Abstract
Windscreen for the passive sampler plays critical role to obtain constant sampling rates. To minimize variation of the sampling rates, smaller pore size of the windscreen would show better performance. However, larger pore size of the windscreen is preferable in the view point of analytical perspective since the larger pore size increases the sampling rate. Therefore, there is a tradeoff between the sampling rate and variation. Several filters having different pore size(11 , 20 , 60 , ㎛㎛ 100 , 140 and 180 ) were tested in this study to ㎛㎛㎛ investigate the effects of pore size to the increase of the sampling rate and its' variation. Filters were replaced with the windscreen of the 3M OVM #3500 badge for this study. These modified passive samplers installed with various windscreen were tested in the environmental chamber against benzene, toluene and o-xylene. 1. Same level of sampling rate were shown for all the filters with no apparent air movement (<0.25m/s) in the chamber during sampling period. 2. Both the random variation and magnitude of the sampling rates were increased as the pore size of the windscreen increased. Passive samplers installed the windscreen of the pore size of 11 and 20 showed relatively ㎛ small variation (<5% RSD). 3. Sampling rates with the windscreen of the pore size of 11 were 36.8cc/min for benzene, 32.6cc/min for toluene, ㎛ and 30.4cc/min for o-xylene respectively. 4. Sampling rates with the windscreen of the pore size of 20 were 38.2cc/min for benzene, 33.0cc/min for toluene, ㎛ and 31.0cc/min for o-xylene respectively. 5. Sampling rates for 3M OVM #3500 badge were 35.4cc/min for benzene, 31.2cc/min for toluene, and 29.5 for o-xlylene respectively. These values were similar to the sampling rates provided by 3M(35.5cc/min for benzene, 31.4cc/min for toluene, and 27.3cc/min o-xylene)