نتایج جستجو برای: source apportionment

تعداد نتایج: 419288  

2016
Amanda S. Willoughby Andrew S. Wozniak Patrick G. Hatcher

Organic aerosols (OA) are universally regarded as an important component of the atmosphere that have far-ranging impacts on climate forcing and human health. Many of these impacts are related to OA molecular characteristics. Despite the acknowledged importance, current uncertainties related to the source apportionment of molecular properties and environmental impacts make it difficult to confid...

Journal: :Chemosphere 2009
Daekyun Kim Benjamin M Kumfer Cort Anastasio Ian M Kennedy Thomas M Young

Soot-associated PAHs were exposed to simulated sunlight to investigate disappearance rates under environmental aging conditions and to examine the robustness of diagnostic ratios for PAH source apportionment. Naphthalene, acenaphthylene, acenaphthene, and fluorene showed an obvious two-phase disappearance in all experiments while phenanthrene and anthracene exhibited this behavior for all but t...

Journal: :Journal of the Air & Waste Management Association 2008
John G Watson L W Antony Chen Judith C Chow Prakash Doraiswamy Douglas H Lowenthal

Receptor models are used to identify and quantify source contributions to particulate matter and volatile organic compounds based on measurements of many chemical components at receptor sites. These components are selected based on their consistent appearance in some source types and their absence in others. UNMIX, positive matrix factorization (PMF), and effective variance are different soluti...

2011
K. E. Yttri D. Simpson

In the present study, natural and anthropogenic sources of particulate organic carbon (OCp) and elemental carbon (EC) have been quantified based on weekly filter samples of PM10 (particles with aerodynamic diameter <10 μm) collected at four Nordic rural background sites [Birkenes (Norway), Hyytiälä (Finland), Vavihill (Sweden), Lille Valby, (Denmark)] during late summer (5 August–2 September 20...

2005
J. J. Cao J. C. Chow S. C. Lee Y. Li S. W. Chen Z. S. An K. Fung J. G. Watson C. S. Zhu S. X. Liu

Characterization and source apportionment of atmospheric organic and elemental carbon during fall and winter of 2003 in Xi’an, China J. J. Cao, J. C. Chow, S. C. Lee, Y. Li, S. W. Chen, Z. S. An, K. Fung, J. G. Watson, C. S. Zhu, and S. X. Liu State Key Laboratory of Loess & Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710075, China Desert Research Inst...

Journal: :The Science of the total environment 2013
Liping Yang Jiangpei Han Jianlong Xue Lingzao Zeng Jiachun Shi Laosheng Wu Yonghai Jiang

Nitrate (NO3-) pollution in aquatic system is a worldwide problem. The temporal distribution pattern and sources of nitrate are of great concern for water quality. The nitrogen (N) cycling processes in a subtropical watershed located in Changxing County, Zhejiang Province, China were greatly influenced by the temporal variations of precipitation and temperature during the study period (Septembe...

2011
J. Genberg M. Hyder K. Stenström R. Bergström D. Simpson E. O. Fors

A one-year study was performed at the Vavihill background station in southern Sweden to estimate the anthropogenic contribution to the carbonaceous aerosol. Weekly samples of the particulate matter PM10 were collected on quartz filters, and the amounts of organic carbon, elemental carbon, radiocarbon (14C) and levoglucosan were measured. This approach enabled source apportionment of the total c...

Journal: :Chemosphere 2002
John G Watson Tan Zhu Judith C Chow Johann Engelbrecht Eric M Fujita William E Wilson

Receptor models infer contributions from particulate matter (PM) source types using multivariate measurements of particle chemical and physical properties. Receptor models complement source models that estimate concentrations from emissions inventories and transport meteorology. Enrichment factor, chemical mass balance, multiple linear regression, eigenvector. edge detection, neural network, ae...

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