic pollution can provide reasonable good results without excessive computing time. This is important when modelling is required for a large number of street locations.