Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 3 of 3
Full-Text Articles in Chemistry
Long-Term Trends And Variability Of Pm₂.₅ Mass, Chemical Components, And Sources Over Nys, Hesham Abdelmonem Hassan
Long-Term Trends And Variability Of Pm₂.₅ Mass, Chemical Components, And Sources Over Nys, Hesham Abdelmonem Hassan
Legacy Theses & Dissertations (2009 - 2024)
Eighteen years of ambient PM2.5 mass and major components are used in this study to harmonize the carbonaceous fraction of PM2.5 data, and to examine long-term trends and seasonal variability changes. The major decreasing trend of PM2.5 mass and major inorganic ions reflects the ambient concentration response to clean air regulations and policies.Although elemental carbon shows a decreasing trend in agreement with most other PM2.5 components, organic carbon shows a different behavior of no-trend to slightly increasing trend in some sites. Organic carbon behavior indicates the growing role of non-combustion sources at the expense of decreasing combustion sources. Seasonal trends …
Ozone And Reactive Oxidized Nitrogen Chemistry In The Northeast U.S, Matthew Ninneman
Ozone And Reactive Oxidized Nitrogen Chemistry In The Northeast U.S, Matthew Ninneman
Legacy Theses & Dissertations (2009 - 2024)
Ongoing reductions in oxides of nitrogen concentrations ([NOx] = nitric oxide ([NO]) + nitrogen dioxide ([NO2])) throughout the continental United States (U.S.) have important implications for tropospheric ozone (O3) and reactive oxidized nitrogen chemistry (NOy ≈ NOx + nitric acid (HNO3) + particle nitrate (pNO3) + peroxy nitrates (PNs) + alkyl nitrates (ANs)). Specifically, decreasing [NOx] concentrations have likely (1) increased the sensitivity of O3 to the [NOx] level, and (2) affected NOy speciation and partitioning. An understanding of the impacts of continued [NOx] reductions is needed to inform current and future air pollution control strategies, especially since the National …
Spatial And Seasonal Variability Of Cloud Condensation Nuclei Number Concentrations Over The Extended North African Continent And The Mediterranean, Hesham Abdel-Monem Afify Hassan
Spatial And Seasonal Variability Of Cloud Condensation Nuclei Number Concentrations Over The Extended North African Continent And The Mediterranean, Hesham Abdel-Monem Afify Hassan
Legacy Theses & Dissertations (2009 - 2024)
The spatiotemporal variability of cloud condensation nuclei (CCN) number concentration is investigated over the extended domain of the North African continent and Mediterranean which is an essential step for better understanding of aerosol-cloud interactions and associated climate impacts over the region. The study is performed by analyzing the output for the period from 2004 to 2011 from the well-validated global chemistry and aerosol transport model GEOS-Chem-APM. The analysis shows that the dominant aerosol type for CCN number concentration is secondary particles all over the domain. Spatial analysis reveals the existence of four characteristic subdomains of variability: over the Mediterranean and …