Data from: Influence of oil and gas emissions on ambient atmospheric non-methane hydrocarbons in residential areas of northeastern Colorado

The Northern Front Range (NFR) region of Colorado has experienced rapid expansion of oil and gas extraction from shale and tight sands reservoirs in recent years due to advances in hydraulic fracturing technology, with over 24,000 wells currently in operation. This region has also been designated as a federal ozone non-attainment area by the U.S. EPA. High ozone levels are a significant health concern, as are potential health impacts from chronic exposure to primary emissions of non-methane hydrocarbons (NMHC) for residents living near wells. From measurements of ambient atmospheric NMHC present in residential areas located in close proximity to wells in Erie, Colorado, we find that the C2-C5 alkanes are enhanced by a factor of 18 - 77 relative to the regional background, and present at higher levels than typically found in large urban centers. When combined with NMHC observations from downtown Denver and Platteville, it is apparent that these compounds are elevated across the NFR, with highest levels within the Greater Wattenberg Gas Field. This represents a large area source for ozone precursors in the NFR. The BTEX aromatic compounds in Erie were comparable to (e.g., benzene) or lower than (e.g., toluene, ethylbenzene, xylene) in large urban centers, however, benzene was significantly higher in Platteville, and within the range of chronic health-based exposure levels. An initial look at comparisons with data sets from previous years reveal that ambient levels for oil and gas-related NMHC in Erie, as well as further downwind in Boulder, have not decreased, but appear to have been increasing, despite tightening of emissions standards for the oil and gas industries in 2008.

科罗拉多州北部前陆（Northern Front Range, NFR）区域近年来因水力压裂（hydraulic fracturing）技术进步，页岩与致密砂岩储层的油气开采规模快速扩张，目前运营的油气井已超2.4万口。该区域还被美国环境保护署（U.S. EPA）划定为联邦级臭氧不达标区域。高臭氧浓度本身是严重的健康隐患，而居住在油气井附近的居民长期暴露于非甲烷烃（non-methane hydrocarbons, NMHC）一次排放物所带来的健康风险同样不容忽视。通过对科罗拉多州伊利市（Erie）紧邻油气井的居民区周边大气环境中非甲烷烃的实测数据进行分析，研究发现C2-C5烷烃的浓度相较于区域本底值提升了18至77倍，且浓度高于大型城市中心的典型水平。结合丹佛市中心与普拉特维尔（Platteville）的非甲烷烃观测数据，可以明确此类化合物在北部前陆区域普遍升高，其中以大瓦滕贝格气田（Greater Wattenberg Gas Field）范围内浓度最高，这表明该区域存在大规模的臭氧前体物排放源。伊利市的BTEX芳香族化合物浓度与大型城市中心相当（如苯）甚至更低（如甲苯、乙苯、二甲苯），但普拉特维尔的苯浓度显著偏高，处于慢性健康暴露阈值范围内。初步对比历年数据集后发现，尽管美国油气行业在2008年收紧了排放标准，但伊利市乃至下游博尔德（Boulder）区域与油气开采相关的非甲烷烃环境浓度不仅未出现下降，反而呈现上升趋势。