Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 26 3-4 1997 12 15 35 42 M. Ghasemkhani 2015 10 03 In this research, air sampling of workplaces was carried out by two methods (long - time and short - time). The mean formaldehyde concentration with long - time method in pathology labs, surgery and endoscopy sections were 0.96 0.25 and 0.13 ppm and with short - time method, 8 hours, was 3, 0.3 and 0.2 ppm. The mean formaldehyde concentration in pathology labs was above the standard values (TLV - Ceiling = 0.3 ppm). In the long - time and short - time air sampling, the time of sampling was significantly effective on the concentration levels (P<0.05). Work practices and administrative procedures are important parts of a control system. If one is asked to perform a task in a certain manner to limit exposure to formaldehyde, it is extremely important that these procedures should be followed. https://ijph.tums.ac.ir/index.php/ijph/article/view/1790 https://ijph.tums.ac.ir/index.php/ijph/article/download/1790/1771