兰州市大气降尘时空变化特征

根据兰州市近年大气降尘的监测数据,对兰州市市区的降尘量进行了分析统计,按月度、季度、采暖期、非采暖期分析降尘的时间变化趋势。统计期间全市3月份降尘量最大,利用方差分析检验了不同季节降尘量的显著性差异,发现全市降尘量分布规律为春季夏季秋季冬季;非采暖期采暖期。按行政区、功能区分析降尘的空间分布变化,结果表明交通干线降尘量最大。     

乌鲁木齐市近年来大气降尘变化规律及空间分布特征

基于乌鲁木齐市多年监测的降尘数据,对乌鲁木齐市城区的降尘量进行了统计分析,得出了乌鲁木齐市近10年来降尘的总体变化规律;利用方差分析方法检验了不同季节降尘的显著性差异,发现采暖期的降尘量明显大于非采暖期;按行政区分析降尘量的分布变化,结果为不同行政区存在差别;利用秩相关系数法对其进行了趋势分析。结果表明,乌鲁木齐市的降尘呈下降趋势。利用Arc GIS9.3中的普通克里格插值方法绘制了乌鲁木齐市城市自然降尘的空间分布图。     

石河子市自然降尘污染特征及其影响因素

通过对石河子市自然降尘及降尘可燃物监测数据以及气候特点,气象因子的分析,指出了该市自然降尘的污染特征、变化规律和影响降尘量的相关因素;提出烟尘污染治理,扩大绿化面积,改变局部小气候,可以有效地降低降尘量,改善该市的大气环境质量。     

武汉市降尘污染特征及影响因素

以武汉市2006—2013年降尘数据为例,采用SPSS19.0软件统计分析了中部地区内陆城市的降尘污染特征及其影响因素。结果表明,月均降尘污染呈5月峰、11月谷三次曲线型,季节降尘污染呈春季夏季冬(秋)季,年均降尘量呈显著下降趋势。各功能区降尘量差异显著,从多到少顺序依次为工业区交通稠密区居商工混区清洁区。根据主成分分析结果,对于武汉这类经济发展中的中部内陆城市来说,气象因素是影响降尘的重要外在因素。社会因素是主要内在影响因素,其中经济发展因子的影响高于环境建设因子。     

连云港市大气降尘时空分布特征

采用2018年1月—2020年2月连云港市17个监测点位降尘数据,分析连云港市大气降尘变化规律和时空分布特征。结果表明,2018年连云港市平均降尘量为11.6 t/(km 2·30 d),超过江苏省考核标准[6 t/(km 2·30 d)],超标倍数为0.93,其呈现出先增大再降低再增大的规律,春季、秋季降尘量最大,与大风、干燥天气有关;除了8月,其他月份县区降尘量均高于市区;市区降尘量变化比较平稳,县区下半年变化幅度比较大。各监测点降尘分布存在明显差异,市环境监测站、胡沟管理处、德源药业、矿山设计院4个监测点的降尘量与PM 2.5及PM 10相关性较高,说明降尘与PM 2.5及PM 10的来源具有一致性。2019年降尘量明显降低且差异略小,除了春季(3和4月)超标,其他季节均达标。     

“十一五”期间新疆大气降尘量时空分布特征及影响因素分析

通过对"十一五"期间新疆134个大气降尘监测点位数据进行统计分析发现,"十一五"期间,全疆年均降尘量维持在22.2~24.6 t/km2.月,变化幅度小于10%。一年内降尘主要集中在3~6月份,占全年降尘量的51%。在空间分布上,新疆年均降尘量呈现明显的南疆高于北疆的特征,南疆五地、州的总降尘量占全疆总降尘量的70.2%,为新疆降尘的主要集中区。特殊的气象、生态环境是决定新疆大气降尘时空分布特征的主要因素。     

大气降尘采样影响因素的研究

试验和调研的内容 1.大气降尘的来源 从降尘的化学组成看,北京城市地区年平均的大气降尘量,69.7％源于土壤,26.99％源于锅炉烟尘,1.3％源于建筑尘(白灰、水泥),剩余2.1％为其他源。其次,由于地面颗粒的再悬浮的反复循环,使烟囱直接排放的烟尘量约占总降尘量的15.9％。 2.不同高度降尘量和粒径分布的对比 降尘的采集量因各地区气候条件,植被情况不同,在不同高度上波动很大。我们在北京城市设置了十一个测点,进行了一年的对比,其结果如下:     

基于因子分析的乌鲁木齐市冬季大气降尘来源与时空变化特征

利用2000—2009乌鲁木齐市不同功能区域大气降尘通量数据,建立因子分析模型,研究了乌鲁木齐市冬季大气降尘的来源与时空变化特征。结果表明,乌鲁木齐市冬季大气降尘的主要来源为燃煤烟尘、工业粉尘、交通道路尘。工业区、交通干线和居住区为全市冬季大气降尘量较大的区域。主城区冬季大气降尘通量呈下降趋势,主要与工业排放和采暖燃煤对大气降尘的贡献减少及相关大气污染控制取得实效有关。交通道路区域的降尘通量呈波动状态,变化较小。清洁点降尘通量前5年保持稳定,而后5年受到人为活动的影响,呈显著增加趋势。     

气溶胶与降尘中多环芳烃的含量分布研究

通过广东省茂名市区四个不同功能点大气气溶胶和降尘中多环芳烃的含量分布研究发现 :1、气溶胶中优控多环芳烃大大高于降尘中的含量 ,为降尘的 5.97～ 1 9.3倍 ;以石化厂区为例 ,非优控多环芳烃在气溶胶中的相对含量更高 ,为降尘的 2 4 .7倍。2、气溶胶中优控多环芳烃和非优控多环芳烃的分布为随分子量增加而含量增高的趋势 ,但降尘中优控多环芳烃的高含量相对集中于萤蒽至苯并 (b)萤蒽之间。3、不同功能区由于排放源的差别所表现出的气溶胶和降尘中优控多环芳烃总量及总量比值、部分强致癌和致癌物含量及含量比值均存在差异。4、对气溶胶和降尘中多环芳烃研究可以对降尘中非优控多环芳烃降解和溶解量进行估算。以石化厂区为例 ,降尘中非优控多环芳烃比原始含量已减少76%。     

大气降尘采集方法比较

该文从实验数据说明了大气降尘量采集方法——湿法和干法有显著差异。作者提到这显然与我区干旱,多风有关。根据统一的《环境监测分析方法》中降尘量的采集,应该用湿法采集。由于我区干燥,集尘缸加水后易自然蒸干,许多站又不能及时添水,造成一些站采用了干法,数据无法规范化,本文提示各站应该按《环境监测分析方法》的规程执行。至于采用湿法干法或两种方法同时测定,那项能代表干旱区大气降尘质量状况?在干早、多风爆地区的实际降尘与风沙的随移性密切相关,尤其南疆地区,从学术研究上,各站可进行深入讨论,对寻求方法的地区可靠性,研究对象的针对性以及制定地区环境质量标准有一定意义。     

“十三五”甘肃省降尘时空变化趋势及影响因素

通过分析"十三五"期间甘肃省降尘及相关数据,对甘肃省降尘时空变化情况进行研究,对其变化趋势和影响因素进行分析。"十三五"期间,甘肃省降尘总体呈下降趋势,下降幅度达24.30%,全省植被覆盖指数上升2.03%,降尘与植被覆盖指数负相关性显著。自然来源中,沙尘天气是影响甘肃省降尘的主要因素。城市精细化管理水平的提高可减少降尘人为来源。     

自然降尘与常规气象因子的相关分析

笔者整理统计了１９９２年至１９９４年逐月自然降水和与之相应的常规气象因子监测数据，找到了自然降尘的季节性分布规律。在此基础上，求得了自然降尘分别与月平均气温、月平均气压、月平均风速、月平均温度、月降水量、月蒸发量的相关系数，并进行了检验，为污染预报工作提供了科学依据。     

Modelling Temperature Trends in New Zealand

If global warming is accelerating, then one might expect temperatures for most stations to be accelerating and perhaps variability to be increasing. In this study, we examine 57 New Zealand temperature time series for evidence of non-linearity and changing variability. These correspond to time series for annual minima, annual means and annual maxima for 19 stations. Estimation is by an extended least-squares method. We find a surprising diversity of behaviour of these series – presumably reflecting their different geographic factors as well as series length. We give evidence of regions where temperatures are decreasing. For series where a linear trend is significant, it is downwards in about one third of the cases. This proportion was higher in the South Island, especially for series of minima. Where a non-linear trend is significant, temperatures are decelerating in about one half of the cases. The ratio of downward to upward trends is highest among annual maxima and South Island minima and smallest in annual means. Where a linear trend in the variability is significant, it is decreasing in 13 cases and increasing in 5 cases, although possibly this is partly due to poorer quality data last century. Where a non-linear trend in the variability is significant, variability is decelerating in about two thirds of the cases. The results are used to project upper and lower return levels of minima, means and maxima for each of the series to the year 2010.     

Distribution of Polycyclic Aromatic Hydrocarbons in Aerosols and Dustfall in Macao

Polycyclic aromatic hydrocarbons (PAHs), widespread environmental pollutants, have been measured in aerosols and dustfall in Macao. In this paper, we compare concentration distributions and determine the partitioning of PAHs in aerosols and dustfall for different areas, sampling times and sampling heights. The results demonstrate that the concentrations of PAHs in aerosols and dustfall vary at the different sites and heights. The concentrations of PAHs and most of the individual PAHs in aerosols at night were higher than those in the daytime when using the unit of g/g and lower than those when using the unit of g m^-3. It is shown that the distribution of individual PAHs in aerosols differs significantly from that in dustfall.     

上海市降尘监测中存在的问题

降尘监测是探索大气可自然沉降颗粒物对环境影响的不可缺少的手段之一.降尘监测因其采样设备简便、操作简单易行等优点被广泛运用,但是监测周期长、环节多等因素都会影响降尘监测的准确性.通过对上海市降尘数据分析发现,上海市降尘监测中存在降尘数据波动大、受周边环境影响大、人为破坏多等问题,并就这些问题提出了若干建议和解决办法.     

兰州市大气降尘中PAHs主要来源及其分布特征

对兰州市春季不同功能区大气降尘有机质中PAHs种类的分析,检出了大气降尘中有机质USEPA优控PAHs有11种以上,含量较高的萘、荧蒽、菲、芘、,占各采样点PAHs总量的70%以上。源解析表明,兰州市各功能区大气降尘中PAHs来源不仅有较高的燃煤源、交通源(汽车尾气),同时PAHs的组成与分布也在很大程度上受到采样点周围居民居住环境的影响。     

Analysis of spatial and seasonal distributions of MODIS aerosol optical properties and ground-based measurements of mass concentrations in the Yellow Sea region in 2009

Satellite-retrieved data on aerosol optical depth (AOD) and Ångström exponent (AE) using a moderate resolution imaging spectrometer (MODIS) were used to analyze large-scale distributions of atmospheric aerosols in East Asia. AOD was relatively high in March (0.44?±?0.25) and low in September (0.24?±?0.21) in the East Asian region in 2009. Sandstorms originating from the deserts and dry areas in northern China and Mongolia were transported on a massive scale during the springtime, thus contributing to the high AOD in East Asia. However, whereas PM10 with diameters ≤10 μm was the highest in February at Anmyon, Cheongwon, and Ulleung, located leeward about halfway through the Korean Peninsula, AOD rose to its highest in May. The growth of hygroscopic aerosols attendant on increases in relative humidity prior to the Asian monsoon season contributed to a high AOD level in May. AE typically appears at high levels (1.30?±?0.37) in August due to anthropogenic aerosols originating from the industrial areas in eastern China, while AOD stays low in summer due to the removal process caused by rainfall. The linear correlation coefficients of the MODIS AOD and ground-based mass concentrations of PM10 at Anmyon, Cheongwon, and Ulleung were measured at 0.4~0.6. Four cases (6 days) of mineral dustfall from sandstorms and six cases (12 days) of anthropogenically polluted particles were observed in the central area of the Korean Peninsula in 2009. PM10 mass concentrations increased at both Anmyon and Cheongwon in the cases of mineral dustfall and anthropogenically polluted particles. Cases of dustfall from sandstorms and anthropogenic polluted particles, with increasing PM10 mass concentrations, showed higher AOD values in the Yellow Sea region.     

Determination of chlorophyll-a amount in Golden Horn, Istanbul, Turkey using IKONOS and in situ data

The objective of this research was to explore an accurate and fast way of estimating chlorophyll-a amount, a water quality parameter (WQP), using IKONOS satellite sensor image and in situ measurements. Since the in situ data of WQPs are limited with the number of sampling locations, deriving a correlation between these measurements and remotely sensed image allows synoptic estimates of the related parameter over large areas even if the areas are in remote and inaccessible locations. In this study, simultaneously collected satellite image data and in situ measurements of chlorophyll-a were correlated using multivariate regression model. Different experiments were designed by changing the numbers and distributions of in situ measurements. Regression coefficients of each design and differences between model-derived data and in situ measurements were calculated to find out the optimum design to produce chlorophyll-a map of study region. Results illustrated that both the number and distribution of in situ measurements have impact on regression analysis, therefore should be selected attentively. Also, it is found that IKONOS imagery is an efficient and effective source to derive chlorophyll-a map of the large areas using limited number of ground measurements.