HR: 16:15h
AN: A14B-02    [Abstracts]
TI: Atmospheric Elemental Carbon Concentrations in 1835 to 2005
AU: * Husain, L
EM: husain@wadsworth.org
AF: Wadsworth Center, New York State Dept. of Health, ESP, PO Box 509, Albany, NY 12201- 0509, United States
AU: * Husain, L
EM: husain@wadsworth.org
AF: Dept. of Environmental Health, School of Public Health, ESP, PO Box 509, Albany, NY 12201-509, United States
AU: Khan, A J
EM: khan@wadsworth.org
AF: Wadsworth Center, New York State Dept. of Health, ESP, PO Box 509, Albany, NY 12201- 0509, United States
AU: Swami, K
EM: swami@wadsworth.org
AF: Wadsworth Center, New York State Dept. of Health, ESP, PO Box 509, Albany, NY 12201- 0509, United States
AU: Bari, A
EM: axb16@health.state.ny.us
AF: Wadsworth Center, New York State Dept. of Health, ESP, PO Box 509, Albany, NY 12201- 0509, United States
AU: Li, J
EM: lijj@yahoo.com
AF: Ambient Air Quality Monitoring, China Natl. Environ. Monitoring Center, 1 South Yuhui Road, Beijing, 100029, China
AU: Ahmed, T
EM: txa03@health.state.ny.us
AF: Dept. of Environmental Health, School of Public Health, ESP, PO Box 509, Albany, NY 12201-509, United States
AB: Atmospheric elemental carbon concentrations, {EC}_atm, were determined for the past ~170 y in northeastern United States by using a novel technique. Assuming wet and dry deposition is the only source of EC in the remote and high altitude lakes, measured elemental carbon concentrations in the lake sediment, {EC}_sed, can be related to {EC}_atm, by {EC} = K{EC}_atm, where K (m³ g^-1) is constant for a given lake and depend upon sedimentation processes. The value of constant K was determined: (1) by measuring {EC}_atm in the monthly composites of daily filters collected at Whiteface Mountain, NY from 1978 to 2005 using the thermal optical method; and (2) {EC}_sed in four bottom sediment cores from West Pine Pond, a remote lake in the vicinity of Whiteface Mountain. The mean {EC}_atm for 1978-1986, 1987-1996, and 1997-2005 periods were 550 ± 150, 225 ± 65, and 66 ± 15 ng m^-3, respectively. Thus, the {EC}_atm has consistently decreased from ~ 1978, and decreased very sharply in 1997. The core was sectioned, and ages determined using ²¹⁰Pb technique. The {EC} in the sediment samples were determined by chemically separating EC and measured its concentration using the thermal optical method. The {EC}_sed for the 2005 -1978 period mimicked the directly measured {EC}_atm in the filters, supporting the hypothesis that the relationship between atmospheric and lake sediment EC concentrations are essentially a constant. From the {EC}_atm and {EC}_sed K was determined to be 10,400 ± 4,400 m³ g^-1. From K and {EC}_sed we calculated {EC}_atm for the 1978 to 1835 period. {EC}_atm varied from 62 to 760 ng m^-3 between 1835 and 2005. The {EC}_atm show monotonic increase from 1835, peaked around 1920 and then decreased gradually till 1980. After 1980, {EC}S_atm decreased sharply to the present. The {EC}_atm was compared with Nouvakou et.al.'s [GRL 30, doi: 10.1029/2002GLO16345] black carbon (BC) emissions based on consumption of fossil fuel and showed good correlation.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0399 General or miscellaneous
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting