郑州市13种绿化带植物中铅质量比的对比研究

利用石墨炉-原子吸收光谱法测定郑州市13种绿化带植物叶片中铅质量比,结果表明:植物叶片中铅质量比范围在0.16 mg/kg~7.65 mg/kg之间。不同空间分布的植物铅质量比差异显著,总体呈现草坪植物灌木乔木的趋势;同一采样点不同植物叶片铅质量比不同;同一植物不同组织部位铅质量比也不同;其中月季花、金叶女贞、白花三叶草作为铅富集能力较强的绿化带植物,有望成为城市空气铅污染修复的理想植物材料。     

中国主要城市疫情管控期间大气环境改善效应研究

利用我国31个省会(省府)城市、直辖市站点大气污染物数据,对全国主要城市2020年新冠疫情管控期间以及复工复产后的大气污染状况进行统计学分析。结果表明:叠加疫情管控影响,相比往年,2020年春节假期前后全国主要城市整体上PM₁₀、NO₂、SO₂、CO平均质量浓度降幅分别达到22.46%、60.13%、13.71%、17.64%;疫情管控期间全国主要城市PM_2.5与PM₁₀偏相关系数为0.952,PM_2.5与SO₂、NO₂、CO的偏相关系数分别为0.705、0.791、0.831。复工复产初期相较疫情管控期间仅有NO₂平均质量浓度上升;随着复工复产进程深入,PM₁₀、SO₂、NO₂平均质量浓度则均有大幅度上升。采暖区SO₂和CO平均质量浓度在疫情管控期分别为非采暖区的2.6倍及1.6倍,两大区域在复工复产后各大气污染物质量浓度变化情况有所差异,也反映出采暖区与非采暖区的大气污染情况的不同。     

运用植物学方法推定大气污染

以桂阳县某村 1998年 5月发生的一起大气污染事故为例 ,阐述了运用植物学方法推定大气污染及其方法、步骤。其主要步骤是 :事故现场调查 ,植物个体发育情况观察 ,植物器官受害症状观察 ,植物组织、细胞观察。方法是 :利用上述观察结果与《植物、大气污染检索表》和《植物、大气污染耐受力表》进行对照分析 ,推定植物是否受到大气污染的危害及其受害程度     

北京市机动车尾气排放PM10组分特征研究

为提高机动车尾气排放可吸入颗粒物PM10成分谱的代表性和准确性,提出并采用在机动车尾气检测线上采用稀释通道采样器随机采集机动车排出PM10的采样方法。采集了591辆轻、重型汽油车和柴油车尾气排放PM10,测试并分析了颗粒物的27种组分。数据表明:机动车排放颗粒物PM10中含量丰富的组分为OC、EC、NH+4、NO-3和SO2-4;柴油车排放PM10中OC和EC的质量分数为49.08%,是汽油车(38.38%)的1.3倍,汽油车的OC/EC(2.36)是柴油车(0.78)的3倍;汽油车排放PM10中的二次转化产物(SO42-+NH4++NO3-)的质量分数为19.37%,是柴油车(3.57%)的5.4倍;汽油车排放NH+4是柴油车的5.3倍。     

成渝地区典型中小城市VOCs污染特征、臭氧生成潜势及来源分析

为了解成渝地区中小城市VOCs污染特征及其来源,选取该区域典型代表城市-遂宁市为研究对象,利用2019年不同时间不同功能区106种VOCs离线观测数据,研究了该市VOCs污染水平和时空特征,分析了VOCs主要成分及其对臭氧的影响,并进行了源解析。结果显示：(1)遂宁市大气中VOCs平均体积分数为39.4×10^-9,8月的浓度较高,其空间排序为工业区>城郊区≈文教区。(2)OVOCs和烷烃是VOCs主要组分,占比达73.4%,且不受时间和空间限制;工业区不同组分浓度均高于城郊区和文教区,城郊区和文教区的同组分占比相差较小;丙酮和乙烷是VOCs中体积分数最大的物种,占总体积分数的37.8%。(3)VOCs组分对OFP贡献率顺序为烯烃>芳香烃>OVOCs>烷烃>炔烃>卤代烃>有机硫,前4类组分对OFP贡献率达97.6%,烯烃对OFP贡献率不仅每日最大,而且还呈现“城郊区>文教区>工业区”空间分布态势;异戊二烯、乙烯是OFP最大的物种,在不同功能区其OFP均高于其他物种,是遂宁市臭氧防治关注重点。(4)VOCs排放源及...     

烟花爆竹燃放对北京市空气质量的影响研究

结合常规污染物浓度和PM_(2.5)化学组分浓度,分析了2015年春节期间烟花爆竹燃放对北京市空气质量的影响。结果表明:烟花爆竹燃放会在短时间内造成严重的大气污染,其中对SO2、PM_(2.5)和PM10的影响最为显著。除夕夜间良乡、官园和怀柔3个监测站点的PM_(2.5)质量浓度峰值分别达730.5、343.4、762.2μg/m~3,为2月17—25日和3月4—8日(观测期间)平均值的5.2、3.1、7.1倍。烟花爆竹燃放对PM_(2.5)组分中的SO_4~(2-)、K+和Cl-的影响最为显著,除夕夜间监测中心点位的SO_4~(2-)、K~+和Cl~-质量浓度峰值分别达92.2、95.6、57.4μg/m~3,为观测期间平均值的4.5、10.5、6.8倍。烟花爆竹燃放产生的气态前体物和NO_3~-、SO_4~(2-)、NH+4、OC等PM_(2.5)二次化学组分在不利的气象条件下会发生化学反应和物理积累,造成PM_(2.5)浓度升高,产生持续性的大气污染。根据各污染物与NH+4的质量浓度比推算得出,除夕、"破五"和元宵节3个时段烟花爆竹燃放对K~+、Cl~-、SO_4~(2-)、SO_2和PM_(2.5)浓度的平均贡献率分别为78.4%、61.1%、37.4%、38.7%和30.1%。     

重庆市春季大气PM10中有机碳、元素碳浓度水平及污染特征分析

2006年4月于重庆市主城区9个采样点和1个城郊对照点同步采集了大气PM10样品,利用热分解示差热导法元素分析仪测定了PM10中的有机碳(OC)、元素碳(EC)的质量浓度,对OC和EC的污染水平、空间分布、OC和EC的浓度关系以及二次有机碳(SOC)等特征进行了较为详细的分析。结果显示,不同区域采样点的OC、EC浓度存在较明显差异,主城区大气环境中OC、EC平均浓度分别为52.5、8.6μg/m3,是对照点OC(16.8μg/m3)、EC(2.9μg/m3)浓度的3.1和3.0倍;主城区总碳气溶胶(TCA)占PM10总浓度的比例均值为33.3%;无论是高污染城区点还是一般城区点,OC和EC浓度间的相关性均不显著;各样点OC/EC值均超过2,表明存在二次有机碳的贡献;初步估算主城区PM10中的二次有机碳浓度均值为39.6μg/m3,占PM10总浓度的16.1%左右。     

西藏自治区“十二五”和“十三五”环境空气质量变化特征

"十二五"以来中国先后颁布了一系列大气污染防治政策并实施相应的大气污染治理措施以提高环境空气质量。为研究西藏自治区"十二五"(2011-2015年)和"十三五"(2016 -2020年)时期环境空气质量变化状况,评估大气污染防治措施实施效果,笔者对2011-2020年西藏自治区7个城市(地区)主要大气污染物浓度和优良天数比例变化进行分析。结果表明:随着一系列大气污染防治措施的实施,西藏自治区环境空气质量显著提升,与"十二五"时期相比,"十三五"时期西藏自治区年平均优良天数比例由97.5%±2.0%提升至99.3%±0.4%,SO₂、 NO₂、 PM₁₀、 PM_2.5浓度年均值和CO 浓度第95百分位数均呈下降趋势,其中CO、PM₁₀和PM_2.5浓度下降幅度较大,O₃日最大8h滑动平均值第90百分位数略有上升。西藏自治区环境空气质量与人口、经济发展程度呈负相关关系。受污染源排放、气象条件和区域传输等因素影响,西藏自治区O₃浓度春、夏季较高,而其余污染物浓度冬季较高。     

对我国大气污染自动监测系统建设的思考

六十年代末七十年代初世界上许多发达国家相继建立了大气污染自动监测系统(APMS)。实现了在一个地区进行多点、同步、连续监测。大气污染自动监测系统可以提供大气污染时间——浓度变化曲线,各类平均值与频数分布统计资料及污染事故发生时的大气污染状况与气象数据;为掌握区域性大气污染特征及变化趋势:研究污染物分布变化规律、评价人体及动植物污染暴露的影响状况;验证大气污染物扩散模式;进行污染的预测预报及控制、环境规划、立法及管理提供科学依据。     

岩溶农业区地下河流域硝酸盐污染来源——以重庆青木关岩溶区为例

于2010年6月—10月每月对青木关地下河水进行监测,利用15N同位素技术并结合水化学指标,分析地下河的水化学特征以及硝态氮来源的时空变化特征。结果表明,地下河出口丁家龙洞硝态氮质量浓度（5.08 mg/L）比入口天池2号点（0.842 mg/L）高6倍多。天池2号点处δ15N为-0.705%~+0.706%,主要受到人造化肥和天然土壤矿化的有机氮的影响,总体变化幅度不大,地下水受外界影响较小。出口丁家龙洞处的δ15N为-2.15%~+3.78%,平均值为+1.01%,总体值高,且变化幅度大。     

The epiphytic lichen hypogymnia physodes as a biomonitor of atmospheric nitrogen and sulphur deposition in Norway

Hypogymnia physodes was sampled from 179 sites of Scots pine forests regularly distributed throughout Norway. The purpose was to map the nitrogen and sulphur contents of lichen thalli on a large-scale geographical basis, and to relate these values to differences in atmospheric deposition and climate.The lichen nitrogen and sulphur concentrations showed large differences; the highest concentration values being 4–5 times greater than the lowest. The highest nitrogen and sulphur values occurred along the coast of southern Norway and on some sites in the inland of southern Norway. There was a close correlation between the two elements. The lichen N/S ratio decreased with increasing latitude.The nitrogen and sulphur contents ofHypogymnia physodes were both significantly correlated to estimated atmospheric deposition of these two elements in Norway. The degree of explanation improved when climatic variables such as temperature sum, altitude, annual precipitation and temperature were included. Factors promoting growth, such as high bark pH, mild winters, hot summers, high precipitation, high ammonium deposition and high evapotranspiration, were all associated with lower lichen nitrogen and/or sulphur concentrations. Unfavourable growth conditions, such as at high altitude, was related to higher concentrations than expected from deposition models. This indicates that differences in element concentration between nearby localities might be related to local differences in climate and lichen growth conditions. This should be taken into consideration whenever using lichens for biomonitoring.     

Use of chironomid deformities to assess environmental degradation in the Yamaska River,Quebec

The frequency of morphological deformities in chironomid larvae was used to assess environmental degradation at 12 sites in the Yamaska River, Quebec, that were known to be either impacted by agriculture or urban centres, or were relatively clean and used as reference sites. A total of 2273 chironomid larvae were examined for deformities. The overall frequency of deformities at polluted sites was 2.7%, whereas no deformities were observed at the reference sites. The highest incidence of deformities was found downstream of two urban centres, site 9 at Acton Vale (5.1% deformed) and site 12 at Ste Hyacinthe (5.3% deformed). The frequency of deformities at the agricultural sites ranged from 0.8 to 2.5% and was comparable to sites receiving municipal sewage effluent. The occurrence of higher frequencies of deformities downstream of urban centres indicates that the frequency of deformities increases with environmental degradation.     

Air Quality Assessment in Delhi: Before and After CNG as Fuel

A number of policy measures have been activated in India in order to control the levels of air pollutants such as particulate matter, sulphur dioxide (SO₂) and nitrogen dioxide (NO₂). Delhi, which is one of the most polluted cities in the world, is also going through the implementation phase of the control policies. Ambient air quality data monitored during 2000 to 2003, at 10 sites in Delhi, were analyzed to assess the impact of implementation of these measures, specifically fuel change in vehicles. This paper presents the impact of policy measures on ambient air quality levels and also the source apportionment. CO and NO₂ concentration levels in ambient air are found to be associated with the mobile sources. The temporal variation of air quality data shows the significant effect of shift to CNG (Compressed Natural Gas) in vehicles.     

Roadside Concentration of Gaseous and Particulate Matter Pollutants and Risk Assessment in Dar-Es-Salaam, Tanzania

This study used manual air sampling method to assess the contribution of road traffic to air pollution level in Dar-es-Salaam City, Tanzania. Samples were collected from 11 different sites. Parameters measured were: sulphur dioxide using pararosaniline method, nitrogen dioxide using saltzman method, particulate matter and particulate lead using filtration method and atomic absorption spectrometric method, respectively. Results showed that hourly average sulphur dioxide concentration range from 127 to 1385 g/m³. The measured values of sulphur dioxide were above the recommended WHO guidelines with an hourly objective value of 350 g/m³ at 87% of the sampling sites. The hourly average nitrogen dioxide concentration ranged from 18 to 53 g/m³. The maximum hourly nitrogen dioxide concentration at 53 g/m³ was below the WHO guideline value of 200 g/m³. The hourly average suspended particulate matter (SPM) ranged from 98 to 1161 g/m³, exceeding the recommended value of 230 g/m³ by WHO at 87% of the sampling sites. The hourly average lead concentration was found to range from 0.60 to 25.6 g/m³, exceeding again the WHO guideline value of 1.5 g/m³at 83% of the sampling sites. Results predicted by Gaussian model when compared with the measured values were found to have a correlation coefficient of 0.8, signifying a good correlation. The risk assessment was undertaken considering the people who spend a significant portion of their time near the roads, such as the Uhuru primary school pupils and the adult population who reside by the roadside. The unit risk realised was 18.2 × 10^–6 for adult population and 2.2 × 10^–6 for pupils, both scenarios showing risk higher than the United Sates of America Environmental Protection Agency (USEPA) acceptable limit of 1× 10^–6. Considering the magnitude of the problem at hand, this study recommends an introduction of mandatory emission tests of SPM, lead and sulphur dioxide (SO₂). The study further recommends the introduction of continuous and/or regular air quality monitoring and the use non-leaded petrol in Tanzania.     

An investigation of arsenic contamination in Peninsular Malaysia based on Centella asiatica and soil samples

The first objective of this study was to provide data of arsenic (As) levels in Peninsular Malaysia based on soil samples and accumulation of As in Centella asiatica collected from 12 sampling sites in Peninsular Malaysia. The second objective was to assess the accumulation of As in transplanted C. asiatica between control and semi-polluted or polluted sites. Four sites were selected which were UPM (clean site), Balakong (semi-polluted site), Seri Kembangan (semi-polluted site) and Juru (polluted site). The As concentrations of plant and soil samples were determined by Instrumental Neutron Activation Analysis. The As levels ranged from 9.38 to 57.05 μg/g dw in soils, 0.21 to 4.33 μg/g dw in leaves, 0.18 to 1.83 μg/g dw in stems and 1.32–20.76 μg/g dw in roots. All sampling sites had As levels exceeding the CCME guideline (12 μg/g dw) except for Kelantan, P. Pauh, and Senawang with P. Klang having the highest As in soil (57.05 μg/g dw). In C. asiatica, As accumulation was highest in roots followed by leaves and stems. When the As level in soils were higher, the uptake of As in plants would also be increased. After the transplantation of plants to semi-polluted and polluted sites for 3 weeks, all concentration factors were greater than 50 % of the initial As level. The elimination factor was around 39 % when the plants were transplanted back to the clean sites for 3 weeks. The findings of the present study indicated that the leaves, stems and roots of C. asiatica are ideal biomonitors of As contamination. The present data results the most comprehensive data obtained on As levels in Malaysia.     

Biochemical responses in tree foliage exposed to coal-fired power plant emission in seasonally dry tropical environment

A biomonitoring study was conducted to investigate the responses of plants exposed to power plant emission in a dry tropical environment. For this purpose, five sampling sites were selected in the prevailing wind direction (NE) at different distance to thermal power plant (TPP) within 8.0 km range and a reference site was selected in eastern direction at a distance of 22.0 km. The two most common tree species, Ficus benghalensis L. (Evergreen tree) and Dalbergia sisso Roxb. (deciduous tree) were selected as test plants. Ambient sulphur dioxide (SO(2)), nitrogen dioxide (NO(2)), suspended particulate matter (SPM), respirable suspended particulate matter (RSPM), dust-fall rate (DFR) and plant responses such as leaf pigments (chlorophyll a, chlorophyll b and carotenoids), ascorbic acid, sugar and sulphate-sulphur (SO4(2-)-S) contents were measured. Ambient SO(2), NO(2), SPM, RSPM and DFR showed significant spatial and temporal variation at different sites. Considerable reduction in pigment (chlorophyll a, chlorophyll b and carotenoids) and sugar contents were observed at sites receiving higher pollution load. Ascorbic acid exhibited significant positive correlation with pollution load. Accumulation of SO4(2-)-S in leaf tissue showed significant positive correlation with ambient SO(2) concentration at all the sites. At the same time, SO4(2-)-S showed significant negative correlation with pigment and sugar content. D. sisso Roxb. tree was found to be more sensitive as compared to F. benghalensis L. tree.     

Evaluation of air pollution phytotoxicity downwind of a phosphate fertilizer factory in India

The effects of air pollution on plants downwind of a fertilizer factory at Udaipur, India, were studied using three woody perennials. Seedlings of these species including a shrub (Carissa carandas L.), a leguminous avenue tree (Cassia fistula L.) and a fruit tree (Psidium guajava L.) were grown in earthen pots at different study sites receiving varying levels of air pollution input. Changes in plant growth, morphological characteristics, photosynthetic pigment, ascorbic acid, N and S contents and in dry matter allocation were considered in relation to the status of ambient air quality. Observations with these parameters have indicated that the ambient air around the factory contained pollutants at phytotoxic levels. Plant height, basal diameter, conopy area, leaf area and chlorophyll, ascorbic acid and foliar-N concentrations decreased with increasing pollution load. However, foliar-S increased slightly at polluted sites. Air pollution load around the factory have also altered the biomass allocation. Root:shoot ratios increased in C. fistula and P. guajava at polluted sites. In contrast, for C. carandas the above ground parts, where foliage assumed predominance showed precedence over the root growth. This species responded characteristically to air pollution stress by allocating more of its photosynthate towards leaf production and shoot growth.     

Measuring reactive nitrogen emissions from point sources using visible spectroscopy from aircraft

Accurate measurements of nitrogen dioxide (NO2), a key trace gas in the formation and destruction of tropospheric ozone, are important in studies of urban pollution. Nitrogen dioxide column abundances were measured during the Texas Air Quality Study 2000 using visible absorption spectroscopy from an aircraft. The method allows for quantification of the integrated total number of nitrogen dioxide molecules in the polluted atmosphere and is hence a useful tool for measuring plumes of this key trace gas. Further, we show how such remote-sensing observations can be used to obtain information on the fluxes of nitrogen dioxide into the atmosphere with unique flexibility in terms of aircraft altitude, and the height and extent of mixing of the boundary layer. Observations of nitrogen dioxide plumes downwind of power plants were used to estimate the flux of nitrogen oxide emitted from several power plants in the Houston and Dallas metropolitan areas and in North Carolina. Measurements taken over the city of Houston were also employed to infer the total flux from the city as a whole.     

Deposition Monitoring in Europe

A monitoring station for atmospheric deposition was designed and constructed. Three such stations were applied in a pilot project for a year on three sites (Speulder forest in The Netherlands, Auchencorth in Scotland and Melpitz in Germany) in different regions in Europe to estimate local inputs and to validate deposition models which are currently used or developed to estimate ecosystem specific deposition in Europe. Fluxes at Auchencorth Moss are lowest for all components, except for those much influenced by the sea as a source. As Melpitz is located far away from seas, these components are lowest at this site. Wet deposition is the dominant source of input at Auchencorth, whereas at Speulder forest, through its roughness and pollution climate, dry deposition is dominant. At this site dry deposition velocities are highest. Melpitz is a polluted site. Particularly sulphur deposition is high. It is recommended to equip several locations in Europe with intensive deposition monitoring methods. Such a network will be an extension of existing monitoring programmes on air pollution, such as that run by Eurepean Monitoring and Evaluation Programme for the long-range transmission of air pollutants in Europe (EMEP). The intensive monitoring locations should be selected based on pollution climates and type of vegetation, common in Europe.     

BIOMONITORING OF AIR POLLUTION IN A SEASONALLY DRY TROPICAL SUBURBAN AREA USING WHEAT TRANSPLANTS

Air pollution has been identified as a serious problem throughout the world which causes tremendous loss to the crops by affecting plant growth and yield. Earlier, air pollution was restricted to urban and industrial regions. Over the last few decades, however, it has become evident that pollutants can be transported over long distances and hence their impact may be felt widely over rural areas. The present study was conducted to evaluate the impact of urban air pollution on suburban agriculture with respect to the changes in photosynthetic rate, stomatal conductance, water-use efficiency, plant height, numbers of tillers, leaves, ears and seeds, chlorophyll, carotenoid, protein, phenol, ascorbic acid, nitrogen and sulphate-sulphur contents and seed weight of pot-grown wheat plants (Triticum aestivum var. HUW 468) kept at different sites around Varanasi city receiving varying levels of pollution load. Mean concentrations of were monitored. The study clearly showed that plants are negatively affected by the ambient levels of air pollutants. Reduction in various parameters directly corresponded with the air pollution levels at different sites.