Robert F. Phalen

Air pollution and health: bridging the gap from sources to health outcomes: conference summary

Abstract“Air Pollution and Health: Bridging the Gap from Sources to Health Outcomes,” an international specialty conference sponsored by the American Association for Aerosol Research, was held to address key uncertainties in our understanding of adverse health effects related to air pollution and to integrate and disseminate results from recent scientific studies that cut across a range of air pollution-related disciplines. The Conference addressed the science of air pollution and health within a multipollutant framework (herein “multipollutant” refers to gases and particulate matter mass, components, and physical properties), focusing on five key science areas: sources, atmospheric sciences, exposure, dose, and health effects. Eight key policy-relevant science questions integrated across various parts of the five science areas and a ninth question regarding findings that provide policy-relevant insights served as the framework for the meeting. Results synthesized from this Conference provide new evidence, reaffirm past findings, and offer guidance for future research efforts that will continue to incrementally advance the science required for reducing uncertainties in linking sources, air pollutants, human exposure, and health effects. This paper summarizes the Conference findings organized around the science questions.A number of key points emerged from the Conference findings. First, there is a need for greater focus on multipollutant science and management approaches that include more direct studies of the mixture of pollutants from sources with an emphasis on health studies at ambient concentrations. Further, a number of research groups reaffirmed a need for better understanding of biological mechanisms and apparent associations of various health effects with components of particulate matter (PM), such as elemental carbon, certain organic species, ultrafine particles, and certain trace elements such as Ni, V, and Fe(II), as well as some gaseous pollutants. Although much debate continues in this area, generation of reactive oxygen species induced by these and other species present in air pollution and the resulting oxidative stress and inflammation were reiterated as key pathways leading to respiratory and cardiovascular outcomes. The Conference also underscored significant advances in understanding the susceptibility of populations, including the role of genetics and epigenetics and the influence of socioeconomic and other confounding factors and their synergistic interactions with air pollutants. Participants also pointed out that short- and long-term intervention episodes that reduce pollution from sources and improve air quality continue to indicate that when pollution decreases so do reported adverse health effects. In the limited number of cases where specific sources or PM2.5 species were included in investigations, specific species are often associated with the decrease in effects. Other recent advances for improved exposure estimates for epidemiological studies included using new technologies such as microsensors combined with cell phone and integrated into real-time communications, hybrid air quality modeling such as combined receptor- and emission-based models, and surface observations used with remote sensing such as satellite data.

Macroscopic to microscopic scales of particle dosimetry: from source to fate in the body

Additional perspective with regards to particle dosimetry is achieved by exploring dosimetry across a range of scales from macroscopic to microscopic in scope. Typically, one thinks of dosimetry as what happens when a particle is inhaled, where it is deposited, and how it is cleared from the body. However, this paper shows a much more complicated picture starting with emissions sources, showing how the source-to-intake fraction (iF) can be used to estimate changes in the inhaled dose due to changes in emissions and then ending with particle–liquid, particle–cellular and subcellular interactions, and movement of ultrafine particles across the lung–blood barrier. These latter issues begin to suggest mechanisms that can lead to adverse health effects; the former can provide guidance to policy decisions designed to reduce the health impact of atmospheric particles. The importance of ultrafine particles, their ability to translocate to other parts of the body, and the potential impact of these particles has advanced significantly over the last decade, including studies that show the movement of ultrafine particles along the olfactory nerves in the nose with direct transport to the brain, the neurological effects of which are still unknown. Incremental advancements continue with regards to understanding particle deposition, including regional and local deposition (including hot spots) and clearance and the factors that affect these variables, in part due to the development and implementation of computational fluid dynamics (CFD) models and digital imaging of the lungs. CFD modeling will continue to provide new information for reducing uncertainty in dosimetric calculations. We understand better today how a number of diseases may develop based on the fate of particles after deposition in the respiratory track and how changes in source emissions might impact that dose. However, a number of uncertainties remain, some of which can be reduced by addressing the research needs stated in this paper.

Generation and Characterization of Complex Gas and Particle Mixtures for Inhalation Toxicologic Studies

Laboratory toxicology studies of the relative potencies of complex, polluted urban atmospheres have been surprisingly slow in confirming results observed by epidemiologists, that is that air pollution can seriously affect human health. The responses of human volunteers and laboratory animal models after exposure to single compounds and simple mixtures of compounds observed in plumes and ambient air are not sufficiently intense to explain the respiratory morbidity and mortality associated with serious air pollution exposure excursions. Yet there is little doubt that during severe episodes such as those that occurred in London in 1952 or in Donora, PA in 1948 some components present in the air were responsible for the observed respiratory- related illnesses and deaths.

Unsolved Problems: Our Brave New World

Unsolved ethical problems and dilemmas can be sorted into several areas: genetic science and engineering, fertility, euthanasia, life extension, terrorism, privacy, virtual worlds, artificial intelligence, and complex systems. The driving factors include the benefits to patients and others, technological advances, and the increasing complexity of societies. Fears of terrorist acts, loss of autonomy, and loss of privacy complicate the future. Simple solutions to the dilemmas are not possible. Some basic ethical issues include privacy and individual freedoms, equitability and justice, public safety and security, and the consent of those affected.

Regulations, Guidelines, and Policies

This chapter presents an overview of ethics-related regulations, guidelines, and policies for health professionals. Such rules have several purposes; to improve professional competence, to fix perceived problems, to protect research subjects, and to protect the promulgators. For those affected, “compliance” is also a goal. On the other side, such rules can be cumbersome, confusing, and sometimes interfere with scientific progress and the introduction of new medical advances. This chapter covers clinical trials, epidemiological studies, clinical practice, human studies, laboratory animal research, publication ethics, and general scientific investigations. Failure to follow the rules can result in censure, loss of funding, denial of promotions, fines, and in some cases incarceration.

Philosophical and Practical Ethics

The vocabulary of ethics includes a specialized terminology and unique concepts; both are important if one is to understand the topic. Ethics has both theoretical and practical aspects. Theoretical (also formal) ethics has a long history, beginning in ancient times. Prominent philosophers and religious writers have made important contributions that affect modern professionals. In contrast, practical ethics includes both the study of how people actually behave and the rules, such as codes of conduct, that professionals must follow to maintain their status and privileges. Codes of conduct solidify the ethical expectations for health professionals, their specialties and subspecialties. This chapter provides a basic ethics foundation, and thus it is a point of departure for further exploration.

Scandals and Their Legacies

Science and medicine are not immune to scandals. Abuse of patients and research subjects, falsification of data, lying about conflicts of interest, and plagiarism occur. In some cases violations have been unintentional (e.g., due to mistakes or negligence). In other cases the motivations have included personal fame, professional advancement, wealth, cynicism, or the drive to achieve a goal for which the ends justify the means. Iconic scandals – World War II Nazi experiments, Tuskegee Syphilis Study, Guatemala Syphilis Studies, Willowbrook Hepatitis Study, and the UCI Fertility Clinic Scandal are analyzed. Personal integrity and following accepted professional ethical standards are some of the means of avoiding scandals. Institutions have responsibilities for establishing and enforcing ethics requirements and for providing access to ethics training

Crimes Against Science, Scientists, and Health Professionals

Crimes against science include attacks triggered by ethnicity, religious beliefs, research results, or normal professional behaviors. Persecutions come from governments, institutions, organizations, and individuals. Science continues to be a target because it is: (1) both important, and a powerful force of change; (2) not well understood by the public; (3) portrayed unfavorably; and (4) not well defended by scientists. Science and scientists are defended by organizations, and by individuals who risk their own security. Academic freedom is essential for the advancement of knowledge and the public good, but such freedom has responsibilities that must be recognized. The future is clouded by national instabilities, the intrusion of politics into science, litigation and legislation, and the actions of extremists. As a result, scientists, and other professionals have educational obligations.

A Better Future (A Survival Guide)

By considering past ethics-related scandals, one sees that even well-meaning professionals are not immune to damaging accusations. The methods for preventing and surviving accusations of ethics violations are varied. Foremost is staying competent and operating within a code of conduct for one’s profession. Beyond professional competence, ethics training, consultation with advisors, knowing the applicable laws, and developing protocols to follow should be considered. When one is accused, a clear and honest defense will be required. Documentation of training and getting early advice from others that understand your situation are helpful. In some cases media training is advised. Staying abreast of changes in one’s profession and preventing ethics-related problems are part of what makes a professional career satisfying and rewarding.

Compliance and Online Training

As ethics training for health professions is largely done online, online safety is an important consideration. Trusted information technologists provide essential up-to-date advice and service related to online activities. Training content is determined by regulations and policies, as is the frequency of retraining and its documentation. The usual goals of training are to improve competence, to achieve compliance, and to modify behaviors. Specializations have differing training requirements; physicians need state-mandated continuing medical education (CME), registered nurses need similar continuing education (CE), persons involved in clinical trials must meet FDA requirements, and researchers require training in human and animal subject research and publication ethics.