Exposure to indoor air pollution from the combustion of solid fuels has been implicated, with varying degrees of evidence, as a causal agent of several diseases in developing countries. In a review of the epidemiological evidence for the health effects of indoor smoke from solid fuels, Bruce et al. concluded that, despite some methodological limitations, epidemiological studies provide compelling evidence of causality for acute respiratory infections (ARI) and chronic obstructive pulmonary disease (COPD). This is reinforced by experimental data, studies of pathogenesis, and indirect evidence from environmental tobacco smoke (ETS) and ambient air pollution studies. (more…)

Global energy consumption in the last half century has increased very rapidly and is expected to continue to grow over the next 50 years. However, we expect to see significant differences between the last 50 years and the next. The past increase was stimulated by relatively “cheap” fossil fuels and increased rates of industrialization in North America, Europe, and Japan; yet while energy consumption in these countries continues to increase, additional factors are making the picture for the next 50 years more complex. These additional complicating factors include the very rapid increase fuel economy in energy use in China and India (countries representing about a third of the world’s population); the expected depletion of oil resources in the not-too-distant future; and the effect of human activities on global climate change. (more…)

Indoor air quality (IAQ) research deals with the presence, levels, health effects, and control of physical, chemical, and biological factors in indoor environments, including homes, workplaces, and vehicles. IAQ research in industrialized countries has examined hundreds of specific factors (e.g., temperature, various chemicals, and mold), sources of pollution environment (e.g., environmental tobacco smoke, occupational factors, consumer cleaning products, and moisture), and control technologies (e.g., ventilation). (more…)

The formation of acidic deposition is largely from the combustion of fossil fuels and the smelting of sulfide ores. Minor natural sources exist such as the formation of hydrochloric and sulfuric acid from gaseous volcanic eruptions.

There are well over 100 gaseous and aqueous phase reactions that can lead to acid formation and more than fifty oxidizing agents and catalysts may be involved. However, in the simplest terms sulfur in fuels is oxidized to SO2 , and SO2 in the atmosphere is further oxidized and hydrolyzed to sulfuric acid. Most nitric acid is formed by the fixation of atmospheric nitrogen gas (N2) to NOx (NO and NO2) during high temperature combustion emissions, followed by further oxidation and hydrolysis that produces nitric acid in the atmosphere. (more…)

There are numerous possible applications for hybrid power systems. The most common examples are (1) remote AC network, (2) distributed generation applications in a conventional utility network, and (3) isolated or special purpose electrical loads.

The classic example of the hybrid energy systems is the remote, diesel-powered AC network. The basic goal is to decrease the amount of fuel consumed by diesel generators and to decrease the number of hours that they operate. The first addition to ‘‘hybridize’’ the system is to add another type of generator, normally using a renewable source. (more…)

The term hybrid energy system refers to those applications in which multiple energy unit conversion devices are used together to supply an energy requirement. These systems are often used in isolated applications and normally include at least one renewable energy source in the configuration. Hybrid energy systems are used an alternative to more conventional systems, which typically are based on a single fossil fuel source. Hybrid energy systems may also be used as part of distributed generation application in conventional electricity grid. (more…)

Electric utility deregulation offers the great promise of market forces leading to lower electric rates, lower air pollution environment, greater energy (and economic) efficiency, and perhaps greater use of renewable energy sources. Ideally, deregulation involves the restructuring of a previously monopolized or nationalized electric utility into separate generation, transmission, distribution, and marketing companies, and allowing wholesale and retail choice of generation company or power marketer. Deregulation has occurred to varying degrees since 1989 in the United Kingdom, Norway, Australia, New Zealand, Chile, Argentina, and about 20 states in the United States. There have been promising results in a few countries and in some U.S. states in some respects, especially lower rates and lower air pollution problems. In most cases, competitive markets have yet to be realized and lower rates can be attributed to other causes, such as previously planned amortization or retirement of expensive power plants, unexpected surplus in natural gas, rate caps, etc. In addition, deregulation has had only a slight beneficial effect on the use of renewable electricity sources. The promise of electric utility deregulation is thus unfulfilled and deserves further study.

Geopolitical considerations have played a major role in many renewable energy policy decisions, e.g., in domestic debates over gasoline taxes, pipeline construction, radioactive waste disposal, and acid rain control legislation in the United States, and in petroleumrelated violence in Nigeria. The most prominent role for geopolitics in energy policy has probably involved international discussions on controlling greenhouse gas emissions, and in oil markets. In the cases of the Kyoto Protocol of 1997 and the 1992 Framework Convention on Climate Change, nations carefully considered their national economic interests, domestic politics, and international trade during the negotiations. European countries, with the lowest rates of population and economic growth along with strong domestic environmental lobbies, have pursued a greater rate of greenhouse gas reduction.

The United States, in contrast, has been stubbornly cautious and backed out of the treaty in 2001 (arguing it is not in its economic best interests), and the oil-rich nations of the Middle East have been least supportive of any emissions controls. In the case of oil markets, with the United States now dependent on imports for over half its supply, energy policy and trade strategy have played major roles in the pursuit of new oil discoveries in Alaska and in warfare in Kuwait, Iraq, and perhaps Afghanistan.

Scientists study Earth’s climate not just from observation but also from a theoretical perspective. Modern-day climate models successfully reproduce the key features of Earth’s climate, including the variations in wind patterns around the globe, the major ocean current systems such as the Gulf Stream, and the seasonal changes in temperature and rainfall associated with Earth’s annual revolution around the sun. The models also reproduce some of the more complex natural oscillations of the climate system. Just as the atmosphere displays random day-to-day variability that we term “weather,” the climate system produces its own random variations, on timescales of years. (more…)

air pollution problems created by coal combustion. Meanwhile, coal-fired power plants and industrial boilers spewed out tons of gaseous and particulate pollutants into the atmo- sphere. During combustion, the small amounts of sulfur and nitrogen in coal combine with oxygen to form sulfur dioxide (SO2), sulfur trioxide (SO3), and the oxides of nitrogen (NOx). (more…)

Fuel cell vehicles are being developed because they promise to meet the requirements expected of automobiles in a market increasingly constrained by environmental and resource limitations. Air pollution and oil dependence have been persistent challenges for vehicles powered by petroleum fuels (gasoline and diesel). Global warming presents a new challenge in the need to limit carbon dioxide (CO) emissions from fossil fuel combustion. (more…)