Abstract: A passive personal formaldehyde dosimeter he.s been developed for determination of formaldehyde in ambient air. The dosimeter consists of a capped polymethyl methacrylate tube packed with glass wool treated with 20% diethanolamine. The formaldehyde Was analyzed by 4-amino-3-hydra-zino-5-mercapto-1,2,4-triazole(AHMT) colormetric method. The continuous generation of gaseous formaldehyde was accomplished by decomposing para-formaldehyde at 30℃. Results indicated that the dosimeter is suitable over a range of formaldehyde concentrations from 120ppb(7-day sample)to 20ppm (8-h sample). The reproducibility was found to be gcod, with a relative standard deviation of less than 16%.A sampling rate of 5.0ml/min has been obtained.