Using An Aethalometer to Using An Aethalometer to Determine Optical Absorption Determine Optical Absorption Features from Different Black Features from Different Black

Carbon SourcesCarbon Sources

By: Shallena MenefieldBy: Shallena MenefieldNew Jersey City UniversityNew Jersey City University

Jersey City, New JerseyJersey City, New Jersey

BackgroundBackgroundAerosol Impacts on ClimateAerosol Impacts on Climate–– Aerosols are introduced Aerosols are introduced

into the atmosphere as into the atmosphere as particulate matter. particulate matter.

–– Aerosol particle sizes of Aerosol particle sizes of most importance range most importance range between 0.1between 0.1μμmm--11μμm.m.

–– A main source of black A main source of black carbon is combustion carbon is combustion derived.derived.

–– Other sources include Other sources include diesel exhaust from diesel exhaust from vehicles. vehicles.

NASA/ MODIS are credited for this satellite image of a large haze, smoke plume over the southern Texas, Gulf of Mexico and the Yucatan Peninsula (2).

BackgroundBackgroundBiomass Burning:Biomass Burning:–– Biomass burning further Biomass burning further

contributes to the gradual contributes to the gradual increase of black carbon increase of black carbon aerosols in our atmosphere.aerosols in our atmosphere.

–– Refers to burning dead or living Refers to burning dead or living biological matter. biological matter.

–– An example of this is when An example of this is when farmers burn fields after harvest.farmers burn fields after harvest.

–– Wheat, rice and corn fields are Wheat, rice and corn fields are commonly burned.commonly burned.

–– Forest fires are also considered Forest fires are also considered biomass burning.biomass burning.

–– Is a primary source of nitrogen Is a primary source of nitrogen oxides, carbon dioxide and oxides, carbon dioxide and hydrocarbons.hydrocarbons.

Picture taken by NASA of a wheat field burning in progress (1).

Black Carbon AerosolsBlack Carbon Aerosols

Black Carbon derives from incomplete combustion of fossil fuels,Black Carbon derives from incomplete combustion of fossil fuels, biofuel, and biomass, biofuel, and biomass, and is emitted in both anthropogenic (from human influences) andand is emitted in both anthropogenic (from human influences) and naturally occurring naturally occurring soot (6).soot (6).Black Carbon warms the planet by absorbing heat in the atmospherBlack Carbon warms the planet by absorbing heat in the atmosphere and by reducing e and by reducing albedo (an objectalbedo (an object’’s ability to reflect sunlight, such as snow) (8).s ability to reflect sunlight, such as snow) (8).Black Carbon stays in the atmosphere for only several days to moBlack Carbon stays in the atmosphere for only several days to months, whereas COnths, whereas CO22 has has an atmospheric lifetime of more than 100 years (6). an atmospheric lifetime of more than 100 years (6). Aerosols that contain black carbon both absorb and reflect incomAerosols that contain black carbon both absorb and reflect incoming sunlight, therefore, ing sunlight, therefore, these particles can exert a regional cooling influence on Earth'these particles can exert a regional cooling influence on Earth's surface that is about 3 s surface that is about 3 times greater than the warming effect of greenhouse gases (7). times greater than the warming effect of greenhouse gases (7).

An electron Microscope Image of a Black Carbon Soot particle (4).

Soot being emitted from a diesel tanker (5).

InstrumentsInstrumentsAethalometerAethalometer–– A piece of equipment that A piece of equipment that

extracts air and measures extracts air and measures the amount of black carbon the amount of black carbon in the air at 7 different in the air at 7 different wavelengths.wavelengths.

–– The 7 wavelengths are: 370 The 7 wavelengths are: 370 nm., 470 nm., 520 nm., 590 nm., 470 nm., 520 nm., 590 nm., 660 nm., 880 nm., and nm., 660 nm., 880 nm., and 950 nm. 950 nm.

–– In an indoor environment, In an indoor environment, the aethalometer monitors the aethalometer monitors the smaller BC particles.the smaller BC particles.

–– An example of this would be An example of this would be the diesel exhaust from the diesel exhaust from buses into schools. buses into schools.

Burning SamplesBurning Samples

The Combustion SystemThe Combustion SystemAfter taking samples of lab After taking samples of lab air with the aethalometer, air with the aethalometer, testing began on black testing began on black carbon accumulations from carbon accumulations from individual burns.individual burns.This system is connected to This system is connected to the aethalometer, so that the the aethalometer, so that the only air that is sampled is the only air that is sampled is the air from the burning sample.air from the burning sample.This method serves as a This method serves as a substitute that helps show substitute that helps show the direct effect of biomass the direct effect of biomass burning burning The burning lasted between The burning lasted between 20 minutes to an hour.20 minutes to an hour.

Condenser

Aethalometer Connection

Water Faucet

Bunsen Burner

Gas

Crucible

Candle

Funnel

H20 Collector

Analyzing the DataAnalyzing the DataThe data was collected on a floppy. The data was collected on a floppy. The data is then analyzed and broken down into graphs.The data is then analyzed and broken down into graphs.First, establish which hours of data will be the primary First, establish which hours of data will be the primary focus. focus. Time focus: 12:00a.m., 7:00a.m., 12:00p.m. and 6:00p.m.Time focus: 12:00a.m., 7:00a.m., 12:00p.m. and 6:00p.m.The absorption, natural log of the wavelengths, and the The absorption, natural log of the wavelengths, and the natural log of the absorptions are calculated.natural log of the absorptions are calculated.This information is then formatted onto a graph, which This information is then formatted onto a graph, which displays a slope known as the Angstrom Coefficient displays a slope known as the Angstrom Coefficient (A=(A=βλβλ--αα).).

AngstrAngströömm Coefficient GraphsCoefficient Graphs

Angstrom CoefficientAngstrom Coefficient--describes wavelength of describes wavelength of aerosol absorbance. aerosol absorbance. It means that there is something absorbing, which It means that there is something absorbing, which is why in most cases it will not reach the goal of 1.is why in most cases it will not reach the goal of 1.If the If the AngstrAngströömm coefficient slope is lower than 1, coefficient slope is lower than 1, there are traces of inorganic dust particles there are traces of inorganic dust particles present.present.If If AngstrAngströömm coefficient slope is higher then 1, coefficient slope is higher then 1, secondary organic particles, such as humic like secondary organic particles, such as humic like substances, are present.substances, are present.

AngstrAngströömm Coefficient GraphCoefficient GraphAngstrom Coefficient (7:00a.m.)

y = -1.19x + 9.33R2 = 0.97

0

0.5

1

1.5

2

2.5

5.8 6 6.2 6.4 6.6 6.8 7LN of Wavelength (nm)

LN o

f Abs

orpt

ion

(Mm

-1)

The deviated point of data shows absorption taking place from something other than black carbon.

AngstrAngströömm Exponent as a Function of Exponent as a Function of TimeTime

After finding the Angstrom exponents of After finding the Angstrom exponents of each date and specific hours, all of the each date and specific hours, all of the angstroms are then put together on a graph angstroms are then put together on a graph as a function of time.as a function of time.This is how we can gradually see an This is how we can gradually see an obvious pattern of black carbon peaks on obvious pattern of black carbon peaks on certain days.certain days.

AngstrAngströömm Exponent as a Function of TimeExponent as a Function of TimeAngstrom Exponents as a Function of Time

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

192

193

194

196

199

200

201

202

203

204

205

206

Julian Date

Ang

stro

m E

xpon

ents

Possible result of California wild fire incident ?

Possible result of construction on the UALR ETAS building flaring up dust?

Averages for the Burned SpecimensAverages for the Burned Specimens

Burned SampleBurned Sample Angstrom Angstrom CoefficientCoefficient

Alpha (Alpha (αα))

Unscented CandleUnscented Candle --0.860.86 0.720.72

Scented Vanilla CandleScented Vanilla Candle --0.960.96 0.960.96

Scented Cinnamon Scented Cinnamon CandleCandle

--0.280.28 0.860.86

Post Oak Tree LeafPost Oak Tree Leaf --1.491.49 0.940.94

Future WorksFuture Works

To use To use spectrophotometer spectrophotometer which is an optical which is an optical instrumentinstrumentmeasures properties of measures properties of light over a light light over a light spectrum.spectrum.This instrument This instrument analyzes the data on analyzes the data on the entire UVthe entire UV-- Visible Visible wavelength rangewavelength range

Future WorksFuture WorksUALR will be UALR will be establishing an establishing an Atmospheric Atmospheric ObservatoryObservatoryCompare indoor Compare indoor and outdoor and outdoor aethalometer data.aethalometer data.

AcknowledgementsAcknowledgements

Department of Energy (D.O.E.)Department of Energy (D.O.E.)Dr. Jeff GaffneyDr. Jeff GaffneyDr. Nancy MarleyDr. Nancy MarleyMikey TackettMikey TackettSurya Surya KilapartyKilapartyUALR Chemistry DepartmentUALR Chemistry DepartmentGCEP/SURE ProgramGCEP/SURE ProgramMr. Milton Mr. Milton ConstantinConstantin

ReferencesReferences1.1. www.nasa.govwww.nasa.gov: : Goddard Space Flight CenterGoddard Space Flight Center. Mike . Mike BettwyBettwy. 2006. July 2008. . 2006. July 2008.

<<http://http://www.nasa.gov/environment/central_am_fires.htmlwww.nasa.gov/environment/central_am_fires.html>.>.2.2. www.nasa.govwww.nasa.gov: : Biomass burning and the Production of Greenhouse GasesBiomass burning and the Production of Greenhouse Gases-- NASA NASA

Langley ResearchLangley Research. Joel S. Levine. 1994. July 2008. . Joel S. Levine. 1994. July 2008. <<http://http://www.nasa.gov/environment/central_am_fires.htmlwww.nasa.gov/environment/central_am_fires.html>.>.

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8.8. Wikipedia Encyclopedia: KeywordWikipedia Encyclopedia: Keyword-- ““AlbedoAlbedo””. . Pavement Albedo.Pavement Albedo. PonPon Brian. 2007. Brian. 2007. August 2008. <August 2008. <www.wikipedia.orgwww.wikipedia.org//>. >.