Ubiquity of Anthropogenic Terpenoids in Cities Worldwide: Emission Ratios, Emission Quantification and Implications for Urban Atmospheric Chemistry. Issue 7 (29th March 2023)

• Record Type: Journal Article
• Authors: Borbon, Agnès; Dominutti, Pamela; Panopoulou, Anastasia; Gros, Valérie; Sauvage, Stéphane; Farhat, Mariana; Afif, Charbel; Elguindi, Nellie; Fornaro, Adalgiza; Granier, Claire; Hopkins, James R.; Liakakou, Eleni; Nogueira, Thiago; Corrêa dos Santos, Tailine; Salameh, Thérèse; Armangaud, Alexandre; Piga, Damien; Perrussel, Olivier
• Is Part Of: Journal of geophysical research. Volume 128:Issue 7(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-29
• Subjects: Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2022JD037566
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Terpenoids (isoprene and monoterpenes) are highly reactive Volatile Organic Compounds (VOCs) known for decades for their biogenic origin. Here, we discuss the nature and magnitude of their anthropogenic emissions. We compiled and re‐analyzed 14 data sets of in situ VOC observations collected over the last decade in contrasting urban areas from mid‐latitudes to subtropical regions. We show the systematic presence of anthropogenic terpenoids in urban ambient air with clear covariations with anthropogenic compounds ( R 2 > 0.50) even during mid‐latitude winters. Despite the emerging importance of monoterpene emissions from consumer products in North American cities, there is some evidence of monoterpene emissions from tailpipe exhaust in cities of the developing world. The traffic‐related fraction of monoterpenes is estimated and can account for up to 40% of their ambient levels. The anthropogenic emission ratios (ER) of some terpenoids (isoprene, α ‐pinene and limonene) are estimated and spatially compared. The anthropogenic emissions of terpenoids are indirectly estimated from those ER combined to regional and global emission inventories (CAMS‐GLOB‐ANT_v4.2) at urban and country scale focusing on France, Lebanon, and Vietnam. Those anthropogenic emissions do not represent more than 3% of other anthropogenic VOC emissions. However, they dominate by one to three orders of magnitude the reactivity of other anthropogenic VOCs regarding NO3 oxidation and ozonolysis. This study raises two questions which need further investigations in the future: (a) the significance of terpenoid emissions from traffic, especially in urban areas of the developing world and (b) the role of anthropogenic terpenoids in nighttime and wintertime atmospheric chemistry at mid‐latitudes. Plain Language Summary: Terpenoids (isoprene and monoterpenes) are part of Volatile Organic Compounds (VOCs). They are key compounds in atmospheric chemistry, responsible for ozone and particle secondary pollution. The terpenoids are known for decades for their biogenic origin. Thanks to the reanalysis of 14 observation data sets collected from mid to subtropical latitudes since the early 2010s, we show their systematic anthropogenic origin in urban atmosphere worldwide and their potential origin from traffic. Despite the emerging importance of the emissions of monoterpenes from domestic consumer products in North American cities, we point out and quantify fossil fuel vehicle emissions as a contributor, accounting for up to 40% of their ambient levels at other locations. For the first time, anthropogenic emissions of terpenoids are estimated at urban and country scales. Those emissions do not represent more than 3% of other anthropogenic and biogenic VOC emissions. However, when taking into account their atmospheric reactivity, anthropogenic terpenoid emissions dominate from ten to a thousand of times in magnitude the ones of anthropogenic VOCs. This suggests the significant role of the anthropogenic fraction of terpenoids in nighttime and wintertime atmospheric chemistry, which needs further investigation in the future. Key Points: Anthropogenic terpenoids are shown to be ubiquitous in urban atmospheres worldwide Traffic‐related emissions can account for up to 40% of ambient monoterpenes at some urban locations Although low in amount, the anthropogenic emissions of terpenoids could be critical for nighttime and wintertime chemistry