Chemical composition of acid precipitation in Pasadena, calif

Research report:Wet-precipitation-only samplers were used to collect acid rainfall in Pasadena, Calif., from February 1976-September 1977. The concentrations of the cations (hydrogen+, ammonium+, potassium+, calcium2+, and magnesium2+) and the anions (chlorine-, nitrate-, and sulfate-) were measured. The chemical composition of Pasadena rainwater was compared with the composition of sea salt, soil dust, fuel oil, flyash, automobile aerosol, cement dust, and gaseous air pollutants. The results showed 35% of the total residue to be due to nitrate from nitrogen oxides, 20% due to sulfate from sulfur dioxide, 4.4% due to ammonium from ammonia, 17.2% due to soil dust, 13.6% due to sea salt aerosol, less than 7% due to fuel oil fly ash, 1.5% due to automobile aerosol, and less than 2% due to cement dust. The most important of these pollutants in Pasadena rainwater are HN03 and NH4. HNO3 is the dominant air pollutant acid in Pasadena, in contrast with the eastern U.S., where HNO3, although increasing in importance, is still less significant than sulfuric acid. (1 graph, 16 references, 2 tables)