Chapter 3
Unravelling the Origin of High Ozone
Concentrations in Southwestern Europe
María Teresa Pay, Carlos Pérez-García Pando, Marc Guevara, Oriol Jorba,
Sergey Napelenok and Xavier Querol
Abstract This study aims to quantify the contributions to surface ozone (O 3 ) concentration in the Iberian Peninsula (IP) from the main NO x emission sectors in the
region along with the imported O 3 during a 10-day episode. The work applies an
Integrated Source Apportionment Method within the CALIOPE air quality system
at 4-km resolution. This study finds that the imported O 3 is overall the larger contribution to its surface concentration. Contributions from local/regional sources are
decisive in the O 3 peaks downwind of main nitrogen oxides (NO x ) hotspots in the
IP under stagnant conditions.
3.1 Introduction
Southwestern EU experiences severe O 3 episodes in summer. Several studies have
advanced our knowledge on the dynamics of O 3 episodes based on a comprehensive
understanding of the circulation patterns [2]. However, there is a lack of studies identifying the sources responsible for the high O 3 over the region, which is crucial to
design adequate mitigation measures. Chemical Transport Models (CTMs) quantify
the impact of sector-specific pollution at the surface of a receptor region. The most
widely used source apportionment approach in CTMs is the brute force, but it is
susceptible to numerical instability in non-linear regimens. Recently, CTM versions
include methods that tag multiple pollutants by source all the way through the pollutant’s lifetime. This integrated source apportionment method allows identifying
main sources contributing to high O 3 concentrations under the actual atmospheric
M. T. Pay (B) · C. Pérez-García Pando · M. Guevara · O. Jorba
Earth Sciences Department, Barcelona Supercomputing Center (BSC), Barcelona, Spain
e-mail: maria.pay@bsc.es
S. Napelenok
Atmospheric Modelling and Analysis Division, National Exposure Research Laboratory, U.S.
Environmental Protection Agency, Research Triangle Park, NC, USA
X. Querol
Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Barcelona, Spain
© Springer Nature Switzerland AG 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity,
https://doi.org/10.1007/978-3-030-22055-6_3
17
Unravelling the Origin of High Ozone
Concentrations in Southwestern Europe
María Teresa Pay, Carlos Pérez-García Pando, Marc Guevara, Oriol Jorba,
Sergey Napelenok and Xavier Querol
Abstract This study aims to quantify the contributions to surface ozone (O 3 ) concentration in the Iberian Peninsula (IP) from the main NO x emission sectors in the
region along with the imported O 3 during a 10-day episode. The work applies an
Integrated Source Apportionment Method within the CALIOPE air quality system
at 4-km resolution. This study finds that the imported O 3 is overall the larger contribution to its surface concentration. Contributions from local/regional sources are
decisive in the O 3 peaks downwind of main nitrogen oxides (NO x ) hotspots in the
IP under stagnant conditions.
3.1 Introduction
Southwestern EU experiences severe O 3 episodes in summer. Several studies have
advanced our knowledge on the dynamics of O 3 episodes based on a comprehensive
understanding of the circulation patterns [2]. However, there is a lack of studies identifying the sources responsible for the high O 3 over the region, which is crucial to
design adequate mitigation measures. Chemical Transport Models (CTMs) quantify
the impact of sector-specific pollution at the surface of a receptor region. The most
widely used source apportionment approach in CTMs is the brute force, but it is
susceptible to numerical instability in non-linear regimens. Recently, CTM versions
include methods that tag multiple pollutants by source all the way through the pollutant’s lifetime. This integrated source apportionment method allows identifying
main sources contributing to high O 3 concentrations under the actual atmospheric
M. T. Pay (B) · C. Pérez-García Pando · M. Guevara · O. Jorba
Earth Sciences Department, Barcelona Supercomputing Center (BSC), Barcelona, Spain
e-mail: maria.pay@bsc.es
S. Napelenok
Atmospheric Modelling and Analysis Division, National Exposure Research Laboratory, U.S.
Environmental Protection Agency, Research Triangle Park, NC, USA
X. Querol
Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Barcelona, Spain
© Springer Nature Switzerland AG 2020
C. Mensink et al. (eds.), Air Pollution Modeling and its Application XXVI,
Springer Proceedings in Complexity,
https://doi.org/10.1007/978-3-030-22055-6_3
17