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| Titel |
How emissions, climate, and land use change will impact mid-century air quality over the United States: a focus on effects at national parks |
| VerfasserIn |
M. Val Martin, C. L. Heald, J.-F. Lamarque, S. Tilmes, L. K. Emmons, B. A. Schichtel |
| 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 ; 15, no. 5 ; Nr. 15, no. 5 (2015-03-10), S.2805-2823 |
| Datensatznummer |
250119516
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| Publikation (Nr.) |
 copernicus.org/acp-15-2805-2015.pdf |
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| Zusammenfassung |
| We use a global coupled chemistry–climate–land model (CESM) to assess the
integrated effect of climate, emissions and land use changes on annual
surface O3 and PM2.5 in the United States with a focus on national
parks (NPs) and wilderness areas, using the RCP4.5 and RCP8.5 projections. We
show that, when stringent domestic emission controls are applied, air quality
is predicted to improve across the US, except surface O3 over the
western and central US under RCP8.5 conditions, where rising background
ozone counteracts domestic emission reductions. Under the RCP4.5 scenario,
surface O3 is substantially reduced (about 5 ppb), with daily maximum
8 h averages below the primary US Environmental Protection Agency (EPA) National Ambient Air Quality Standards (NAAQS) of 75 ppb (and even 65 ppb)
in all the NPs. PM2.5 is significantly reduced in both scenarios (4 μg m−3; ~50%), with levels below the annual US EPA NAAQS of
12 μg m−3 across all the NPs; visibility is also improved
(10–15 dv; >75 km in visibility range), although some western US parks
with Class I status (40–74 % of total sites in the US) are still above the
2050 planned target level to reach the goal of natural visibility conditions
by 2064. We estimate that climate-driven increases in fire activity may
dominate summertime PM2.5 over the western US, potentially offsetting
the large PM2.5 reductions from domestic emission controls, and keeping
visibility at present-day levels in many parks. Our study indicates that
anthropogenic emission patterns will be important for air quality in 2050.
However, climate and land use changes alone may lead to a substantial
increase in surface O3 (2–3 ppb) with important consequences for O3
air quality and ecosystem degradation at the US NPs. Our study illustrates
the need to consider the effects of changes in climate, vegetation, and fires
in future air quality management and planning and emission policy making. |
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