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| Titel |
North American isoprene influence on intercontinental ozone pollution |
| VerfasserIn |
A. M. Fiore, H. Levy II, D. A. Jaffe |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 11, no. 4 ; Nr. 11, no. 4 (2011-02-22), S.1697-1710 |
| Datensatznummer |
250009372
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| Publikation (Nr.) |
 copernicus.org/acp-11-1697-2011.pdf |
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| Zusammenfassung |
| Changing land-use and climate may alter emissions of biogenic isoprene, a
key ozone (O3) precursor. Isoprene is also a precursor to peroxy
acetyl nitrate (PAN) and thus affects partitioning among oxidized nitrogen
(NOy) species, shifting the balance towards PAN, which more efficiently
contributes to long-range transport relative to nitric acid (HNO3)
which rapidly deposits. With a suite of sensitivity simulations in the
MOZART-2 global tropospheric chemistry model, we gauge the relative
importance of the intercontinental influence of a 20% increase in North
American (NA) isoprene and a 20% decrease in NA anthropogenic emissions
(nitrogen oxides (NOx), non-methane volatile organic compounds (NMVOC)
and NOx + NMVOC + carbon monoxide + aerosols). The surface O3 response
to NA isoprene emissions (ΔO3_ISOP) in surface air over NA
is about one third of the response to all NA anthropogenic emissions
(ΔO3_ANTH; although with different signs). Over
intercontinental distances, ΔO3_ISOP is relatively larger;
in summer and fall, ΔO3_ISOP in surface air over Europe and
North Africa (EU region) is more than half of ΔO3_ANTH.
Future increases in NA isoprene emissions could thus offset decreases in EU
surface O3 resulting from controls on NA anthropogenic emissions. Over
the EU region, ΔPAN_ISOP at 700 hPa is roughly the same magnitude
as ΔPAN_ANTH (oppositely signed). Outside of the continental
source region, the percentage changes in PAN are at least twice as large as
for surface O3, implying that long-term PAN measurements at high
altitude sites may help to detect O3 precursor emission changes. We
find that neither the baseline level of isoprene emissions nor the fate of
isoprene nitrates contributes to the large diversity in model estimates of
the anthropogenic emission influence on intercontinental surface O3 or
oxidized nitrogen deposition reported in the recent TF HTAP multi-model
studies (TFHTAP, 2007). |
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