[Pollution Characteristics and Source Analysis of Carbon and Nitrogen Components in Ambient PM in Huangshi City].

Based on stable isotope technology and a PMF model, the pollution characteristics and sources of carbon and nitrogen components in ambient PM in Huangshi City were explored. The results showed that the total carbon concentration[(TC)] and the total carbon isotopic composition (C) in ambient PM in Huangshi City both showed seasonal variation characteristics of being high in winter and low in summer, with values of (4.4±1.2) μg·m and (-26.3±0.5)‰ in summer and (9.9±3.5) μg·m and (-25.5±0.5)‰ in winter, respectively. The total nitrogen concentration[(TN)]was significantly lower in summer[(9.1±9.1) μg·m]than that in winter[(62.4±26.4) μg·m], whereas the total nitrogen isotopic composition (N) was obviously enriched in summer[(12.8±1.9)‰]compared with that in winter[(2.9±4.0)‰]. In addition to the contribution from local sources, the carbon and nitrogen components were mainly affected by the short-range regional emission in northern Hunan and the long-distance transport in the northwest. The MixSIAR model and the PMF model indicated that the vehicle emission source was the main source of carbon components in PM, with contribution rates of 38.9% and 39.3%, respectively. MixSIAR results showed that NO emission sources had a greater impact on nitrogen components in PM of different seasons than NH emission sources, and their contribution was higher in summer (80%) than that in winter (66.8%), among which the NO emissions from coal combustion (summer:36.1%; winter:20.2%) had the largest contribution. By contrast, the PMF model indicated that the main source of nitrogen components was vehicle emissions (59.8%). Combining multiple models to overcome the uncertainty and subjectivity of single-model analysis can provide a theoretical basis for actively controlling and reducing fine particulate matter emissions and effectively dealing with urban aerosol pollution.