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Author: Shoma Yamanouchi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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This thesis examines total columns of C2H2, C2H6, CH4, CH3OH, CO, H2CO, HCl, HCN, HCOOH, HF, HNO3, N2O, NH3, and O3 measured using Fourier transform infrared (FTIR) spectroscopy to study Toronto-area atmospheric composition. The thesis has three scientific objectives: to quantify trends in the time series of trace gas concentrations, to determine how emissions from biomass burning events affect air quality over Toronto and whether observations in Toronto can be used to quantify wildfire emissions, and to examine the spatial representativeness and temporal variability of the FTIR NH3 columns over Toronto.Trends and enhancement events were determined by fitting trended Fourier series to the total columns, and bootstrapping was used to identify the statistical significance. Trends from 2002 to 2019 were examined, and the GEOS-Chem chemical transport model was used to identify major sources of CO and CH4 over Toronto, which were CH4 oxidation and wetland emissions, respectively. Transport of wildfire plumes over the site results in enhanced columns of biomass burning species. Several simultaneous enhancements of CO, HCN, and C2H6 were observed, and the measured columns were used to derive emission ratios and emission factors for HCN and C2H6 for fire events in 2012, 2015, and 2017. For the 2015 and 2017 events, simultaneous enhancements of HCOOH and CH3OH were observed, and their emission ratios and emission factors were also examined. Atmospheric NH3 is a pollutant, and a major source of fine particulate matter. In this study, three NH3 datasets were used: TAO FTIR total columns, three years of surface in situ measurements, and ten years of total column measurements from the Infrared Atmospheric Sounding Interferometer (IASI). The datasets were used to quantify NH3 temporal variability over Toronto, Canada. All three time series showed positive trends in NH3 over Toronto: 3.56 ± 0.85 %/year from 2002 to 2019 in the FTIR columns, 8.88 ± 5.08 %/year from 2013 to 2017 in the surface in situ data, and 8.38 ± 1.54 %/year from 2008 to 2018 in the IASI columns. The multiscale datasets were also compared to assess the representativeness of the FTIR measurements.
Author: Shoma Yamanouchi
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
This thesis examines total columns of C2H2, C2H6, CH4, CH3OH, CO, H2CO, HCl, HCN, HCOOH, HF, HNO3, N2O, NH3, and O3 measured using Fourier transform infrared (FTIR) spectroscopy to study Toronto-area atmospheric composition. The thesis has three scientific objectives: to quantify trends in the time series of trace gas concentrations, to determine how emissions from biomass burning events affect air quality over Toronto and whether observations in Toronto can be used to quantify wildfire emissions, and to examine the spatial representativeness and temporal variability of the FTIR NH3 columns over Toronto.Trends and enhancement events were determined by fitting trended Fourier series to the total columns, and bootstrapping was used to identify the statistical significance. Trends from 2002 to 2019 were examined, and the GEOS-Chem chemical transport model was used to identify major sources of CO and CH4 over Toronto, which were CH4 oxidation and wetland emissions, respectively. Transport of wildfire plumes over the site results in enhanced columns of biomass burning species. Several simultaneous enhancements of CO, HCN, and C2H6 were observed, and the measured columns were used to derive emission ratios and emission factors for HCN and C2H6 for fire events in 2012, 2015, and 2017. For the 2015 and 2017 events, simultaneous enhancements of HCOOH and CH3OH were observed, and their emission ratios and emission factors were also examined. Atmospheric NH3 is a pollutant, and a major source of fine particulate matter. In this study, three NH3 datasets were used: TAO FTIR total columns, three years of surface in situ measurements, and ten years of total column measurements from the Infrared Atmospheric Sounding Interferometer (IASI). The datasets were used to quantify NH3 temporal variability over Toronto, Canada. All three time series showed positive trends in NH3 over Toronto: 3.56 ± 0.85 %/year from 2002 to 2019 in the FTIR columns, 8.88 ± 5.08 %/year from 2013 to 2017 in the surface in situ data, and 8.38 ± 1.54 %/year from 2008 to 2018 in the IASI columns. The multiscale datasets were also compared to assess the representativeness of the FTIR measurements.
Author: Cynthia Whaley
Publisher:
ISBN:
Category :
Languages : en
Pages : 258
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Author: Guy P. Brasseur
Publisher: Springer Science & Business Media
ISBN: 3642189849
Category : Science
Languages : en
Pages : 310
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Praise for Guy P. Brasseur's Atmospheric Chemistry in a Changing World American Meteorological Society "This volume summarizes and integrates more than a decade of atmospheric chemistry research. During the period under consideration, great progress has been made in computing, modeling, and observational techniques, and methods have also improved. Here, suggestions for the highest priority research for the next decade are made, and important information is related regarding impacts on the environment."
Author: R. B. Husar
Publisher: Elsevier
ISBN: 1483150739
Category : Science
Languages : en
Pages : 830
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Book Description
Sulfur in the Atmosphere covers the proceedings of the International Symposium held in Dubrovnik, Yugoslavia on September 7-14, 1977. The text focuses on the processes involved in the transfer of sulfur through the atmospheric environment, particularly noting its distribution in space in gas, liquid, and solid phases. The book first offers information on the properties of sulfur and the processes involved in its determination, as well as measurement methods, chemical transformations, dry and wet deposition, and aerosol dynamics. The publication also looks at water-soluble sulfur compounds in aerosols, chemical properties of tropospheric sulfur aerosols, and sampling and analysis of atmospheric sulfates and related species. The text examines the techniques involved in the identification of chemical composition of aerosol sulfur compounds. Topics include thermal volatilization, thermometric methods, wet chemical identification, and laser Raman spectroscopy. The publication also reviews the calculation of long term sulfur deposition in Europe; transmission of sulfur dioxide on local, regional, and continental scale; and airborne sampling system for the monitoring of plume. The book is a dependable source of data for readers interested in the transfer of sulfur through the atmospheric environment.
Author: Barbara J. Finlayson-Pitts
Publisher: Elsevier
ISBN: 0080529070
Category : Science
Languages : en
Pages : 993
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Book Description
Here is the most comprehensive and up-to-date treatment of one of the hottest areas of chemical research. The treatment of fundamental kinetics and photochemistry will be highly useful to chemistry students and their instructors at the graduate level, as well as postdoctoral fellows entering this new, exciting, and well-funded field with a Ph.D. in a related discipline (e.g., analytical, organic, or physical chemistry, chemical physics, etc.). Chemistry of the Upper and Lower Atmosphere provides postgraduate researchers and teachers with a uniquely detailed, comprehensive, and authoritative resource. The text bridges the "gap" between the fundamental chemistry of the earth's atmosphere and "real world" examples of its application to the development of sound scientific risk assessments and associated risk management control strategies for both tropospheric and stratospheric pollutants. - Serves as a graduate textbook and "must have" reference for all atmospheric scientists - Provides more than 5000 references to the literature through the end of 1998 - Presents tables of new actinic flux data for the troposphere and stratospher (0-40km) - Summarizes kinetic and photochemical date for the troposphere and stratosphere - Features problems at the end of most chapters to enhance the book's use in teaching - Includes applications of the OZIPR box model with comprehensive chemistry for student use
Author:
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ISBN:
Category : Chemical kinetics
Languages : en
Pages : 52
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Category : Acid precipitation (Meteorology)
Languages : en
Pages : 744
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Author: Iain D. Stewart
Publisher: Elsevier
ISBN: 0128156902
Category : Science
Languages : en
Pages : 184
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The Urban Heat Island (UHI) is an area of growing interest for many people studying the urban environment and local/global climate change. The UHI has been scientifically studied for 200 years and, although it is an apparently simple phenomenon, there is considerable confusion around the different types of UHI and their assessment. The Urban Heat Island—A Guidebook provides simple instructions for measuring and analysing the phenomenon, as well as greater context for defining the UHI and the impacts it can have. Readers will be empowered to work within a set of guidelines that enable direct comparison of UHI effects across diverse settings, while informing a wide range of climate mitigation and adaptation programs to modify human behaviour and the built form. This opens the door to true global assessments of local climate change in cities. Urban planning and design strategies can then be evaluated for their effectiveness at mitigating these changes. - Covers both on-surface and near-surface, or canopy, measurements and impacts of Urban Heat Islands (UHI) - Provides a set of best practices and guidelines for UHI observation and analysis - Includes both conceptual overviews and practical instructions for a wide range of uses
Author: Congmeng Lyu
Publisher:
ISBN:
Category : Atmospheric chemistry
Languages : en
Pages : 157
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Ground-level ozone, which forms photochemically in the atmosphere from precursor emissions of oxides of nitrogen (NOx) and volatile organic compounds, is a criteria pollutant that harms human health and public welfare. For a representative summer episode, premature mortality and potential productivity losses (PPLs) of selected crops and trees attributable to ozone exposure have been quantified using ozone fields from the Community Multiscale Air Quality (CMAQ) model. We applied exposure-response models for the increased risk of premature mortality due to long-term exposure to ozone over a theoretical minimum risk exposure level (TMREL) and for the reduced accumulation of vegetative biomass for four crop species and eleven tree species using the W126 metric designed to capture impacts on plants. To elucidate which emissions contributed to these disbenefits, we applied adjoint-based sensitivity analysis, which efficiently estimates sensitivities of concentration-based metrics with respect to numerous emissions parameters simultaneously. The adjoint of CMAQ was applied to the continental U.S. to calculate the influence of spatially-resolved ozone precursor emissions on the annual average, domain-wide daily maximum 8-hour average over the TMREL (elevated MDA8), premature mortality attributable to exposure to ozone above the TMREL, and PPLs. These quantities provide the impact in terms of the percent reduction in precursor emissions. Additionally, locations where similar percent reductions in ozone precursor emissions would impact one or more endpoints greater than average have been identified. NOx emissions were found to contribute most to the three metrics. The distinct spatial patterns of emissions influences on public welfare disbenefits as compared to the elevated MDA8 and premature mortality suggest that the current regulatory averaging time motivates different emissions control strategies than those that could most directly protect public welfare.Recently, oil and natural gas (O&NG) production activities in the Denver-Julesburg Basin have expanded rapidly. Associated nonmethane hydrocarbon (NMHC) emissions contribute to photochemical formation of ground-level ozone and include benzene as well as other hazardous air pollutants. Using positive matrix factorization (PMF) and chemical mass balance (CMB) methods, we estimate how much O&NG activities and other sources contribute to morning NMHC mixing ratios measured from 2013 to mid-2016 at a site in Platteville, CO, in the Denver-Julesburg Basin, and at a contrasting site in downtown Denver. A novel adjoint sensitivity analysis method is then used to estimate corresponding contributions to ozone and ozone-linked mortality in the Denver region. Average 6 - 9 am NMHC mixing ratios in Platteville were seven times higher than those in Denver in 2013 but four times higher in 2016. CMB estimates that O&NG activities contributed to the Platteville (Denver) site an average of 96% (56%) of NMHC on a carbon basis while PMF indicated 92% (33%). Average vehicle-related contributions of NMHC are estimated as 41% by CMB and 53% by PMF in Denver. Estimates of the fractional contribution to potential ozone and ozone-linked mortality from O&NG activities are smaller while those from vehicles are larger than the NMHC contributions. CMB (PMF) indicate that greater than 78% (40%) of annual average benzene in Denver is attributable to vehicle emissions while greater than 75% (67%) of benzene in Platteville is attributable to O&NG activities.The Community Multiscale Air Quality (CMAQ) model calculates the impact of emissions on atmospheric composition, including inorganic aerosols, while considering the transport and reactions of chemical constituents. Adjusting emissions by comparing modeled concentrations with observations is justified when the science processes are well understood as is the case for inorganic species such as ammonia (NH3). The Finite Difference Mass Balance (FDMB) method and four-dimensional variational (4D-Var) data assimilation leverage differences in simulated and actual observations to revise estimates of emissions with spatial specificity. In this study, we evaluate the capability of a CMAQ-based data assimilation system to improve NH3 emissions, which are relatively uncertain given the diversity of emissions processes in the agricultural sector. To do so, the iterative FDMB and a Python-based four-dimensional variational framework (Py4Dvar) are integrated with CMAQ and its adjoint to constrain NH3 emissions with observations from the satellite-based Cross-track Infrared Sounder (CrIS). Observing System Simulation Experiments (OSSEs) are conducted with the CrIS observation operator to evaluate the extent to which emissions are expected to be recovered with the hybrid assimilation framework. The OSSEs conducted with the 2007 modeling platform and 2016 CrIS data on a regional domain in Georgia and the OSSEs conducted with the 2017 modeling platform and 2017 CrIS data on the continental U.S. domain result in promising recovery of the true emissions.
Author:
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 662
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