四城市空气粗、细颗粒物元素质量谱及富集特征

以武汉市 X荧光光谱分析数据为例 ,介绍了粗、细颗粒物中元素的质量谱及富集特征。并且 ,比较了广州、武汉、兰州、重庆四城市的污染元素及可能污染元素的某些富集特征     

中国4城市空气颗粒物元素的因子分析

因子分析在研究空气颗粒物来源上得到了广泛的应用。本文应用最大方差旋转因子分析法对中国4城市空气中粗、细颗粒物元素的来源进行了分析。结果指出粗、细颗粒物因子大致可分为土壤源因子和工业污染源因子两大类。粗颗粒物主要来自土壤源,细颗粒物主要来自工业污染源,并指出土壤源因子对粗颗粒物的贡献大于对细颗粒物的贡献。     

空气细颗粒物(PM2.5)污染特征及其毒性机制的研究进展

细颗粒物(PM2.5)是指空气动力学直径≤2.5μm的颗粒物,其表面吸附大量的有毒有害物质,并可通过呼吸沉积在肺泡,甚至可通过肺换气到达其他器官.由于细颗粒物的重要性,美国EPA已经于1997年颁布了细颗粒物的空气质量标准,年均值为0.015mg/m3,日均值为0.065mg/m3,然而我国至今仍未制定细颗粒物空气质量标准.颗粒物上吸附的化学组分主要可分成自然来源及燃煤或燃油等人为污染来源两大类,特别是来自工业性和居住区燃煤及汽车燃油尾气.空气细颗粒物污染表现为形态各异、成分复杂等特征.细颗粒物有明显的毒性作用,可引起机体呼吸系统、免疫系统等较为广泛的损害.细颗粒物与心肺疾病密切相关,如增加入院率、急诊次数、呼吸疾病及症状增加、肺功能下降,甚至于过早死亡.简要概述了细颗粒物的污染特征及其毒性机制研究进展.     

淮安市区大气中颗粒物PM_(10)、PM_(2.5)污染水平

通过对淮安市大气颗粒物中PM10、PM2．5的监测与污染水平分析,得出了淮安市区PM10与PM2．5浓度呈冬秋季高,夏春季低的特征。PM2.5和PM10的比值范围在0．62～0．65之间,即PM2．5在PM10以下颗粒物中所占比例大约为63％。     

ICP-MS法测定南京市环境空气PM_(2.5)中多种元素

采用聚四氟乙烯膜采样,硝酸-过氧化氢-氢氟酸微波消解样品,ICP-MS法测定南京某国控点环境空气PM_(2.5)中30种元素,结果目标元素在0μg/L~500μg/L之间线性良好,方法检出限为0.02 ng/m~3~15 ng/m~3,实际样品6次测定结果的RSD为0.5%~19.6%,加标回收率为78.5%~126%;所测元素的年日均值为0.03 ng/m~3~1 462 ng/m~3,占PM_(2.5)总量的7.3%。主要来自化石燃烧、机动车排放和钢铁冶炼的Cd、Zn、Se、Pb、Sb、Cu、As富集程度较高,Al、Ba、Be、Fe主要来自土壤岩石等自然源,富集度低。元素测定值季节分布呈秋冬高、春夏低的态势,与PM_(2.5)的季节变化趋势一致。     

苏州市区PM_(2.5)中元素污染特征

2014年使用EHM-X100型在线金属分析仪自动监测苏州市区大气PM2.5中Pb、Cu、K等24种元素质量浓度,并结合当地工业经济发展和降雨、土壤等环境状况对元素污染特征进行分析研究。结果表明:这24种元素的年均质量浓度在0.002μg/m3~0.834μg/m3之间,并总体呈现冬季质量浓度最高,春、秋季次之,夏季最低的变化趋势;Fe、Ca和Zn 3种元素在总质量浓度中占比较高,这可能与当地产业布局、建筑业及交通状况等有关,是人类活动所导致的污染。     

我国居住建筑室内PM_(2.5)研究现状及进展

分析了我国居住建筑室内PM_(2.5)污染水平,总结了现阶段PM_(2.5)的研究方法,主要包括理论分析法、数值模拟法和实验测试法。指出室外源是室内PM_(2.5)的主要污染来源,而室内烟草烟雾、烹饪及人员活动也会严重影响室内PM_(2.5)浓度。针对目前研究中存在的问题,提出了标定典型建筑在不同影响因素下的I/O比范围、研究家具和家电的颗粒物释放状况、加强农村室内外空气颗粒物污染调查等建议。     

广州市冬季PM_(2.5)污染过程二次水溶性无机离子组分特征

为了解广州地区灰霾天气成因,基于城市超级站,对2013年12月1日—12月8日期间2次灰霾天气过程的水溶性无机离子污染特征进行研究。结果表明:监测期间二次离子(SNA)SO_4~(2-)、NO_3~-、NH_4~+分别占PM_(2.5)质量浓度的15.8%、7.4%、7.0%;2次污染过程SNA对PM_(2.5)贡献显著,机动车排放和燃煤是PM_(2.5)的主要污染来源。广州冬季属于富氨区,2次污染过程都伴随着NH_4~+显著增加,NH_4~+主要以(NH_4)_2SO_4和NH_4NO_3形式存在。     

南阳市PM_(10)、PM_(2.5)污染特征及其与气象因子的关系

利用2015年1月1日至12月31日南水北调中线源头南阳市主城区5个国控空气质量监测站24 h自动连续采样的PM_(10)、PM_(2.5)质量浓度数据和同期气象要素观测数据,分析了南阳市大气颗粒物浓度的污染特征及其与气象因子的关系。结果表明:2015年南阳市PM_(10)、PM_(2.5)年均质量浓度分别为0.136、0.074 mg/m~3,超标率分别为31.8%、39.2%;PM_(10)、PM_(2.5)峰值均出现在1月,PM_(10)谷值出现在11月,PM_(2.5)谷值出现在9月;PM_(10)四季日变化均呈双峰型,而PM_(2.5)冬季日变化呈双峰型,其他季节无明显峰值;PM_(2.5)/PM_(10)值在43%~65%,均值54%;PM_(10)、PM_(2.5)与大气压呈显著正相关,与温度、相对湿度呈显著负相关,与风速、降水相关性不明显。     

潍坊市大气环境中PM2.5和PM10的污染特征及来源解析

于2017年1月—2018年1月在潍坊市城区8个监测点位按季节采集了环境空气颗粒物样品,对其组分进行分析;采用电子低压冲击仪（ELPI）稀释采样法和稀释四通道法2种源采样方法同步采集源样品,建立了潍坊市本地化的燃煤源、钢铁源等排放源的颗粒物源成分谱;结合排放源清单,利用化学质量平衡受体模型（CMB）开展不同行业的细颗粒物（PM_2.5）和可吸入颗粒物（PM₁₀）的精细化来源解析。结果表明,各监测点位ρ（PM_2.5）、ρ（PM₁₀）年均值均超过环境空气质量二级标准;潍坊市城市扬尘、土壤风沙尘、建筑水泥尘特征组分分别为硅（Si）、Si、钙（Ca）,燃煤尘和造纸碱回收尘的特征组分均为硫酸根离子（SO₄^2-）;PM_2.5首要的贡献源类为煤烟尘,分担率为36%;其次为机动车尘,分担率为25.4%;扬尘的分担率为21.8%;煤烟尘中分担率最高的是工业燃煤（18%）;机动车尘中以载货汽车分担率最大（14%）。PM₁₀首要的贡献源类也是煤烟尘,分担率为30.9%,其次是扬尘（27.6%）、机动车尘（21.5%）;煤烟尘中分担率最高的是工业燃煤,为15.4%,机动车尘中以载货汽车分担率最大,为11.8%。工艺过程的分担率均较低。     

Concentrations of As, Be, Cr, Hg, Mn, and Ni in ambient air at four urban locations in Japan

The metal concentrations of As, Be, Cr, Hg, Mn, and Ni in ambient air were measured at four sites in Japan from October 1997 to March 2006. The mean metal concentration data measured from the four sites (K1, K2, M, and Y) are found on the order of Mn > Cr–Ni > As > Hg > Be. The concentrations of Mn with the highest mean value were fairly variable across four sites such as 45.9 ± 42.8 (K1), 25.6 ± 19.4 (K2), 22.5 ± 19.7 (M), and 25.4 ± 19.8 ng m^???3 (Y). In contrast, the concentrations of Be with the lowest mean value were less variable across four sites with means of 0.03 to 0.04 ng m^???3. Inspection of the seasonal patterns indicates the peak occurrence of most metals during spring, although relative dominance during winter is seen at the most polluted area (K1). Evaluation of long-term patterns indicates that the noticeably high values of metals in the early stage of study reduced gradually across the years, although the metal concentration levels in most areas were affected significantly by anthropogenic activities. However, efforts to control pollution levels seemed to gradually contribute to a decrease in metal concentration levels of all study sites through the years.     

PM2.5 and volatile organic compounds (VOCs) in ambient air: a focus on the effect of meteorology

PM(2.5) and VOCs (benzene, toluene, m-p-o-xylenes) concentrations were measured in an urban and a suburban site in Athens, Greece, during the period between April and November 2004. This period, which is considered to be the warmer period in Greece, is characterized by the development of sea-breeze over the Attica Basin. Additionally strong Northern, North-eastern winds called "The Etesians", predominate during the summer months (July-August), acting positively to the dispersion of pollutants. In this campaign, 24 days with sea-breeze development were observed, 15 days with northern winds, 6 days with southern winds while the rest of the days presented no specific wind profile. Maximum concentrations of PM(2.5), VOCs and nitrogen oxides, were detected during the days with sea-breeze, while minimum concentrations during the days with northern winds. Ozone was the only pollutant that appeared to have higher concentrations in the background site and not in the city centre, where benzene presented strong negative correlation with ozone, indicating the photochemical reaction of hydrocarbons that lead to the ozone formation. The BTX ratios were similar for both sites and wind profiles, indicating common sources for those pollutants. T/B ratio ranged in low levels, between 3-5 for site A and 2-5 for site B, suggesting vehicles emissions as the main sources of volatile compounds. Finally, the strong correlations of PM(2.5) and benzene concentrations, between the two sampling sites, indicate that both the city centre and the background site, are affected by the same sources, under common meteorological conditions (sea-breeze, northern winds).     

Time series modelling of respiratory hospital admissions and geometrically weighted distributed lag effects from ambient particulate air pollution within Kathmandu Valley,Nepal

The distributed lag effects of ambient particulate air pollution exposure on respiratory hospital admissions in Kathmandu Valley are modelled using daily time series data. The extended exposure to PM₁₀ is accounted for by assigning weights to daily average PM₁₀ which decline geometrically as the lag period increases in days. Results show that the percent increase in chronic obstructive pulmonary disease (COPD) hospital admissions and respiratory admissions including COPD, asthma, pneumonia, and bronchitis per 10 μg/m³ rise in PM₁₀ are found to be 4.85% for 30 days lag effect, about 15.9% higher than that observed for same-day lag effect and 3.52% for 40 days lag effect, about 28.9% higher than the observed value for same-day lag effect, respectively.     

Ambiental dust speciation and metal content variation in TSP, PM10 and PM2.5 in urban atmospheric air of Harare (Zimbabwe)

The effects of timber harvesting on stream water quality and efficiency of alternate streamside management zones were evaluated in Pockwock Lake and Five Mile Lake watersheds in central Nova Scotia, Canada. The streamside management zone (SMZ) included a 20 m no cut, 20 m select cut and a 30 m select cut buffer strips along the stream. Water quality of eight streams, six in harvested and two in not-harvested watersheds were monitored for two years before and two years after the harvesting of timber. Nonparametric statistical tests on stream water quality showed that there was significant change in the concentration of potassium in six streams, manganese in five streams, zinc in two streams and total nitrogen in one stream after timber harvesting. There was no significant change in the quality of water in two streams used as control sites in the neighboring watersheds of similar size and hydrological characteristics. The results show that forest management practices were most favorable in streams maintained with 30 m select cut followed by 20 m no cut and 20 m select cut SMZ. The streamside zone width and treatment of select cut or no cut in the zone played an important role in filtering or retaining the minerals in surface water runoff. In buffer zones of similar width, the buffer zone with no cut or forested buffer was relatively more effective at protecting stream water quality than select cut SMZ. The vegetation in the zone may have decreased the flow velocity and increased residence time and thus increased filtration and retention of minerals in the riparian soil.     

An Assessment on Variation of Sulphur Dioxide and Particulate Matter in Erzurum (Turkey)

Sulphur dioxide and PM₁₀ levels are investigated in Erzurum during the periods of 1990–2000 heating season to assess air pollution level. For that reason, emissions of sulphur dioxide and particulate matter were calculated by using consumption of fuels and Turkish emission factors. These emission values were evaluated together with air pollution levels, which were measured at six stations in Erzurum atmosphere during 1990–2000 winter periods. Results reveal that in 1990–1994 heating period, there is an increasing trend in the emissions and air pollution levels over Erzurum, and the air quality limits were not met. The daily 24 h limit (short-term limit) was exceeded 127 days in 1992–1993 winter period. The reason for this increase was found to be the switching to use of low-quality fossil fuels instead of cleaner ones. Results also indicated that there was a considerable decrease in emissions of air pollutants and air pollution levels after 1995. This can be explained by the consumption of more high-quality fossil fuels. The correlation coefficient of SO₂ with PM₁₀ is obtained as r² = 0.85, which is a high value supporting the idea that both pollutants are emitted from the same source.     

Concentrations, sources, and exposure profiles of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM10) in the north central part of India

Airborne particulates (PM₁₀) from four different areas within Agra city (a semi-arid region) were collected using respirable dust samplers during the winter season (Nov. 2005–Feb 2006) and were then extracted with methylene chloride using an automated Soxhlet Extraction System (Soxtherm^®). The extracts were analyzed for 17 target polycyclic aromatic hydrocarbons (PAHs) and the heterocycle carbazole. The average concentration of total PAH (TPAH) ranged from 8.04 to 97.93 ng m^???3. The industrial site had the highest TPAH concentration followed by the residential, roadside, and agricultural sites. Indeno(1,2,3-cd)pyrene, benzo(g,h,i)perylene, and benzo(b)fluoranthene were the predominant compounds found in the samples collected from all of the sites. The average B(a)P-equivalent exposure, calculated by using toxic equivalent factors derived from literature and the USEPA, was approximately 7.6 ng m^???3. Source identification using factor analysis identified prominent three, four, four, and four probable factors at industrial, residential, roadside, and agricultural sites, respectively.     

Mercury, Methylmercury, and Selenium Concentrations in Eggs of Common Loons (Gavia immer) from Canada

Concentrations of Hg and Se were determined for a total of 125Common Loon (Gavia immer) eggs collected from lakes in Alberta, Saskatchewan, Ontario, Quebec, New Brunswick and NovaScotia, Canada between 1972 and 1997. Resulting data were compared to Hg and/or Se concentrations known or suspected tocause reproductive impairment in birds. Organic (methyl) Hg analyses were also performed on a subset of 24 loon eggs. Thirty-nine of 125 eggs had total Hg levels exceeding those (0.6 g g^-1 ww, or 2.5 g g^-1 dw)previously reported to be associated with reproductive impairment in common loons (Barr, 1986), and 9 of 125 eggshad Hg concentrations higher than the level associated withreproductive impairment in birds generally 1 g g^-1 ww; (Thompson, 1996). Selenium concentrations in loon egg samples were less than levels known to cause reproductiveimpairment in birds. A weak but significant positive correlation was observed between egg-Hg and -Se concentrations(r = 0.511, p < 0.05). On average, methylmercury accounted for about 87% of total Hg in 24 eggs analysed for both total and organic Hg. In this subset of eggs, the relationship between organic (methyl) Hg and Se was significant (r = 0.538, p = 0.007) while that found between inorganic Hg and Se in the same eggs was not significant (r = 0.353, p = 0.091). This relationship was unexpected and was contrary to relationships established for organic and inorganic Hg vs. Se in adult loon liver and kidney tissue (Scheuhammer et al., 1998b).     

Diversity of epiphytic lichens and metal contents of Parmelia caperata thalli as monitors of air pollution in the town of Pistoia (c Italy)

The results of a biomonitoring survey carried out in the town of Pistoia (central Italy) using the biodiversity of epiphytic lichens and the accumulation of heavy metals in thalli of Parmelia caperata as indicators of air pollution are reported. Compared to previous surveys, the overall situation generally improved, with higher lichen diversity at most stations and lower metal concentrations in P. caperata thalli. However, the general picture according to a calibrated scale of environmental naturality/alteration was substantially negative, with about 87% of the study area classified as `altered' (including the lichen desert) or `semi-altered'. To explain this apparent contradiction, it has been suggested that lichen colonization is determined by declining SO₂ concentrations, while major injuries to lichen communities are caused by the constantly high levels of NO_X. In spite of the low levels of Pb measured in P. caperata thalli, vehicular traffic was excluded as the main source of atmospheric pollution. Domestic heating seems to be the main cause of changes in the diversity of epiphytic lichens in the study area.