本研究对北京市中心城区2014年期间的83个和2016-2017年的153个大气颗粒物样品进行了研究，检测了颗粒物中的12种常见硝基多环芳烃、水溶性有机碳、水溶性离子以及有机碳元素碳等，通过研究采样期间大气颗粒物及其所含化学组分的浓度季节变化来探究其污染特征以及来源。 从整体浓度水平来看，在夏季和冬季非采暖期，NPAHs浓度都比多环芳烃低一个数量级；而在冬季供暖期，硝基多环芳烃浓度水平甚至会低两个数量级。多环芳烃在夏季、非采暖期和采暖期具有明显的季节浓度变化，而硝基多环芳烃浓度的季节变化不如多环芳烃显著。 在所研究的多环芳烃以及硝基多环芳烃里，潜在致癌性最强的三种多环芳烃为苯并[b]荧蒽，苯并[a]芘以及二苯[ah]并蒽，硝基多环芳烃中致癌性最强的两种为3-硝基荧蒽和6-硝基?。潜在致癌风险情况与有毒有机物浓度变化情况呈现一致的规律。从对个体致癌风险指数的研究中可以看出，即使硝基多环芳烃浓度更低，但致癌毒性却可以比多环芳烃更强。 本研究中采用主成分分析法对采样期间多环芳烃以及硝基多环芳烃进行来源分析得出，在所有的污染来源中，交通排放是最为主要的污染物来源。然而，在冬季采暖期间煤炭燃烧也是一个不可忽视的来源。在对硝基多环芳一次来源与二次来源占比的研究中发现，采样期间所研究NPAHs来源情况为：夏季和冬季采样期间，3-硝基菲和9-硝基菲都全部来自于二次反应。主要来源于二次反应的硝基多环芳烃为1-硝基萘、2-硝基荧蒽、2-硝基芘和2-硝基芴。在整个采样期间，9-硝基蒽和7-硝基苯[a]蒽这两种物质的一次来源和二次来源浓度相差不多。主要来源于一次直接排放的化合物为3-硝基荧蒽和1-硝基芘，但在冬季采暖期，这两种物质分别有70.8%和43%来源于光化学反应。而6-硝基苯并[a]芘和6-硝基?则在整个采样期间都是来源于一次直接排放。通过特征物比值法2-硝基荧蒽与1-硝基芘比值可以得出，在整个采样阶段中，硝基多环芳烃的生成都主要来源于一次直接排放。 在三次重污染天气条件下，冬季时期PM1、PM2.5和PM10样品浓度随时间变化的趋势几乎一致。春季时期两次重污染天气中PM2.5和PM10浓度变化情况依旧很一致，而PM1的变化趋势与前两者趋势差异都相对变大。冬季大气颗粒物中OC%显著高于春季3月和4月，EC%冬季值虽然也高于春季两个采样阶段，但季节差异不如OC%明显。三次重污染天气条件下，不同粒径情况的元素碳与有机碳比值均表现为白天的均值高于夜晚的情况。大部分离子浓度变化规律为冬季高于春季，春季两次重污染过程浓度相差不大。二次无机颗粒物SNA占据水溶性离子浓度总值的绝大部分。NH4+、NO3-、SO42-、K+四种离子绝大部分质量浓度都集中在PM1中，Cl-在PM1上也有较多的浓度分布，但在直径2.5-10μm的大气颗粒物中也有较高的浓度占比，Mg2+、Ca2+和Na+则主要分布在粒径大于2.5μm的粗颗粒物中。SOC浓度变化是随着风速、降雨量的增加而降低。除了冬季燃煤条件对SOC浓度的影响，冬季更多的静稳天气以及低降雨量，导致北京中心城区冬季SOC浓度普遍高出春季时期SOC浓度值。

In this experiment 83 atmospheric particulates samples in 2014 and 153 samples in 2016-2017 in the central urban area of Beijing were collected. 12 common nitropolycyclic aromatic hydrocarbons, water soluble organic carbon, water soluble ion, organic carbon and elemental carbon of atmospheric particulates were analysed. Concentration of atmospheric particulates and their chemical constituents was analysed in order to explore its pollution characteristics and sources during sampling period. From the total concentration level, NPAHs concentration was an order of magnitude lower than PAHs in the summer and non-heating period. While during heating period, the concentration level of NPAHs is even two orders of magnitude lower. Polycyclic aromatic hydrocarbons have significant seasonal variation in summer, non-heating period and heating period, while the seasonal variation of NPAHs concentration is not as significant as that of PAHs. Among these PAHs and NPAHs, three strongest potential carcinogenicity PAHs were BbF, Bap and DahA, two NPAHs were 3-NFL and 6-NChr. The potential carcinogenic risk is consistent with the variation of the concentration of toxic organic matter. It can be summarized from the study on the individual carcinogenic risk index that even though the concentration of NPAHs is lower, the carcinogenic toxicity can be stronger than that of PAHs. The source apportionment of PAHs and NPAHs during sampling period was conducted by principal component analysis. Of all the sources of pollution, transport is the most important source of pollutants. However, coal burning during winter heating time is also an important source. It was found in the study on the proportion of primary and secondary sources of NPAHs, the sources during the sampling period were as followed. 3-NPh and 9-NPh all came from the second reaction during summer and winter sampling periods. NPAHs mainly derived from the secondary reaction were 1-NN, 2-NFL, 2-NP and 2-NF. The sources of 9-NA and 7-NBaA were similar during the entire sampling period. 3-NFL and 1-NP derived primarily from direct discharge while during winter heating season, 70.8% and 43% of the two substances came from photochemical reactions. 6-NBaP and 6-NChr were derived from direct discharge during the entire sampling period. It can be obtained by the feature ratio method (2-NFL/1-NP), the generation of nitropahs was mainly derived from direct emission in the whole sampling stage. In the three times of heavy pollution, the concentration of PM1, PM2.5 and PM10 samples in winter was almost consistent with the change of time. The changes of PM2.5 and PM10 concentration in two heavy pollution days in spring is still consistent. However, the variation trend of PM1 is relatively large. The OC% of atmospheric particulates in winter was significantly higher than that in March and April in spring. Although the winter value of EC% is higher than the two sampling periods in spring, the seasonal difference is not as obvious as OC%. The ratio of element carbon and organic carbon in different particle sizes was higher than that of night in three times of heavy pollution. Most of the ion concentration was higher in winter than spring, and little difference was observed during two heavy pollution process in spring. The secondary inorganic particle occupies most of the total water soluble ion concentration. Most of the NH4+、NO3-、SO42-、K+ mass concentration is concentrated in PM1. There are lots of Cl- distributed in PM1, while there is a higher concentration in the atmospheric particulates of 2.5 to 10 μm. Mg2+, Ca2+ and Na+ are mainly distributed in coarse particles with particle size greater than 2.5 μm. The change of SOC concentration decreases with the increase of wind speed and rainfall. In addition to the effect of coal burning conditions on SOC concentration in winter, more static weather and low rainfall in winter have caused the SOC concentration in winter to be higher than that in spring period in Beijing.