People with asthma who live near or downwind from a source of toxic emissions commonly express concerns about the possible impact of hazardous air pollution on their health, especially when these emissions are visible or odorous. Citizens frequently turn to their local and state health departments for answers, but health departments face many challenges in addressing these concerns. These challenges include a lack of asthma statistics at the local level, limited exposure information, and a paucity of scientific knowledge about the contributions of hazardous air pollutants to asthma induction or exacerbation. Health agencies are creatively developing methods to address these challenges while working toward improving asthma surveillance data at the state and local levels. Recent community health investigations suggest that hazardous air pollutants that are occupational asthmagens or associated with odors may deserve more attention. In seeking to address community concerns about hazardous air pollution and asthma, community health investigations may also help to fill gaps in our scientific knowledge and identify areas for further research or environmental intervention. The solutions to community problems associated with environmental contamination and asthma, however, require sustained, coordinated efforts by public and private groups and citizens. Public health agencies can make a unique contribution to this effort, but additional resources and support will be required to develop information systems and epidemiologic capacity at the state and local levels. Key words: asthma; air pollutants, environmental; epidemiology; hazardous waste sites; odors; population surveillance.

Health Investigations Branch, Division of Health Studies, Agency for Toxic Substances and Disease Registry, USA As a public health agency within the US Department of Health and Human Services, the Agency for Toxic Substances and Disease Registry (ATSDR) is responsible for implementing the health-related provisions of the Superfund Act. Much of its work is carried out to address health concerns in communities near sources of environmental contamination, usually in consultation with other local, state, and federal agencies. Over the last decade, ATSDR has considered, supported or conducted health investigations in a variety of different communities across the country. Communication with community residents has been an integral part of the process in all of these activities. The approach to communicating results needs to begin early by developing relationships and clarifying expectations, and it needs to remain flexible. Through examples taken from specific situations, we illustrate many of the lessons we have gained from trying to apply the principles of good community involvement to the design and conduct of health investigations and to the communication of study results.