北京地区冬季典型PM2.5重污染案例分析

对2013年1月10—14日发生的持续性PM2.5重污染过程从污染过程演变、气象条件影响、与气态污染物关系、区域污染背景、PM2.5浓度空间分布演变及其与地面风场的关系、PM2.5组分特征等多个方面进行全面的分析,较为完整地还原了该次重污染案例的形成原因以及主要影响因素。主要结论包括:该次重污染过程是稳定气象条件下导致的局地污染物积累,再叠加华北区域性污染的影响共同造成,其中10、12日北京地区PM2.5浓度的快速增长反映了周边污染传输的显著影响;逆温不但造成污染物难以扩散,且不同的逆温类型对PM2.5浓度水平有显著影响,同时还发现逆温的破坏导致近地面高浓度污染物向上扩散,造成百花山出现峰值高污染浓度现象;NO2与PM2.5浓度水平的高相关性反映交通污染二次转化对PM2.5浓度水平的影响,在较高湿度条件下,SO2浓度水平对湿度敏感且表现为负相关性;该次污染过程中OM、SO2-4、NO-3、NH+4等组分在PM2.5质量浓度中的占比超过70%,说明燃煤、机动车等仍是北京地区最主要的污染来源,同时SO2-4占比最高也说明区域污染传输对该次重污染的显著贡献。     

Characteristics of atmospheric carbonyls and VOCs in Forest Park in South China

The diurnal variation of atmospheric carbonyls and VOCs in a forest in south China were studied in summer 2004. Twenty kinds of carbonyls and eight kinds of VOCs were identified and quantified. Formaldehyde and acetaldehyde were the two most abundant carbonyls, while the most abundant VOCs were isoprene, followed by o-xylene. Most C₃-C₁₀ carbonyls had higher concentrations from 09:00 to 15:00, and their levels were lower during night-time and often reached the lowest in early morning. Formaldehyde and acetaldehyde, however, showed two high levels in their diurnal patterns partly due to their different sources and sinks. The VOCs had different diurnal patterns compared to most carbonyls. The highest concentrations were observed from 03:00 to 06:00 for 1-butene, from 06:00 to 12:00 for isoprene, and from 12:00 to 15:00 for α-pinene. The highest levels for aromatic hydrocarbons occurred during midnight and the lowest in late afternoon. According to the study, emissions from vegetation and photo-oxidation of gas-phase hydrocarbons were the main sources for some carbonyls and VOCs in this region. Other compounds, such as formaldehyde, acetaldehyde and BTEX, showed anthropogenic sources.     

便携式GC/MS热脱附法直接测定环境空气中挥发性有机物

采用便携式气相色谱/质谱联用热脱附法直接测定环境空气中的挥发性有机物,优化了试验条件。方法在5×10-9~100×10-9范围内线性良好,39种化合物的检出限为1.1μg/m3~19μg/m3,标准气体平行测定的RSD≤11.0%,回收率在80%~120%之间。     

Polycyclic aromatic hydrocarbons in surface sediments from drinking water sources of Taihu Lake, China: sources, partitioning and toxicological risk

Sources, partitioning and toxicological risk of 15 priority polycyclic aromatic hydrocarbons (PAHs) in surface sediments from drinking water sources of Taihu Lake, with an area of 2428 km(2) located in the most developed and populated area of China, were studied, and the results were compared with those in other lakes of China and the USA. Concentrations of the 15 PAHs in sediments ranged from 436.6 to 1334.9 ng g(-1) (dw). Gasoline combustion, coal combustion, diesel combustion from shipping and spillage of petroleum were apportioned to be the main sources of PAHs in this area by principal component analysis, which contributed 35.19%, 26.43%, 25.41% and 12.97% to the PAH sources estimated by further multiple linear regression. Levels of PAHs in sediments were negatively correlated with contents of clay and fine silt (<16 μm), while positively with contents of medium silt, coarse silt and sand (>16 μm). Humin with size larger than 16 μm contained the largest part of the burden of PAHs in sediments, but the specific partitioning domain (bound humic acid, lipid or insoluble residue) depended on properties of organic matter reflected by optical absorbance at 465 and 665 nm. Total toxic benzo[a]pyrene equivalent (TEQ(carc)) of the carcinogenic PAHs in sediments varied from 31.8 to 209.3 ngTEQ(carc) g(-1). Benzo[a]pyrene and dibenzo[a,h]anthracene contributed 45.36 and 25.31% to total TEQ(carc), posing high toxicological risk to this area.     

Total petroleum hydrocarbon distribution in soils and groundwater in Songyuan oilfield, Northeast China

In order to investigate the distribution of the total petroleum hydrocarbons (TPH) in groundwater and soil, a total of 71 groundwater samples (26 unconfined groundwater samples, 37 confined groundwater samples, and 8 deeper confined groundwater samples) and 80 soil samples were collected in the Songyuan oilfield, Northeast China, and the vertical variation and spatial variability of TPH in groundwater and soil were assessed. For the groundwater from the unconfined aquifer, petroleum hydrocarbons were not detected in three samples, and for the other 23 samples, concentrations were in the range 0.01–1.74 mg/l. In the groundwater from the confined aquifer, petroleum hydrocarbons were not detected in two samples, and in the other 35 samples, the concentrations were 0.04–0.82 mg/l. The TPH concentration in unconfined aquifer may be influenced by polluted surface water and polluted soil; for confined aquifer, the injection wells leakage and left open hole wells may be mainly responsible for the pollution. For soils, the concentrations of TPH varied with sampling depth and were 0–15 cm (average concentration, 0.63 mg/g), >40–55 cm (average concentration, 0.36 mg/g), >100–115 cm (average concentration, 0.29 mg/g), and >500–515 cm (average concentration, 0.26 mg/g). The results showed that oil spillage and losses were possibly the main sources of TPH in soil. The consequences concluded here suggested that counter measures such as remediation and long-term monitoring should be commenced in the near future, and effective measures should be taken to assure that the oilfields area would not be a threat to human health.     

上海青浦地区大气降水的化学特征

利用上海青浦地区2003—2014年观测的大气降水监测资料,分析该区域12 a以来大气降水的酸化程度、化学组成特征,探讨降水中化学成分的不同来源及相对贡献。结果表明:降水pH年均值为4.43~6.33,酸雨频率为2.6%~86.8%,降水酸化程度大致经历了明显恶化和波动变化2个阶段。降水电导率年均值为1.77~4.01 m S/m,呈下降趋势。降水中各离子雨量加权平均当量浓度顺序为SO_4~(2-)NH_4~+Ca~(2+)NO_3~-Cl~-Na~+Mg~(2+)F-K~+,SO_4~(2-)、NH+4、Ca~(2+)和NO_3~-是降水中的主要离子,占离子总量的83.0%;降水类型由硫酸型向硫酸和硝酸混合型转变。降水离子中的二次组分SO_4~(2-)、NO_3~-和NH_4~+绝大部分来源于人为源,Ca~(2+)、Mg~(2+)和K+主要来自于土壤源和人为源的贡献,Cl~-主要来自海洋源,同时人为源的影响也不可忽视。     

基于主成分分析-多元线性回归的松花江水体中多环芳烃源解析

对松花江全流域14个监测断面的16种美国环保局优先控制的多环芳烃(PAHs)的主要来源及其贡献率应用主成分因子分析-多元线性回归模型(PCA-MLR)进行了来源解析。结果表明:松花江全流域为化石和石油燃料的复合PAHs污染,水体环境中PAHs首要污染源为化石燃料燃烧和交通污染,合计贡献率为63.1%,第二大污染源为工业和民用燃煤污染,合计贡献率为36.9%,沿江的石化、石油基地、大型焦化厂、电厂都是PAHs的主要来源。     

实行年度目标考核是促进监测工作发展的有效方法

实行年度目标责任制考核 ,为监测站的改革和发展找到了一条有效途径。文章通过对年度目标考核责任制的方式、方法及实施后所取得成效的介绍 ,为监测站的改革与发展提供了借鉴     

秸秆焚烧对北京市空气质量的影响

用火焰原子吸收光谱法测试了北京市两个采样点 1 #站 (十三陵站 ,清洁对照点 )和 5#站 (天坛站 ,居民生活区 )1 1 0个大气颗粒物样品中的水溶性钾 ,以表征秸秆焚烧颗粒物。 1 #站水溶性钾的质量浓度年均值为 1 .2 1 μg/m3,其中以1 998年 6月份浓度 (3 .0 7μg/m3)最高 ,是 5月份 (1 .0 2μg/m3)的 3倍 ;5#站水溶性钾的质量浓度年均值为 1 .94μg/m3,6月份 (4 .2 2 μg/m3)最高 ,是 5月份 (1 .97μg/m3)的 2 .1倍。数据分析结果表明 1 998年 6月份麦收季节存在以秸秆焚烧为主的生物质燃烧现象 ,使大气颗粒物中有机碳浓度水平升高 ,并对北京市的空气质量带来负面影响