乌鲁木齐市降尘的浓度水平和空间分布及与城市PM_(10)的相关性分析

以2005—2009年乌鲁木齐市城市大气降尘数据为依据,对乌鲁木齐市城市自然降尘的浓度水平和变化规律进行了研究,用Arc-GIS绘出乌鲁木齐市城市自然降尘的空间分布图,并分析和探讨了城市降尘与PM10相关性及防治对策。     

消费电子产品生产过程中挥发性有机物(VOCs)排放特征的研究

选取塑胶零件、印刷线路板及主板3类消费电子产品部件为研究对象,利用活性炭管采样,样品溶剂解吸后采用GC/MS分析,获得了各排气筒及车间内VOCs含量水平与组分特征.通过计算排放量,得出了分物种VOCs排放系数.结果表明,塑胶零件生产线排气筒总挥发性有机物(TVOCs)浓度为48.01~115.05 mg·m-3,印刷线路板为6.08~11.36 mg·m-3,主板为29.81~30.21 mg·m-3.塑胶零件生产车间内TVOCs浓度为4.23~120.58 mg·m-3,印刷线路板为1.50~2.02 mg·m-3,主板为7.01~9.93 mg·m-3.环烷烃类、酯类、苯类为主要排放物质.对于不同产品生产线的排气筒及车间废气,浓度和物种均有很大差异;对于相同产品,浓度有差异但物种基本相同.按产品分类,共计算得出了36个分物种VOCs排放系数,其中,塑胶零件、印刷线路板及主板TVOCs排放系数分别为0.626 kg·kg-1涂料用量、0.123 kg·kg-1油墨用量、0.028 kg·kg-1印刷线路板用量.通过排放量计算结果分析,3种产品中,塑胶零件生产为VOCs主要排放源,车间内无组织排放为主要排放方式.     

Pollution levels and characteristics of phthalate esters in indoor air in hospitals

The concentrations of phthalate esters(PAEs) in Chinese hospitals were investigated by simultaneously determining concentrations of gas- and particle-phase PAEs. PAEs were detected in two third-class first-grade hospitals, two second-class first-grade hospitals, and a community health service center. Hospital drugstores had the highest concentration(24.19 μg/m3), which was 1.54 times that of newly decorated houses. The second highest concentration was found in the transfusion rooms, averaging 21.89 μg/m3; this was followed by the concentrations of PAEs in the nurse's workstations, the wards, and the doctor's offices, with mean concentrations of 20.66, 20.0, and 16.92 μg/m3, respectively. The lowest concentrations were found in the hallways(16.30 μg/m3). Of the six different kinds of PAEs found, major pollutants included diethyl phthalates, dibutyl phthalates, butylbenzyl phthalates and di(2-ethylhexyl) phthalates, comprising more than 80% of all PAEs present.Meanwhile, a comparison between different wards showed that PAE concentrations in the maternity wards were 1.63 times higher than in the main wards. Based on known health hazards, our results suggest that the PAEs seriously influence the health of the pregnant women and babies; therefore, it is of great importance to take the phthalate concentrations in hospitals into consideration. In addition, hospital indoor air was more seriously contaminated than the air of newly decorated houses.     

城市土地利用类型与PM2.5浓度相关性研究——以武汉市为例

随着我国工业化的不断发展,在我国的主要经济发展地区的雾霾天气不断爆发,使我国的大气环境日益恶化,严重影响了人们的日常生活和身体健康。PM2.5作为雾霾的重要组成成分,也日渐成为环境领域的研究热点问题。随着全球性变化研究领域逐渐加强了对土地利用与生态环境的相关研究,因此无论从法律和社会经济发展的角度,还是从生态资源保护与环境可持续发展的角度,土地利用与PM2.5的相关研究都显得相当重要。研究目的:分析武汉市各类用地类型与PM2.5浓度的相关性程度。研究方法:使用ENVI与ArcGIS对武汉市2013年MODIS气溶胶产品进行空间分析与插值处理,再应用SPSS将其与武汉市2013年10个观测点的PM2.5浓度数据作相关性分析,以证实MODIS气溶胶厚度与PM2.5浓度的相关性,并建立两者的线性回归方程,然后利用计算后的武汉市整体PM2.5浓度分布与各土地利用类型进行相关性研究。研究结果:武汉市PM2.5浓度有明显的空间分布特征,绿化面积比例与PM2.5浓度呈显著负相关,建设用地面积比例与PM2.5浓度呈显著正相关,未利用地面积比例虽然与PM2.5浓度呈正相关,但相关性较低,而耕地与水体对PM2.5浓度没有显著影响。研究结论:土地利用类型对武汉市PM2.5浓度的分布有显著的影响,其与搭载MODIS传感器的遥感卫星监测方式的结合能成为研究大范围特定区域PM2.5浓度空间格局的新方法,并且增加城市绿化面积,控制建设用地规模能有效减少PM2.5浓度。     

杭州地区大气细颗粒物浓度变化特征分析

利用2012年杭州地区(杭州、桐庐、建德、淳安)大气颗粒物监测仪TEOM1405D的连续观测资料,对该地区PM2.5质量浓度的变化特征及其与气象条件的关系进行了分析研究.结果表明,2012年杭州、桐庐、建德、淳安PM2.5年平均浓度分别为50.0±25.7、46.5±22.0、42.1±21.8、36.9±21.2μg·m-3,空间上呈现至北向南逐渐下降的变化趋势.受边界层高度、降水等气象条件影响,4个站点PM2.5浓度的季节变化基本表现为秋季冬季春季夏季,其中秋、冬季PM2.5超标日数高达80%左右.杭州地区PM2.5日变化呈现明显的双峰型特征,其峰值出现时间与人们的早晚出行高峰有较好的对应关系.对比不同站点PM2.5浓度变化可以看出人口密集城市区域气溶胶浓度要显著高于乡村地区.通过拟合小时平均值最大出现频率得出杭州地区最具代表性大气状态下PM2.5的浓度值为21.2μg·m-3.风向风速与PM2.5浓度的关系表明杭州主要以本地污染为主,桐庐受本地污染和区域输送双重影响,建德主要表现为区域输送.     

未来RCP4.5情景下黄海DMS浓度变化模拟与分析

使用CORDEX-EA过去气候态(2000-2009年)与RCP4.5情景下近未来气候态(2041-2050年)大气强迫结果驱动中国东部陆架海域耦合DMS模块生态模型,模拟了黄海过去及近未来表层DMS浓度(C_DMS),探究了黄海近未来C_DMS时空分布的变化及其影响因素.结果表明:近未来黄海C_DMS的年循环发生变化,北黄海C_DMS极高值出现月份由5、9月转变为4、10月,南黄海由4、9月转变为4、8月;局部C_DMS高值区也发生变化,春季山东半岛附近海域、夏季苏北浅滩、南黄海中东部、秋季南黄海东部C_DMS高值区加强,夏季山东半岛附近C_DMS高值区减弱.近未来热通量、风应力对山东半岛、南黄海中东部海域C_DMS影响较大;降水量、云量对西朝鲜湾C_DMS的影响占优;苏北浅滩C_DMS受多个气候因子共同作用.     

稻田灌溉河流CH4和N2O排放特征及影响因素

随着农业氮肥大量施用,大量碳氮营养物质以淋溶或径流形式进入周边灌溉水体,使其成为甲烷(CH4)和氧化亚氮(N2O)的重要排放源.以我国东南部地区典型稻田灌溉河流为研究对象,于2014年9月至2016年9月连续两年原位观测表层水体CH4和N2O溶存浓度及其排放通量,旨在明确稻田灌溉河流CH4和N2O的排放特征、排放强度及其主要驱动因子.结果表明,观测期内c(CH4溶存)的年平均值为(390.57±43.95)nmol·L-1(92.80～1 577.54 nmol·L-1),c(N2O溶存)的年平均值为(40.23±3.20)nmol·L-1(10.05～75.40 nmol·L-1).CH4和N2O的排放通量(年平均)分别为(20.73±6.08)mg·(m2·h)-1和(34.30±7.12)μg·(m2·h)-1.CH4和N2O溶存浓度和排放通量整体上均呈现出春夏排放高,秋冬排放低的季节变化趋势.两年CH4累计排放总量为(3 876.30±1 153.96)kg·hm-2,N2O累计排放总量为(5.74±0.98)kg·hm-2.两者持续性全球增温潜势(SGWP,以CO2-eq计)平均为(87.99±15.73)t·(hm2·a)-1.CH4排放通量与水温、底泥可溶性有机碳(DOC)显著正相关,而与水体溶解氧(DO)显著负相关;N2O排放通量与水温、水中铵态氮(NH4+-N)和硝态氮(NO3--N)显著正相关,而与水体DO显著负相关.该研究可为科学估算我国农业灌溉流域CH4和N2O排放总量提供数据支撑和重要参考.     

Comparison of temporal and Spatial Characteristics of Ozone Pollution at Ground Level in the Eastern China

Monitoring data from ozone（O3） automatic stations in three typical cities with different climatic areas in the southern and northern parts of eastern China are used to analyze temporal and spatial characteristics of ozone pollution at ground level. The results show that ozone pollution level has distinct regional differences and the concentration in the suburbs is higher than that in the urban areas. The seasonal variation of ozone concentration in different climatic areas is greatly affected by the variation of precipitation. Ozone concentration in Shenyang and Beijing , in the temperate zone, has one perennial peak concentration, occurring in early summer, May or June. Ozone concentration in Guangzhou, in sub-tropical zone, has two peak values year round. The highest values occur in October and the secondary high value in June. The ozone season in the south is longer than that in the north. The annual average daily peak value of ozone concentrations in different climates usually occur around 3 pm. The diurnal variation range of ozone concentration declines with the increase of latitude. Ozone concentration does not elevate with the increase of traffic flow. Ozone concentration in Guangzhou has a distinct reverse relation to CO and NOx. This complicated non-linearity indicates that the equilibrium of ozone photochemical reaction has regional differences. Exceeding the rate of Beijing＇s lh ozone concentration is higher than that of Guangzhou, whereas the average 8h ozone level is lower than that of Guangzhou, indicating that areas in low latitude are more easily affected by moderate ozone concentrations and longer exposure. Thus, China should work out standards for 8h ozone concentration.     

RELATIONSHIP OF NITRATE CONCENTRATIONS TO DISTANCE OF WELL SCREEN OPENINGS BELOW CASING WATER LEVELS1

ABSTRACT: Data from 54 well in central and eastern Kansas developed in unconsolidated deposits of Quaternary age indicate that nitrate concentrations are inversely related to the depth of the well screen opening below the water level in the well casing because this relationship was found to exist in an area of Nebraska and in a large area of Kansas, the relationship is generally valid over a wide geo- graphical area. In addition, the data indicate that the incidence of nitrate concentrations exceeding 45 milligrams per liter and nitrate concentrations, in general, are significantly lower in water from wells with screens deeper than 25 feet below the water table in unconfined aquifers or where screens are placed in deep confined aquifers. No concentrations of nitrate greater than 45 milligrams per liter were in obseved wells where screens were deeper than 60 feet below the casing water level. These findings suggest that general placement of well screens as far below the water table as possible in unconfined unconsolidated aquifers in Kansas. and possibly other areas of the Midwest, may be an effective measure in preventing undesirable nitrate concentrations in ground water supplies. particularly in areas where nitrate is a problem.     

Trace Element Contaminants in Sediments From the Noaa National Status and Trends Programme Compared to Data From Throughout the World

The National Oceanic and Atmospheric Administration's (NOAA) National Status and Trends (NS&T) Programme has analyzed samples of surface sediment collected at almost 300 coastal and estuarine sites throughout the United States since 1984. the overall distributions for concentrations of each element are approximately lognormal allowing a definition of geometric means and of “high” concentrations as those exceeding the mean plus one standard deviation of the lognormal distribution. Those mean and “high” concentrations should be useful for comparing the NS&T data set and with other reports on sediment contamination. A world-wide data set, constructed from data in the literature, was summarized in an identical manner. It was found, after excluding locally extreme values, that the NS&T and world-wide data sets yielded very similar mean and “high” concentrations for Cu, Ni, Pb and Zn. Chromium was the sole element showing higher summary statistics in the NS&T data set, a result attributed to NS&T sampling in areas of naturally (not contaminated) elevated Cr content. It remains undetermined, however, why the world-wide data set, even with exclusion of “hot spots”, yielded higher means and “highs” for Cd, Hg, As, and Ag.