Automatic Semi-continuous

Field-Deployable Thermal/Optical

OCEC Carbon Aerosol Analyzer

Sunset Laboratory Inc.

Robert A. Cary

David F. Smith

Introduction

� Why Organic and Elemental Carbon

Measurements?

�Climate effects

�Tracer for Sources

�Health effects

�Visibility

� Semi-continuous Field Instrument Specifications,

Features and Data

� Field version better suited for continuous

monitoring at one location over a period of time

OCEC Field Instrument

� Basic functions

�Automatically samples and analyzes carbon in a semi-

continuous method

�Accurate thermal/optical OCEC sampler

�Semi-continuous operation with minimal operator input

�Field deployable to an enclosed site

�Pre-set sample collection time(certain hours of the day)

or pre-set collection cycle times(repeated time cycle)

�Sample collection variance from 30 minutes to 4 hours.

One or two hour cycles are typical

Basic Functions (continued)

�Sunset Laboratory transmittance based OCEC parameters or user defined (NIOSH 5040, IMPROVE, EPA STN, or any user entered parameter)

�Measure EC by optical measurement and also thermal measurement

�Fast analysis protocol to maximize sample collection time

�Sensitive and smooth detector system

Features

� Time resolution as small as 30

minutes(recommended under unusually high

levels)

� Minimum quantifiable levels of 0.4ugC/m^3 for

OC and EC

� Sensitive NDIR detector measures carbon after

it evolves from the filter and is oxidized to CO2.

� Computer operated flow controllers for all gases

to allow for efficient use of gases

Features (continued)

� Minute by minute optical EC

measurements(OptEC)

� Minimal maintenance

� Portable computer allows for easy operation and

data storage

� Laser enables pyrolysis correction and

compatibility with accepted OCEC method 5040

(NIOSH, National Institute of Safety and Health)

Denuder/Cyclone Inlet

Semi-Continuous OCEC Instrument Diagram

Current Production Model

Model 4 Rack-Mount OCEC

Gas Inputs and other connections

Sample

Inlet

Serial Cable

to computer

Support

Gases

NDIR

Serial Cable

Remote SSR

Pump Control

Remote

TC

Vacuum

Line to

Ballast

Tank

Inlet Requirements

�Pre-Cleaned Metal Tubing Only

(Copper or SS)

�Cyclone for size selection

�Denuder for removal of Organic Vapors

COMMON MAINTENANCE ITEMS

�1. Gases – 6 months to 2 years

�2. Filters – Usually changed weekly,

though may need to be more often or can

be less often

�3. Heating coils – need to be replaced

when they burn out. 1-2 Years

OC and EC – Suburban Area

Two Hour Samples

OC and EC, ug/cubic meter - Suburban Area

0

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4/15/2004

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micrograms C per cubic meter

Organic Carbon

Elemental Carbon

Minute Optical EC – Suburban Area

Minute Optical EC, ug C/cubic meter

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micrograms EC per cubic meter

OCEC with PM2.5 Vienna - February

OC/EC - Busy EU Intersection February 2006

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OptOC (ugC/M3) OptEC (ugC/M3) PM2_5 AKC

Weekend Weekend Weekend

OCEC with PM2.5 Vienna - March

OC/EC - Busy EU Intersection March 2006

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OptOC (ugC/M3) OptEC (ugC/M3) PM2_5 AKC

WeekendWeekend Weekend

OCEC and Windspeed - Vienna

OC/EC - Busy EU Intersection February 2006

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0.00

3.00

6.00

9.00

12.00

15.00

OptOC (ugC/M3) OptEC (ugC/M3) wind speed [m/s]

Denuder installed

Weekend Weekend Weekend

Nightly OCEC Events in Portland

OC, EC ug/cub m EC/TC raio Portland, Oregon

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10/25/2006 0:00 10/26/2006 0:00 10/27/2006 0:00 10/28/2006 0:00 10/29/2006 0:00 10/30/2006 0:00 10/31/2006 0:00

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0.3Wednesday Thursday Friday Saturday Sunday Monday

Los Angeles SOA and Ozone

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SOA (ug/m

3)

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O3 (ppb)

SOA O3

Primary OC Correlation with CO

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Primary OC (ug/m

3)

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CO (ppm)

Primary OC

CO

Forest Fire Event in Columbia Gorge

Bonneville Dam/Columbia Gorge - Forest Fire Event

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8/ 29/ 2006 0:00 8/ 30/ 2006 0:00 8/ 31/ 2006 0:00 9/ 1/ 2006 0:00 9/ 2/ 2006 0:00 9/ 3/ 2006 0:00 9/ 4/ 2006 0:00 9/ 5/ 2006 0:00 9/ 6/ 2006 0:00

Da t e and Time

0

0.05

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0.35

Optical EC and Aethelometer® BC

Three Day BC vs. OptEC

(5 min BC vs. 1 hr. OptEC)

0

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0 200 400 600 800 1000 1200 1400 1600

Time S egment s

UgC/M

3

AethEC

OptEC

Optical EC vs. Aethelometer® BC

BC vs OptEC (Hourly average)

y = 1.1877x + 0.0147

R2 = 0.9526

0

0.5

1

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2.5

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3.5

0.00 0.50 1.00 1.50 2.00 2.50 3.00

Sunset OptEC (ugC/M3)

Aeth

alom

ete

r BC (ugC/M

3)

BC

Linear (BC)`

Applications

� Ambient air quality and environmental exposure measurements

� Indoor air exposure assessment monitoring

� Long term environmental research such as studying the effects of regulatory changes implemented

� Workplace assessments

� Natural/man-made disaster effects over temporary periods such as extreme weather patterns, seasonal temperature inversions, or large fires