The Effect of Various Aerosols on the Response of Guinea Pigs to Sulfur Dioxide

Abstract

Various types of particulate aerosols (1 to 21 mg/m/sup 3/) were tested for significant synergistic effect with SO/sub 2/. Pulmonary resistance increase after 1-h exposure was the measure of irritation. The 2.6 ppM SO/sub 2/ increased resistance 20%; 10 mg/m/sup 3/ NaCl, KCl, and NH/sub 4/SCN aerosols with approx. 2 ppM SO/sub 2/ increased resistance approx. 47, 68 and 103%, respectively. Potentiation ratio (aerosol/SO/sub 2/ alone) was 2.4, 3.3, and 5.0, respectively, which corresponds with solubility of SO/sub 2/ in the particular salt. Soluble Fe, Mn, and V aerosols also potentiated SO/sub 2/, but insoluble salts of Fe and Mn had no effect. These catalytic aerosols worked faster than NaCl possibly because they convert SO/sub 2/ to H/sub 2/SO/sub 4/. Fly ash may have had a beneficial effect, but only statistical manipulations made it significant. Resistance returns to normal after SO/sub 2/ exposure but remains elevated after SO/sub 2/:aerosol exposure (studied for 5 h post-exposure at maximum). Both solubility and conversion to H/sub 2/SO/sub 4/ are responsible for effects noted.