ECOC:

ECOC (Elemental Carbon – Organic Carbon) analysis has been performed at WOHL since 1999. This test is being used as a marker for Diesel exhaust. WOHL does this test using the NIOSH 5040 method and the Sunset Labs Carbon Analyzer. This method is rapidly becoming the preferred test for measurement of Diesel Particulate Matter (DPM) in air.

WOHL provides the following options for ECOC analysis:
Elemental Carbon by NIOSH 5040 (for non-mine air sampling)
Organic/Total Carbon by NIOSH 5040 (for mine air sampling)
(WOHL will also correct for carbonate interference occurring in the organic carbon result if requested)
Elemental Carbon on Quartz wipes (a qualitative test for evidence of combustion)

WOHL will also work with you for more specialized ECOC analysis, for example graphite in air or on surfaces. Please call us at 800-446-0403 and ask for Adam Bednarek or RJ Messling.

Frequently Asked Questions ( FAQ’s ):

Q. What media should I use and for how long at what flow rate?
A. The answer depends on what type of environment you will be sampling.

Media:
1. Non-mine air sampling: Use WOHL-made 37 mm. Quartz fiber filters in three-piece cassettes at 2-4 LPM, min. vol. of 140 L.

2. Mine air samples: (absolutely necessary for coal mines): Use SKC’s DPM cassettes with a 10 mm conductive nylon cyclone in the sampling train. Needed to minimize fine coal dust interference and possibly some organic/carbonate (e.g. limestone) dust potential interferences. Also to prevent clogging of the impactor cassette. Use a flow rate of to 1.7 –2.0 LPM.

Supplies for Sampling Diesel Exhaust:
Sampling pumps/ Cylcones: WOHL can provide a limited number of sampling pumps or cyclones.

Media: WOHL will provide heat-conditioned 37 mm quartz fiber filters in standard 3-piece cassettes free with the cost of analysis. The SKC DPM cassettes can be ordered directly from SKC.

Q. How good is this test at measuring Diesel exhaust?
A. Generally speaking, very good if elemental (not total or organic) carbon is being used for measurement. There are relatively few known EC interferences in most occupational settings and these can be minimized easily.

• Carbon black. (found in inks, tire dust) Do not sample when this material is known to be present. Tire dust interference can be reduced or eliminated using a (respirable) cyclone.
• Fuel oil combustion. (e.g. home heating, industrial or power plant) Do not sample near or downwind of chimneys, smokestacks, flues etc. where fuel oil is being used.
• Coal fly ash. Do not sample if this material is present in the air (e.g. unloading, moving, trucking etc. of coal fly ash).
• Candle soot. Sampling should not be done in enclosed areas where candles are being burned.
• Gasoline engine exhaust. EC is produced by gasoline-fueled engines when they are worn out, out-of-tune (overly rich fuel/air ratio) or being started in cold weather. In general, the EC produced by gas engines under these conditions is just as bad the EC produced by Diesel fueled engines. If possible, avoid sampling near areas of heavy motor vehicle traffic.

Q. May I see your method?
A. Yes. WOHL uses a very slightly modified method of NIOSH 5040. Please contact the laboratory for a copy of this method.


Q. Where can I find out more about Diesel exhaust related topics?
A. There are a number of relavent Websites and sources
www.dieselnet.com
www.DEEP.org
AIHA
www.acgih.org