The Health Effects Institute
"A Partnership of the U.S. Environmental Protection Agency and Industry"
HEI Accountability Research
What is Accountability?Recent decades have seen substantial gains in air quality in the US and Western Europe, with visible pollution far less in evidence, and with downward trends in concentrations of several major pollutants. In large part, these gains have been achieved through increasingly stringent air quality regulations which often require costly control measures to implement. Though risk assessments estimate a substantial burden of premature mortality and excess morbidity, even at current ambient pollution levels, evidence is lacking on the extent to which control measures have improved health, prompting efforts to attempt to assess and collect such evidence. Providing evidence that air quality regulations improve public health is part of this broader effort to assess the performance of environmental regulatory policy, an effort that has been termed accountability.
HEI's recent efforts include a monograph entitled, Assessing the Health Impacts of Air Quality Regulations: A Monograph on Concepts and Methods, and epidemiologic studies of the health impacts of actions taken to improve air quality. The monograph, written by a multi-disciplinary group, sets out a conceptual framework for accountability, identifies the types of evidence required by the framework, and the methods by which that evidence can be obtained. Request for Applications (RFA) 04-1 Measuring the Health Impact of Actions Taken to Improve Air Quality, seeks to fund relevant research, including studies that take advantage of the opportunities afforded by imminent regulatory actions.
Targets of Opportunity
Continually changing air pollution regulations in the United States, Europe, and elsewhere offer an immediate set of opportunities for accountability research on national, regional, and local scales over both the short and long terms. As HEI learns of new targets of opportunity for accountability research, we will post them on this page, so that the research community can respond to them in a timely fashion. In the United States, some potential targets include:
Heavy-Duty Diesel/Low Sulfur Fuel Rule
The EPA recently promulgated regulations to reduce heavy-duty diesel-vehicle emissions by reducing fuel sulfur content and implementing emission reduction controls (eg, particle traps and various technologies for reducing nitrogen oxides [NOx]). The regulations include a step change in sulfur content limits for diesel fuel from 500 ppm to 15 ppm effective July 1, 2006, and a more gradual introduction of new vehicles with added controls in model years 2007 and 2010. The anticipated reductions in sulfur content and vehicle emissions due to these regulations provide a context in which accountability could be assessed.
Local interventions
Relatively rapid changes in ambient pollutant concentrations may occur in a localized area as a result of a major change in local source emissions due to regulatory action. Numerous opportunities exist for studies of such interventions throughout the United States and elsewhere. For example, since 2001 the New York City Metropolitan Transit Authority (MTA) has operated its diesel bus fleet using fuel with ultralow sulfur levels and has been phasing in carbon diesel filter trap control technology for those buses. In addition, the MTA has converted portions of its bus fleet from diesel to natural gas. Each of these actions potentially reduces neighborhood levels of diesel-related particle components and thereby potentially affects health outcomes. Control programs for major stationary sources (such as power plants, waste incineration, or industrial facilities) might also offer opportunities for accountability research. Because local interventions occur within relatively compressed temporal and spatial domains, studies that aim to document cause-effect relations between local reductions in emissions and changes in exposure and health outcomes may be economically and logistically feasible.
Implementation of PM2.5 and Ozone National Ambient Air Quality Standards
State implementation plans (SIPs) being developed in the United States could serve as the basis for prospective accountability studies. Such studies could utilize existing ozone measurements and the extensive data on nationwide concentrations of particulate matter less than 2.5 in aerodynamic diameter (PM2.5) that are being collected from a new monitoring network to establish baseline conditions against which future emissions reductions could be assessed. The SIP process could also serve as the basis for comprehensive assessments that address changes in emissions, ambient pollutant concentrations, population exposures or doses, and, ultimately, health outcomes.
EPA’s Air Toxics Control Plan
The EPA is required to assess the health risks and (if necessary) control the ambient levels of 188 hazardous air pollutants, or air toxics. Accountability research concerning these air toxics might include longitudinal measurements of emissions and ambient concentrations and identification of health endpoints that could be tracked in the near term. This approach is probably most suitable for hazardous air pollutants associated with short-term effects (eg, irritant responses for which there are well established biomarkers of personal exposure or effects).
Tier II Regulations for Light and Medium Duty Vehicles and Fuels
Beginning in 2004, and phasing in through 2009, the EPA is implementing a substantial tightening of the current emission standards for light- and medium-duty on-road vehicles. These standards require, among other features, substantial reductions in emissions of volatile organic compounds (VOCs) and NOx, reduction by 2006 of sulfur in gasoline to an average of no more than 30 ppm, and application of the same standards to medium-duty as well as light-duty vehicles. Some of these changes will take place over a long time (ie, at the rate of introduction of new vehicles) whereas others, especially the substantial lowering of sulfur in gasoline, is required to take place over a much shorter interval for all gasoline in the United States.
California Diesel Emissions Reductions Programs
California is implementing a number of programs to reduce emissions from existing and new diesel engines used for on-road, non-road, and stationary purposes. These include funding programs (eg, the Moyers program to fund retrofits and replacements of school buses and other diesel vehicles) as well as a range of regulatory initiatives (California Air Resources Board 2000). These efforts are intended to result in both near-term and longer-term reductions in emissions and exposures.
Other Efforts to Improve Fuel Quality and Fuel Characteristics
Over the past decade, a number of efforts have been taken to improve the characteristics of gasoline. These include, among others, introduction in January 1995 of Reformulated Federal Gasoline in major metropolitan areas (which among other changes required a substantial reduction in benzene content and increase in oxygen content) and, in a number of states, introduction of gasoline with reduced volatility. In addition to these potential retrospective opportunities, recent efforts to reduce use of MTBE as an additive and increase use of ethanol may pose additional opportunities to measure changes in human exposure and health effects.
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Last updated August 26, 2004