Green roof technology can partially mitigate the adverse effects of urbanization by controlling stormwater runoff, pre-filtering water, minimizing climate change outcomes and reducing heat island effects. However, improvements to current green roof systems and innovative approaches are paramount to advancing environmental benefits and consumer acceptance of this technology. Regular green roofs are hindered by high cost and mass, as well as the incorporation of large amounts of polymers. Hydroponic green roofs (HGRs) require specific setups, maintenance and frequent replacement of plant-growing substrate, with limited energy savings in the heating and cooling load of the building due to the space between the roof surface and the hydroponic setup. In this review, a comparison of regular and HGRs is provided, and research into the environmental benefits of these technologies, including stormwater control, water purification and lifecycle assessment, is summarized. Following this, the prospect of porous concrete (PC), as a combined plant-growth substrate and structural layer in a novel extensive hydroponic green roof (EHGR) design is proposed, through a compilation and analysis of recent studies reporting the feasibility of this construction material for different applications. The mechanical, hydrological and vegetative properties of PC are discussed. Finally, a new green roof system that incorporates both PC and hydroponics, termed the EHGR system, is presented. This new green roof system may help offset the effects of urbanization by providing stormwater and pollution control, runoff delay and physical and thermal benefits, while concurrently producing biomass from a reusable substrate.

A national need is to prepare for and respond to accidental or intentional disasters categorized as chemical, biological, radiological, nuclear, or explosive (CBRNE). These incidents require specific subject-matter expertise, yet have commonalities. We identify 7 core elements comprising CBRNE science that require integration for effective preparedness planning and public health and medical response and recovery. These core elements are (1) basic and clinical sciences, (2) modeling and systems management, (3) planning, (4) response and incident management, (5) recovery and resilience, (6) lessons learned, and (7) continuous improvement. A key feature is the ability of relevant subject matter experts to integrate information into response operations. We propose the CBRNE medical operations science support expert as a professional who (1) understands that CBRNE incidents require an integrated systems approach, (2) understands the key functions and contributions of CBRNE science practitioners, (3) helps direct strategic and tactical CBRNE planning and responses through first-hand experience, and (4) provides advice to senior decision-makers managing response activities. Recognition of both CBRNE science as a distinct competency and the establishment of the CBRNE medical operations science support expert informs the public of the enormous progress made, broadcasts opportunities for new talent, and enhances the sophistication and analytic expertise of senior managers planning for and responding to CBRNE incidents.

In the late 1970s, the Environmental Protection Agency (EPA) unveiled the bubble policy as a central part of Jimmy Carter's plan to reform environmental regulations that many believed had grown too proscriptive and too costly for American industry. Since the EPA's formation, regulators had dictated method and means for reducing air pollution. The bubble returned the prerogative to business. But despite bipartisan support, the bubble never took off. Drawing on EPA records and interviews, this article shows how skeptical regulators intentionally made the bubble unwieldy, driving away businesses wary of uncertainty. Though Ronald Reagan's election seemed to lift the bubble's fortunes, his undiscerning assault on the administrative state ironically deflated the EPA's development of a viable alternative to the proscriptive model.

Recent federal regulations require new light-duty vehicles to have lower greenhouse gas emissions and better fuel economy. This paper presents the reasoning used by the U.S. Environmental Protection Agency (EPA) in its benefit-cost analysis of the standards. According to EPA, many available technologies could achieve these goals without affecting other vehicle qualities, and fuel savings would pay for the increased technology costs with short payback periods. This lack of market adoption of cost-effective energy-saving technologies has been termed the energy efficiency gap or energy efficiency paradox. It suggests that either there are additional costs, such as changes in vehicle qualities, not considered in cost estimates, or markets for energy-saving technologies are not achieving all cost-effective savings. EPA argued that, even if consumers do not accurately consider expected future fuel savings when buying new vehicles, consumers are projected to receive those savings; the latter measure should reflect the impacts of the rule on fuel expenditures. For the cost side, EPA used a measure of technology costs required to meet the standards while maintaining baseline (2008) vehicle attributes. Estimates of how these costs would be affected by changes in vehicle attributes were not included.