Evaluation of an urban NMHC emission inventory by measurements and impact on CTM results

Abstract

This paper presents an evaluation of the consistency of an urban state-of-the-art hydrocarbon (HC) emission inventory. The evaluation was conducted through the comparison of this inventory with hourly HC measurements during two summer months in the centre of Marseille, on the Mediterranean French coast. Factors of under or overestimation could be calculated for each compound on the basis of a systematic HC to HC ratio analysis. These results, associated with a deep analysis of the speciation profiles, show that most of the common and highly concentrated hydrocarbons (such as butanes) are too much predominant in the emission speciation, while the heavy and less common species (branched alkanes, substituted aromatics) are under-represented in the inventory. The urban diffuse sources appear here as one critical point of the inventories. The disagreements were shown to have a strong incidence on the representation of the air mass reactivity. In a last step, the identified uncertainties in emissions were implemented in an air-quality model for sensitivity studies. It was shown that the observed biases in the inventory could affect the regional ozone production, with a probable impact on ozone peaks of 2e10 ppbv over the area.

Emission ratios of anthropogenic volatile organic compounds in northern mid‐latitude megacities: Observations versus emission inventories in Los Angeles and Paris

“…Over the last two decades, source‐receptor modeling has also provided an independent evaluation of the quality of emission inventories in various urban areas worldwide [ Fujita et al ., ; Niedojadlo et al ., ; Lanz et al ., ; Gaimoz et al ., 2010; Morino et al ., ]. The composition of urban emissions was also compared between measurements and emission inventories by studying emission ratios of various VOCs relative to an inert tracer (CO, acetylene) [ Warneke et al ., ; McKeen et al ., ; Coll et al ., ]. Observed concentrations are not only the result of emissions but also of transport/mixing and chemistry.…”

Spatial and seasonal variability of measured anthropogenic non-methane hydrocarbons in urban atmospheres: Implication on emission ratios

“…Several papers have shown the importance of VOC emissions on both ozone and SOA formation through air quality modeling studies (e.g. Zhang et al, 2004;Hodzic et al, 2009;Coll et al, 2010;Kim et al, 2011). Some VOC, such as benzene and 1,3-butadiene, are classified as toxic air pollutants and are subject to regulations (US EPA, 2008; Directive 98/70/CE).…”

“…Vautard et al, 2003;Hodzic et al, 2005;Liousse et al, 2010;Gaimoz et al, 2011). Recent studies have determined urban emission ratios (ER) of several NMHC versus inert species such as carbon monoxide or acetylene (C 2 H 2 ) from ambient concentrations, and successfully used these ambient ratios to evaluate emission database (Baker et al, 2007;Warneke et al, 2007;Gentner et al, 2009;Coll et al, 2010;Russo et al, 2010;Borbon et al, 2013a). These studies point to strong disagreement between emission inventories and observations, especially regarding the dominating sources.…”

Speciation of anthropogenic emissions of non-methane volatile organic compounds: a global gridded data set for 1970–2012

“…The profiles distribute total NMVOC emissions of anthropogenic NMVOC sources across 305 single NMVOC species or species classes. The IER database is widely used for emission analysis and creating input data for atmospheric dispersion models in Europe (Coll et al, 2010;Kühlwein et al, 2002;Vautard, 2003). This database is used as the main data source for the profile mapping of Europe.…”