Physiological Effects of Sulfuric Acid Mist on Plant Canopies. Final Report, July 1, 1977-October 31, 1980

摘要

Corn plants 4 to 6 wks old were exposed to low concentrations of sulfuric acid mist droplets. The test plants were grown under greenhouse conditions and tested in a specially designed laminar flow exposure chamber. Tests were performed at 90 exp 0 F and at relative humidities ranging from 40 to 90%. A sulfuric acid particle diameter of 1.7 mu m was used. The particle cloud was generated by a vibrating orifice aerosol generator. Particle diameters and cloud concentrations at plant level were recorded. Particles tagged with uranine dye were used to characterize deposition rates. The particle diameter was found to increase with increasing relative humidity due to the hygroscopic nature of sulfuric acid particles. Plant exposures were continuous for 48 hrs. Specimen leaves were checked for local damage upon completion of the tests. No damage was observed. The particle loading realized during these exposure periods was 10 exp 5 particles/m exp 2 . Additional tests were made by heavily misting corn plants with sulfuric acid solutions of pH 0.5, 1.0, 2.0, and 3.0. Immediate damage occurred with the 0.5 pH mistings. After 48 hrs, damage was observed on the specimens misted with the 1.0 and 2.0 pH solutions. Specimens misted with the 3.0 pH solution showed no visible damage. (ERA citation 06:024370)