The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Michael K Stenstrom - One of the best experts on this subject based on the ideXlab platform.
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modeling of highway stormwater runoff
Science of The Total Environment, 2005Co-Authors: Masoud Kayhanian, Michael K StenstromAbstract:Highways are stormwater intensive landuses since they are impervious and have high pollutant Mass Emissions from vehicular activity. Vehicle Emissions include different pollutants such as heavy metals, oil and grease, particulates from sources such as fuels, brake pad wear and tire wear, and litter. To understand the magnitude and nature of the stormwater Emissions, a 3-year study was conducted to quantify stormwater pollutant concentrations, Mass Emission rates, and the first flush of pollutants. Eight highway sites were monitored over 3 years for a large suite of pollutants. The monitoring protocol emphasized detecting the first flush and quantifying the event mean concentration. Grab and flow-weighted composite samples, rainfall, and runoff data were collected. A new runoff model with four parameters was developed that to describe the first flush of pollutants for a variety of rainfall and runoff conditions. The model was applied to more than 40 events for 8 pollutants, and the parameters were correlated to storm and site conditions, such as total runoff, antecedent dry days, and runoff coefficient. Improved definitions of first flush criteria are also presented.
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seasonal first flush phenomenon of urban stormwater discharges
Water Research, 2004Co-Authors: Masoud Kayhanian, Michael K StenstromAbstract:Abstract California's climate, typified by winter and spring precipitation and summer drought, is often called a Mediterranean climate, and creates a long period for pollutant build-up. The initial storms of the winter season usually have higher pollutant concentrations, which is called a seasonal first flush. To investigate the existence of a seasonal first flush, we analyzed four major data sets, collected over the 1999–2000 to 2002–2003 wet seasons. Trends in seasonal loads were quantified by plotting pollutant concentrations or cumulative pollutant load versus cumulative rainfall or cumulative runoff volume. Pollutant concentrations in the first part of the wet season were ranged from 1.2 to 20 times higher than concentrations near the end of the season, and Mass Emission rates were similarly higher at the beginning of the season. A seasonal first flush existed for most cases and was strongest for organics, minerals and heavy metals except lead. This result suggests that applying treatment Best Management Practices (BMPs) early in the season could remove several times more pollutant Mass than randomly timed or uniformly applied BMPs.
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Event mean concentration and loading of litter from highways during storms.
The Science of the total environment, 2004Co-Authors: Lee-hyung Kim, Masoud Kayhanian, Michael K StenstromAbstract:Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over 2 years. Gross pollutants were defined as larger than 0.5 cm and were classified into three categories. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. Event mean concentrations and Mass Emission rates are presented. No statistically significant correlations of litter production were noted, although the event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. The Mass Emission rates will be useful to estimate total litter production for developing total maximum daily loads.
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First Flush Stormwater Runoff from Highways
Bridging the Gap, 2001Co-Authors: Michael K Stenstrom, Lee-hyung Kim, Sim-lin Lau, H.-h. Lee, Shuhab D. Khan, Masoud KayhanianAbstract:Stormwater is now receiving attention from regulatory agencies and has become an important component in watershed planning. In many cases, pollutant Mass Emissions from stormwater exceed those from wastewater treatment plants. Land use has been identified as an important parameter in predicting stormwater quality. Land uses associated with vehicular activity, such as parking lots, are thought to be high contributors of stormwater pollutants. Other factors, such as greater pollutant concentrations or Mass Emissions at the onset of rainfall, usually called a “first flush,” or higher Emissions from the first storm of the season, usually called a “seasonal first flush,” have been identified. In order to determine the magnitude of the first flush from freeway runoff, three sites in the west Los Angeles area were sampled for 14 storms during the 1999-2000 rainy season. Samples were collected very early in the storm in order to compare water quality from the first runoff to water quality from the middle of the storm. A large range of water quality parameters and metals were analyzed. The data show large first flushes in concentration profiles and moderate first flushes in Mass Emission rates.
Masoud Kayhanian - One of the best experts on this subject based on the ideXlab platform.
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modeling of highway stormwater runoff
Science of The Total Environment, 2005Co-Authors: Masoud Kayhanian, Michael K StenstromAbstract:Highways are stormwater intensive landuses since they are impervious and have high pollutant Mass Emissions from vehicular activity. Vehicle Emissions include different pollutants such as heavy metals, oil and grease, particulates from sources such as fuels, brake pad wear and tire wear, and litter. To understand the magnitude and nature of the stormwater Emissions, a 3-year study was conducted to quantify stormwater pollutant concentrations, Mass Emission rates, and the first flush of pollutants. Eight highway sites were monitored over 3 years for a large suite of pollutants. The monitoring protocol emphasized detecting the first flush and quantifying the event mean concentration. Grab and flow-weighted composite samples, rainfall, and runoff data were collected. A new runoff model with four parameters was developed that to describe the first flush of pollutants for a variety of rainfall and runoff conditions. The model was applied to more than 40 events for 8 pollutants, and the parameters were correlated to storm and site conditions, such as total runoff, antecedent dry days, and runoff coefficient. Improved definitions of first flush criteria are also presented.
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seasonal first flush phenomenon of urban stormwater discharges
Water Research, 2004Co-Authors: Masoud Kayhanian, Michael K StenstromAbstract:Abstract California's climate, typified by winter and spring precipitation and summer drought, is often called a Mediterranean climate, and creates a long period for pollutant build-up. The initial storms of the winter season usually have higher pollutant concentrations, which is called a seasonal first flush. To investigate the existence of a seasonal first flush, we analyzed four major data sets, collected over the 1999–2000 to 2002–2003 wet seasons. Trends in seasonal loads were quantified by plotting pollutant concentrations or cumulative pollutant load versus cumulative rainfall or cumulative runoff volume. Pollutant concentrations in the first part of the wet season were ranged from 1.2 to 20 times higher than concentrations near the end of the season, and Mass Emission rates were similarly higher at the beginning of the season. A seasonal first flush existed for most cases and was strongest for organics, minerals and heavy metals except lead. This result suggests that applying treatment Best Management Practices (BMPs) early in the season could remove several times more pollutant Mass than randomly timed or uniformly applied BMPs.
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Event mean concentration and loading of litter from highways during storms.
The Science of the total environment, 2004Co-Authors: Lee-hyung Kim, Masoud Kayhanian, Michael K StenstromAbstract:Total captured gross pollutants in stormwater runoff were monitored at six Southern California highway sites over 2 years. Gross pollutants were defined as larger than 0.5 cm and were classified into three categories. The gross pollutants were 90% vegetation and 10% litter. Approximately 50% of the litter was composed of biodegradable materials. Event mean concentrations and Mass Emission rates are presented. No statistically significant correlations of litter production were noted, although the event mean concentrations show an increasing trend with antecedent dry days and a decreasing trend with total runoff volume or total rainfall. The Mass Emission rates will be useful to estimate total litter production for developing total maximum daily loads.
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First Flush Stormwater Runoff from Highways
Bridging the Gap, 2001Co-Authors: Michael K Stenstrom, Lee-hyung Kim, Sim-lin Lau, H.-h. Lee, Shuhab D. Khan, Masoud KayhanianAbstract:Stormwater is now receiving attention from regulatory agencies and has become an important component in watershed planning. In many cases, pollutant Mass Emissions from stormwater exceed those from wastewater treatment plants. Land use has been identified as an important parameter in predicting stormwater quality. Land uses associated with vehicular activity, such as parking lots, are thought to be high contributors of stormwater pollutants. Other factors, such as greater pollutant concentrations or Mass Emissions at the onset of rainfall, usually called a “first flush,” or higher Emissions from the first storm of the season, usually called a “seasonal first flush,” have been identified. In order to determine the magnitude of the first flush from freeway runoff, three sites in the west Los Angeles area were sampled for 14 storms during the 1999-2000 rainy season. Samples were collected very early in the storm in order to compare water quality from the first runoff to water quality from the middle of the storm. A large range of water quality parameters and metals were analyzed. The data show large first flushes in concentration profiles and moderate first flushes in Mass Emission rates.
Constantinos Sioutas - One of the best experts on this subject based on the ideXlab platform.
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Chemical characteristics and oxidative potential of particulate matter Emissions from gasoline, diesel, and biodiesel cars
Environmental Science and Technology, 2009Co-Authors: Lam Cheung Ka, Miriam Gerlofs, Theodoros Tzamkiozis, Andrea Polidori, Flemming R. Cassee, Leonidas Ntziachristos, Zissis Samaras, Constantinos SioutasAbstract:Three light-duty vehicles in five different configurations [a Honda Accord operating with diesel with a closed-coupled oxidation catalyst and an underfloor catalyst replaced in some tests with a diesel particle filter (DPF), a Toyota Corolla operating with gasoline, and a VW Golf alternatively operating with petrodiesel or biodiesel] were tested in a dynamometer facility to develop an improved understanding of the factors affecting the toxicity of particulate exhaust Emissions. The vehicles were tested using a variety of real-world driving cycles, more than the certification test (New European Driving Cycle). Particle samples were collected and analyzed for elemental and organic carbon (EC and OC, respectively), water soluble and water insoluble organic carbon (WSOC and WISOC, respectively), and inorganic ions, and the Emission rates (mg/km) for each vehicle/configuration were determined. A dithiothreitol (DTT) assay was used to assess the oxidative potential of the particulate matter (PM) samples. The DPF-equipped diesel and gasoline vehicles were characterized by the lowest overall PM Mass Emissions, while the diesel and biodiesel cars produced the most potent exhaust in terms of oxidative activity. When the DPF was fitted on the Honda Accord diesel vehicle, the Mass Emission rates and distance-based oxidative potential were both decreased by 98%, compared to the original configuration. Correlation analysis showed that the DTT consumption rate was highly associated with WSOC, WISOC, and OC (R = 0.98, 0.93, and 0.94, respectively), consistent with previous findings.
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evolution of particle number distribution near roadways part iii traffic analysis and on road size resolved particulate Emission factors
Atmospheric Environment, 2005Co-Authors: Max K Zhang, Anthony S Wexler, Debbie A Niemeier, Yifang Zhu, William C Hinds, Constantinos SioutasAbstract:On-road size-resolved particulate Emission factors were computed using concurrently measured carbon monoxide (CO) as a freeway dilution indicator and correlating roadside particle measurements to CO measurements. The Emission factors derived for the total particle number agree well with previous on-road investigations. However, this study extends this analysis to produce unique receptor-dependent, size-resolved, road and grid-level Emission factor distributions. Both mileage- and fuel-based particle number and Mass Emission factors at road and grid levels, along with CO Emission factors, are presented and the results from freeways with distinctly different percentages of heavy-duty diesel truck traffic are compared. The effects of plume processing on particle number near roadways are shown to be much more profound than on particle Mass, further indicting that the adverse health effects observed near roadways are at least partially related to particle numbers.
Jean Claude Benoist - One of the best experts on this subject based on the ideXlab platform.
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Chemical and odor characterization of gas Emissions released during composting of solid wastes and digestates
Journal of Environmental Management, 2019Co-Authors: Carlos Andrés Rincón, Amaury De Guardia, Annabelle Couvert, Sophie Le Roux, Isabelle Soutrel, Mylène Daumoin, Jean Claude BenoistAbstract:Hazardous and odorous gas Emissions from composting and methanization plants are an issue of public concern. Odor and chemical monitoring are thus critical steps in providing suitable strategies for air pollution control at waste treatment units. In this study, 141 gas samples were extensively analyzed to characterize the odor and chemical Emissions released upon the aerobic treatment of 10 raw substrates and five digestates. For this purpose, agricultural wastes, biowastes, green wastes, sewage sludge, and municipal solid waste (MSW) were composted in 300 L pilots under forced aeration. Gas exhausts were evaluated through dynamic olfactometry and analytical methods (i.e., GC/MS) to determine their odor concentration (OC in OU m) and chemical composition. A total of 60 chemical compounds belonging to 9 chemical families were identified and quantified. Terpenes, oxygenated compounds, and ammonia exhibited the largest cumulative Mass Emission. Odor Emission rates (OU h) were computed based on OC measurements and related to the initial amount of organic matter composted and the process time to provide odor Emission factors (OEFs in OU gOM). The composting process of solid wastes accounted for OEFs ranging from 65 to 3089 OU gOM, whereas digestates composting showed a lower odor Emission potential with OEF fluctuating from 8.6 to 30.5 OU gOM. Moreover, chemical concentrations of single compounds were weighted with their corresponding odor detection thresholds (ODTs) to yield odor activities values (OAVs) and odor contribution (PO, %). Volatile sulfur compounds were the main odorants (PO = 54-99%) regardless of the operational composting conditions or substrate treated. Notably, methanethiol was the leading odorant for 73% of the composting experiments.
Mats Bohgard - One of the best experts on this subject based on the ideXlab platform.
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Chemical composition and Mass Emission factors of candle smoke particles
Journal of Aerosol Science, 2009Co-Authors: Joakim Pagels, Aneta Wierzbicka, Erik Nilsson, Christina Isaxon, Andreas Dahl, Anders Gudmundsson, Erik Swietlicki, Mats BohgardAbstract:The aim of this study is to investigate the physical and chemical properties of particle Emissions from candle burning in indoor air. Two representative types of tapered candles were studied during steady burn, sooting burn and smouldering (upon extinction) under controlled conditions in a walk-in stainless steel chamber. Steady burn emits relatively high number Emissions of ultrafine particles dominated by either phosphates or alkali nitrates. The likely source of these particles is flame retardant additives to the wick. Sooting burn in addition emits larger particles mainly consisting of agglomerated elemental carbon. This burning mode is associated with the highest Mass Emission factors. Particles emitted during smouldering upon extinction are dominated by organic matter. A Mass closure was illustrated for the total Mass concentration, the summed Mass concentration from chemical analysis and the size-integrated Mass concentration assessed from number distribution measurements using empirically determined effective densities for the three particle types.