The regional impact of urban emissions on air quality in Europe: the role of the urban canopy effects
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10437420" target="_blank" >RIV/00216208:11320/21:10437420 - isvavai.cz</a>
Result on the web
<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=NIgHvAobCm" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=NIgHvAobCm</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.5194/acp-21-14309-2021" target="_blank" >10.5194/acp-21-14309-2021</a>
Alternative languages
Result language
angličtina
Original language name
The regional impact of urban emissions on air quality in Europe: the role of the urban canopy effects
Original language description
Urban areas are hot spots of intense emissions, and they influence air quality not only locally but on a regional or even global scale. The impact of urban emissions over different scales depends on the dilution and chemical transformation of the urban plumes which are governed by the local- and regional-scale meteorological conditions. These are influenced by the presence of urbanized land surface via the so-called urban canopy meteorological forcing (UCMF). In this study, we investigate for selected central European cities (Berlin, Budapest, Munich, Prague, Vienna and Warsaw) how the urban emission impact (UEI) is modulated by the UCMF for present-day climate conditions (2015-2016) using two regional climate models, the regional climate models RegCM and Weather Research and Forecasting model coupled with Chemistry (WRF-Chem; its meteorological part), and two chemistry transport models, Comprehensive Air Quality Model with Extensions (CAMx) coupled to either RegCM and WRF and the "chemical" component of WRF-Chem. The UCMF was calculated by replacing the urbanized surface by a rural one, while the UEI was estimated by removing all anthropogenic emissions from the selected cities. We analyzed the urban-emission-induced changes in near-surface concentrations of NO2, O-3 and PM2.5. We found increases in NO2 and PM2.5 concentrations over cities by 4-6 ppbv and 4-6 mu gm(-3), respectively, meaning that about 40 %-60% and 20 %-40% of urban concentrations of NO2 and PM2.5 are caused by local emissions, and the rest is the result of emissions from the surrounding rural areas. We showed that if UCMF is included, the UEI of these pollutants is about 40 %-60% smaller, or in other words, the urban emission impact is overestimated if urban canopy effects are not taken into account. In case of ozone, models due to UEI usually predict decreases of around -2 to -4 ppbv (about 10 %-20 %), which is again smaller if UCMF is considered (by about 60 %). We further showed that the impact on extreme (95th percentile) air pollution is much stronger, and the modulation of UEI is also larger for such situations. Finally, we evaluated the contribution of the urbanization-induced modifications of vertical eddy diffusion to the modulation of UEI and found that it alone is able to explain the modeled decrease in the urban emission impact if the effects of UCMF are considered. In summary, our results showed that the meteorological changes resulting from urbanization have to be included in regional model studies if they intend to quantify the regional footprint of urban emissions. Ignoring these meteorological changes can lead to the strong overestimation of UEI.
Czech name
—
Czech description
—
Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10500 - Earth and related environmental sciences
Result continuities
Project
<a href="/en/project/GJ19-10747Y" target="_blank" >GJ19-10747Y: Modeling the interactions of air pollution with meteorology over urban areas in high resolution</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Atmospheric Chemistry and Physics
ISSN
1680-7316
e-ISSN
—
Volume of the periodical
21
Issue of the periodical within the volume
18
Country of publishing house
DE - GERMANY
Number of pages
24
Pages from-to
14309-14332
UT code for WoS article
000703069800001
EID of the result in the Scopus database
2-s2.0-85116317827