Effects of two different biogenic emission models on modelled ozone and aerosol concentrations in Europe
<p>Biogenic volatile organic compound (BVOC) emissions are one of the essential inputs for chemical transport models (CTMs), but their estimates are associated with large uncertainties, leading to significant influence on air quality modelling. This study aims to investigate the effects of usi...
| Main Authors: | , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2019-03-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/19/3747/2019/acp-19-3747-2019.pdf |
| Summary: | <p>Biogenic volatile organic compound (BVOC) emissions are one of
the essential inputs for chemical transport models (CTMs), but their
estimates are associated with large uncertainties, leading to significant
influence on air quality modelling. This study aims to investigate the
effects of using different BVOC emission models on the performance of a CTM
in simulating secondary pollutants, i.e. ozone, organic, and inorganic
aerosols. European air quality was simulated for the year 2011 by the
regional air quality model Comprehensive Air Quality Model with Extensions
(CAMx) version 6.3, using BVOC emissions calculated by two emission models:
the Paul Scherrer Institute (PSI) model and the Model of Emissions of Gases
and Aerosol from Nature (MEGAN) version 2.1. Comparison of isoprene and monoterpene
emissions from both models showed large differences in their general amounts,
as well as their spatial distribution in both summer and winter. MEGAN
produced more isoprene emissions by a factor of 3 while the PSI model
generated 3 times the monoterpene emissions in summer, while there was
negligible difference (<span class="inline-formula">∼4</span> %) in sesquiterpene emissions
associated with the two models. Despite the large differences in isoprene
emissions (i.e. 3-fold), the resulting impact in predicted summertime ozone
proved to be minor (<span class="inline-formula"><i><</i>10</span> %; MEGAN <span class="inline-formula">O<sub>3</sub></span> was higher than
PSI <span class="inline-formula">O<sub>3</sub></span> by <span class="inline-formula">∼7</span> ppb). Comparisons with measurements from the
European air quality database (AirBase) indicated that PSI emissions might
improve the model performance at low ozone concentrations but worsen performance at
high ozone levels (<span class="inline-formula"><i>></i>60</span> ppb). A much larger effect of the
different BVOC emissions was found for the secondary organic aerosol (SOA)
concentrations. The higher monoterpene emissions (a factor of <span class="inline-formula">∼3</span>) by the PSI model led to higher SOA by <span class="inline-formula">∼110</span> % on average
in summer, compared to MEGAN, and lead to better agreement between modelled and
measured organic aerosol (OA): the mean bias between modelled and measured OA
at nine measurement stations using Aerodyne aerosol chemical speciation monitors
(ACSMs) or Aerodyne aerosol mass
spectrometers (AMSs) was reduced by 21 %–83 % at rural or remote stations. Effects on inorganic aerosols (particulate
nitrate, sulfate, and ammonia) were relatively small (<span class="inline-formula"><i><</i>15</span> %).</p> |
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| ISSN: | 1680-7316 1680-7324 |