The importance of accounting for enhanced emissions of monoterpenes from new Scots pine foliage in models - A Finnish case study

Models to predict the emissions of biogenic volatile organic compounds (BVOCs) from terrestrial vegetation largely use standardised emission potentials derived from shoot enclosure measurements of mature foliage. In these models, the potential of new foliage to emit BVOCs is assumed to be similar, o...

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Bibliographic Details
Published in:Atmospheric Environment: X
Main Authors: Ditte Taipale, Juho Aalto, Pauliina Schiestl-Aalto, Markku Kulmala, Jaana Bäck
Format: Article in Journal/Newspaper
Language:English
Published: Elsevier 2020
Subjects:
Online Access:https://doi.org/10.1016/j.aeaoa.2020.100097
https://doaj.org/article/44cfeccbf57d47a0b365a8cbcfcb3e39
Description
Summary:Models to predict the emissions of biogenic volatile organic compounds (BVOCs) from terrestrial vegetation largely use standardised emission potentials derived from shoot enclosure measurements of mature foliage. In these models, the potential of new foliage to emit BVOCs is assumed to be similar, or up to twice as high, as that of mature foliage, and thus new conifers foliage is predicted to have a negligible to minor contribution to canopy BVOC emissions during spring time due to the small foliage mass of emerging and growing needles. Extensive observations have, however, recently demonstrated that the potential of new Scots pine needles to emit several different BVOCs can be up to about 500 times higher than that of the corresponding mature foliage. Thus, we build on these discoveries and investigate the potential impact of considering these enhanced emissions from new Scots pine foliage on estimates of monoterpene emissions and new atmospheric aerosol particle formation and their subsequent growth. We show that the importance of taking the enhanced monoterpene emission potential of new Scots pine foliage into account decreases as a function of season, tree age and latitude, and that new foliage could be responsible for the majority of the whole tree's foliage emissions of monoterpenes during spring time, independently of tree age and location. Our results suggest that annual monoterpene emission estimates from Finland would increase with up to ~25% if the enhanced emissions from new Scots pine foliage were also considered, with the majority being emitted during spring time where also new particle formation has been observed to occur most frequently. We estimate that our findings can lead to increases in predictions of the formation rates of 2 nm particles during spring time by ~75–280% in northern Finland and by ~130–870% in southern Finland. Likewise, simulated growth rates of 2–3 nm particles would increase by ~65–180% in northern Finland and by ~110–520% in southern Finland if the enhanced emissions of ...