A new method to link PM10 concentrations from automatic monitors to the manual gravimetric reference method according to EN12341

Automatic on-line monitors for particulate matter with an aerodynamic diameter up to 10 μm (PM10) (TEOM, beta attenuation) are widely used in air pollution monitoring networks. However, the data cannot always be considered equivalent to the manual gravimetric reference method, which is required in Europe as well as in US for compliance measurements. In this paper, a new method is described to obtain reference equivalent PM10 data series from automatic beta-attenuation monitors based on a limited number of gravimetric PM10 data. The correction procedure was tested with long-term data series from 5 Swiss sites with different exposure characters (urban street canyon, motorway, suburban, rural) and was shown to produce PM10 data, which fulfilled all requirements of EN12341, except at a background site with very low PM10 concentrations. At all sites, including the background site, the correction produced excellent agreement of the corrected monitor data for annual means and a satisfactory match of the number of days exceeding the short time limit value of 50 μg m−3 compared to reference equivalent PM10 data.