| 秋冬季节华北背景地区PM1污染特征及来源 |
| 摘要点击 2171 全文点击 702 投稿时间：2016-12-12 修订日期：2017-02-19 |
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| 中文关键词 区域背景 霾 化学成分 粒径分布 有机气溶胶 |
| 英文关键词 regional background haze chemical composition size distribution organic aerosols |
| 作者 | 单位 | E-mail | | 张周祥 | 中国气象科学研究院, 灾害天气国家重点实验室, 中国气象局大气化学重点开放实验室, 北京 100081 | zhzhoux@126.com | | 张养梅 | 中国气象科学研究院, 灾害天气国家重点实验室, 中国气象局大气化学重点开放实验室, 北京 100081 | ymzhang@camscma.cn | | 张小曳 | 中国气象科学研究院, 灾害天气国家重点实验室, 中国气象局大气化学重点开放实验室, 北京 100081
中国科学院区域大气环境研究卓越创新中心, 北京 100081 | | | 王亚强 | 中国气象科学研究院, 灾害天气国家重点实验室, 中国气象局大气化学重点开放实验室, 北京 100081 | | | 沈小静 | 中国气象科学研究院, 灾害天气国家重点实验室, 中国气象局大气化学重点开放实验室, 北京 100081 | | | 孙俊英 | 中国气象科学研究院, 灾害天气国家重点实验室, 中国气象局大气化学重点开放实验室, 北京 100081 | | | 周怀刚 | 上甸子区域大气本底站, 北京 101507 | |
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| 中文摘要 |
| 利用高分辨率飞行时间气溶胶质谱仪（HR-ToF-AMS）在华北背景地区——上甸子区域大气本底站开展亚微米气溶胶（NR-PM1）化学组分及粒径分布的连续观测实验，观测时段为2015年10月17日至2016年1月27日，涵盖了秋、冬两季.结果表明，整个观测期间NR-PM1平均质量浓度为25.2 μg·m-3，PM1中有机物占绝对优势，硝酸盐占的比例高于硫酸盐.各化学组分平均粒径分布以积聚模态为主，其中，有机物峰形最宽，峰值粒径最小，硝酸盐峰值粒径最大，表明有机物在颗粒物形成、增长初期及老化阶段均有贡献，硝酸盐在气溶胶粒子老化过程中更易于增长为大粒子.有机物种元素特性分析结果显示，秋、冬季有机气溶胶平均氧碳比（O/C）和氢碳比（H/C）为0.58和1.58，OM/OC达1.91，有机气溶胶的氧化程度高于城市站点平均水平.在华北地区污染环境下，有机气溶胶演变途径Van Krevelen拟合曲线斜率为-0.21，其老化潜质和速率较珠三角地区和欧美地区城市要慢.对比污染时段和清洁时段化学组成特征发现，在污染时段，硝酸盐质量浓度及其对PM1的贡献率超过硫酸盐，有机物氧化程度明显高于清洁时段.后径向轨迹气团分析结果显示，污染时段气团来向较为复杂，来自西部，南部以及东北部气团均有贡献，清洁时段，主要受来自西伯利亚洁净空气的影响，对站点污染物扩散作用明显. |
| 英文摘要 |
| The campaign of investigating the chemical compositions and particle size distributions of NR-PM1(non-refractory PM1) was conducted by using a High Resolution Time of Flight Aerosol Mass Spectrometer(HR-ToF-AMS) at the Shangdianzi(SDZ) regional atmospheric background site(117.07°E, 40.39°N), northeast of Beijing, from October 17th 2015 to January 27th 2016. The results showed that organics was the main component of PM1, and the proportion of nitrate was higher than that of sulfate in autumn and winter. The mean mass-resolved size distributions for the main components displayed accumulation mode. The wider organic peak shape and larger nitrate peak size indicated that the organics contributed to both small and large particles at the beginning of the particle formation, growth and aging processes, while most of nitrate particles preferred to grow into large particles during the aging process. The ratios of elements between OM and OC, O/C and H/C were calculated as 1.91, 0.58 and 1.58 respectively. The slope of Van Krevelen diagram of organic aerosols during polluted episode was -0.21, whose oxidation state was higher than those of other city sites. Nitrate was the major contributor of NR-PM1 during the polluted period, while organics was significantly higher than that during clean period. The results of back trajectories analysis demonstrated that the air masses were complex during the pollution episode. The northwest wind from central Inner Mongolia and Siberia dominated the clean episodes, which was conducive to the spread of pollutants. |
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