This technical resource document describes several methods for preparing a site-specific risk assessment for a source (i.e., a single emission point within one facility), a group of sources (i.e., multiple emission points within one facility), or a group of similar facilities (e.g., within the same source category) that emit(s) toxic air pollutants. Air toxics may be emitted from power plants, factories, cars and trucks, and common household products. Sources that stay in one place are referred to as stationary sources. Vehicles and other moving sources of air pollutants are called mobile...

(Main) This resource document is the first in the Air Toxics Risk Assessment (ATRA) Library series. It presents an overview of the overall process and tools for evaluating cumulative risk from multiple air toxics emitted from sources at the community level and developing and implementing risk reduction activities to bring about meaningful environmental change. Volume 1: Technical Resource Manual discusses the overall air toxics risk assessment process and the basic technical tools needed to perform these analyses. The manual addresses both human health and ecological analyses. It also...

(Appendices) This resource document is the first in the Air Toxics Risk Assessment (ATRA) Library series. It presents an overview of the overall process and tools for evaluating cumulative risk from multiple air toxics emitted from sources at the community level and developing and implementing risk reduction activities to bring about meaningful environmental change. Volume 1: Technical Resource Manual discusses the overall air toxics risk assessment process and the basic technical tools needed to perform these analyses. The manual addresses both human health and ecological analyses. It also...

This Manual is designed to support the new efforts that communities and neighborhoods across the nation are making to improve the environmental quality and health of the places where they live and work. Efforts to understand and improve air quality are a key part of this work to create healthy local environments. But many communities have found the work to understand and improve local air quality to be complex and difficult. Even regulatory agencies with expertise may have difficulty answering community questions regarding the combined impacts of releases from multiple sources. While some...

Natural gas plays a key role in our nation's clean energy future. The United States has vast reserves of natural gas that are commercially viable as a result of advances in horizontal drilling and hydraulic fracturing technologies, which enable greater access to gas in rock formations deep underground. These advances have spurred a significant increase in the production of both natural gas and oil across the country. Responsible development of America's oil and gas resources offers important economic, energy security, and environmental benefits. However, as the use of hydraulic fracturing has...

Natural gas plays a key role in our nation's clean energy future. Recent advances in drilling technologies-including horizontal drilling and hydraulic fracturing-have made vast reserves of natural gas economically recoverable in the US. Responsible development of America's oil and gas resources offers important economic, energy security, and environmental benefits. Hydraulic fracturing is a well stimulation technique used to maximize production of oil and natural gas in unconventional reservoirs, such as shale, coalbeds, and tight sands. During hydraulic fracturing, specially engineered...

This report reviews the current state of knowledge on the transport and fate of MTBE in ground water, with emphasis on the natural processes that can be used to manage the risk associated with MTBE in ground water or that contribute to natural attenuation of MTBE as a remedy. It provides recommendations on the site characterization data that are necessary to manage risk or to evaluate monitored natural attenuation (MNA) of MTBE, and it illustrates procedures that can be used to work up data to evaluate risk or assess MNA at a specific site. The U.S. Environmental Protection Agency is charged...

The U.S. Environmental Agency (EPA) is charged by Congress with protecting the nation's land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading to a compatible balance between human activities and the ability of natural systems to nurture life. To meet this mandate, EPA's research program is providing data and technical support for solving environmental problems today and building a science knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect our health, and...

Under the Chemical Safety Information, Site Security and Fuels Regulatory Relief Act, the President delegated to the Administrator of the U.S. Environmental Protection Agency (EPA) the task of assessing the incentives for reduction in accidental chemical releases created by public disclosure of off-site consequence analysis information. This document reports the results of EPA's assessment. In the wake of the chemical tragedy in Bhopal, India, and a series of large chemical accidents in the U.S. in the late 1980s, Congress added new provisions to the Clean Air Act for the prevention of...

Climate change, interacting with changes in land use and demographics, will affect important human dimensions in the United States, especially those related to human health, settlements, and welfare. The challenges presented by population growth, an aging population, migration patterns, and urban and coastal development will be affected by changes in temperature, precipitation, and extreme climate-related events. In the future, with continued global warming, heat waves and heavy downpours are very likely to further increase in frequency and intensity. Cold days and cold nights are very likely...