Spatiotemporal variation of methane and other trace hydrocarbon concentrations in the valley of Mexico

Mexico City is the world's largest and most polluted urban center. We examine the distribution of methane and other hydrocarbons within the Valley of Mexico, using it as a model for the role developing megacities will play in the next century of geochemical cycling. Seventy-five whole air samples were analyzed with multivariate statistical techniques, including factor analysis using principal components. Methane concentrations are highly variable in space and time, due to air circulations and source distribution. Landfills and open sewage canals are major inputs. Emissions into and out from the valley are modeled to be ∼515 t per day. Per capita emission is 0.01 t per annum per person, consistent with the global average for human related anaerobic generation. Natural gas leaks are small, and likely to be higher in other developing megacities; Mexican natural gas use has been discouraged out of earthquake safety concerns. In contrast, liquefied petroleum gas loss constitutes the major emission of propane and butane estimated at a leak rate of 5-10%. Kyoto and other environmental conventions have ignored methane as a greenhouse gas. Our analysis underscores the need to consider methane and other hydrocarbons, and the urbanization process, in future emission protocols. © 2002 Elsevier Science Ltd. All rights reserved

Compensation of atmospheric CO2 buildup through engineered chemical shrinkage

Retrieval of background carbon dioxide into regional chemical extractors would counter anthropogenic inputs in a manner friendly to established industries. We demonstrate via atmospheric transport/scaling calculations that for idealized flat removal units, global coverage could be less than two hundred thousand square kilometers. The disrupted area drops to a small fraction of this with engineering into the vertical to bypass laminarity. Fence structures and artificial roughness elements can both be conceived. Sink thermodynamics are analyzed by taking calcium hydroxide as a sample reactant. Energy costs could be minimized at near the endothermicity of binding reversal. In the calcium case the value is 25 kcal mole-1, as against a fuel carbon content of 150 in the same units. Aqueous kinetics are less than favorable for the hydroxide, but misting could counteract slow liquid phase transfer. Properties of superior scrubbers are outlined

Chemical transport modeling of potential atmospheric CO2 sinks

The potential for carbon dioxide (CO2) sequestration via engineered chemical sinks is investigated using a three dimensional chemical transport model (CTM). Meteorological and chemical constraints for flat or vertical systems that would absorb CO2 from the atmosphere, as well as an example chemical system of calcium hydroxide (Ca(OH)2) proposed by Elliott et al. [Compensation of atmospheric CO2 buildup through engineered chemical sinkage, Geophys. Res. Lett. 28 (2001) 1235] are reviewed. The CTM examines land based deposition sinks, with 4° × 5° latitude/longitude resolution at various locations, and deposition velocities (v). A maximum uptake of ∼20 Gton (1015 g) Cyr-1 is attainable with v ≥ 5 cms-1 at a mid-latitude site. The atmospheric increase of CO2 (3 Gtonyr-1) can be balanced by an engineered sink with an area of no more than 75, 000 km2 at v of 1 cms-1. By building the sink upwards or splitting this area into narrow elements can reduce the active area by more than an order of magnitude as discussed in Dubey et al. © 2002 Elsevier Science Ltd. All rights reserved

Atmospheric effects of the emerging mainland Chinese transportation system at and beyond the regional scale

Local surface travel needs in the People's Republic of China (mainland China) have traditionally been met largely by nonpolluting bicycles. A major automobile manufacturing/importing effort has begun in the country over the last decade, and planning documents indicate that the Chinese may strive to acquire more than 100 million vehicles early in the next century. By analogy with large automotive fleets already existing in the western world, both regional and global scale pollution effects are to be expected from the increase. The present work adopts the latest projections of Chinese automobile manufacture and performs some quantitative assessments of the extent of pollution generation. Focus for the investigation is placed upon the oxidant ozone. Emissions of the precursor species nitrogen oxides and volatile organics are constructed based on data for the current automotive sector in the eastern portion of the United States. Ozone production is first estimated from measured values for continental/oceanic scale yields relative to precursor oxidation. The estimates are then corroborated through idealized two dimensional modeling of the photochemistry taking place in springtime air flow off the Asian land mass and toward the Pacific Ocean. The projected fleet sizes could increase coastal and remote oceanic ozone concentrations by tens of parts per billion (ppb) in the lower troposphere. Influences on the tropospheric aerosol system and on the major greenhouse gas carbon dioxide are treated peripherally. Nitrogen oxides created during the vehicular internal combustion process will contribute to nitrate pollution levels measured in the open Pacific. The potential for soot and fugitive dust increases should be considered as the automotive infrastructure develops. Since the emerging Chinese automotive transportation system will represent a substantial addition to the global fleet and all the carbon in gasoline is eventually oxidized completely, a significant rise in global carbon dioxide inputs will ensue as well. Some policy issues are treated preliminary. The assumption is made that alterations to regional oxidant/aerosol systems and to terrestrial climate are conceivable. The likelihood that the Chinese can achieve the latest vehicle fleet goals is discussed, from the points of view of new production, positive pollution feedbacks from a growing automobile industry, and known petroleum reserves. Vehicular fuel and maintenance options lying before the Chinese are outlines and compared. To provide some perspective on the magnitude of the environmental changes associated with an Asian automotive buildup, recent estimates of the effects of future air traffic over the Pacific Rim are described

Modern Teacher Education - Supporting the Vast Landscape of 21st Century Pedagogy

Learners have changed; Teaching has changed; Expectations have changed. How to best support modern learners is the challenge of all educators at all grade levels. The students of today are sophisticated users of technology, they are multitasking constantly and can sometimes be more comfortable with the technology than they are interacting with teachers and peers in the real world. Marc Prensky described them as “Digital Natives” over 10 years ago implying that they are efficient users of technology. This is not always the case. While they are exposed to various technologies and can successfully use them outside the classroom their use of these same tools as learning support tools can be lacking. Digital natives have different learning styles and different concerns than previous students. Educators need to keep up with this changing landscape and need to learn, develop and innovate new ways to support todays’ learners. Supporting today’s learners now requires more than just educating them in a specific content area but also includes supporting them in the use of technology tools in an education setting. Supporting educators through areas of primary training such as teacher preparation programs and degree programs are one way to accomplish this but also the many credible teacher training programs that provide experience, peer support or certifications are also excellent tools. Through this chapter we will take a close look at pedagogy, learning styles, support tools, and the skills needed to be a modern educator

Assessing the Rock Island Community Garden Program

As part of Sustainable Working Landscapes Initiative with Augustana College’s Upper Mississippi Center, students in Urban Design and Environmental Justice (Geography 325) conducted research on Rock Island’s community garden program this fall. The City of Rock Island currently has 21 vacant-lot community gardens and plans to expand the program to 24 gardens in 2019. The purpose of this project was to develop an initial assessment of the community garden program and provide general information about the benefits of urban gardens. Students worked with Dr. Strunk to conduct a survey with current garden program participants and tested soil from 14 gardens for lead contamination. Students collected 3 soil samples from 3 different sections of most gardens (north, middle, south sections). The soil tests showed that sections of 5 different gardens (#3N, #10M, #11N, #11M, #11S, #15N, and #21)have elevated lead levels above the EPA standard of 400 parts per million. The remaining 8 gardens will be tested for soil lead contamination in early 2019. Students also created informational resources about the health benefits of gardens, conducted research about features of successful after-school gardening programs to be discussed with Rock Island-Milan school officials, and developed a proposal for a recipe book that can be used to raise awareness about the diversity of cultural practices in gardens and raise money for small-scale garden grants. Finally, students developed a proposal for a rainwater harvesting system and created designs for a sign for Rock Island Urban Farms and a future community garden site on city property