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Thursday January 21, 2016

Peak Benzene Air Levels in the Porter Ranch Community

EFF -- The air sampling data used to generate the Porter Ranch community peak benzene levels graph were obtained from the SoCalGas Web site. The analyzed air monitoring data covers the period from November 1, 2015, to January 9, 2016. The information available includes measured concentrations for volatile organic compounds (VOCs),including benzene, toluene, ethylbenzene, and xylenes. Benzene levels are evaluated here because the measurements for this VOC were the highest and most closely approached a level of concern. This level of concern was previously established by OEHHA and is called an acute Reference Exposure Level (REL). An acute REL is a level at which infrequent one-hour exposure is not likely to cause adverse effects in people, including potentially sensitive people such as infants and children. The peak levels of benzene in air are evaluated and compared to this REL.

Benzene air level data from all of the available Porter Ranch community air monitoring sites (generally eight different locations) was evaluated, and the highest concentration reported was listed as the peak benzene level for that monitoring day. Some monitoring days had several data sets available for that day (e.g. morning and afternoon). The highest benzene concentration listed in all data sets available for a given monitoring day was listed as the peak benzene concentration for that day. Monitoring days without bars indicating benzene levels indicate days where samples were not taken, or where all the benzene air concentrations in the several air samples were below the level of detection for the analytical chemistry lab that analyzed the air samples.

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