USE OF METAL-FILMS IN STUDYING SULFURIC-ACID DROPLETS IN THE ATMOSPHERE

The technique presented in this paper can be used to detect and measure concentration and size spectra of sulfuric acid droplets to within a very good accuracy. Light extinction measurement through reaction spots is employed to yield the size distribution of sulfuric acid droplets when sampled on a thin metal, film. By photometry through optical microscope or densitometry on electron micrographs from exposed thin metal films, one can calculate the size distribution and concentration of urban particulate sulfuric acid with error less than 12%. Using this technique, the size spectra of acid droplets can be measured accurately regardless of their contact angle or spread on flat surface when sampled. The technique can be used for a very easy estimation of acid concentration when used in places where acid concentration is at a very high level such as acid plants. © 1979 Air & Waste Management Association.