Abstract
Air samples collected inside and outside buildings of the Univ of Essex, UK, in summer were analyzed for ammonia and acid gases and their particulate salts. The indoor/outdoor ratios for hydrochloric acid, nitric acid, sulfur dioxide, and ammonia were 0.48, 0.22, 0.22, and 10.7, respectively. The average indoor/outdoor ratios of their particulate salts were 0.52 for chloride, 0.43 for nitrate, 0.81 for sulfate, and 0.96 for ammonium. The indoor concentrations correlated well with those outdoors, except for ammonia. Ammonia levels indoors were 2.1-3.5 times higher than those outdoors, indicating that for pollutants with strong indoor sources there is little correlation between indoors and outdoors.