Environmental airborne benzene is a ubiquitous hazardous air pollutant whose emissions are generated from multiple sources, including industrial emissions, fuel station emissions, and automobile emissions. Chronic occupational exposures to elevated levels of benzene are known to be associated with leukemic cancers, in particular, acute myeloid leukemia (AML), though epidemiological evidence regarding environmental exposures and subsequent AML development is lacking. This investigation uses historical airborne monitoring data from six counties in the State of Florida to characterize the environmental cancer risk from airborne benzene concentrations using current Federal and State regulatory analysis methodology, and a comparative analysis based on occupational epidemiological evidence. Airborne benzene concentrations were collected from 24 air toxics monitoring stations in Broward, Duval, Orange, Miami-Dade, Hillsborough, and Pinellas counties. From the years 2003--2006, 3,794 air samples were collected using 8, 12, and 24 hr samples with sub-ambient pressure canister collectors consistent with EPA benzene methodological protocols 101 and 176. Mean benzene concentrations, by site, ranged from 0.18--3.58 ppb. Using risk analysis methodology consistent with the EPA and the Florida Department of Environmental Protection (FLDEP) the resulting cancer risk estimates ranged from 4.37 x 10-6 to 8.56 x 10-5, exceeding the FLDEP's acceptable cancer risk level, 1 x 10-6 for all monitoring sites. The cumulative lifetime exposures were calculated in ppm-years by site, ranging from 0.036--0.702 ppm-years. A comparative analysis with available epidemiological literature revealed that associations between benzene exposure and cancer outcomes were related to cumulative lifetime exposures in great excess of 1 ppm-years. The results of this investigation indicate that it is not reasonable to expect additional cancer outcomes in Florida residents as a result of airborne benzene exposures consistent with measured concentrations, despite the fact that all regulatory risk calculations exceed acceptable cancer risk levels in the State of Florida.
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机译：空气中的环境苯是一种普遍存在的有害空气污染物，其排放来自多种来源，包括工业排放，加油站排放和汽车排放。尽管缺乏有关环境暴露和随后AML发生的流行病学证据，但长期职业性暴露于苯水平升高与白血病（特别是急性髓细胞性白血病）有关。这项调查使用来自佛罗里达州六个县的历史航空监测数据，使用当前的联邦和州法规分析方法，根据职业流行病学证据进行比较分析，从空气中苯浓度中表征环境癌症风险。从Broward，Duval，Orange，Miami-Dade，Hillsborough和Pinellas县的24个空气毒物监测站收集了空气中苯的浓度。从2003--2006年开始，使用8小时，12小时和24小时样品以及低于EPA苯方法学规程101和176的低压罐收集器，共收集了3,794份空气样品。平均苯的浓度范围为0.18- -3.58 ppb。使用与EPA和佛罗里达州环境保护局（FLDEP）一致的风险分析方法，得出的癌症风险估计值范围为4.37 x 10-6至8.56 x 10-5，超过了FLDEP可接受的癌症风险水平1 x 10-6用于所有监视站点。累积的终生暴露量是按站点的ppm年计算的，范围为0.036--0.702 ppm年。与现有的流行病学文献进行的比较分析表明，苯暴露与癌症结局之间的关联与累积的终身暴露量（每年超过1 ppm）相关。这项调查的结果表明，尽管所有法规风险计算都超过了佛罗里达州可接受的癌症风险水平，但由于空气中苯暴露与测得的浓度一致，在佛罗里达州居民中预期会有更多的癌症结果是不合理的。
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