Student Research: Hongbin Xiao
MS, , 2000
Evaluation of Passive Samplers for Monitoring Six Aldehyde Compounds
The goal of this project is to validate a passive sampler that is stable for seven-day monitoring of personal exposures to aldehydes for large population studies. The target aldehydes are formaldehyde, acetaldehyde, acrolein, crotonaldehyde, glyoxal, and methylglyoxal and were selected according to their toxicity and prevalence. Investigation of the commercially available GMD formaldehyde sampler showed high background contamination and erratic collection rates for targeted aldehydes except for formaldehyde. Modifications were made to the absorption medium and coating solution. A passive syringe-style Sep-Pak sampler (PSSP) was then developed and evaluated in controlled chambers. The effective collection rates of the PSSP were 3.3, 2.4, 2.9, 1.8, 1.4 and 1.9 cc/min for formaldehyde, acetaldehyde, acrolein, glyoxal, crotonaldehyde, and methylglyoxal, respectively. The detection limits were below the reported urban ambient levels. The imprecision was well below 20% for monitoring durations ranging from one to seven days. Storage stability tests showed that the exposed PSSPs maintained constant aldehyde levels for up to 33 days. Unexposed PSSPs showed stable aldehydes backgrounds in the shelf-life tests for up to 31 days. The mailing-out approach was tested as a cost-effective way of monitoring exposures in the general population. No significant losses or gains of formaldehyde, acetaldehyde, acrolein, and methylglyoxal from unrefrigerated samples were observed for up to 17 days of mailing. In conclusion, this PSSP sampler is suitable for population exposure studies using the mailing-out approach.