| Popis: |
Fine and coarse mode aerosol particles were collected for 16 months at three rural sites spanning a 600 km length of the Ohio River Valley. Particle mass and concentrations of 15 elements are reported as means, quarterly means and parameters of the frequency distributions. Results are also presented from analysis of two regional episodes: a high sulfur event and a forest fire. Fine particle mass and elemental composition are remarkably uniform from site to site. Sulfur is the predominant element in the fine particles, and shows a marked annual cycle. The mean ratio of potassium to silicon in the fine particles is 8 times the value found in crustal materials and in the coarse aerosol. Factor analysis of element concentrations indicates three clusters throughout the year: 1. (1) coarse particle crustal elements; 2. (2) fine particle sulfur and selenium and 3. (3) fine particle manganese, iron and zinc. A high temperature, crystalline alumino-silicate characteristic of combustion was identified in the aerosol particles. |
