Chemical and stable isotopic characteristics of PM2.5 emitted from Chinese cooking.

This study investigated the characteristics of air pollutants generated from preparing Chinese cuisine and analyzed the isotopic compositions of carbon and nitrogen in particulate matter with a diameter <2.5 μm (PM2.5) to source apportionment study. The CO and CO2 concentrations and temperatures were measured using suitable instruments in real time during cooking, including stir-fry, fry, deep-fry, hot-pot, and mixed cooking, and periods with non-cooking. Personal environmental monitoring instruments were used to collect PM2.5 for carbon and nitrogen elements and isotopes analysis. Our data indicated that the concentrations of CO and CO2 and the temperature were higher during periods of cooking, especially for the fry and stir-fry methods, than during periods with non-cooking. The concentrations of PM2.5, total carbon, and total nitrogen were also higher during cooking; the maximum concentrations were measured during fry. The values of δ13C were considerably lower during the periods of cooking (mean: -28.15‰) than during non-cooking (-27.18‰). The average values of δ15N were 8.63‰ and 11.74‰ during deep-fry and hot-pot cooking, respectively. The δ13C values can be used to distinguish between cooking and other non-cooking sources and further assess the effect of different cooking activities on PM2.5. The δ15N only can be used to investigate the effect of deep-fry on PM2.5. Moreover, the δ13C signature suggested that fry emits higher products of incomplete combustion than do other cooking activities. These findings can assist in pollution source identification of PM2.5, emission control, and the study of combustion characteristics.