Automatic Semi-continuous Field-Deployable Thermal/Optical … · Automatic Semi-continuous...

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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

Serial Cable

to computer

Support

Serial Cable

Remote SSR

Pump Control

Remote

Vacuum

Line to

Ballast

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

4/15/2004

4/16/2004

4/17/2004

4/18/2004

4/19/2004

micrograms C per cubic meter

Organic Carbon

Elemental Carbon

Minute Optical EC – Suburban Area

Minute Optical EC, ug C/cubic meter

4/15/2004

4/16/2004

4/17/2004

4/18/2004

4/19/2004

micrograms EC per cubic meter

OCEC with PM2.5 Vienna - February

OC/EC - Busy EU Intersection February 2006

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

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

WeekendWeekend Weekend

OCEC and Windspeed - Vienna

OC/EC - Busy EU Intersection February 2006

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

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

0.3Wednesday Thursday Friday Saturday Sunday Monday

Los Angeles SOA and Ozone

7/16/05

7/17/05

7/18/05

7/19/05

7/20/05

7/21/05

7/22/05

7/23/05

7/24/05

7/25/05

7/26/05

7/27/05

SOA (ug/m

O3 (ppb)

SOA O3

Primary OC Correlation with CO

11/1/05

11/2/05

11/3/05

11/4/05

11/5/05

11/6/05

11/7/05

11/8/05

11/9/05

11/10/0

5 0:00

11/11/0

5 0:00

11/12/0

5 0:00

Primary OC (ug/m

CO (ppm)

Primary OC

Forest Fire Event in Columbia Gorge

Bonneville Dam/Columbia Gorge - Forest Fire Event

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

Optical EC and Aethelometer® BC

Three Day BC vs. OptEC

(5 min BC vs. 1 hr. OptEC)

0 200 400 600 800 1000 1200 1400 1600

Time S egment s

AethEC

Optical EC vs. Aethelometer® BC

BC vs OptEC (Hourly average)

y = 1.1877x + 0.0147

R2 = 0.9526

0.00 0.50 1.00 1.50 2.00 2.50 3.00

Sunset OptEC (ugC/M3)

r BC (ugC/M

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

Automatic Semi-continuous Field-Deployable Thermal/Optical … · Automatic Semi-continuous...

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