Dilution-based emissions sampling from stationary sources: Part 1--Compact sampler methodology and performance.

Area of Science:

• Environmental Science
• Analytical Chemistry
• Air Pollution Control

Background:

• Characterizing fine particle emissions from stationary sources is crucial for environmental monitoring.
• Existing regulatory methods may have limitations in detecting semivolatile species and achieving low detection limits.
• Dilution sampling simulates real-world atmospheric mixing conditions for emissions.

Purpose of the Study:

• To design and evaluate a compact dilution sampler (CDS) for fine particle emissions.
• To assess the performance of the CDS compared to a reference dilution sampler and regulatory methods.
• To investigate the sampler's capability in characterizing semivolatile species in stack effluents.

Main Methods:

• Development and description of the compact dilution sampler (CDS).
• Comparative performance testing against a reference dilution sampler.
• Evaluation against U.S. EPA Conditional Test Method 040 (filterable particulate matter) and EPA Method 202 (condensable particulate matter).
• Analysis of fine particulate matter (PM2.5) and semivolatile species.

Main Results:

• The CDS demonstrated comparable performance to a reference sampler for gas-fired units and a diesel generator.
• The CDS achieved lower detection limits for particulate emissions compared to current regulatory methods.
• Significant differences were observed when comparing CDS data with EPA methods, particularly concerning condensable and semivolatile particulate matter.
• Effective determination of emissions from liquid fuel combustors in 1-hour sampling was achieved.

Conclusions:

• The compact dilution sampler is a viable tool for characterizing fine particle emissions, including semivolatile components.
• The CDS offers improved detection limits, potentially enhancing regulatory compliance and environmental assessment.
• Careful attention to operational parameters, such as dilution air quality and sample volume, is essential for accurate measurements, especially for low-emitting sources like gas-fired units.