北方城镇大气环境中烟尘排放总量控制研究初探

本文通过对北方城镇烟尘污染产生的原因、污染现状及治理水平的分析,提出了烟尘总量控制的原则、对策及控制措施。     

Characterization of aerosol optical properties, chemical composition and mixing states in the winter season in Shanghai, China

Physical and chemical properties of ambient aerosols at the single particle level were studied in Shanghai from December 22 to 28, 2009. A Cavity-Ring-Down Aerosol Extinction Spectrometer（CRD-AES） and a nephelometer were deployed to measure aerosol light extinction and scattering properties, respectively. An Aerosol Time-of-Flight Mass Spectrometer（ATOFMS）was used to detect single particle sizes and chemical composition. Seven particle types were detected. Air parcels arrived at the sampling site from the vicinity of Shanghai until mid-day of December 25, when they started to originate from North China. The aerosol extinction,scattering, and absorption coefficients all dropped sharply when this cold, clean air arrived.Aerosol particles changed from a highly aged type before this meteorological shift to a relatively fresh type afterwards. The aerosol optical properties were dependent on the wind direction.Aerosols with high extinction coefficient and scattering Angstrom exponent（SAE） were observed when the wind blew from the west and northwest, indicating that they were predominantly fine particles. Nitrate and ammonium correlated most strongly with the change in aerosol optical properties. In the elemental carbon/organic carbon（ECOC） particle type, the diurnal trends of single scattering albedo（SSA） and elemental carbon（EC） signal intensity had a negative correlation. We also found a negative correlation（r =-0.87） between high mass-OC particle number fraction and the SSA in a relatively clean period, suggesting that particulate aromatic components might play an important role in light absorption in urban areas.     

丹东北方环保工程有限公司

丹东北方环保工程有限公司（丹东市水技术机电研究所）创立于1991年,是我国较早专业从事现代环保技术、设备及其系统的科研生产单位之一。公司现有总占地面积48,000m2的厂区、建筑面积35,000m2的科研楼和厂房,拥有各种设备400多台（套）,资产总计1．2亿元。北环公司是中国环保产业协会理事单位、水污染治理委员会专家组成员单位、专业委员会副主任委员单位、辽宁省环保产业协会副会长单位、丹东市环保产业协会会长单位。     

转机就在一刹那

他商人抢购一空。情急之下,他突然心生一计,将当地用来盛茶叶的箩筐全部买下。当其他商人准备将所购的茶叶运回时,才发现已无箩筐可买,无奈只得求助于这位北方商人。就这样,北方商人轻而易举地赚了一大笔钱,还省下了往北方运茶叶的运费,直接将银子带回了家。     

《北方环境》征稿启事

《北方环境》杂志是由国家新闻出版总署批准,内蒙古自治区环境保护厅主管,内蒙古自治区环境科学研究院、内蒙古自治区环境监测中心站主办的综合性环境期刊。国内统一刊号CN15－1354／X,国际标准刊号ISSN1007－0370,国际大16开本。每月28日出版。每期定价15．00元。本刊本着反映环境科研成果,开展学术交流。促进环境科技、环境科学事业发展,振兴北方经济的办刊宗旨。为广大读者、作者服务。     

北方地区节能环保的采暖方式

冬季来临北方地区多年以来因传统采暖方式引发的一系列问题仍未能彻底解决。     

基于土地利用和气候变化的北方农牧交错带界线变迁

基于1961~2005 年中国北方9 省、自治区的218 个气象站点的气象资料及1986 年和2000 年的土地利用数据,从全球气候变化和土地利用变化角度分别界定了北方农牧交错带的地理位置,并分析了其界线变迁特征.结果表明,北方农牧交错带的地理位置还存在一定争议.交错带整体上已向西北移动.西北界已向北深入到纯牧区,东南界附近也由农牧交错区转成纯农区.气候界线向东南变迁,土地利用界线向西北变迁,两者变迁方向相反.东北段和华北段的界线变迁幅度远大于西北段.     

美国空军在越南战争中的空袭作战

正美国侵略越南的战争历时12年,是第二次世界大战后持续时间最长、规模最大的一次局部战争。在这场战争中,美国空军投入了大量兵力,除遂行空中阻滞作战和近距空中支援任务外,还集中进行了两次持续时间较长、规模较大的空中战役,重点空袭了越南人民武装力量的交通线和防空系统。     

Size-resolved aerosol ionic composition and secondary formation at Mount Heng in South Central China

To understand the size-resolved aerosol ionic composition and the factors influencing secondary aerosol formation in the upper boundary layer in South Central China, size-segregated aerosol samples were collected using a micro-orifice uniform deposit irnpactor （MOUDI） in spring 2009 at the summit of Mount Heng （1269 m asl）, followed by subsequent laboratory analyses of 13 inorganic and organic water-soluble ions. During non- dust-storm periods, the average PM1.8 concentration was 41.8 μg·m^-3, contributing to 55% of the PM10. Sulfates, nitrates, and ammonium, the dominant ions in the fine particles, amounted to 46.8% of the PM1.8. Compared with Mount Tai in the North China Plain, the concentrations of both fine and coarse particles and the ions contained therein were substantially lower. When the air masses from Southeast Asia prevailed, intensive biomass burning there led to elevated concentrations of sulfates, nitrates, ammonium, potassium, and chloride in the fine particles at Mount Heng. The air masses originating from the north Gobi brought heavy dust storms that resulted in the remarkable production of sulfates, ammonium, methane sulfonic acid, and oxalates in the coarse particles. Generally, the sulfates were primarily produced in the form of （NH4）2SO4 in the droplet mode via heterogeneous aqueous reactions. Only approximately one-third of the nitrates were distributed in the fine mode, and high humidity facilitated the secondary formation of fine nitrates. The heterogeneous formation of coarse nitrates and ammonium on dry alkaline dust surfaces was found to be less efficient than that on the coarse particles during non-dust-storm periods.     

Exposure measurement, risk assessment and source identification for exposure of traffic assistants to particle-bound PAHs in Tianjin, China

To investigate the levels of exposure to particulate-bound polycyclic aromatic hydrocarbon(PAH) and to estimate the risk these levels pose to traffic assistants(TAs) in Tianjin(a megacity in North China), a measurement campaign(33 all-day exposure samples, 25 occupational-exposure samples and 10 indoor samples) was conducted to characterize the TAs' exposure to PAHs, assess the cancer risk and identify the potential sources of exposure. The average total exposure concentration of 14 PAHs was approximately 2871 ± 928 ng/m3(on-duty), and 1622 ± 457 ng/m3(all-day). The indoor PAHs level was 1257 ± 107 ng/m3. After 8000 Monte Carlo simulations, the cancer risk resulting from exposure to PAHs was found to be approximately 1.05 × 10-4. A multivariate analysis was applied to identify the potential sources, and the results showed that, in addition to vehicle exhaust, coal combustion and cooking fumes were also another two important contributors to personal PAH exposure. The diagnostic ratios of PAH compounds agree with the source apportionment results derived from principal component analysis.