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191.
192.
Kang Sun Xingang Liu Jianwei Gu Yunpeng Li Yu Qu Junling An Jingli Wang Yuanhang Zhang Min Hu Fang Zhang 《环境科学学报(英文版)》2015
Size-resolved aerosol samples were collected by MOUDI in four seasons in 2007 in Beijing. The PM10 and PM1.8 mass concentrations were 166.0 ± 120.5 and 91.6 ± 69.7 μg/m3, respectively, throughout the measurement, with seasonal variation: nearly two times higher in autumn than in summer and spring. Serious fine particle pollution occurred in winter with the PM1.8/PM10 ratio of 0.63, which was higher than other seasons. The size distribution of PM showed obvious seasonal and diurnal variation, with a smaller fine mode peak in spring and in the daytime. OM (organic matter = 1.6 × OC (organic carbon)) and SIA (secondary inorganic aerosol) were major components of fine particles, while OM, SIA and Ca2 + were major components in coarse particles. Moreover, secondary components, mainly SOA (secondary organic aerosol) and SIA, accounted for 46%–96% of each size bin in fine particles, which meant that secondary pollution existed all year. Sulfates and nitrates, primarily in the form of (NH4)2SO4, NH4NO3, CaSO4, Na2SO4 and K2SO4, calculated by the model ISORROPIA II, were major components of the solid phase in fine particles. The PM concentration and size distribution were similar in the four seasons on non-haze days, while large differences occurred on haze days, which indicated seasonal variation of PM concentration and size distribution were dominated by haze days. The SIA concentrations and fractions of nearly all size bins were higher on haze days than on non-haze days, which was attributed to heterogeneous aqueous reactions on haze days in the four seasons. 相似文献
193.
为研究天津市春季道路扬尘PM_(2.5)和PM_(10)中碳组分特征及来源,于2015年4月用样方法采集天津市道路扬尘样品,利用再悬浮采样器将样品悬浮到滤膜上,经热光碳分析仪测定有机碳(OC)和元素碳(EC),利用非参数检验、OC/EC比值分析、相关分析及聚类分析对其污染特征和来源进行探讨.结果表明,PM_(2.5)中ω(TC)为4. 89%(次干道)~18. 83%(快速路),ω(OC)为3. 57%(次干道)~15. 39%(快速路),ω(EC)为1. 32%(次干道)~3. 44%(快速路); PM_(10)中ω(TC)为8. 14%(次干道)~19. 71%(快速路),ω(OC)为5. 91%(次干道)~16. 28%(快速路),ω(EC)为1. 96%(主干道)~3. 43%(快速路);快速路中各碳组分质量分数均较高,次干道中各碳组分质量分数均较低,可能是由于快速路中车流量较大,机动车尾气排放量较大,而次干道车流量较小;各类型道路中ω(OC)明显大于ω(EC),ω(EC)在不同道路类型中差异不大;两相关样本非参数检验表明,各碳组分质量分数在PM_(2.5)和PM_(10)间均无显著性差异;相关性分析表明道路扬尘中OC、EC来源大致相同.通过OC/EC比值分析及聚类分析可知,天津市春季道路扬尘中碳组分主要来源于燃煤、机动车尾气以及生物质燃烧. 相似文献
194.
HUANG Hong LEE Shun-cheng CAO Jun-ji ZOU Chang-wei CHEN Xin-geng FAN Shao-jia 《环境科学学报(英文版)》2007,19(1):35-43
Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor (I/O) ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission (PIXE) method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5μg/m^3 for summer period, and 109.9-123.7 μg/m^3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m^3 for summer period, and 8416.8-8900.6 ng/m^3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources. 相似文献
195.
为研究伊犁河谷核心区春季大气细颗粒物(PM2.5)中无机元素、水溶性离子和碳组分特征和来源,于2021年4月20~29日在伊犁河谷核心区布设6个环境采样点,对PM2.5中水溶性离子、无机元素和碳组分等51种化学组分进行分析,并使用化学质量平衡(CMB)模型对其来源进行解析.结果表明,采样期间ρ(PM2.5)变化范围介于9~35μg·m-3.Si、 Ca、 Al、 Na、 Mg、 Fe和K等地壳元素占比较高,占PM2.5的12%,表明春季PM2.5受到明显的扬尘源的影响.富集因子结果表明,Zn、 Ni、 Cr、 Pb、 Cu和As元素主要来源于化石燃料燃烧和机动车排放.元素组分的空间分布特征受采样点周边环境的影响,新政府片区受燃煤源的影响较大,故As浓度较高,伊宁市局和第二水厂受机动车影响较大,Sb和Sn浓度较高.PM2.5中9种水溶性离子(WSIIs)的浓度占PM2.5的33.2%,其中ρ(SO2- 相似文献
196.
为研究嘉兴地区嘉善冬季污染时段和清洁时段PM2.5化学组分特征,结合气象数据对2019年1月嘉兴市嘉善县善西超级站在线自动监测PM2.5及化学组分数据、气态污染物(NO2和SO2)进行了分析.结果表明,2019年1月嘉善善西超级站污染时段PM2.5浓度(97.18μg·m-3)为清洁时段(36.77μg·m-3)的2.6倍.污染时段水溶性离子浓度(41.58μg·m-3)较清洁时段(19.82μg·m-3)高21.76μg·m-3,但占比有所降低,含碳组分比例增加.OC;EC比值为3.93,可能受到燃煤及机动车排放的共同影响.低风速及高湿有利于NO2和SO2等气态污染物进行二次转化,污染时段硫转化率和氮转化率均比清洁时段高,分别增高7.93%和54.11%,说明NOx向硝酸盐二次转化较为明显,导致颗粒物浓度升高.聚类分析结果显示67.34%气流来自北方,且相应的气流轨迹上污染物浓度比周边高,说明污染物存在一定的长距离输送.结合风玫瑰图可以看出,污染主要为本地及其周边的输送,污染物的长距离输送在短时会使污染浓度突增.因此,在重点关注本地及周边污染的同时,偏北气流下的污染物区域输送不可忽视. 相似文献
197.
198.
199.
采用二氯甲烷液—液萃取预处理水样,气相色谱—质谱联用技术分析了炼油厂生化曝气池进、出水,腈纶厂干法纺丝废水及其经SBR小试处理的出水中二氯甲烷可萃取的有机组分,并半定量地评估了生化处理对这些有机组分的去除效果。结果表明,炼油厂生化曝气池对酚类及芳烃类化合物的去除效果较好,而长链脂肪烃的去除率相对较低;腈纶干法纺丝工艺废水中可萃取的有机组分主要为N,N二甲基甲酰胺,其相对含量大于95%(m/m),该废水经SBR小试处理后,原水中各种可萃取的有机化合物均得到分解,结构发生了变化,但不能全部彻底地转化为CO2和水。 相似文献
200.
本研究基于2014~2017年长三角地区2100余组环境空气PM2.5组分监测数据,建立了组分监测数据有效性的审核指标.以百分位数法(P2.5,P97.5)确定了长三角地区阴离子(A)与阳离子(C)电荷当量浓度比(A/C)、所测组分浓度之和(∑组分)与PM2.5实测浓度比、基于物质重构的PM2.5质量浓度(PM2.5,重构)与PM2.5实测浓度比、 S/SO42-和K/K+的双侧95%参考范围分别为:(0.82, 1.35)、(0.63, 0.94)、(0.62, 1.00)、(0.28, 0.50)和(0.66, 2.31),且上述指标各月的平均值和参考范围基本不受季节变化影响. NH+4的理论浓度与实测浓度检验结果表明, NH+4的化学形态呈现季节性变化,春夏季主要以NH 相似文献