INVESTIGATION OF ENVIRONMENTAL AEROSOL BY ATOMIC-FORCE MICROSCOPY

We have been successful in imaging environmental aerosol particles by atomic force microscopy (AFM). The material under investigation was ru ral aerosol collected with an 11-stage low-pressure impactor. On polye ster substrates, particles smaller than 20 mn could be observed. From the AFM data, size distributions have been determined and compared wit h the expected performance of the used cascade impactor. The mean part icle sizes (aerodynamic equivalent diameter) were in good agreement wi th the values derived from AFM experiments. Moreover, we have obtained atomically resolved images on single aerosol particles; to our knowle dge, this is the first time this has been accomplished on environmenta l samples. AFM images of larger impactor stages showed good agreement with light and electron microscopy micrographs.