车内空气污染及控制

近年来,人们越来越关注车内空气污染。但人们对车内空气污染的了解甚少。本文就车内空气污染的污染源、污染物、健康影响、治理措施,相关标准等一系列问题,作系统论述。     

Assessment of the phytoextraction potential of high biomass crop plants

A hydroponic screening method was used to identify high biomass crop plants with the ability to accumulate metals. Highest values of shoot accumulation were found in maize cv. Ranchero, rapeseed cv. Karat, and cardoon cv. Peralta for Pb (18 753 mg kg(-1)), Zn (10 916 mg kg(-1)), and Cd (242 mg kg(-1)), respectively. Subsequently, we tested the potential of these three cultivars for the phytoextraction of a metal spiked compost, finding out that, in cardoon and maize plants, increasing Zn and Cd concentrations led to lower values of root and shoot DW. By contrast, rapeseed shoot growth was not significantly affected by Cd concentration. Finally, a metal polluted soil was used to check these cultivars' phytoextraction capacity. Although the soil was phytotoxic enough to prevent the growth of cardoon and rapeseed plants, maize plants phytoextracted 3.7 mg Zn pot(-1). We concluded that the phytoextraction performance of cultivars varies depending on the screening method used.     

Monitoring air quality with lichens: a comparison between mapping in forest sites and in open areas

Four different methods of epiphytic lichen mapping were used for the assessment of air quality in the region under the influence of the Sostanj Thermal Power Plant (Salek Valley, Slovenia). Three methods were based on the presence of different lichen species (VDI, EU and ICP-Forest), the fourth on a frequency and coverage assessment of different growth forms of epiphytic lichens, e.g. crustose, foliose and fruticose (SI). A comparison of the results from the assessment of air quality between forest sites (ICP-Forest, SI) and open areas (VDI, EU and SI), obtained by the different methods of epiphytic lichen mapping, is presented in the contribution. Data showed that lichen species richness is worse in forest sites in comparison with open areas. From the data obtained it can be concluded that epiphytic lichen mapping in open areas is a better method for the assessment of air pollution in a given area than mapping in forest sites. The species-based methods in open areas are more powerful and useful for air quality assessment in polluted research areas than the SI and ICP-Forest methods.     

Global fallout Pu recorded in lacustrine sediments in Lake Hongfeng, SW China

Studies on the distribution and isotope compositions of fallout Pu are important for source characterization of possible future non-fallout Pu contamination in aquatic environments, and useful for dating of recent sediments to understand the pollution history of environmental contaminants. We present the historical record of atmospheric Pu fallout reconstructed from a sediment core from Lake Hongfeng, China. The Pu activity profile was in agreement with the 137Cs profile. Inventories were 50.7 Bq m(-2) for 239+240Pu and 1586 Bq m(-2) for 137Cs. The average 240Pu/239Pu atom ratio was 0.185+/-0.009, indicating that Pu originated from global stratospheric fallout rather than from direct tropospheric or close-in fallout from the Chinese nuclear testing conducted in the 1970s. Our data suggested that Lake Hongfeng would be an ideal setting for monitoring atmospheric fallout and environmental changes in this region.     

Atmospheric pollutants monitoring by analysis of epiphytic lichens

The Canoparmelia texana epiphytic lichenized fungi was used to monitor atmospheric pollution in the S?o Paulo metropolitan region, SP, Brazil. The cluster analysis applied to the element concentration values confirmed the site groups of different levels of pollution due to industrial and vehicular emissions. In the distribution maps of element concentrations, higher concentrations of Ba and Mn were observed in the vicinity of industries and of a petrochemical complex. The highest concentration of Co found in lichens from the S?o Miguel Paulista site is due to the emissions from a metallurgical processing plant that produces this element. For Br and Zn, the highest concentrations could be associated both to vehicular and industrial emissions. Exploratory analyses revealed that the accumulation of toxic elements in C. texana may be of use in evaluating the human risk of cardiopulmonary mortality due to prolonged exposure to ambient levels of air pollution.     

Particle fluxes above forests: observations, methodological considerations and method comparisons

This paper reports a study designed to test, evaluate and compare micro-meteorological methods for determining the particle number flux above forest canopies. Half-hour average particle number fluxes above a representative broad-leaved forest in Denmark derived using eddy covariance range from -7x10(7) m(-2) s(-1) (1st percentile) to 5x10(7) m(-2) s(-1) (99th percentile), and have a median value of -1.6x10(6) m(-2) s(-1). The statistical uncertainties associated with the particle number flux estimates are larger than those for momentum fluxes and imply that in this data set approximately half of the particle number fluxes are not statistically different to zero. Particle number fluxes from relaxed eddy accumulation (REA) and eddy covariance are highly correlated and of almost identical magnitude. Flux estimates from the co-spectral and dissipation methods are also correlated with those from eddy covariance but exhibit higher absolute magnitude of fluxes.     

Elimination of Methanol and Ethanol by Biofiltration: An Experimental Study

This study presents the experimental results obtained during long-term operation of two biofilters treating two alcohols: methanol and ethanol. The biofilters used for this purpose were previously packed with a compost material made from tobacco processing residues. The alcohols concentrations tested lay between 0.40 and 3.20 g/m³ for methanol, and 0.55 and 5.05 g/m³ for ethanol. The empty bed residence time in each biofilter was 60 s. Biofilter inlet loads of less than 190 and 300 g/m³/h for the methanol and ethanol additions respectively, were thereafter evaluated. In addition, the concentrations of nutrient nitrogen were also varied, from 0.1 to 2.0 g-N/l and from 0.3 to 11.3 g-N/l for the ethanol and the methanol, respectively. The results thus obtained have made it possible to select the optimal nitrogen concentrations which, for the cases examined, turn out to be 0.3 g-N/l and between 2 and 3.8 g-N/l for the ethanol and methanol substrates, respectively. The maximum elimination capacities obtained in this study were 82 and 150 g/m³/h, respectively for the methanol and ethanol cases. It was therefore concluded that, for a readily biodegradable compound such as ethanol, the nitrogen requirement is substantially lower than that needed for the methanol degradation, the latter appearing to be more difficult to degrade biologically under similar operating conditions. The production rate of the co-product carbon dioxide during methanol and ethanol biofiltration was also investigated. Also, a good correlation was found to exist between the temperature and the conversion achieved in the biofilter.     

生物质热电厂大气影响评价的研究

为确定生物质能发电环境方面的可行性,分析了生物质能发电的工艺流程,相比于火电的优缺点,并进行了生物质能热电联厂的大气环境影响评价研究。结果表明：预测评价的烟尘、SO2和NO2排放浓度分别为11,63mg／m^3、200．3mg／m^3和378．7mg／m^3,均远低于火力发电的排放值;在不同条件下、不同地点SO2和NO2的1小时、日均浓度也均远低于火力发电的浓度值。说明了生物质能发电在环境友好性方面具有明显的优势。     

室内甲醛污染影响因素的多元回归分析

本文在室内甲醛质量守恒定律基本公式合理推导的基础上,对影响甲醛浓度的主要因素做了正交实验。对实验数据进行多元回归分析,建立室内甲醛浓度预测模型。对模型做检验,检验结果表明,本文的预测模型能较好地预测室内空气中的甲醛浓度。     

典型铬渣简易掩埋场铬渣及土壤铬污染特征和处置分析

通过钻孔采样分析,研究了典型铬渣简易掩埋场地下铬渣及土壤铬中Cr6 、总Cr的分布特征和污染状况,结果表明,铬渣简易掩埋场铬污染程度严重,引起了周边和地下深部较大面积的土壤污染,深度达到了地下的基岩.铬含量在土壤层剖面中分布呈现规律性变化,即随土壤深度增加,Cr6 、总Cr含量逐渐下降,但绝大多数超过了危险废物毒性鉴别标准.从铬污染程度上看,总体上存在铬渣>土壤>人工填土.在此基础上,提出了铬渣及污染土壤的处置方式,为铬渣污染治理和资源化利用提供科学依据.