A Sampling Method for Monitoring of Organic Halogen Compounds in Air

Some organic halogen compounds (halocarbons) are recognized or suspected to be mutagen and/or carcinogen. A sampling method which determines the average concentration levels of halocarbons for 1~2 weeks and their total exposure levels for a long period has been proposed. Halocarbons in air were adsorbed by a selected activated carbon and desorbed by hexane. Air was supplied to the carbon column at a constant low flow rate (50~100 ml/min) for a long time by a miniscale vacuum pump fitted with a capillary tube (Fig. 1). The activated carbon which was made from coal and with particle size of 0.25~0. 42 mm showed good performance of adsorption and desorption. The amount of the carbon enough to adsorb the halocarbons almost completely was 5 g. The adsorbed halocarbons were eluted with hexane at a flow rate of 30~50ml/h by a simple equipment (Fig. 3). The desorption efficiencies were sufficiently high for all compounds (Table 4). The eluate was analyzed by a gas chromatograph equipped with electron capture detector. The average concentrations of the halocarbons for 1~2 weeks could be determined at many sites by the proposed sampling method, and this method was expected to be useful to monitor, and evaluate air pollution with halocarbons.