Air Pollution Monitoringgurme/Dec 09 - 01... · Air Pollution Monitoring 33 USA on August 1, 1995,...

GURME

Air Pollution Monitoring

Dr. Sarath Guttikunda@ Desert Research Institute, Reno, USA & UrbanEmissions.Info

GURM Why do we Monitor?E

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• ComplianceCompliance• Trends in ambient pollution• Spatial and temporal analysisSpatial and temporal analysis• Hot spot analysis• Model verification• Model verification• General issues

– Uses of data– Uses of data– Variability among monitor types– Spatial representativeness

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p p

GURM and ForecastingE

… and Forecasting

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GURM Type of MonitoringE

Type of MonitoringForecasting Data Sources

Parameters Time Resolution

Real-time availability

Cost/Resources

Written records of ∼PM - - LowWritten records of episodes

∼PM - - Low

Meteorological Data

Visibility ∼PM HourlyDaily

Yes Lowy

Reports of smoke/haze ∼PM Varies Possible Low

Satellite images ∼PM HourlyDaily

Yes Low

Air Quality DataQua ty ata

Surface

Continuous PM, O3, CO, NO2, NOx, SO2, and more Hourly Possible Moderate

Samplers PM, O3, CO, NO2, NOx, SO2, and more Typically Daily

No ModerateDaily

Passive samplers PM, O3, CO, NO2, NOx, SO2, and more Integrated No Low

Upper-Air

Ozonesonde O3 Periodic No High

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Aircraft PM, O3, CO, NO2, NOx, SO2, and more Episodic No Very high

LIDAR PM, O3, CO, others Hourly Yes Very high

GURME

Monitors

GURM Typical Continuous Gas MonitorsE

Typical Continuous Gas Monitors● Ambient air is continuously drawn into the monitor, pre-treated

(e.g. particles, hydrocarbons, and/or H2S removed), and(e.g. particles, hydrocarbons, and/or H2S removed), and measured either directly or via chemical reaction using a spectroscopic method

● Direct measurement● Direct measurementCO: gas filter correlationSO2: UV fluoresenceO UV h t t iO3: UV photometric

● After reaction with O3

NO2: by difference (NOx-NO) using chemiluminescence and catalytic converter

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GURM Typical Particle MonitoringE

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● Filter sampler for 24-hr (daily) PM massp ( y)– Single channel or sequential

● Continuous (hourly) monitors● Continuous (hourly) monitors– Tapered Element Oscillating Microbalance

(TEOM)(TEOM)– Beta Attenuation Monitors (BAM)

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GURM Daily Filter SamplersE

y pFilter Sampler

• Ambient air is drawn through inlet (to remove largerAmbient air is drawn through inlet (to remove larger particles)

• Material collects on the filter; filter is later analyzed f h i l ifor mass or chemical species

• Problems– Potential loss of volatile materialPotential loss of volatile material– Not available for short time intervals– Not available in real time

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GURM Continuous Particle Monitors (1 of 2)E

Tapered Element Oscillating Microbalance (TEOM)• Determines mass by variation

in frequency of filter element on an oscillating arm

• Differential mass for each hour• Problems

– Negative mass values due to volatilization

– Volatilizing nitrates and carbon species, particularly during cold weather or high humidity causes underestimation of

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underestimation of PM mass

GURM Continuous Particle Monitors (2 of 2)E

Beta Attenuation Monitor (BAM)• Mass of PM collects on a filter and is

exposed to beta ray, the attenuation of which is proportional to the mass on the filter

• Problems– PM species attenuate beta rays differently – Relative humidity (RH) can influence

calculation of PM mass from attenuation data causing under or overestimation of PM mass during periods of fluctuating RH values

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GURM PM2 5 Federal Reference Method (FRM)E

PM2.5 Federal Reference Method (FRM)

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GURM

Speciation Monitors (EPA speciation network)

E Mass Aerosol Sampling System (MASS)URG Corporation, Raleigh, NC

Reference Ambient Air Sampler (RAAS)Andersen Instruments Smyrna GAAndersen Instruments, Smyrna, GA

Spiral Aerosol Speciation Sampler (SASS)Met One Instruments, Grants Pass, OR

Interagency Monitoring of Protected Visual

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g y gEnvironments (IMPROVE) SamplerAir Resource Specialists, Ft. Collins, CO

GURM

Other Speciation MonitorsE

Partisol 2300 Speciation SamplerRupprecht & Patashnick, Albany, NY

Dual Channel Sequential Filter Sampler q p

and Sequential Gas SamplerDesert Research Institute, Reno, NV

Dichotomous Virtual ImpactorAndersen Instruments, Smyrna, GA

Paired Minivols

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Airmetrics, Inc., Springfield, OR

GURM

I. Inlets . . . Fine Particle InletsCut Point Slope

ECut Point Slope

Type (d50) (√d84/d16) Flow Rate

Harvard sharp cut impactor 2.5 µm 1.02 4 L/min

R&P sharp cut cyclone 2.5 µm 1.23 5 L/min

GRT sharp cut cyclone 2.5 µm 1.24 6.8 L/min

Harvard sharp cut impactor 2.5 µm 1.06 10 L/minURG cyclone 2.5 µm 1.32 10 L/min

/EPA WINS impactor 2.48 µm 1.18 16.7 L/minBGI sharp cut cyclone 2.5 µm 1.19 16.7 L/minURG cyclone 2.5 µm 1.35 16.7 L/min

Harvard sharp cut impactor 2.5 µm 1.25 20 L/min

Andersen/AIHL cyclone 2.7 µm 1.16 24 L/min

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IMPROVE cyclone 2.3 µm 1.18 28 L/min

Bendix/Sensidyne 240 cyclone 2.5 µm 1.7 113 L/min

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Inlets . . . Examples of InletsE WINS impactor Bendix cyclone

AirmetricsAirmetricsimpactors

PM10

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10

PM2.5 Sharp cut cyclone

GURM

I. Inlets . . . PM10 InletsCut Point Slope

ECut Point Slope

Type (d50) (√d84/d16) Flow Rate

Harvard sharp cut impactor 10 µm 1.11 4 L/min

Harvard sharp cut impactor 10 µm 1.09 10 L/minHarvard sharp cut impactor 10 µm 1.09 10 L/min

Andersen 246B impactor 10.2 µm 1.41 16.7 L/min

Harvard sharp cut impactor 10 µm 1.06 20 L/min

Andersen med-vol impactor 10 µm 1.6 113 L/min

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Andersen hi-vol impactor 9.7 µm 1.4 1,133 L/min

TEI/Wedding cyclone 9.6 µm 1.37 1,133 L/min

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Inlets . . . Examples of PM10 InletsE

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GURM

Filter HoldersDichotomous samplerE Dichotomous sampler polyethylene 37mm filter holder

FRM samplerDelrin 47mm filter holder ring with stainless steel gridg

Nuclepore polycarbonate filter holderholder

Savillex molded FEP filter h ldholder

Speciation sampler

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Teflon-coated aluminum filter holder

GURM

Sampling Substrates . . . Types of Media

E Teflon membrane

• Mass and elemental analysis, sometimes ions

Nylon membrane

• Nitric acid, also adsorbs other gases (SO )sometimes ions

• Not for carbon

Quartz fiber

other gases (SO2)

Etched polycarbonate

• Scanning electronQuartz fiber

• Ions and carbon (after annealing)

• Scanning electron microscopy, elements, mass with extensive de-charging

• Not for mass or elements

Cellulose fiber

de charging

• Not for ions or carbon

Teflon-coated glass fiber• Gas sampling with

impregnates (citric acid/NH3, triethanolamine/NO2, sodium

Teflon coated glass fiber

• Mass, ions, organic compounds (e.g., PAH)

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/ 2,chloride/HNO3, sodium carbonate/SO2)

• Not for carbon or elements

GURME

Optical Sensorsp

GURM

Continuous Mass Surrogates (particle scattering measurements)

E TSI DusTrak Optec NGN-2

Greentek RadianceM903nephelometernephelometerwith smartheater

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GURM Visibility SensorsE

y

● Nephelometers● Transmissometer (weather

visibility sensors)Measurements● Measurements

– Measures light scattering– Provides continuous data– Correlated with PM– Lower cost PM measurement

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GURM Bangkok Visibility IndexE

Bangkok Visibility Index

20

14

16

18

m)

8

10

12

Vis

bili

ty (

km

2

4

6V

0

Jan

-60

May

-61

Oct

-62

Feb

-64

Jul-

65N

ov-6

6A

pr-

68A

ug

-69

Dec

-70

May

-72

Sep

-73

Feb

-75

Jun

-76

Nov

-77

Mar

-79

Jul-

80D

ec-8

1A

pr-

83Se

p-8

4Ja

n-8

6Ju

n-8

7O

ct-8

8F

eb-9

0Ju

l-91

Nov

-92

Ap

r-94

Au

g-9

5D

ec-9

6M

ay-9

8Se

p-9

9F

eb-0

1

23Air Pollution MonitoringSource: Climatology Division, meteorology department, Thailand

GURM NephelometersE

p● Nephelometers

– Measure light scatter from particles– Sensitive to aerosols < 2.5 µmSensitive to aerosols 2.5 µm– Heater dries air (removes affect of humidity)– Not sensitive to flow rate– Lower maintenance costsLower maintenance costs

● Problems– Sensitive to humidity

Carbon can absorb light and bias data– Carbon can absorb light and bias data

Light Extinctionbext

Light Absorption babs

Light Scattering bscat

Light Scatteringby Gases

bsg

Light Scatteringby Particles

bsp

Light Absorptionby Particles

bap

Light Absorptionby Particles

bag

Light Scatteringby Coarse Particles

bscp

Light Scatteringby Fine Particles

bsfp

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The relationship of the components of light extinction.

GURME

Satellite

GURM Satellite (1 of 5)E

● Polar-orbiting or geostationary

● Advantage– Data available from around the world

● Visible imagery● Aerosol optical depth

● Disadvantage– No direct pollutant measurements– Only works during daylight and when O y o s du g day g a d e

skies are cloud-free– No vertical resolution

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Images courtesy of University of Wisconsin, Madison

GURME

Ground Based

GURM OzonesondeE

● Sensor attached to a radiosonde● Measures vertical profile of ozone● Examines aloft ozone conditions

Problems for forecasting● Problems for forecasting– Expensive– Very sparse, non-routine networksy p ,

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Courtesy of T&B systems

GURM Ozonesonde – ExampleE

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Morning (6 a.m.) and afternoon (4 p.m.) ozonezonde data showing ozone concentration (black line), temperature (red), dew point temperature (blue), and winds from Las Vegas, Nevada, USA on July 1, 2005. Courtesy of T&B systems.

GURM LidarE

Lidar

An early transportable LIDAR from CSIRO on location during a plume tracking experiment

Cross section of a plume displayed during data acquisition obtained by LIDAR (located to the left), showing the height of the mixing layer (red) and structure in the plume (blue). If an appropriate wave-length is used, LIDAR can measure SO2 concentration in the plume

a plume tracking experiment.

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a app op ate a e e gt s used, ca easu e SO2 co ce t at o t e p u edirectly.

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Aircraft

GURM AircraftE

● Provide multi-pollutant monitoring● Able to fly in area of concern● Useful for monitoring aloft carryover, transport g y p

of pollution, and mixing processes● Morning flights profile useful forecasting

information● Problems

– Expensive– Data not available in real-time

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GURM Aircraft – ExampleE

2500 FreeAtmosphere

2500 FreeAtmosphere

1500

2000

de (m

agl

)

NOy T O3 ResidualLayer

1500

2000

de (m

agl

)

NOy T O3 ResidualLayer

500

1000

Alti

tud

Surface

LowLevelJet500

1000

Alti

tud

Surface

LowLevelJet

00 10 20 30 40 50 60 70 80 90

Concentration (ppb) Temperature (oC)

SurfaceLayer

00 10 20 30 40 50 60 70 80 90

Concentration (ppb) Temperature ( oC)

SurfaceLayer

Temperature (C) 10 m/s NorthAircraft Spiral and Upper-Air Winds at Gettysburg, PA

(0600 EST on August 1, 1995)

Temperature ( oC) 10 m/s North

Aircraft measurement of ozone, NOy, temperature, and winds provide aloft information about the air quality conditions in the nocturnal low-level jet. In this example, aircraft data collected near Gettysburg, Pennsylvania, USA A t 1 1995 t 0600 EST h d t l j t th t t t d i ll ti l h d d

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USA on August 1, 1995, at 0600 EST showed a nocturnal jet that transported air pollution over several hundred kilometers during the overnight hours. This aloft pollution mixed to the surface during the late morning hours.

GURME

How many are enough?y g

GURME

Google Earth, Delhig

GURM

Monitor Density and LocationAnalysis TechniquesE Analysis Techniques

More the MerrierMore the Merrier

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Penfold et al., 2003

GURM

Monitor Density and LocationAnalysis Techniques

E

Points Lines Population ElevationInput Data:

Analysis Techniques

Point, line, or polygon geographic data

Gridded Data: Create distanceCreate distance contours or density plots from the data sets

Reclassified Data:Reclassified Data: Reclassify them to create a common scale

Weight and combine datasetsWeight and combine datasetsHigh Suitability

Low Suitability

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Output suitability model

GURME

Google Earth, Delhig

GURM Monitor RepresentativenessE

● Representativenessp– Do monitors measure the prevailing conditions at

site, location, or region?– Do collocated monitors measure similar

conditions (variations can exist among monitoring techniques)tec ques)

– Do closely located monitors measure similar conditions?

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GURM Data AvailabilityE

● Regional maximum differences from evolving and changing networks– Adding or removing sites from a network can affect overall network

monitoring results

y

– The same is true for sites removed from the network● Data availability

– Filter sampling may measure PM on different schedules (daily or every third or sixth day), which makes analysis more difficulty), y

CPCB – Real Time Datahttp://164 100 43 188/cpcbnew/movie htmlhttp://164.100.43.188/cpcbnew/movie.html

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GURM SummaryE

● Monitor types– Gas monitors– Particle samplers and monitors– Continuous – real-time, good for forecasting– Samplers – not real-timeSamplers not real time– Other

● Visibility sensors● Satellite measurements● Satellite measurements● Ozonesondes

● General issuesUses of data– Uses of data

– Variability among monitor types– Spatial representativeness

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– Data availability

GURME

Thank You

Dr Sarath GuttikundaDr. Sarath GuttikundaNew Delhi, India

More details @ www.urbanemissions.info