Technical Bulletin No. 0025: The Effect of Hydrogen Sulfide on Various Surfaces (AQTB)
Industrial stack off gases, containing hydrogen sulfide, can cause darkening of light colored painted surfaces, particularly those covered with paints containing compounds of lead. The attached National Council Technical Bulletin No. 25, first issued in 1965, critically reviews the literature on this subject and summarizes research conducted by the National Council's Rutgers University Air Pollution Project. This investigation was conducted then by Mr. C. J. Gregory, under the direction of Dr. R.M. Manganelli of the Department of Environmental Science. Results obtained indicated that relative humidity had a marked effect on the darkening of basic lead carbonate films by hydrogen sulfide, the darkening effect increasing with the humidity. Coated wood surfaces showed less darkening than ceramics. It was found that fading of darkening surfaces occurred rapidly, particularly on exposure to sunlight, and that the fading rate is highest during the initial period of exposures. Secondary exposures produce considerably less darkening than initial ones, and atmospheric oxygen was not required for fading of paint films which became darkened before drying. These results served to shed further light on problems encountered in interpreting the results obtained with hydrogen sulfide exposure, test surfaces and lead acetate impregnated tapes for measuring ambient levels of hydrogen sulfide.