In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 23, No. 3 ( 2023-02-03), p. 1893-1918
Abstract:
Abstract. The number of large urban agglomerations is steadily
increasing worldwide. At a local scale, their emissions lead to air
pollution, directly affecting people's health. On a global scale, their
emissions lead to an increase of greenhouse gases, affecting climate. In
this context, in 2017 and 2018, the airborne campaign EMeRGe (Effect of
Megacities on the transport and transformation of pollutants on the Regional
to Global scales) investigated emissions of European and Asian major
population centres (MPCs) to improve the understanding and predictability of
pollution outflows. Here, we present two methods to identify and
characterise pollution outflows probed during EMeRGe. First, we use a set of
volatile organic compounds (VOCs) as chemical tracers to characterise air
masses by specific source signals, i.e. benzene from anthropogenic pollution
of targeted regions, acetonitrile from biomass burning (BB, primarily during
EMeRGe-Asia), and isoprene from fresh biogenic signals (primarily during
EMeRGe-Europe. Second, we attribute probed air masses to source regions and
estimate their individual contribution by constructing and applying a simple
emission uptake scheme for the boundary layer which combines FLEXTRA back
trajectories and EDGAR carbon monoxide (CO) emission rates (acronyms are
provided in the Appendix). During EMeRGe-Europe, we identified anthropogenic
pollution outflows from northern Italy, southern Great Britain, the
Belgium–Netherlands–Ruhr (BNR) area and the Iberian Peninsula. Additionally, our
uptake scheme indicates significant long-range transport of pollution from
the USA and Canada. During EMeRGe-Asia, the pollution outflow is dominated
by sources in China and Taiwan, but BB signals from Southeast Asia and India
contribute as well. Outflows of pre-selected MPC targets are identified in
less than 20 % of the sampling time, due to restrictions in flight
planning and constraints of the measurement platform itself. Still, EMeRGe
combines in a unique way near- and far-field measurements, which show
signatures of local and distant sources, transport and conversion
fingerprints, and complex air mass compositions. Our approach provides a
valuable classification and characterisation of the EMeRGe dataset, e.g. for
BB and anthropogenic influence of potential source regions and paves the
way for a more comprehensive analysis and various model studies.
Type of Medium:
Online Resource
ISSN:
1680-7324
DOI:
10.5194/acp-23-1893-2023
DOI:
10.5194/acp-23-1893-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2092549-9
detail.hit.zdb_id:
2069847-1
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