نتایج جستجو برای: urban particles
تعداد نتایج: 325807 فیلتر نتایج به سال:
Toxicological studies have provided evidence of the toxicity of ultrafine particles (UFP), but epidemiological evidence for health effects of ultrafines is limited. No quantitative summary currently exists of concentration-response functions for ultrafine particles that can be used in health impact assessment. The goal was to specify concentration-response functions for ultrafine particles in u...
The impact of road dust emissions on PM10 and PM2.5 (atmospheric particulate matter with diameteer < 10 μm and 2.5 μm mass concentrations recorded from 2003 to 2010 at 11 locations (rural, urban and industrial) in southern Spain was estimated based on the chemical characterization of PM and the use of a constrained Positive Matrix Factorization, where the chemical profile of local road dust sam...
در سالهای اخیر تلاش زیادی برای سنتز کمپلکس های سوپرامولکول و پلیمرهای کوئوردیناسیونی بر مبنای لیگاندهای آلی چند دندانه شده است. این مواد به دلیل داشتن خواص منحصر به فرد، کاربردهای زیادی در صنعت دارند. سنتز پلیمرهای کوئوردیناسیونی جدید از سرب(ii) در ابعاد بالک(توده) و نانو با استفاده از روش گرادیان دمایی و به روش شاخه جانبی صورت گرفته و با روش طیف سنجی ir و پایداری گرمایی آن ها توسط آنالیزهای وز...
Two Aerodyne Aerosol Mass Spectrometers (AMS) were deployed at three sites representing urban, semi-rural and rural areas during the Pacific 2001 experiment in the Lower Fraser Valley (LFV), British Columbia, Canada in August 2001. The AMS provides on-line quantitative measurements of the size and chemical composition of the non-refractory fraction of submicron aerosol particles. A significant ...
Diurnal variation of number size distribution (particle size 3–800 nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a highly polluted urban environment was investigated during October and November 2002 in New Delhi, India. Continuous monitoring for more than two weeks with the time resolution of 10 min was conducted usi...
Black carbon (BC) exerts profound impacts on air quality and climate because of its high absorption cross-section over a broad range of electromagnetic spectra, but the current results on absorption enhancement of BC particles during atmospheric aging remain conflicting. Here, we quantified the aging and variation in the optical properties of BC particles under ambient conditions in Beijing, Ch...
polycyclic aromatic hydrocarbons (pahs) are a group of organic compounds made up of two or more fused benzene rings in linear, angular or cluster arrangements. the pahs are formed by incomplete combustion or high temperature pyrolytic process involving organic matter. thirty sampling sites were selected to characterize the pahs concentrations in ambient air in tehran. sixteen pahs were measured...
Neuston samples were collected at 21 stations during an ~700 nautical mile (~1300 km) expedition in July 2012 in the Laurentian Great Lakes of the United States using a 333 μm mesh manta trawl and analyzed for plastic debris. Although the average abundance was approximately 43,000 microplastic particles/km², station 20, downstream from two major cities, contained over 466,000 particles/km², gre...
A Geographic Information System (GIS) is increasingly recognized as an effective tool for urban modeling. As a part of NASA's multidisciplinary project, this article develops GIS modeling methods of constructing measurements of urban components to monitor and model urban respiration. The first step is to create an Oracle database that stores spatially and temporally referenced measures of trace...
Introduction: Air pollution is one of the problems of the recent century caused by vehicles, industries and other urban activities. The City of Yazd faces air pollution due to its high population, vehicular traffic and industrial places around the city. One of the important parameters of air pollution is suspended air particles that have harmful effects on the health of people, plants and objec...
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