Cao Cong, Wang Ge-Hui, Wu Can, Li Jian-Jun, Liu Lang, Li Jin, Yu Xing
State Key Laboratory of Loess and Quaternary Geology, Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Huan Jing Ke Xue. 2018 Apr 8;39(4):1473-1483. doi: 10.13227/j.hjkx.201708039.
PM was simultaneously collected using a high-volume sampler at 4 h intervals from the mountainside and the foot of the mountain in the Mt. Huashan region, inland China, during the summer of 2016, and the samples were analyzed for inorganic ions, to investigate the chemical characteristics and vertical distribution of the fine particles in the region. The results showed that the concentrations of PM were (46.9±38.2) μg·m and (76.0±44.3) μg·m on the mountainside and at the foot of Mt. Huashan, respectively. The concentrations of inorganic ions in PM was higher at the foot of the mountain than on the mountainside, with the order of the mass concentrations of the major ionic species being SO > NO > NH > Ca. Among all the inorganic ions, SO, NO, and NH are the dominant species, accounting for 89% and 85% of the total, on the mountainside and at the foot, respectively. The fine particulate NH existed mostly in the forms of (NH)SO and NHNO on the mountainside, and in the forms of NHHSO and NHNO at the foot of the mountain. Mass concentrations of PM and its major components on the mountainside showed clear diurnal variations, with maximums between 12:00-16:00, mainly due to the transport of the pollutants from the ground surface by the planetary boundary layer height variation and the valley breeze. In contrast, the diurnal variations of PM and its major components at the foot are characterized with two maxima, peaking between 08:00-12:00 in the daytime and 00:00-04:00 in the nighttime, respectively, mainly due to the increased emissions from both the morning rush-hour traffic and the nighttime on-road heavy-duty vehicles. Acidity of the fine particles was estimated by using the equivalent ratio of anions to cations and the thermodynamic equilibrium model ISORROPIA Ⅱ. Both methods showed that the acidity of PM at the ground surface site is stronger than that on the mountainside in the Mt. Huashan region.
2016年夏季，在中国内陆华山地区，使用大容量采样器每隔4小时同时从山腰和山脚下采集一次颗粒物（PM）样本，并对样本中的无机离子进行分析，以研究该地区细颗粒物的化学特征和垂直分布。结果表明，华山山腰和山脚下的PM浓度分别为（46.9±38.2）μg·m³和（76.0±44.3）μg·m³。山脚下PM中无机离子的浓度高于山腰，主要离子种类的质量浓度顺序为SO₄²⁻＞NO₃⁻＞NH₄⁺＞Ca²⁺。在所有无机离子中，SO₄²⁻、NO₃⁻和NH₄⁺是主要成分，在山腰和山脚下分别占总量的89%和85%。山腰处细颗粒物NH₄⁺主要以（NH₄）₂SO₄和NH₄NO₃的形式存在，山脚下则以NH₄HSO₄和NH₄NO₃的形式存在。山腰处PM及其主要成分的质量浓度呈现明显的日变化，最大值出现在12:00 - 16:00之间，主要是由于行星边界层高度变化和山谷风将污染物从地面输送上来。相比之下，山脚下PM及其主要成分的日变化特征是有两个最大值，分别在白天的08:00 - 12:00和夜间的00:00 - 04:00达到峰值，主要是由于早高峰交通和夜间道路重型车辆排放增加。通过使用阴离子与阳离子的当量比和热力学平衡模型ISORROPIAⅡ估算细颗粒物的酸度。两种方法均表明，华山地区地面站点的PM酸度比山腰处更强。
