SULFUR-DIOXIDE, HYDROGEN-SULFIDE, TOTAL REDUCED SULFUR, CHLORINATED HYDROCARBONS AND PHOTOCHEMICAL OXIDANTS IN SOUTHERN CALIFORNIA MUSEUMS

Indoor and outdoor concentrations of the air pollutants ozone, NO2, SO2, H2S, total reduced sulfur (TRS), peroxyacetyl nitrate (PAN), methyl chloroform and tetrachloroethylene, have been measured at three southern California museums. Indoor maxima were 175 ppb for NO2, 77 ppb for O3, 0.7 ppb for PAN, 1.2 ppb for C2Cl4, > 6.3 ppb for CH3CCl3, 2.5 ppb for SO2, 1.4 ppb for TRS, and 46 ppt for H2S. Indoor levels and indoor/outdoor (I/O) ratios for the chlorinated hydrocarbons pointed out to indoor sources. Outdoor and indoor levels of SO2 and TRS were low at all three museums, but I/O ratios for SO2 were high and averaged 0.89. H2S concentrations were low, 16-46 ppt at one museum and less than 6 ppt at the other two museums. I/O ratios for the air pollutants with outdoor sources (ozone, PAN and NO2) showed substantial variations, from low values of 0.02-0.33 at locations without influx of outdoor air to high values of 0.85-0.88 at locations experiencing high influx of outdoor air. Of the 10 institutions we have surveyed in southern California to date, eight exhibit high I/O ratios, e.g. 0.60-1.00 for PAN. Of the four museums surveyed that were equipped with HVAC and chemical filtration, only two yielded the expected low I/O ratios.