Changes in PM<sub>2.5</sub> concentrations and their sources in the US from 1990 to 2010
<p>Significant reductions in emissions of SO<span class="inline-formula"><sub>2</sub></span>, NO<span class="inline-formula"><sub><i>x</i></sub></span>, volatile organic compounds (VOCs), and primary particulate ma...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/9dc94ed98653416593c505a7233c7eb6 |
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| Sumario: | <p>Significant reductions in emissions of SO<span class="inline-formula"><sub>2</sub></span>, NO<span class="inline-formula"><sub><i>x</i></sub></span>, volatile organic compounds (VOCs), and primary particulate matter (PM) took place in the US from 1990 to 2010. We evaluate here our understanding of the links between
these emissions changes and corresponding changes in concentrations and
health outcomes using a chemical transport model, the Particulate Matter
Comprehensive Air Quality Model with Extensions (PMCAMx), for 1990, 2001, and 2010. The use of the Particle Source Apportionment Algorithm (PSAT) allows us to link the concentration reductions to the sources of the corresponding
primary and secondary PM. The reductions in SO<span class="inline-formula"><sub>2</sub></span> emissions (64 %,
mainly from electric-generating units) during these 20 years have dominated the reductions in PM<span class="inline-formula"><sub>2.5</sub></span>, leading to a 45 % reduction in sulfate levels. The predicted sulfate reductions are in excellent agreement with the
available measurements. Also, the reductions in elemental carbon (EC)
emissions (mainly from transportation) have led to a 30 % reduction in EC concentrations. The most important source of organic aerosol (OA) through
the years according to PMCAMx is biomass burning, followed by biogenic
secondary organic aerosol (SOA). OA from on-road transport has been reduced
by more than a factor of 3. On the other hand, changes in biomass burning OA and biogenic SOA have been modest. In 1990, about half of the US
population was exposed to annual average PM<span class="inline-formula"><sub>2.5</sub></span> concentrations above 20 <span class="inline-formula">µ</span>g m<span class="inline-formula"><sup>−3</sup></span>, but by 2010 this fraction had dropped to practically
zero. The predicted changes in concentrations are evaluated against the
observed changes for 1990, 2001, and 2010 in order to understand whether the model represents reasonably well the corresponding processes caused by the
changes in emissions.</p> |
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