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ASU Scholarship Showcase


This growing collection consists of scholarly works authored by ASU-affiliated faculty, students and community members, and contains many open access articles. ASU-affiliated authors are encouraged to Share Your Work in the ASU Digital Repository.


Series
  • ATMOSPHERIC CHEMISTRY AND PHYSICS
Date Range
2013 2016


This paper presents an analysis of methane emissions from the Los Angeles Basin at monthly timescales across a 4-year time period – from September 2011 to August 2015. Using observations acquired by a ground-based near-infrared remote sensing instrument on Mount Wilson, California, combined with atmospheric CH[subscript 4]–CO[subscript 2] tracer–tracer correlations, we observed −18 to +22 % monthly variability in CH[subscript 4] : CO[subscript 2] from the annual mean in the Los Angeles Basin. Top-down estimates of methane emissions for the basin also exhibit significant monthly variability (−19 to +31 % from annual mean and a maximum month-to-month change of 47 …

Contributors
Wong, Clare K., Pongetti, Thomas J., Oda, Tom, et al.
Created Date
2016-10-26

The southeast Pacific Ocean is covered by the world's largest stratocumulus cloud layer, which has a strong impact on ocean temperatures and climate in the region. The effect of anthropogenic sources of aerosol particles on the stratocumulus deck was investigated during the VOCALS field experiment. Aerosol measurements below and above cloud were made with a ultra-high sensitivity aerosol spectrometer and analytical electron microscopy. In addition to more standard in-cloud measurements, droplets were collected and evaporated using a counterflow virtual impactor (CVI), and the non-volatile residual particles were analyzed. Many flights focused on the gradient in cloud properties on an E-W …

Contributors
Twohy, C. H., Anderson, James, Toohey, D. W., et al.
Created Date
2013-03-05

Cloud and fog droplets efficiently scavenge and process water-soluble compounds and, thus, modify the chemical composition of the gas and particle phases. The concentrations of dissolved organic carbon (DOC) in the aqueous phase reach concentrations on the order of ~ 10 mgC L[superscript −1] which is typically on the same order of magnitude as the sum of inorganic anions. Aldehydes and carboxylic acids typically comprise a large fraction of DOC because of their high solubility. The dissolution of species in the aqueous phase can lead to (i) the removal of species from the gas phase preventing their processing by gas …

Contributors
Ervens, B., Wang, Y., Eagar, J., et al.
Created Date
2013-05-21

This study reports emission of organic particulate matter by light-duty vehicles (LDVs) and heavy-duty vehicles (HDVs) in the city of São Paulo, Brazil, where vehicles run on three different fuel types: gasoline with 25 % ethanol (called gasohol, E25), hydrated ethanol (E100), and diesel (with 5 % biodiesel). The experiments were performed at two tunnels: Jânio Quadros (TJQ), where 99 % of the vehicles are LDVs, and RodoAnel Mário Covas (TRA), where up to 30 % of the fleet are HDVs. Fine particulate matter (PM[subscript 2.5]) samples were collected on quartz filters in May and July 2011 at TJQ and …

Contributors
Sayuri Oyama, Beatriz, de Fatima Andrade, Maria, Herckes, Pierre, et al.
Created Date
2016-11-18

Large urban emissions of greenhouse gases result in large atmospheric enhancements relative to background that are easily measured. Using CO[subscript 2] mole fractions and Δ[superscript 14]C and δ[superscript 13]C values of CO[subscript 2] in the Los Angeles megacity observed in inland Pasadena (2006–2013) and coastal Palos Verdes peninsula (autumn 2009–2013), we have determined time series for CO[subscript 2] contributions from fossil fuel combustion (C[subscript ff]) for both sites and broken those down into contributions from petroleum and/or gasoline and natural gas burning for Pasadena. We find a 10 % reduction in Pasadena C[subscript ff] during the Great Recession of 2008–2010, …

Contributors
Newman, Sally, Xu, Xiaomei, Gurney, Kevin, et al.
Created Date
2016-03-22

Recent advances in fossil fuel CO[subscript 2] (FFCO[subscript 2]) emission inventories enable sensitivity tests of simulated atmospheric CO[subscript 2] concentrations to sub-annual variations in FFCO[subscript 2] emissions and what this implies for the interpretation of observed CO[subscript 2]. Six experiments are conducted to investigate the potential impact of three cycles of FFCO[subscript 2] emission variability (diurnal, weekly and monthly) using a global tracer transport model. Results show an annual FFCO[subscript 2] rectification varying from −1.35 to +0.13 ppm from the combination of all three cycles. This rectification is driven by a large negative diurnal FFCO[subscript 2] rectification due to the …

Contributors
Zhang, Xia, Gurney, Kevin, Rayner, Peter, et al.
Created Date
2016-02-19

In this study, WRF-Chem is utilized at high resolution (1.333 km grid spacing for the innermost domain) to investigate impacts of southern California anthropogenic emissions (SoCal) on Phoenix ground-level ozone concentrations ([O[superscript 3]]) for a pair of recent exceedance episodes. First, WRF-Chem control simulations, based on the US Environmental Protection Agency (EPA) 2005 National Emissions Inventories (NEI05), are conducted to evaluate model performance. Compared with surface observations of hourly ozone, CO, NO[superscript X], and wind fields, the control simulations reproduce observed variability well. Simulated [O[superscript 3]] are comparable with the previous studies in this region. Next, the relative contribution of …

Contributors
Li, Jialun, Georgescu, Matei, Hyde, Peter, et al.
Created Date
2015-08-21

The notable increase in biofuel usage by the road transportation sector in Brazil during recent years has significantly altered the vehicular fuel composition. Consequently, many uncertainties are currently found in particulate matter vehicular emission profiles. In an effort to better characterise the emitted particulate matter, measurements of aerosol physical and chemical properties were undertaken inside two tunnels located in the São Paulo Metropolitan Area (SPMA). The tunnels show very distinct fleet profiles: in the Jânio Quadros (JQ) tunnel, the vast majority of the circulating fleet are light duty vehicles (LDVs), fuelled on average with the same amount of ethanol as …

Contributors
Brito, J., Rizzo, L. V., Herckes, Pierre, et al.
Created Date
2013-12-17

Primary emissions from anthropogenic and biogenic sources as well as secondary formation are responsible for the pollution levels of ambient air in major urban areas. These sources release fine particles into the air that negatively impact human health and the environment. Organic molecular markers, which are compounds that are unique to specific PM[subscript 2.5] sources, can be utilized to identify the major emission sources in urban areas. In this study, 43 representative PM[subscript 2.5] samples, for both daytime and nighttime periods, were built from individual samples collected in an urban site of the Monterrey metropolitan area (MMA) during the spring …

Contributors
Mancilla, Y., Mendoza, A., Fraser, Matthew, et al.
Created Date
2016-01-26

Megacities are major sources of anthropogenic fossil fuel CO[subscript 2] (FFCO[subscript 2]) emissions. The spatial extents of these large urban systems cover areas of 10 000 km[superscript 2] or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO[subscript 2] emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO[subscript 2] emission product, Hestia-LA, to simulate atmospheric CO[subscript 2] concentrations across the LA megacity at spatial resolutions as fine as ∼ 1 km. We evaluated multiple WRF configurations, selecting one that …

Contributors
Feng, Sha, Lauvaux, Thomas, Newman, Sally, et al.
Created Date
2016-07-22