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851.
西安市及周边地区MODIS气溶胶光学厚度与PM10浓度关系模型研究简 总被引:2,自引:0,他引:2
西安是空气污染监控和防治有代表性的西部大型城市。研究了西安市及周边地区上空气溶胶光学厚度与PM10浓度的关系模型。利用2011—2012年MODIS卫星气溶胶光学厚度(AOD)遥感产品,通过数据匹配,利用地面气象观测站点的能见度数据和相对湿度数据对AOD产品进行垂直标高订正和湿度订正,2项订正显著提高了AOD和地面PM10浓度的相关性,相关系数从0.36提高到0.65,按季节分类统计和订正春至冬四季的相关系数分别为0.57、0.71、0.62和0.87,夏季和冬季的订正更为有效,可用性更高,这可能由于受到不同季节气溶胶来源和特征的影响。为研究中国西部大型城市,特别是西安市空气环境监测和区域联防联控提供了一种有效方法。 相似文献
852.
853.
Potassium bromate (KBrO3) is a widely used food additive, a water disinfection by-product and a known nephrotoxic agent. The effect of KBrO3 on rat blood, especially on the anti-oxidant defense system, was studied in this work. Animals were given a single oral dose of KBrO3 (100 mg/kg body weight) and sacrificed 12, 24, 48, 96 and 168 h after this treatment. Blood was collected from the animals and separated into plasma and erythrocytes. KBrO3 administration resulted in increased lipid peroxidation, protein oxidation, hydrogen peroxide levels and decreased the reduced glutathione content indicating the induction of oxidative stress in blood. Methemoglobin levels and methemoglobin reductase activity were significantly increased while the total anti-oxidant power was greatly reduced upon KBrO3 treatment. Nitric oxide levels were enhanced while vitamin C concentration decreased in KBrO3 treated animals. The activities of major anti-oxidant enzymes were also altered upon KBrO3 treatment. The maximum changes in all these parameters were 48 h after the administration of KBrO3 and then recovery took place. These results show for the first time that KBrO3 induces oxidative stress in blood and impairs the anti-oxidant defense system. Thus impairment in the anti-oxidant power and alterations in the activities of major anti-oxidant enzymes may play an important role in mediating the toxic effects of KBrO3 in the rat blood. The study of such biochemical events in blood will help elucidate the molecular mechanism of action of KBrO3 and also for devising methods to overcome its toxic effects. 相似文献
854.
广州市2002~2003年空气污染指数分析 总被引:8,自引:1,他引:7
根据广州市2002年1月1日至2003年12月31日的空气污染指数资料,对广州市每日的空气污染指数和可吸入颗粒物、NO2和SO2的污染指数、空气污染指数的月平均值和年平均值、空气质量级别、首要污染物等指标进行了统计分析.结果表明,广州市的空气污染状况与大尺度的天气现象如季风和降雨量等密切相关. 相似文献
855.
北京市常见树种叶片吸滞颗粒物能力时间动态研究 总被引:3,自引:0,他引:3
目前,以显微镜观察叶片微观结构已被证明是研究叶片吸滞颗粒物机理的有效方法.本文利用颗粒物再悬浮法和原子力显微镜,观察了北京市主要园林树种吸滞颗粒物的能力和叶片的表面特征,并探讨了不同树种吸滞颗粒物能力随时间变化的规律及叶片微观结构对滞尘能力的影响.结果表明:1针叶树种吸滞总悬浮颗粒物(TSP)能力大于阔叶树种,排序为:油松((27.13±0.44)μg·cm~(-2))白皮松((10.74±0.23)μg·cm~(-2))五角枫((8.24±0.18)μg·cm~(-2))柳树((7.71±0.18)μg·cm~(-2))银杏((6.43±0.17)μg·cm~(-2))杨树((6.17±0.19)μg·cm~(-2)),不同时间段树种滞尘能力不一致;2观测期间,针叶树种吸滞TSP和粗颗粒物(PM10)能力随月份呈U型趋势,在8、9和10月最低,随后又逐渐上升,而阔叶树种吸滞颗粒物能力则呈倒U型趋势,在7、8月最高,但不同树种吸滞细颗粒物(PM2.5)能力随时间变化均无明显规律性;3通过对叶片表面原子力显微镜(AFM)结构观测发现,叶片表面粗糙度越大,其吸滞颗粒物能力越强. 相似文献
856.
857.
Nares Chuersuwan Subuntith Nimrat Sukanda Lekphet Tida Kerdkumrai 《Environment international》2008,34(5):671
This research was the first long-term attempt to concurrently measure and identify major sources of both PM10 and PM2.5 in Bangkok Metropolitan Region (BMR). Ambient PM10 and PM2.5 were evaluated at four monitoring stations and analyzed for elemental compositions, water-soluble ions, and total carbon during February 2002–January 2003. Fifteen chemical elements, four water-soluble ions, and total carbon were analyzed to assist major source identification by a receptor model approach, known as chemical mass balance. PM10 and PM2.5 were significantly different (p < 0.05) at all sites and 24 h averages were high at traffic location while two separated residential sites were similar. Seasonal difference of PM10 and PM2.5 concentrations was distinct between dry and wet seasons. Major source of PM10 at the traffic site indicated that automobile emissions and biomass burning-related sources contributed approximately 33% each. Automobiles contributed approximately 39 and 22% of PM10 mass at two residential sites while biomass burning contributed about 36 and 28%. PM10 from re-suspended soil and cooking sources accounted for 10 to 15% at a residential site. Major sources of PM2.5 at traffic site were automobile and biomass burning, contributing approximately 32 and 26%, respectively. Biomass burning was the major source of PM2.5 mass concentrations at residential sites. Meat cooking also accounted for 31% of PM2.5 mass at a low impact site. Automobile, biomass burning, and road dust were less significant, contributed 10, 6, and 5%, respectively. Major sources identification at some location had difficulty to achieve performance criteria due to limited source profiles. Improved in characterize other sources profiles will help local authority to better air quality. 相似文献
858.
Toledo VE de Almeida Júnior PB Quiterio SL Arbilla G Moreira A Escaleira V Moreira JC 《Environmental monitoring and assessment》2008,139(1-3):49-59
The Oswaldo Cruz Foundation Campus (FIOCRUZ), in a suburban region of the city of Rio de Janeiro, was selected as a case study
to assess the pollution released from vehicle and industrial facilities in Basin III, the most polluted area of the city.
Concentrations of particulate matter (PM10) and trace metals in airborne particles were determined in an intensive field campaign.
The samplings were performed every six days for 24 h periods, using a PM10 high volume sampler, from September 2004 to August
2005. PM10 mass concentrations were determined gravimetrically and the metals by ICP-OES. For PM10, the arithmetic mean for
the period is 169 ± 42 μg m−3 which is 3.4 times the national recommended standard of 50 μg m−3. Additionally, 51% of the samplings exceeded the recommended 24 h limit of 150 μg m−3. Ca, Mg, Fe, Zn and Al were the metals that presented the higher concentrations. The correlation matrix gave two main clusters
and three significant principal components (PC). Both PC1 and PC2 are associated to crustal, vehicular and industrial emissions
while PC3 is mainly associated to geological material. Enrichment factors for Zn, Cu, Cd and Pb indicate that for these elements,
anthropic sources prevail over natural inputs. PM10 levels showed a good correlation with hospital admissions for respiratory
diseases in children and elderly people. 相似文献
859.
Monitoring of ambient particles and heavy metals in a residential area of Seoul, Korea 总被引:2,自引:0,他引:2
In this study, ambient TSP, PM10, and PM2.5 in a residential area located in the northern part of Seoul were monitored every
other month for 1 year from April 2005 to February 2006. The monthly average levels of TSP, PM10, and PM2.5 had ranges of
71∼158, 40∼106, and 28∼43 μg/m3, respectively. TSP and PM10 showed highest concentration in April; this seems to be due to Asian dust from China and/or Mongolia.
However, the fine particle of PM2.5 showed a relatively constant level during the monitoring period. Heavy metals in PM 10
and PM2.5, such as Cr, As, Cd, Mn, Zn and Pb, were also analysed during the same period. The monthly average concentrations
of heavy metal in PM2.5 were Cr:1.9∼22.7 ng/m3; As:0.9∼2.5 ng/m3; Cd: 0.6∼7 ng/m3; Mn:6.1∼22.6 ng/m3; Zn: 38.9∼204.8 ng/m3, and Pb: 21.6∼201.1 ng/m3. For the health risk assessment of heavy metals in ambient particles, excess cancer risks were calculated using IRIS unit
risk. As a result, the excess cancer risks of chromium, cadmium, and arsenic were shown to be more than one per million based
on the annual concentration of heavy metals, and chromium showed the highest excess cancer risk in ambient particles in Seoul. 相似文献
860.
PM<Subscript>10</Subscript> and Ultrafine Particles Counts In-Vehicle and On-Road in the Athens Area
E. Diapouli G. Grivas A. Chaloulakou N. Spyrellis 《Water, Air, & Soil Pollution: Focus》2008,8(1):89-97
This work presents the first results of a study concerning on-road and in-vehicle exposure to particulate matter in the area
of Athens. PM10 concentration measurements were conducted by TSI DustTrak, while driving along routes with different characteristics of traffic
density, during September 2003–March 2004. Concurrent measurements of the ultrafine particles (UFPs) number concentration
were also conducted, by condensation particle counter during part of the days. Pedestrian exposure to PM10 and UFPs was also studied through stationary measurements on the kerbside of selected roads on November 2003 and February
2004. A major avenue, a heavy-trafficked road across a children hospital and two central roads, one in a residential and one
in a commercial area were selected for measurement. The results indicate that every day commuters are exposed to significant
concentration levels. Higher exposures were observed in heavy-trafficked areas and during rush hours. Mean PM10 in-vehicle and on-road concentrations ranged from 30–320 μg/m3 and 70–285 μg/m3, respectively. The ultrafine particles number concentrations were in the range of 5.0 × 104–17.3 × 104 particles/cm3 in-vehicle and 3.1 × 104–7.3 × 104 particles/cm3 on the kerbside of a central residential road. Both PM10 and UFPs concentrations presented repeated short-term peak exposures. The results clearly point out the importance of the
road microenvironment (in-vehicle and on kerbside) for population exposure in urban areas. 相似文献