Use of Laser Technology toMonitor Ammonia

Prepared by

Dave Goorahoo, Matt Beene,Charles Krauter and Barry Goodrich

Center for Irrigation Technology (CIT) and Center for Irrigation Technology (CIT) and College of Agricultural Science and Technology (CAST)College of Agricultural Science and Technology (CAST)California State University, Fresno (CSUF) California State University, Fresno (CSUF)

CSU/ARICSU/ARI Project Project•• California State University (CSU)California State University (CSU)

•• Agricultural Research Initiative (ARI)Agricultural Research Initiative (ARI)Monitoring Ammonia, Methane and Other Emissions In RealTime At Dairies and Other Agricultural OperationsPrincipal Investigators: Dave Goorahoo and Charles Krauter,Begun 7/1/02, to be completed 12/31/06

•• California Air Resources Board (CARB)California Air Resources Board (CARB)

•• California Dairy research Foundation (CDRF)California Dairy research Foundation (CDRF)

•• California Water Institute (CWI)California Water Institute (CWI)

•• Numerous Dairy CooperatorsNumerous Dairy Cooperators

Major Goal and ObjectivesMajor Goal and Objectives

The overall goal of the studyThe overall goal of the study is to contribute to on going efforts to make dairy

operations sustainable by: (a) identifying probable areas that contribute to

environmental degradation; and, (b) recommending management practices to

mitigate these adverse effects.

The objectives are:The objectives are:

•(1)Quantify spatial and temporal variability CH4, H2S and NH3 emissions on dairy;

•(2) Correlate emissions with climatic, soil, water and livestock parameters; and,

•(3) Evaluate the influence of various management practices on the gaseous emissions.

BackgroundBackground•• Over the past five years we have been monitoringOver the past five years we have been monitoring

ammonia emissions from various agricultural operationsammonia emissions from various agricultural operationsin the San Joaquin Valley.in the San Joaquin Valley.

•• Use of “Active” sampling filter packs, sometimes referredUse of “Active” sampling filter packs, sometimes referredto as “denuders”to as “denuders”

•• The filter packs require several hours of sampling toThe filter packs require several hours of sampling toacquire sufficient NHacquire sufficient NH33 for detection in the laboratory for detection in the laboratory

Ammonia Filter PacksAmmonia Filter Packs•• Filter disks are impregnated with a reactingFilter disks are impregnated with a reacting

substance, (5% citric acid in 95% ethanol).substance, (5% citric acid in 95% ethanol).

•• Air is pumped through the filter, NHAir is pumped through the filter, NH33 is isscrubbed out, forming ammonium citratescrubbed out, forming ammonium citratethat stays on the filter paperthat stays on the filter paper

•• Lab analysis determines micrograms of NHLab analysis determines micrograms of NH33on the filter disk.on the filter disk.

FilterFilter holder

Air line connectionNut

InletCompleteDenuder

Citrateimpregnatedfilter

Field Monitoring of Ammonia EmissionsField Monitoring of Ammonia Emissions•• NHNH33 was sampled in the field with active was sampled in the field with active

denuders on a portable tower at 1, 2, 5, 10 and 18denuders on a portable tower at 1, 2, 5, 10 and 18meters elevation.meters elevation.

•• Samples taken continuously from 2 days beforeSamples taken continuously from 2 days beforeto 5 days after the fertilizer application.to 5 days after the fertilizer application.

•• Wind speed was monitored at each sample heightWind speed was monitored at each sample heightto calculate NHto calculate NH33 fluxes and gradients fluxes and gradients

Determination of NHDetermination of NH33 in the sample in the sample•• Air pulled through the filtersAir pulled through the filters

•• Filters were changed diurnally.Filters were changed diurnally.

•• Flow rate through the denuders recorded forFlow rate through the denuders recorded foreach sampling period.each sampling period.

•• Lab analysis of NHLab analysis of NH33 on the denuder disk on the denuder diskmultiplied by the volume of air determinedmultiplied by the volume of air determinedconcentration NHconcentration NH33/meter/meter33 of sampled air. of sampled air.

DW-FS

DW-Field

DW-LN

Upwind

380 meters380 meters

N

Generally, Data collectedwhen wind was from NW

Denuder samplecollection ranged from asshort 2 hours to as longas 72 hours

21.392.2301.02.9

RHtemperature (F)wind directionwind speed (m/s)

Meteorological Conditions

Sampling over 3hrs.

Desirable wind speedand direction.

Fallow field.

WIND SPEED & DIRECTION September 15 (1400-1730)

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WD

AMMONIA CONCENTRATIONS SEPTEMBER 15 (1400-1730)

0123456789

10

0.00 200.00 400.00 600.00 800.00

µg NH3-N/m3

sam

ple

heig

ht

UW

DW-LN

DW-FS

DW-FIELD

WIND SPEED & DIRECTION Sept 10 (1145) - Sept 11 (1305)

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wswd

AMMONIA CONC. SEPTEMBER 10-11

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0.00 100.00 200.00 300.00

µg NH3-N/m3

sam

ple

heig

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UWDW-LNDW-FIELD

55.1434471.4variable 1.2

RHtemperature (F)wind directionwind speed (m/s)

Meteorological Conditions

Sampling over 24 hrs.

Variable wind speed anddirection.

Fallow field.

Tunable Diode Laser (TDL) SystemsTunable Diode Laser (TDL) Systems•• The filter pack method for collectingThe filter pack method for collecting

atmospheric NHatmospheric NH3 3 requires several hours torequires several hours tocollect a sample in most instances.collect a sample in most instances.

•• Time period may be too long toTime period may be too long tocharacterize short term operations.characterize short term operations.

•• The TDL system measures The TDL system measures Real TimeReal Time gas gasconcentration over an open path.concentration over an open path.

Tunable Diode Laser (TDL)- Principle of Operation

GasFinder Gases and Sensitivities

0.010.010.10.11111HF (low)HF (low)

0.010.010.10.11111HClHCl

0.010.010.10.11111HCNHCN

10101001001000100010001000CO2CO2

0.010.010.10.11111CH4CH4

0.20.22220202020H2SH2S

0.050.050.50.55555NH3NH3

0.0010.0010.010.010.10.10.10.1HF (high)HF (high)

100m path100m path(ppm)(ppm)

10m path10m path(ppm)(ppm)

1m path1m path(ppm)(ppm)

SensitivitySensitivity(ppm-m)(ppm-m)

GasGas

A uniform background concentration of 1 ppm over 50m gives areading of 50 ppm-m.

GasFinder

GasFinder

1m

A concentrated cloud of 50 ppm, 1m in diameter, in abackground of 0 ppm also gives a reading of 50 ppm-m

Retroreflector

Retroreflector

50m

GasFinder measures ppm-metres

Conversion of Conversion of ppmppm- m data- m data•• Divide by path length to get Divide by path length to get ppmppm

•• Use molecular weight, Universal gasUse molecular weight, Universal gasconstant, pressure and temperature toconstant, pressure and temperature toconvert convert ppmppm to mg per m to mg per m33 of gas of gas

•• Use wind speed to convert mg per m3 toUse wind speed to convert mg per m3 tohorizontal flux at a given height in mg/mhorizontal flux at a given height in mg/m33/s/s

Ammonia fluxes measured with active samplers before, during and after acidification of Lagoon at CSUF dairy

0.0

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0 1 2 3 4 5 6Sample Elevation ( meters)

NH

3 flu

x ( µ

g N

H3 /

m2 /s

)

During Acidification Pre-Acidiification Post-Acidiification

pH = 6.3

pH = 7.5

pH = 6.9

Generic Benefits of TDL• Very high resolution - about 0.003 cm-1

– Enables measurement of individual spectral lines

– No spectral interference from other gases

– Linear over wide dynamic range

• Very sensitive - ppm to ppb levels

• Fast response times – typically 1 second

• High reliability - no moving parts

• Non-contact method - suitable for corrosives

• Amenable to fiber optics - multiple path capability

• Widely applicable - many species absorb in NIR

• Potential for multiple species

Using TDL Data for Modeling Emission ratesUsing TDL Data for Modeling Emission rates

•• Attempt to do inverse dispersion modeling usingAttempt to do inverse dispersion modeling usingthe EPA approved model: Industrial Sourcethe EPA approved model: Industrial SourceComplex Short Term version 3 (ISC-STv3).Complex Short Term version 3 (ISC-STv3).

•• Due to the limited number of laser unitsDue to the limited number of laser unitsavailable we were unable to obtain simultaneousavailable we were unable to obtain simultaneousupwind and downwind concentrationsupwind and downwind concentrations

•• This presents the problem of determining whatThis presents the problem of determining whatportion of the measured concentrationportion of the measured concentrationdownwind of a source is attributable to thatdownwind of a source is attributable to thatsource.source.

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Time ( P D T)

Downwind Upwind

S ys t e m o f f l ine f o r A lig nme nt

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w ind speed w ind direction

Ammonia Concentrations for two paths over an open lot

••Assuming that the TDL instruments are keptAssuming that the TDL instruments are keptwithin optimum operating temperaturewithin optimum operating temperatureconditions, the TDL technology is suitable forconditions, the TDL technology is suitable fordetecting the gas concentrations from dairydetecting the gas concentrations from dairylagoons during the summer temperatures inlagoons during the summer temperatures inSJVSJV

••During intense fog condition observed duringDuring intense fog condition observed duringthe Fall season, the lasers failthe Fall season, the lasers fail

Summary of FindingsSummary of Findings

•• Data collected with the TDL depict the periods ofData collected with the TDL depict the periods ofrelatively higher diurnal emissions which generally gorelatively higher diurnal emissions which generally goundetected with the filter pack samplingundetected with the filter pack sampling

•• It is essential to conduct monitoring during the fall,It is essential to conduct monitoring during the fall,winter and spring seasons to assess the performance ofwinter and spring seasons to assess the performance ofthe TDL system under these conditions, while at thethe TDL system under these conditions, while at thesame time examining any seasonal variability in thesame time examining any seasonal variability in thegaseous emissions.gaseous emissions.

•• At least one more set of each lasers are needed if we areAt least one more set of each lasers are needed if we areto obtain simultaneous upwind and downwindto obtain simultaneous upwind and downwindconcentrations data necessary for validation of EPAconcentrations data necessary for validation of EPAmodel.model.

Summary of Findings (Cont’d)Summary of Findings (Cont’d)

CONTACTSCONTACTS• Charles Krauter: (559) 278- 5114, fax: 278 6033

charles_krauter@csufresno.edu• Dave Goorahoo (559) 278-8448, fax: 278 6033

dave_goorahoo@csufresno.edu• Barry Goodrich (559) 278-6784, fax: 278 6033

lgoodrich@csufresno.edu• Matt Beene (559) 278-6784, fax: 278 6033

mattbeene@csufresno.edu

THANK YOUTHANK YOU☺☺!!