Development of Volatility Distributions for Organic Matter in Biomass Burning Emissions

Area of Science:

• Atmospheric Chemistry
• Environmental Science
• Organic Geochemistry

Background:

• Organic emissions from biomass burning significantly impact atmospheric chemistry.
• Current models for secondary organic aerosol formation often lack crucial semi- and intermediate volatility organic compounds (S/I-VOCs).
• Understanding the volatility distribution of S/I-VOCs from various biomass burning sources is essential but uncertain.

Purpose of the Study:

• To develop and apply a novel sampling and analysis method for S/I-VOCs from biomass burning.
• To quantify the volatility distributions of S/I-VOCs across different biomass burning sources.
• To assess the potential for inferring gas-particle partitioning behavior from these measurements.

Main Methods:

• A filter-in-tube sorbent sampling method was employed to collect S/I-VOCs from biomass burning experiments.
• Samples were analyzed using thermal desorption-gas chromatography-mass spectrometry (TD/GC/MS).
• Volatility distributions were calculated based on saturation concentrations (logC*) ranging from -2 to 6.

Main Results:

• Intermediate volatility organic compounds (IVOCs) constituted 75%-90% of captured organic matter, with semi-volatile (SVOCs) and low volatility (LVOCs) organic compounds present in smaller proportions.
• Volatility distributions were broadly consistent across different biomass burning sources.
• Particulate matter emission factors varied significantly, spanning two orders of magnitude.

Conclusions:

• The novel filter-in-tube method effectively captures and quantifies S/I-VOCs from biomass burning.
• The findings provide crucial data for improving atmospheric models and understanding secondary organic aerosol formation.
• This simplified approach enhances the study of the full range of organic emissions from combustion sources.