Quantification of benzene, toluene, ethylbenzene and xylenes in the air of indoor environments

ABSTRACT Air pollution is not restricted to open air areas. High concentrations of petroleum-based air pollutants may occur, such as benzene, toluene, ethylbenzene and xylenes (BTEX), in indoor environments. The BTEX, even in low concentrations, of the order of parts per billion (ppb), cause human health problems. The objective of this work was to apply a technique of measurement of BTEX, at ppb level, using only eight hours of sampling in an indoor environment. To this end, passive tube samplers were used associated with analysis by thermal desorption, gas chromatography and mass spectrometry. The calibration method applied to this analytical system was also presented. The use of this method allowed the quantification of BTEX in a combustion engines research laboratory, at concentrations of 4.64, 7.87, 10.47 and 21.36 ppb, respectively. These results are close to the range found by other indoor studies in Brazil. The evaluation of BTEX in the combustion laboratory, besides it only takes 16 hours, considering the sampling and the analysis procedures, confirmed the sensitivity of the methodology used.

摘要 空气污染并非仅局限于室外区域。室内环境中也可能出现高浓度的石油基空气污染物，例如苯（benzene）、甲苯（toluene）、乙苯（ethylbenzene）和二甲苯（xylenes，以下简称BTEX）。即便浓度处于十亿分之一（parts per billion，ppb）量级的低浓度BTEX，也会引发人体健康问题。本研究旨在应用一种针对ppb级BTEX的检测技术，仅需8小时的室内采样时长。为此，本研究采用被动式采样管（passive tube samplers）结合热脱附-气相色谱-质谱联用法（thermal desorption, gas chromatography and mass spectrometry）进行分析，并介绍了适配该分析系统的校准方法。运用该方法，本研究在某内燃机研发实验室中完成了BTEX的定量检测，各组分浓度分别为4.64、7.87、10.47和21.36 ppb。该结果与巴西其他室内环境研究测得的浓度范围相近。本次针对该内燃机实验室的BTEX检测，仅需采样与分析总耗时16小时，验证了所用方法的灵敏度。