Revisiting Acetonitrile as Tracer of Biomass Burning in Anthropogenic‐Influenced Environments
Yibo Huangfu, Bin Yuan, Sihang Wang, Caihong Wu, Xianjun He, Jipeng Qi, J. A. de Gouw, C. Warneke, J. B. Gilman, Armin Wisthaler, Thomas Karl, M. Graus, B. T. Jobson, Min Shao
Abstract
Abstract Acetonitrile (CH 3 CN) has been widely employed as biomass burning tracer. However, the current application of CH 3 CN absolute mixing ratio as the thresholds may misidentify biomass burning due to the interference from other CH 3 CN sources in anthropogenic‐influenced environments. High levels of CH 3 CN were observed with minor biomass burning impact but still followed a similar correlation with carbon monoxide (CO), suggesting their shared source, most likely, vehicular emission. By analyzing the available literature including more than 30 worldwide field measurements, the enhancement ratios (EnRs) of CH 3 CN to CO for biomass burning were found as 2.01 ± 0.16 ppbv/ppmv, well distinguished from the EnRs obtained in urban measurement (0.26 ± 0.04 ppbv/ppmv). An example is given and the application of EnR to identify biomass burning is discussed. The results suggest that the correlation between CH 3 CN and CO and their EnRs can be used as more specific indicators for biomass burning.