Abstract
Abstract. An accurate speciation mapping of non-methane volatile organic compounds (NMVOC) emissions has an important impact on the performance of chemical transport models (CTMs) in simulating ozone mixing ratios and secondary organic aerosols. Taking the INTEX-B Asian NMVOC emission inventory as the case, we developed an improved speciation framework to generate model-ready anthropogenic NMVOC emissions for various gas-phase chemical mechanisms commonly used in CTMs in this work, by using an explicit assignment approach and updated NMVOC profiles. NMVOC profiles were selected and aggregated from a wide range of new measurements and the SPECIATE database v.4.2. To reduce potential uncertainty from individual measurements, composite profiles were developed by grouping and averaging source profiles from the same category. The fractions of oxygenated volatile organic compounds (OVOC) were corrected during the compositing process for those profiles which used improper sampling and analyzing methods. Emissions of individual species were then lumped into species in different chemical mechanisms used in CTMs by applying mechanism-dependent species mapping tables, which overcomes the weakness of inaccurate mapping in previous studies. Emission estimates for individual NMVOC species differ between one and three orders of magnitude for some species when different sets of profiles are used, indicating that source profile is the most important source of uncertainties of individual species emissions. However, those differences are diminished in lumped species as a result of the lumping in the chemical mechanisms. Gridded emissions for eight chemical mechanisms at 30 min × 30 min resolution as well as the auxiliary data are available at http://mic.greenresource.cn/intex-b2006. The framework proposed in this work can be also used to develop speciated NMVOC emissions for other regions.
Highlights
Non-methane volatile organic compounds (NMVOCs) include a variety of chemical species that can be emitted from biomass burning, biogenic, and anthropogenic sources
From a comprehensive review of available profiles, we found that oxygenated volatile organic compounds (OVOC) contribute a large fraction of total NMVOC emissions from biofuel combustion and diesel vehicles (Schauer et al, 1999, 2001; Andreae and Merlet, 2001)
Emphasis is placed on OVOCs and alkenes with high maximum incremental reactivity (MIR) and relatively high contribution to ozone formation potentials (OFPs)
Summary
Non-methane volatile organic compounds (NMVOCs) include a variety of chemical species that can be emitted from biomass burning, biogenic, and anthropogenic sources NMVOCs differ significantly in their impacts on ozone and SOA formation, and these differences need to be represented appropriately in chemical transport models (CTMs). Such CTMs have been used to guide the development of emission control strategies by governmental agencies (e.g., US EPA, 2007; Wang et al, 2010; Xing et al, 2011), predict the effects of changes of emissions on the formation of ozone and SOA Such CTMs have been used to guide the development of emission control strategies by governmental agencies (e.g., US EPA, 2007; Wang et al, 2010; Xing et al, 2011), predict the effects of changes of emissions on the formation of ozone and SOA (e.g., Hogrefe et al, 2004; Y. Zhang et al, 2010, 2014), and study the sensitivity of the model predictions of pollutant concentrations to different gas-phase chemical mechanisms (e.g., Kim et al, 2011; Zhang et al, 2012)
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