Flux Measurements of Biogenic Volatile Organic Compounds by Disjunct Eddy
Sampling and Ion Trap Mass Spectrometry Analysis
EMSL Project ID
3057
Abstract
Volatile Organic Compounds (VOCs) are major contributors to the formation of ozone and particulates in the lower troposphere. Emissions from vegetation can be significant contributions to the total VOC emissions, especially in densely forested landscapes. Therefore, investigating biogenic VOCs sources is important in advancing our understanding of air quality and tropospheric chemistry. During the analysis process many VOCs can react and are lost during sample collection and storage, which further complicates analysis using traditional analytical methods. The goal of this research is to apply a novel analytical technique for continuous, in-situ and high-resolution field measurements of a wide range of biogenic VOC fluxes. This technique incorporates the following components:1. A sample collection and enrichment apparatus for trapping and improving detection limits of VOCs
2. An Ion Trap Mass Spectrometer (ITMS) for quantitatively analyzing VOCs injected from the sample collection/enrichment system
3. A sonic anemometer to determine wind speed/directions for disjunct eddy correlation calculations of biogenic VOC fluxes.
This disjunct eddy correlation/ion trap mass spectrometry instrument will allow continuous measurements of a mixture of biogenically emitted VOCs (including isoprene, monoterpenes, methylbutenol, oxygenated VOC and possibly sesquiterpenes). The real-time concurrent measurement of multiple biogenic VOC fluxes will be an improvement over previous measurements. Total biogenic VOC fluxes and individual contributions will be analyzed and compared with existing measurements where fast sensors are available (e.g. isoprene).
The ion trap mass spectrometer used in this instrument combination is a Teledyne Discovery II. Several of these instruments also exist at the EMSL at Pacific Northwest Laboratories. Scientists there have considerable experience in optimizing sampling and detection conditions as well as troubleshooting periodic instrumentation difficulties. It is through the collaboration between our group and the EMSL scientists that we hope to improve instrument performance and develop future collaborative efforts.
Project Details
Project type
Exploratory Research
Start Date
2002-11-12
End Date
2003-12-08
Status
Closed
Released Data Link
Team
Principal Investigator