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Gas Chromatograghy Lab

Smoke samples collected during experiments in the Fire Lab combustion chamber, from the FASS towers at wild or prescribed fires, or from aircraft traversing a smoke plume, are analyzed in the Gas Chromatography Lab. Fire emissions (smoke) contain a complex mixture of gases.

The major emission products of biomass burning are carbon compounds- carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), other hydrocarbons (such as propane), and aerosols. Quantifying these emissions is critical to assessing the impact of wild and prescribed fires on air quality, regional and global atmospheric chemistry, and the role of fire in the carbon cycle. 

Function and Objective: 

The results of the laboratory analyses are reported in scientific journals for different types of fires and fuels. They are used to produce emission factors for major smoke chemical components. Emission factors are used to predict the quantity of emissions from different types and sizes of fires of different vegetation types and fuel loadings, and are reported in units of grams of a specific compound emitted per kilogram of fuel burned. Emission factors are inputs into models assessing the impacts of emissions on global atmospheric chemistry.

Canister samples of smoke collected in field or laboratory experiments are analyzed for CO2, CO, methane, and other hydrocarbons. We have three gas chromatograph configured to measure the different gases in smoke. One gas chromatograph measures CO2, CO, and hydrocarbons in the canisters. It has two columns and flame ionization detectors (FIDs) to simultaneously measure CO2 and CO with a packed column, and methane and C2 to C4 hydrocarbons with a second capillary column.

Another gas chromatograph uses a reduction gas detector (RGD) for analysis of trace level CO and hydrogen. It allows us to measure CO at ppb levels in clean air or from highly diluted samples collected from aircraft sampling experiments.

The third gas chromatograph has a mass selective detector (GC/MS) and is integrated with a sample pre-concentrator to detect low concentrations of a wide range of hydrocarbons and halocarbons.

Teflon filter samples are weighed to calculate the fine particulate concentration (PM 2.5) emitted during different phases of the fire (flaming, intermediate, smoldering). The sample filters from the field are conditioned and weighed in a controlled environment room. This is because the particulate matter on the filters are sensitive to moisture and vary in weight with room humidity. A micro-balance weighs the filters to within 1 microgram. The weights are used with filter flow data to calculate particulate concentrations.

Photo: Gas lab
Photo: Gas lab
Modified: Mar 12, 2014