Measurement of the specific surface area and particle size distribution of atmospheric aerosol reference materials

The investigation of the surface area of atmospheric aerosols is important as it provides a metric for their adverse health effects; however, few previous studies have considered this parameter. This study investigated the BET specific surface areas of aerosols, as well as the particle size distributions and chemical compositions of the three commercially available atmospheric aerosol reference materials; namely SRM1649a, CRM#28 and CRM#8. SRM1649a and CRM#28 consist mainly of coarse particles, while CRM#8 consists mainly of fine (or ultrafine) particles. The specific surface areas of the reference materials were; SRM1649a: 2.0±0.2m²g^-1, CRM#28: 2.0±0.2m²g^-1 and CRM#8: 35.7±5.3m²g^-1. CRM#8 had a higher value for the specific surface area. The specific surface area for CRM#8 was likely to be associated with the characteristics of diesel particulate matters. When the estimation of specific surface area of aerosol particles is based on the assumption that all particles are spherical and not aggregates/agglomerates, using particle number and mass distribution, the estimated value is likely to be significantly lower than the actual value, in particular, for fine or ultrafine particles. The actual specific surface area of atmospheric aerosols should be measured to avoid the underestimation of their adverse health effects.