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Concentrations of carbon monoxide in indoor and outdoor air of Ghalyun cafes 全文
2015
Fazlzadeh, Mehdi | Rostami, Roohollah | Hazrati, Sadegh | Rastgu, Ali
Indoor and outdoor carbon monoxide (CO) concentrations were measured in 68 Ghalyun cafes in Ardabil City of Iran. One hour sampling was performed in each location and hourly mean concentrations were reported. Respective mean concentrations of CO in indoor and outdoor air were 24.75±17.17 and 2.65±1.33 ppm with an average indoor to outdoor air concentration ratio of 13.3±13.1. Within the variables studied; type of the tobacco smoked, location of the cafe inside the building, and utilizing mechanical ventilator, respectively, were recognized as the most influential factors controlling CO concentrations in Ghalyun cafes (p<0.05). 73.5% of workers (27.3 and 95.7% of cafes located on ground floors and basements, respectively) were exposed to higher levels of CO than the corrected OEL–TWA (Occupational Exposure Limit) of 10.4 ppm.
显示更多 [+] 显示较少 [-]Temporal and spatial distribution of tropospheric NO2 over Northeast Asia using OMI data during the years 2005–2010 全文
2015
Kim, Deok–Rae | Lee, Jae–Bum | Keun Song, Chang | Kim, Seung–Yeon | Ma, Young–ll | Lee, Kyung–Mi | Cha, Jun–Seok | Lee, Sang–Deok
This study aimed to examine the main characteristics of tropospheric nitrogen dioxide (NO2) concentrations over the Northeast Asia, using the Ozone Monitoring Instrument (OMI) data from 2005 to 2010. The annual mean NO2 concentrations (AMNC) had an increasing trend mainly due to increasing NO2 emissions in China except during the 2008 Beijing Olympic Games period, while the reduction policies of South Korea and Japan have led it to be stagnant or decreased. To investigate further regional characteristics of NO2 increasing trends in China, we divided our study area into 6 geographical regions (sectors 1–6) and then considering 4 different socio–economic levels (groups 1–4) among main cities in Eastern regions (sector 2 and 4) where the concentrations level is the highest in China and NO2 concentrations show continued increasing trend. Especially OMI NO2 and emissions consistently showed that metropolitan/big—sized and developed cities (group 1), such as Beijing and Shanghai, had an increasing trend of NO2 concentrations until 2007 and decreasing thereafter, while small/mid–sized and developing cities (groups 2 and 3) kept a continuous increasing trend over all periods. The seasonal change in NO2 concentrations showed the apparent increasing trend in winter and no significant trend in summer in all groups except for group 1. These results indicate that an increase in AMNC in Northeast Asia was mainly attributed to the increasing NO2 concentrations in winter in groups 2 and 3. Therefore, it strongly suggests the importance of the NO2 management for groups 2 and 3 to improve air quality in the Northeast Asia.
显示更多 [+] 显示较少 [-]Human impact on atmospheric precipitation in a protected area in Western Poland. Results of long–term observations: Concentrations, deposition and trends 全文
2015
Walna, Barbara
The paper presents the results of long–term measurements of rain chemistry in the woodland area of the Wielkopolski National Park (Western Poland) experiencing some human impact. The ions predominating in precipitation turned out to be those of ammonium and sulfates, which is indicative of human impact related with agriculture and animal breeding as well as with SO2 emissions. In the period 2002–2013 it is possible to identify, for both precipitation and throughfall, statistically significant decreasing trends in the concentrations and deposition of sulfates, ammonium and potassium, and an increasing trend for fluoride. Both bulk deposition and throughfall of N was higher than that of S. The deposition of nitrogen with throughfall was near to the critical load. High levels of acid–forming ions were observed in both, the winter and late–spring seasons, which proves not only the impact of heating but also of the local industry. Notable is the simultaneous occurrence of extremely high levels of acid–forming ions in some precipitation events, which might have many important implications for the soil, water and biota. There was a change in the pattern of atmospheric chemistry observed as a statistically significant downward trend in the rates of ionic concentration equivalents.
显示更多 [+] 显示较少 [-]Atmospheric levels and health risk of polycyclic aromatic hydrocarbons (PAHs) bound to PM2.5 in Guangzhou, China 全文
2015
Liu, Jingjing | Man, Ruilin | Ma, Shexia | Li, Juansheng | Wu, Qi | Peng, Juanying
The polycyclic aromatic hydrocarbons (PAHs) in PM2.5 contribute significantly to health risk. The objectives of this study were to assess the occurrence and variation in the concentrations and sources of PM2.5-bound PAHs sampled from the atmosphere of a typical southeastern Chinese city (Guangzhou) from June 2012 to May 2013, with the potential risks being investigated. The annual average concentration of PM2.5 was 64.88μgm−3. The annual average concentration of PAHs in PM2.5 was 33.89ngm−3. Benzo(a)pyrene (BaP) was found to be the predominant PAH in all PM2.5 samples throughout the year, constituting approximately 8.78% of the total PAH content. The significant meteorological parameters for most of the PAHs were sunshine time, air pressure, and humidity, together representing 10.7–52.4% of the variance in atmospheric PAH concentrations. Motor-vehicle exhaust and coal combustion were probably the main sources of PAHs in PM2.5 in Guangzhou. The average inhalation cancer risk (ICR) for a lifetime of 70years was 5.98×10−4 (ranging from 8.39×10−5 to 1.95×10−3).
显示更多 [+] 显示较少 [-]Factors driving the seasonal distribution of zooplankton in a eutrophicated Mediterranean Lagoon 全文
2015
Ziadi, Boutheina | Dhib, Amel | Turki, Souad | Aleya, Lotfi
The distribution of the zooplankton community was studied along with environmental factors at five sampling stations in Ghar El Melh Lagoon (GML) (Mediterranean Sea, northern Tunisia). GML is characterized by specific following properties: broad and shallow, freshwater supply (Station 1); connection to the sea (S2); stagnation (S3 especially), and eutrophic conditions with enhanced nutrient concentrations (S4 and S5). Samples were taken twice monthly from February 2011 to January 2012. Twenty-three zooplankton groups comprising 10 larval stages were identified. Zooplankton assemblages were largely dominated by copepods (37.25%), followed respectively by ciliates (21.09%), bivalve larvae (14.88%) and gastropod veligers (12.53%). Redundancy analysis indicated that while no significant difference was found in the distribution of zooplankton at any station, a strong difference was observed according to season. Both temporal and physicochemical fluctuations explain more than 50% of changes in zooplankton abundances.
显示更多 [+] 显示较少 [-]Influence of anthropogenic activities on PAHs in sediments in a significant gulf of low-latitude developing regions, the Beibu Gulf, South China Sea: Distribution, sources, inventory and probability risk 全文
2015
Li, Pingyang | Xue, Rui | Wang, Yinghui | Zhang, Ruijie | Zhang, Gan
Fifteen polycyclic aromatic hydrocarbons (PAHs) in 41 surface sediment samples and a sediment core (50cm) from the Beibu Gulf, a significant low-latitude developing gulf, were analyzed. PAHs concentrations were 3.01–388ngg−1 (mean 95.5ngg−1) in the surface sediments and 10.5–87.1ngg−1 (average 41.1ngg−1) in the sediment core. Source apportionment indicated that PAHs were generated from coke production and vehicular emissions (39.4%), coal and biomass combustion (35.8%), and petrogenic sources (24.8%). PAHs were mainly concentrated in the industrialized and urbanized regions and the harbor, and were transported by atmospheric deposition to the marine matrix. The mass inventory (1.57–2.62t) and probability risk showed sediments here served as an important reservoir but low PAH risk. Different from oil and natural gas in developed regions, coal combustion has always been a significant energy consumption pattern in this developing region for the past 30years (56±5%).
显示更多 [+] 显示较少 [-]Indoor environmental quality in chemistry and chemical engineering laboratories at Izmir Institute of Technology 全文
2015
Indoor air pollution in university research laboratories may be important to building occupants, especially for those who work in the laboratories. In this study, indoor air quality (IAQ) and indoor environmental comfort were investigated in research laboratories of two departments at a university. PM2.5, PM10, TVOC (total volatile organic compounds), and CO concentrations, and three comfort variables which are temperature, relative humidity, and CO2 were measured. PM2.5 concentration was determined gravimetrically by collecting particles on glass fiber filters, whereas the remaining pollutants and comfort variables were measured using a monitoring device. IAQ measurements showed that levels of all pollutants were under the limits in both of the departments except for TVOC in one laboratory which had a mean concentration of 182ppb. The comfort variables were in the comfort ranges for laboratories in both of the departments except for temperature in one laboratory with a mean value of 30 °C. In conclusion, measures are needed for extensive uses of organic solvents because ventilation may not be sufficient to keep VOC concentrations within the limits, and to provide thermal comfort.
显示更多 [+] 显示较少 [-]Global change effects on biogeochemical processes of Argentinian estuaries: An overview of vulnerabilities and ecohydrological adaptive outlooks 全文
2015
The aims of this work are to provide an overview of the current stresses of estuaries in Argentina and to propose adaptation strategies from an ecohydrological approach. Several Argentinian estuaries are impacted by pollutants, derived mainly from sewage discharge and agricultural or industrial activities. Anthropogenic impacts are expected to rise with increasing human population. Climate-driven warmer temperature and hydrological changes will alter stratification, residence time, oxygen content, salinity, pollutant distribution, organism physiology and ecology, and nutrient dynamics. Good water quality is essential in enhancing estuarine ecological resilience to disturbances brought on by global change. The preservation, restoration, and creation of wetlands will help to protect the coast from erosion, increase sediment accretion rates, and improve water quality by removing excess nutrients and pollutants. The capacity of hydrologic basin ecosystems to absorb human and natural impacts can be improved through holistic management, which should consider social vulnerability in complex human–natural systems.
显示更多 [+] 显示较少 [-]Source apportionment of carbonaceous fine particulate matter (PM2.5) in two contrasting cities across the Indo–Gangetic Plain 全文
2015
Villalobos, Ana M. | Amonov, Mansur O. | Shafer, Martin M. | Devi, J Jai | Gupta, Tarun | Tripathi, Sachi N. | Rana, Kushal S. | McKenzie, Michael | Bergin, Mike H. | Schauer, James J.
Agra and Kanpur are heavily polluted Indian cities and are the fourth and second largest cities in Uttar Pradesh State, respectively. PM2.5 was collected from December 2011 to May 2012 in Agra and from December 2011 to October 2012 in Kanpur every 6th day. The samples were chemically analyzed to determine organic carbon (OC), water soluble organic carbon (WSOC), elemental carbon (EC), secondary inorganic ions, and particle–phase organic compounds. A chemical mass balance (CMB) receptor model using organic tracers was used to estimate source contributions to PM2.5. Concentrations of carbonaceous aerosols were on average 23±16μg/m3 in Agra and 33±21μg/m3 in Kanpur during the winter and summer periods, and had a strong seasonal trend with highest levels in winter (December–February) and then decreasing to summer (March–May). Five primary sources were identified. In Agra, biomass burning was the major source of OC in the winter months with decreasing relative and absolute concentrations in summer. In Kanpur, biomass burning was also the most important primary source of OC, but was about half the concentration found in Agra. Mobile source contributions to OC were on average 25±9% and 25±22% in Agra and Kanpur, respectively, with similar absolute concentrations of 2.5±1.9μg/m3 in most months. Secondary organic aerosol (SOA) was estimated from non–biomass burning WSOC and the unapportioned OC, with each method indicating SOA as a major source of OC in the winter in both cities, apportioning 25% of OC in Agra and 65% in Kanpur. SOA in Kanpur in December was four times higher than in Agra. Overall, results suggest differences in aerosol chemical composition and sources at these two sites across the Indo–Gangetic plain with biomass burning making up a larger fraction of the particulate OC in Agra, and SOA being a more important contributor to OC mass in Kanpur.
显示更多 [+] 显示较少 [-]Introduction of the alien Xenostrobus securis (Bivalvia: Mytilidae) into Hong Kong, China: Interactions with and impacts upon native species and the earlier introduced Mytilopsis sallei (Bivalvia: Dreissenidae) 全文
2015
Morton, Brian | Leung, K.F.
This constitutes the first record of the Australian alien mytilid Xenostrobus securis in China. The introduction occurred prior to 2010 probably via shipping arriving at Yantian in Mirs Bay, China, close to Hong Kong. Point sources of infection could be Australia or Korea or Japan where it has similarly been introduced. Analysis of X. securis in Hong Kong shows that it tolerates a wide range of salinities from 5.4‰ to 28.7‰. Water temperatures in Hong Kong match those in its native range.In Hong Kong, X. securis co-occurs with the similarly introduced Mytilopsis sallei and a native bivalve community. The population structure of X. securis suggests a lifespan of >2years with new generations produced by conspecifics. Such a life history strategy is also exhibited by M. sallei. Now established in China, northern Asia, the Mediterranean and, most recently, the Iberian Atlantic, the invasion of other locations by X. securis seems probable.
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