Optimized Approach for Measuring Ethylene Oxide in Mobile Source Exhaust.

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Air Pollution Monitoring

Background:

• Growing concern over health impacts of ethylene oxide (EtO), a carcinogenic and mutagenic air contaminant.
• Challenges in accurately measuring EtO in complex matrices like combustion emissions.
• Need for reliable methods to assess EtO exposure from mobile sources.

Purpose of the Study:

• Evaluate EPA Methods TO-15 and TO-15A for measuring EtO in heavy-duty diesel vehicle (HDDV) exhaust.
• Address analytical interferences affecting EtO quantification in complex emission samples.
• Determine the presence of EtO in HDDV exhaust using an optimized measurement approach.

Main Methods:

• Chassis dynamometer testing of two HDDVs to collect exhaust emissions.
• Analysis of samples using EPA Method TO-15 and an optimized EPA Method TO-15A.
• Identification and mitigation of coeluting interferents, such as ethyl nitrite, in TO-15 analysis.

Main Results:

• EPA Method TO-15 analysis showed interference from ethyl nitrite, causing positive bias for EtO.
• An optimized TO-15A method was developed to resolve the coelution issue.
• No detectable levels of EtO were found in HDDV exhaust using the optimized TO-15A approach.

Conclusions:

• Accurate quantification of EtO in mobile source exhaust requires optimized analytical methods like TO-15A.
• The developed method is crucial for reliable assessment of EtO emissions from combustion sources.
• Further application of this optimized approach is recommended for mobile and other combustion emission testing.