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Institution

United States Environmental Protection Agency

GovernmentWashington D.C., District of Columbia, United States
About: United States Environmental Protection Agency is a government organization based out in Washington D.C., District of Columbia, United States. It is known for research contribution in the topics: Population & Environmental exposure. The organization has 13873 authors who have published 26902 publications receiving 1191729 citations. The organization is also known as: EPA & Environmental Protection Agency.


Papers
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Journal ArticleDOI
TL;DR: Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation.
Abstract: Recent work has shown that particle-phase reactions contribute to the formation of secondary organic aerosol (SOA), with enhancements of SOA yields in the presence of acidic seed aerosol. In this study, the chemical composition of SOA from the photooxidations of α-pinene and isoprene, in the presence or absence of sulfate seed aerosol, is investigated through a series of controlled chamber experiments in two separate laboratories. By using electrospray ionization−mass spectrometry, sulfate esters in SOA produced in laboratory photooxidation experiments are identified for the first time. Sulfate esters are found to account for a larger fraction of the SOA mass when the acidity of seed aerosol is increased, a result consistent with aerosol acidity increasing SOA formation. Many of the isoprene and α-pinene sulfate esters identified in these chamber experiments are also found in ambient aerosol collected at several locations in the southeastern U.S. It is likely that this pathway is important for other bioge...

566 citations

Journal ArticleDOI
TL;DR: An overview of the principals of the electrokinetic remediation technique in soils is presented in this paper, where the types of waste and media in which the technology could potentially be applicable are outlined and some envisioned environmental uses of conduction phenomena in soils under electric fields.

565 citations

Journal ArticleDOI
TL;DR: Progress is highlighted in the synthesis and catalytic applications of magnetic catalysts in organic synthesis and the heterogenization of the catalyst using magnetic nanoparticles allows it to be recovered and reused using an external magnet.

563 citations

Journal ArticleDOI
TL;DR: Methods for apportioning sources of ambient particulate matter using the positive matrix factorization (PMF) algorithm are reviewed and recommendations for documenting the methodological details of future PMF analyses are made.
Abstract: Methods for apportioning sources of ambient particulate matter (PM) using the positive matrix factorization (PMF) algorithm are reviewed. Numerous procedural decisions must be made and algorithmic parameters selected when analyzing PM data with PMF. However, few publications document enough of these details for readers to evaluate, reproduce, or compare results between different studies. For example, few studies document why some species were used and others not used in the modeling, how the number of factors was selected, or how much uncertainty exists in the solutions. More thorough documentation will aid the development of standard protocols for analyzing PM data with PMF and will reveal more clearly where research is needed to help future analysts select from the various possible procedures and parameters available in PMF. For example, research likely is needed to determine optimal approaches for handling data below detection limits, ways to apportion PM mass among sources identified by PMF, and ways to estimate uncertainties in the solution. The review closes with recommendations for documenting the methodological details of future PMF analyses.

563 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined published literature on neighbourhood air quality modifications by green interventions and provided a better understanding of the interactions between vegetation and surrounding built-up environments and ascertain means of reducing local air pollution exposure using green infrastructure.

563 citations


Authors

Showing all 13926 results

NameH-indexPapersCitations
Joel Schwartz1831149109985
Timothy A. Springer167669122421
Chien-Jen Chen12865566360
Matthew W. Gillman12652955835
J. D. Hansen12297576198
Dionysios D. Dionysiou11667548449
John P. Giesy114116262790
Douglas W. Dockery10524457461
Charles P. Gerba10269235871
David A. Savitz9957232947
Stephen Polasky9935459148
Judith C. Chow9642732632
Diane R. Gold9544330717
Scott L. Zeger9537778179
Rajender S. Varma9567237083
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202356
202279
2021780
2020787
2019852
2018929