Nitrogen deposition threatens species richness of grasslands across Europe

Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha⁻¹ yr⁻¹) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range.     

Externalities of Fugitive Dust

It is known that fugitive dust can cause human health and environmental problems, alone or in combination with other air pollutants. These problems are referred to as ‘external costs’ that have been traditionally ignored. However, there is a growing interest towards quantifying externalities to assist policy and decision-making. With this in mind, the present study aimed at discussing the environmental regulations that deal with fugitive dust, the impact of fugitive dust on human health and global climate system, and the available methods for calculating fugitive dust externalities. The damage cost associated with human health and global environmental problems was predicted based on the environmental strategy priority model. The damage cost estimated by the model ranged from 40 to 374 EUR/kg of emitted fugitive dust with a mean value of 120 EUR/kg of emitted fugitive dust. It was also found that PM_2.5 and PM₁₀ have contributed to about 60% and 36% of the estimated damage cost, respectively. The remaining 4% was attributed to both nitrate and sulfate aerosols.     

Assessing the steady-state [·NO<Subscript>2</Subscript>] in environmental samples

Based on available literature data of [NO₂ ⁻], steady-state [·OH], and ·OH generation rate upon nitrate photolysis in environmental aqueous samples under sunlight, the steady-state [·NO₂], could be calculated. Interestingly, one to two orders of magnitude more ·NO₂ would be formed in photochemical processes in atmospheric water droplets compared to transfer from the gas phase. The relative importance of nitrite oxidation compared to nitrate photolysis as an ·NO₂ source would be higher in atmospheric than in surface waters. The calculated levels of ·NO₂ could lead to substantial transformation of phenol into nitrophenols in both atmospheric and surface waters.     

Inorganic constituents of urban air pollution in the Lazio region (Central Italy)

A field study was carried out at six locations in the Lazio region (Central Italy) aimed at characterising atmospheric particulate matter (PM₁₀ and PM_2.5) from the point of view of the chemical composition and grain size distribution of the particles, the mixing properties of the atmosphere, the frequency and relevance of natural events. The combination of four different analytical techniques (ion chromatography, X-ray fluorescence and ICP for inorganic components, thermo-optical analysis for carbon compounds) yielded sound results in terms of characterisation of the air masses. During the first three months of the study (October-December 2004), many pollution events of natural (sea-salt or desert dust episodes) or anthropogenic nature were identified and characterised. More than 90% of the collected mass was identified by chemical analysis. The central role played by the mixing properties of the lower atmosphere when pollution events occurred was highlighted. The results show a major impact of primary anthropogenic pollutants on traffic stations and a homogeneous distribution of secondary pollutants over the regional area. An evaluation of the sources of PM and an identification of possible reliable tracers were obtained using a chemical fractionation procedure.     

鞍山市空气颗粒物中酞酸酯的季节变化与功能区差异

采用气相色谱-质谱仪(GC-MS)对辽宁省鞍山市空气颗粒物中15种酞酸酯夏季和冬季的浓度进行了分析测定,研究了酞酸酯污染水平的季节变化,不同功能区酞酸酯浓度的差异,以及DBP和DEHP在夏冬两季中的污染特点,将鞍山市夏冬两季酞酸酯的浓度与国内外部分城市进行了比较,分析了产生上述结果的原因,基本说明了鞍山市空气颗粒物中酞酸酯的污染状况。     

天津市空气颗粒物中酞酸酯的分布特征

采用气相色谱-质谱仪(GC-MS)对天津市空气颗粒物中15种酞酸酯(PAEs)夏季和冬季的浓度进行了分析测定,研究了酞酸酯污染水平的季节变化,不同季节酞酸酯的功能区差异,15种酞酸酯在颗粒物中的分布特征,以及DBP和DEHP在夏冬两季中的污染特点,分析了产生上述结果的原因,基本说明了天津市空气颗粒物中酞酸酯的污染状况和特点。     

电导率加和性质及其在降水监测数据处理中的应用

采用相对电导率差（CPD）法、电导率-pH不等式法对某监测站大气降水的实测电导率和pH值等数据进行质量分析。根据分析结果认为可用CPD法来检验、评估降水中各种离子成分的分析是否完整、准确,用电导率-pH不等式法来检验电导率和pH值的测定值是否存在明显的误差。     

铅冶炼企业周边大气降尘中铅、镉、砷量及其对土壤的影响

通过在2012年5月-2013年4月1个周期年内,对修复基地和对照点每月大气降尘中铅、镉、砷沉降量的监测,结果表明：修复基地大气降尘中铅、镉、砷含量明显较对照点高,年总沉降量分别是对照点的17．6倍、16．3倍和14．1倍,表明铅冶炼企业对基地大气降尘中铅、镉、砷含量影响显著;大气降尘中铅、镉、砷沉降量受位置和时间影响较大,在相距不到100 m的测点间,沉降量相差1倍以上,冬季主导风明显、地面植被少、二次扬尘大,使处于铅冶炼企业下风向的基地降尘中铅、镉、砷沉降量较大。沉降量时空不均匀与土壤污染不均匀现状一致,也验证了铅冶炼企业是基地大气和土壤重金属污染的主要来源。以降尘缸模拟土壤进行测算,结果表明大气降尘中镉对土壤污染速度最快,风险最大。     

基于环境库兹涅茨曲线特征的桂林市大气环境状况研究

根据2006年-2012年桂林市经济发展主要指标和大气环境污染指标的统计资料,分析了该市人均 GDP 与SO2、NO x、烟（粉）尘排放量及 PM10质量浓度和 API优良率等大气环境指标的相关关系,建立了经济发展与大气环境指标之间的模拟曲线。模拟结果表明,桂林市处于工业时期,随着人均GDP增加,SO2和烟（粉）尘排放得到了一定程度的缓解,而NO x 和 PM10排放从长期看还处于上升趋势。建议改善能源结构,调整产业结构和工业布局,制定财税激励政策,开展环境综合整治,加大机动车排污防治力度,进一步控制大气污染。     

石家庄市大气颗粒物中水溶性无机离子污染特征研究

用超声萃取－离子色谱法分析了石家庄市大气颗粒物中8种水溶性无机离子。结果表明,NO3－、SO2－4、NH4＋及 Ca2＋为主要组分;各个离子的质量浓度均有季节及空间变化差异;不同粒径颗粒物中 SO2－4和 NO3－相关性均很好,NH4＋与 SO2－4、NO3－在细颗粒物中具有良好的相关性,Ca2＋在粗粒子中与 NO3－和 SO2－4的相关性也较好。SO2－4／NO3－质量比季节变化表明,春、夏季固定源与流动源对大气颗粒物贡献相当,秋季流动源贡献较大,冬季固定源贡献较大。PM2．5中SO2与SO2－4、NO2与 NO3－转化率表明,SO2－4、NO3－主要是由二次转化而来。