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1.
上海市浦东城区冬季颗粒物数浓度及其谱分布特征   总被引:5,自引:1,他引:4  
采用APS-3321空气动力学粒径谱仪对上海市浦东城区2012年12月至2013年2月0.5~20 μm大气颗粒物浓度及其谱分布进行了实时监测.结果发现,上海市浦东城区冬季大气颗粒物数浓度为360个/cm3,其中0.5~1.0 μm颗粒物数为345个/cm3,占总颗粒物的95.7%;1.0~2.5 μm颗粒物数为15 个/cm3,占颗粒物总数的4.1%;2.5~20.0 μm颗粒物数为0.6 个/cm3,占颗粒物总数的0.2%.当空气质量为AQI≤50、50<AQI≤100、100<AQI≤200、AQI>200时,颗粒物数浓度分别为77.5、243.2、522.6、868.5个/m3. 随着空气污染的加重,小于PM2.5颗粒物数浓度增加显著且对总的颗粒物数浓度的贡献也有所增加,且AQI>200时,PM2.5中1.0~2.5 μm颗粒物数浓度贡献增幅最大;此外,不同空气质量条件下,颗粒物数浓度的日变化存在一定差异,这对于空气污染防治具有重要意义.  相似文献
2.
广州地区秋冬季细颗粒物PM2.5化学组分分析   总被引:1,自引:0,他引:1       下载免费PDF全文
分析了广州地区2009年-2010年秋冬季节大气中PM2.5样品的水溶性离子、重金属元素、有机碳/元素碳(OC/EC)、多环芳烃质量浓度和粒径分布。初步掌握了广州地区秋冬季节大气中PM2.5的化学组分和特点,有机质(OM)是广州地区秋冬季PM2.5中最主要的成分,其次是硫酸根离子、硝酸根离子和铵根;PM2.5中有机碳和元素碳的空间分布特征相似,并受一次源排放影响;PM2.5中的重金属含量以铝、锌、铅相对较高,且城区高于城郊;PM2.5中17种多环芳烃、苯并( a)芘( BaP)的浓度均为城郊高于市区。  相似文献
3.
Analysis of summer and winter vegetable samples during 2002–2003 for pesticidal contamination was carried out on Gas Chromatograph-Electron Capture Detector with capillary columns. The contamination levels of winter vegetables (average concentration of 4.57, 6.80 and 5.47 ppb respectively for Lindane, Endosulphan and DDT) were found to be slightly higher than the summer vegetables (average concentration of 4.47, 3.14 and 2.82 ppb respectively for Lindane, Endosulphan and DDT). The concentration of these organochlorine pesticides in summer and winter vegetables were well below the established tolerances but continuous consumption of such vegetables even with moderate contamination level can accumulate in the receptor's body and may lead to chronic effects that could be fatal.  相似文献
4.
In the `Des Vieux Arbres' ecological reserve situated within northwestern Québec, 40 band dendrometers were installedon 7 of the major boreal tree species. The late Spring–early Summer daily radial activity registered in 1997 was related todaily weather variables. For each tree species, the daily mean i) cumulative radial increment and ii) radial activity indexedseries obtained by first-difference standardization were analyzed. The results indicate the existence of strong similarities among the 7 species. All showed strong synchronousfluctuations in radius during late winter and early spring. Thisperiod ended with a short but sharp increase in radial increments that marked the passage of water into the stem. Thisinitial swelling, less obvious in Pinus species was followed by a prolonged period of little change in radial activity. Meteorological data indicated that air temperature waspositively related to stem swelling during the late winter–earlyspring period. Both air and soil temperatures became negatively related to radial expansion once the passage of water has occurred in the stem. Starting in early June, all species registered a sustained increase in radial increments possiblyassociated with active cell division. After this, radial expansion was negatively related to air temperature and positively to rainfall.  相似文献
5.
Monitoring of 80 winter vegetable samples during 1997–1998 for pesticidal contamination was carried out on GC-ECD and GC-NPD systems with capillary columns following multiresidueanalytical technique. The tested samples were found 100%contaminated with low but measurable amounts of pesticideresidues. Among the four major chemical groups, residue levels oforganophosphorous insecticides were highest followed bycarbamates, synthetic pyrethroids and organochlorines. About 32%of the samples showed contamination with organophosphorous andcarbamate insecticides above their respective MRL values. On thebasis of observations made in these studies, it is suggested thatmore extensive monitoring studies covering all vegetable cropsfrom different agro-climatic regions of the state be carried outto know exact level of pesticidal contamination, which may serveas basis for future policy on chemical use.  相似文献
6.
Winter Quarters Bay (WQB) is a small embayment located adjacent to McMurdo Station, the largest researchbase in Antarctica. The bay is approximately 250 m wide andlong, with a maximum depth of 33 m. Historically, trashfrom the McMurdo Station was piled on the steep shoreline ofWQB, doused with fuel and ignited. That practice hasceased, and the adjacent land area has been regraded tocover the residual waste. The bottom of WQB remainslittered with drums, equipment, tanks, tires, cables, andother objects, especially the southeastern side of the baywhere dumping took place. Sediments are contaminated withPCBs, metals, and hydrocarbon fuels. The objectives of this study were to map the distributionof organic contaminants in WQB, assess the toxicity of WQB sediments using a simple microbial test, anddetermine correlations between toxicity and contaminantlevels. The study suggests that adverse ecological effectshave occurred from one or more of the contaminants found inWQB but the source of the toxic impacts to bay sedimentsremains unknown. Whole sediment toxicity was onlycorrelated with oil-equivalent while solvent extracts ofsediments were correlated with PAHs and oil-equivalent. Theauthors recommend that an integrated research plan bedeveloped that focuses on determining what additionalinformation is needed to make informed decisions on possibleremediation of WQB.  相似文献
7.
A study was begun in the winter of 2000–2001 and continued through the winter of 2001–2002 to examine air quality at the Green Rock snowmobile staging area at 2,985 m elevation in the Snowy Range of Wyoming. The study was designed to evaluate the effects of winter recreation snowmobile activity on air quality at this high elevation site by measuring levels of nitrogen oxides (NO x , NO), carbon monoxide (CO), ozone (O3) and particulate matter (PM10 mass). Snowmobile numbers were higher weekends than weekdays, but numbers were difficult to quantify with an infrared sensor. Nitrogen oxides and carbon monoxide were significantly higher weekends than weekdays. Ozone and particulate matter were not significantly different during the weekend compared to weekdays. Air quality data during the summer was also compared to the winter data. Carbon monoxide levels at the site were significantly higher during the winter than during the summer. Nitrogen oxides and particulates were significantly higher during the summer compared to winter. Nevertheless, air pollutants were well dispersed and diluted by strong winds common at the site, and it appears that snowmobile emissions did not have a significant impact on air quality at this high elevation ecosystem. Pollutant concentrations were generally low both winter and summer. In a separate study, water chemistry and snow density were measured from snow samples collected on and adjacent to a snowmobile trail. Snow on the trail was significantly denser and significantly more acidic with significantly higher concentrations of sodium, ammonium, calcium, magnesium, fluoride, and sulfate than in snow off the trail. Snowmobile activity had no effect on nitrate levels in snow.  相似文献
8.
根据南通市2016和2017年冬季大气多参数站自动监测PM2.5数据和在线离子色谱分析仪Marga监测的PM2.5中水溶性离子数据,分析了南通市冬季PM2.5中水溶性离子污染特征。结果表明,南通市2016和2017年冬季,ρ(PM2.5)分别为58和54 μg/m3,均高出其年均值(14 μg/m3);ρ(水溶性离子)总占ρ(PM2.5)百分比分别为74.5%和74.3%;二次离子ρ(NO-3、SO2-4和NH+4)占ρ(PM2.5)百分比分别为66.8%和66.6%;各水溶性离子占比大小依次为:NO-3、SO2-4、NH+4、Cl-、K+、Na+、Ca2+、Mg2+。对ρ(NO-3)/ ρ(SO2-4)分析表明,移动源已经成为南通市冬季的主要污染源,且呈逐年增强趋势。对氯氧化率和硫氧化率的分析表明,南通市冬季存在较明显的二次污染,SO2的转化程度大于NO2。除Na+和Mg2+外,其他离子与PM2.5均呈显著相关性,NO-3、SO2-4与NH+4之间的相关系数最高,Cl-与除Na+外的所有阳离子均呈显著相关性。  相似文献
9.
采用2015—2017年秋、冬季江苏省环境空气质量监测数据,从空气质量优良(达标)率、首要污染物、主要污染物浓度分析空气质量现状及特点。结果表明,江苏省秋、冬季空气质量优良(达标)率在60%左右,其中沿海地区空气质量达标率最高(71.1%),西北地区达标率最差(52.2%)。污染日的首要污染物主要为PM2.5,占比高达91.5%。ρ(PM2.5)/ρ(PM10)存在地区差异,江苏西北地区扬尘源贡献较大,江苏南部地区的二次颗粒物贡献更明显。ρ(NO2)/ρ(SO2)逐年持续升高,表明大气污染类型从燃煤性污染转变为复合型污染。  相似文献
10.
于2007-2008年溪源水库蓄水前,2014-2015年溪源水库蓄水后对溪源宫水源地水体进行采样,分析了冬春季水体的理化指标、浮游植物生物量及群落组成。蓄水前共鉴定出浮游植物6门26属43种,水体水质状况较好,浮游植物细胞密度平均为7.31×105 cells/L,以硅藻、绿藻门为优势门类,两者占浮游植物总生物量的比例约为54.7%、32.2%,水体呈贫-中营养状态。蓄水后,水体氮、磷营养盐浓度分别约为蓄水前的2.4倍、3倍,浮游植物细胞密度平均为1.42×107 cells/L,约为蓄水前的20倍,且群落结构发生改变,优势门类为硅藻、蓝藻、绿藻,所占比例分别为40.2%、38.7%、14.4%,蓝藻门比例有显著提高,约为蓄水前的5倍。说明建库蓄水对浮游植物的影响显著。  相似文献
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