The paper discusses stratification of particulate and volatile organic compound (VOC) pollutants in horizontal flow paint spray booths, as part of a joint U.S. Air Force/EPA research and development program on emissions from paint spray booths. The test program discussed in the paper was designed to characterize the pollutants both within and exiting a typical back-draw booth for which emissions control strategies are being developed. The results of one series of tests indicate that the pollutants, both particulate and VOC, fall to the lower level of the booth or stratify at the level at which they were generated. This might be expected since the densities of typical pollutants found in spray booths are greater than air. The results showed, however, that the concentration of pollutants in the lower level prior to exiting the booth was significantly greater than expected. Data indicated that, for the 16 ft (4.9 m) high booth tested, the concentration at the exit of the booth below the 8 ft (2.4 m) level was 5-25 times greater than the concentration above that level. The importance of these findings is that it might be possible to partition a booth's air flow into two zones, one lean and the other concentrated. The concentrated zone could be directed to a proportionally smaller VOC control system of significantly less capital and operating cost.

"Presented at 14th Annual Army Environmental Research and Development Symposium, Williamsburg, VA, 11/14-16/89." Prepared for U.S. Environmental Agency, Office of Research and Development. "Report for September 1988-October 1989." Includes bibliographical references. Microfiche.