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Your search keyword '"Chen, Lung-Wen A."' showing total 21 results
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21 results on '"Chen, Lung-Wen A."'

11. Black and organic carbon emission inventories: review and application to California

Author

Chow, Judith C., Watson, John G., Lowenthal, Douglas H., Antony Chen, Lung-Wen, and Motallebi, Nehzat

Subjects
California -- Environmental policy, Air quality -- Management, Air pollution -- Control, Environmental auditing -- Methods, Company business management, Environmental services industry, Environmental issues, Science and technology
Abstract

ABSTRACT Particulate black or elemental carbon (EC) (black carbon [BC]) and organic carbon (OC) affect climate, visibility, and human health. Several 'top-down' and 'bottom-up' global emission inventories for these components [...]

Published
2010
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13. A Side by Side Comparison of Filter-Based PM(sub 2.5) Measurements at a Suburban Site: A Closure Study

Author

Haines, Jennifer C, Chen, Lung-Wen A, Taubman, Brett F, Doddridge, Bruce G, and Dickerson, Russell R

Subjects
Environment Pollution
Abstract

Reliable determination of the effects of air quality on public health and the environment requires accurate measurement of PM(sub 2.5) mass and the individual chemical components of fine aerosols. This study seeks to evaluate PM(sub 2.5) measurements that are part of a newly established national network by comparing them with a more conventional sampling system. Experiments were carried out during 2002 at a suburban site in Maryland, United States, where two samplers from the U.S. Environmental Protection Agency (USEPA) Speciation Trends Network: Met One Speciation Air Sampling System STNS and Thermo Scientific Reference Ambient Air Sampler STNR, two Desert Research Institute Sequential Filter Samplers DRIF, and a continuous TEOM monitor (Thermo Scientific Tapered Element Oscillating Microbalance) were sampling air in parallel. These monitors differ not only in sampling configuration but also in protocol-specific sample analysis procedures. Measurements of PM(sub 2.5) mass and major contributing species were well correlated among the different methods with r-values > 0.8. Despite the good correlations, daily concentrations of PM(sub 2.5) mass and major contributing species were significantly different at the 95% confidence level from 5 to 100% of the time. Larger values of PM(sub 2.5) mass and individual species were generally reported from STNR and STNS. The January STNR average PM(sub 2.5) mass (8.8 (micro)g/per cubic meter) was 1.5 (micro)g/per cubic meter larger than the DRIF average mass. The July STNS average PM(sub 2.5) mass (27.8 (micro)g/per cubic meter) was 3.8 (micro)g/per cubic meter larger than the DRIF average mass. These differences can only be partially accounted for by known random errors. Variations in flow control, face velocity, and sampling artifacts likely influence the measurement of PM(sub 2.5) speciation and mass closure. Simple statistical tests indicate that the current uncertainty estimates used in the STN network may underestimate the actual uncertainty.

Published
2007

15. Brownness of Organic Aerosol over the United States: Evidence for Seasonal Biomass Burning and Photobleaching Effects

Author

Chen, Lung-Wen Antony, Chow, Judith C., Wang, Xiaoliang, Cao, Junji, Mao, Jingqiu, and Watson, John G.

Abstract

Light-absorptivity of organic aerosol may play an important role in visibility and climate forcing, but it has not been assessed as extensively as black carbon (BC) aerosol. Based on multiwavelength thermal/optical analysis and spectral mass balance, this study quantifies BC for the U.S. Interagency Monitoring of Protected Visual Environments (IMPROVE) network while developing a brownness index (γBr) for non-BC organic carbon (OC*) to illustrate the spatiotemporal trends of light-absorbing brown carbon (BrC) content. OC* light absorption efficiencies range from 0 to 3.1 m2gC–1at 405 nm, corresponding to the lowest and highest BrC content of 0 and 100%, respectively. BC, OC*, and γBrexplain >97% of the variability of measured spectral light absorption (405–980 nm) across 158 IMPROVE sites. Network-average OC* light absorptions at 405 nm are 50 and 28% those for BC over rural and urban areas, respectively. Larger organic fractions of light absorption occur in winter, partially due to higher organic brownness. Winter γBrexhibits a dramatic regional/urban–rural contrast consistent with anthropogenic BrC emissions from residential wood combustion. The spatial differences diminish to uniformly low γBrin summer, suggesting effective BrC photobleaching over the midlatitudes. An empirical relationship between BC, ambient temperature, and γBris established, which can facilitate the incorporation of organic aerosol absorptivity into climate and visibility models that currently assume either zero or static organic light absorption efficiencies.

Published
2021
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19. Brown carbon aerosols from burning of boreal peatlands: microphysical properties, emission factors, and implications for direct radiative forcing

Author

Chakrabarty, Rajan K., primary, Gyawali, Madhu, additional, Yatavelli, Reddy L. N., additional, Pandey, Apoorva, additional, Watts, Adam C., additional, Knue, Joseph, additional, Chen, Lung-Wen A., additional, Pattison, Robert R., additional, Tsibart, Anna, additional, Samburova, Vera, additional, and Moosmüller, Hans, additional

Published
2016
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21. Exposure to PM2.5 and PAHs from the Tong Liang, China Epidemiological Study.

Author

Chow, Judith C., Watson, John G., Chen, Lung-Wen Antony, Ho, Steven Sai Hang, Koracin, Darko, Zielinska, Barbara, Tang, Deliang, Perera, Frederica, Junji Coo, and Lee, S. C.

Subjects
POLYCYCLIC aromatic hydrocarbons, AIR pollution, COAL-fired power plants, POLLUTION, ATMOSPHERIC aerosols, WINTER, ENVIRONMENTAL sampling, COAL combustion & the environment, CARBON & the environment
Abstract

Chemically speciated PM2.5 and particle-bound polycyclic aromatic hydrocarbon (PAH) measurements were made at three sites near urban Tong Liang, Chongqing, a Chinese inland city where coal combustion is used for electricity generation and residential purposes outside of the central city. Ambient sampling was based on 72-hr averages between 3/2/2002 and 2/26/2003. Elevated PM2.5 and PAR concentrations were observed at all three sites, with the highest concentrations found in winter and the lowest in summer. This reflects a coupling effect of source variability and meteorological conditions. The PM2.5 mass estimated from sulfate, nitrate, ammonium, organics, elemental carbon, crustal material, and salt corresponded with the annual average gravimetric mass within ± 10%. Carbonaceous aerosol was the dominant species, while positive correlations between organic carbon and trace elements (e.g., As, Se, Br, Pb, and Zn) were consistent with coal-burning and motor vehicle contributions. Ambient particle-bound PAHs of molecular weight 168-266 were enriched by 1.5 to 3.5 times during the coal-fired power plant operational period. However, further investigation is needed to determine the relative contribution from residential and utility coal combustion and vehicular activities. [ABSTRACT FROM AUTHOR]

Published
2006
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