Estimations of isoprenoid emission capacity from enclosure studies: measurements, data processing, quality and standardized measurement protocols

摘要

The capacity for volatile isoprenoid production under standardizedenvironmental conditions at a certain time (E_S, the emission factor) isa key characteristic in constructing isoprenoid emission inventories.However, there is large variation in published E_S estimates for anygiven species partly driven by dynamic modifications in E_S due toacclimation and stress responses. Here we review additional sources ofvariation in E_S estimates that are due to measurement and analyticaltechniques and calculation and averaging procedures, and demonstrate thatestimations of E_S critically depend on applied experimental protocolsand on data processing and reporting. A great variety of experimental setupshas been used in the past, contributing to study-to-study variations inE_S estimates. We suggest that past experimental data should bedistributed into broad quality classes depending on whether the data can orcannot be considered quantitative based on rigorous experimental standards.Apart from analytical issues, the accuracy of E_S values is stronglydriven by extrapolation and integration errors introduced during dataprocessing. Additional sources of error, especially in meta-databaseconstruction, can further arise from inconsistent use of units andexpression bases of E_S. We propose a standardized experimental protocolfor BVOC estimations and highlight basic meta-information that we stronglyrecommend to report with any E_S measurement. We conclude thatstandardization of experimental and calculation protocols and criticalexamination of past reports is essential for development of accurateemission factor databases.