Adsorption of toluene onto activated carbons exposed to 100Â ppb ozone

The effects of 100 ppb ozone exposure on the adsorption of 1 ppm toluene on activated carbon are presented for dry (less than 5% RH) and humid (55% RH) air. In dry air, the 10% toluene breakthrough times of granular carbon beds exposed to ozone for 208 days are 17% less than those of unexposed carbon beds. At 55% RH, the corresponding reduction in toluene breakthrough time is 78%. For a humid environment with 100 ppb ozone, filter life would be reduced by more than half compared to the expected life based on tests in the absence of ozone. This degradation is attributed to changes in carbon surface chemistry, surface area, and pore volume that occur with relatively brief exposure to the ozone.