Improving Public Health Services through Space Technology and Spatial Information Systems

Every day there are natural and human caused disasters that impact public health and that have adverse impacts on the affected societies and their economic productivity. In addition, there are very subtle, evolutionary forces of global change with profound impacts on human health and well being. Satellites have long been used to illustrate and measure global and regional Earth system processes by observing circulation patterns in the atmosphere and hydrosphere; but, the direct impacts of these patterns on human health have only recently been thrust into “prime time” awareness of the scientific, economic, and policy arenas. Public health infrastructures and mechanisms that link less dramatic environmental events to public health outcomes are just beginning to emerge. Earth system science requirements needed to integrate environmental monitoring with health services rest on (a) verifying, validating, and benchmarking the medical value of spectral and spatial observations for health; and (b), developing decision-support tools that enhance and streamline disease surveillance and information dissemination. This paper describes an effort to link air quality to respiratory health, reviews initiatives that address how data and information can be accessed to improve health services and explain how these services can assist in developing the etiology of air quality factors in health. AIR QUALITY AND PUBLIC HEALTH Public health is defined as the science and art of preventing disease, prolonging life, and promoting health through organized efforts of society (Eisenberg et al., 2001, p.230). It is concerned with populations rather than individuals. Its chief responsibilities are to monitor population health, identify societal health needs, foster policies that promote health, and evaluate health services. A broader definition includes domesticated animal and plant species that are the foundation of food supplies and that also serve as disease transmission pathways. Medical and health communities recognize five broad categories of diseases: (1) infectious and zoonotic, e.g. AIDS, TB, influenza, gastroenteritis, plague; (2) degenerative, e.g. arteriosclerosis; (3) environmental, e.g. asthma, cholera, meningitis, malaria, yellow fever; (4) neoplastic, e.g. cancer; and (5), metabolic, e.g. diabetes. This paper concentrates on environmental and selected zoonotic diseases whose origins or transmission pathways depend on airborne mechanisms. Public health officials are only partly concerned with the effects of air quality on populations, and these must be considered in context of other risk factors that link demographics, life style, socioeconomic status and nutrition, access to health care, exposure rates, and genetic heritage (Dearry, 2005; Brilliant, 2007). Doctors and public health officials are aware of environmental factors in health, but the day-to-day pace of data and information-gathering procedures in hospital admissions and emergency room visits seldom Erice International Seminars on Planetary Emergencies, 40 Session, Aug. 19-24, 2008 2 leave time for referencing factors that might have triggered a respiratory or cardiovascular outcome. Finding the smoking guns requires working at the interface between two communities of practice: environmental health and public health. This is precisely where there is too little infrastructure, too few trained personnel, and too little time to fully assess causes and effects (etiology). Physicians, school nurses, emergency responders, clinicians, and others in healthcare professions have been trained to diagnose their patient’s “chief complaints,” not necessarily to inquire about that person’s physical whereabouts or duration of a possible exposure. There is also a need to integrate geospectral and geospatial data into digital systems that allow health professionals to access reliable environmental data for more in-depth diagnoses, and that enable issuance of public health alerts (Lang, 2000; Morain and Budge, 2006; Griffin, 2007; Morain and Budge, 2008). Relating air quality to human health There is a rich literature linking airborne contaminants to health outcomes (see, for example: Bar-Ziv and Goldberg, 1974; Policard and Collet, 1952; Norboo et al., 1991; Gloster and Alexandersen 2004; Vineis 2004; Wu et al., 2004; Yu et al. 2004; Becker et al., 2005; Cringoli et al. 2005; Grattan et al. 2005; Park et al., 2005a; Sulaiman et al. 2005; Selinus et al. 2005; Kuehn, 2006; and, Schlesinger et al. 2006). Public health is impacted by exposures to airborne toxic gasses, microscopic mineral and chemical substances, and by organisms bound onto air particles (Kellogg et al., 2004; Stetzenbach et al., 2004; Kaiser, 2005; Griffin, 2007; Griffin et al., 2007). An individual’s health is determined by complex interactions between genetic factors and environmental factors. Many of the latter represent the pathways for transmitting infectious or contagious diseases throughout whole populations. Moreover, prolonged exposures to injurious air quality events such as dust storms, high-levels of smoke and industrial emissions, and toxic gas emissions exacerbate chronic obstructive pulmonary diseases (COPD aka COL[ung]D), allergic reactions, and a host of respiratory conditions affecting particular age groups within a population (Pope, 2004; Zanobetti and Schwartz, 2005). The annual toll of these air quality impacts on public health directly affects every nation’s health care facilities, GDP, and quality of life (Schmidt, 2005). Moreover, there is ample evidence that the toll is rising because of global changes in climate variability, land-use, economic development, population dynamics, and technological advances ( Sultan et al., 2005; Park et al., 2005b). Consequently, air quality and public health are highly intertwined and complex, especially in context of global change (Varmus et al, 2004; Park et al., 2005b). Figure 1 shows avenues that airborne biological contaminants use to spread across environments. Clearly, air quality is a critical environmental variable for health officials because atmospheric circulation patterns and modern commercial jet aircraft can expose populations to chronic, and sometimes lethal, contaminants anywhere and anytime. Erice International Seminars on Planetary Emergencies, 40 Session, Aug. 19-24, 2008 3 Figure 1. Particulate size distribution and related biophysical impacts. Modified from Kaiser (2005). Connecting satellite data to human health Public health cannot be monitored directly from environmental sensors because disease transmission pathways are seldom direct. However, environments that harbor potential health threats can be observed by sophisticated sensors operating in space. Through the accumulated literature, it is clear that long term, systematic air quality monitoring from integrated sensor systems is needed by medical and health professionals to determine the etiology and epidemiology of respiratory diseases. Air quality data for dust, aerosols, volcanic ash, and smoke from fires have been collected for over four decades by progressive generations of space sensors. It is apparent now that the northern mid-latitudes are home to growing numbers of emerging and re-emerging infectious diseases (Epstein, 1997; Binder et al., 1999; Gauderman et al., 2004; Morens et al., 2004; Fauci et al. 2005; Gyan et al., 2005; WMO, 2005; Kuske, 2006), and that an integrated global observing strategy is required to monitor these changing patterns (Kennel et al., 1997; Morain and Budge, 2008). The most heavily populated areas of North America, Western Europe, and Japan represent a triple threat because they have the highest concentration of air travelers to global destinations; are home to societies adding the highest concentrations of industrial emissions and biological contaminants into the air; and comprise the hemisphere over which there is measureable evidence for global change. Satellite data confirm the existence of a persistent ring of hemispheric aerosols around the northern mid-latitudes contributed by industrialized societies. The Earth’s wind and ocean circulation systems also play a role in raising the rates of respiratory diseases like chronic asthma, myocardial infarction (MI), tuberculosis, severe acute respiratory syndrome (SARS), and influenza. Dust storms so large that they can be animated using time-series satellite imagery can be seen to move across Asia toward North America. Similarly, dust entrained by winds over North Africa can be carried to the Caribbean. These phenomena have captured the attention of the World Health Organization (WHO), the International Council for Science (ICSU), and the Group on Earth Observations (GEO). While the medical community recognizes the adverse effects that dust, smoke, and ash can have on a population, they have lacked timely and reliable information for issuing warnings or implementing mitigation programs. WMO is proceeding to develop an International Sand and Dust Storm Warning and Assessment System (ISDSWAS) to alert governments and health officials of pending environmental episodes through a network Erice International Seminars on Planetary Emergencies, 40 Session, Aug. 19-24, 2008 4 of interactive and interoperable data centers. For its part, members of GEO are implementing GeoNetCAST as an element of the Global Earth Observing System of Systems (GEOSS) to broadcast and communicate weather information to authorities at the local level. Technologies for making air quality measurements continue to improve, but the data and observations themselves are not systematically stored for retrieval and medical research. Science, technology, and policy communities face huge challenges in capturing and storing air quality data, of modelling complex biological, chemical, and physical processes that impair health, and in helping to find reliable measures for tracking health outcomes in populations (ICSU Scoping Group, 2007). Biogeochemical and dynamical processes of airborne pathogens and pollutants must be vigorously researched so that epidemiologists can begin to understand the medical consequences of air masses traversing regions and continents. What is needed, moreover, are long term archives of global air quality data and information for use in longitudinal studies of sentinel populations. Another equally challenging research area is to translate findings into actionable human health mitigations and policies that protect populations at risk. The grand challenge is to add health professionals into efforts that merge environmental surveillance with human health syndromes. Health surveillance systems Health decisions are always based on the best available information. One challenge for integrating air quality data and information into routine public health practices is to develop systems that constantly monitor conditions that trigger health responses. Environmentally induced risks having either PM2.5 (respirable) or PM10 (inhalable) respiratory outcomes are a growing international concern. In some cases authorities rely on reports received at clinics, hospitals, and other care facilities. Others access databases having information on syndromes and outbreaks in local areas and across regions. Only a few assess environmental conditions at the global scale (Westphal et al., 1987 and 1988; Goudie et al., 2001). Decision support systems that provide early detection and analysis of environmental events enhance the ability of officials to warn populations at risk. In future, solutions to health surveillance systems will need to integrate environmental data that characterize complex physical and biogeochemical processes thought to have health consequences. The next generation of modellers may well be required to form teams of collaborating partners from the biogeophysical sciences with those from the medical sciences to assess changing and highly variable situations. Several pioneering surveillance systems are being developed that provide electronic access to spatial and environmental data and information on diseases and syndromes. Two of these are the Syndrome Reporting Information System (SYRIS) by ARES Corporation, and the Environmental Public Health Tracking Network (EPHTN) by the Centers for Disease Control and Prevention in the USA. Both have enhanced their system’s utility by incorporating mapping, visualization, and analytical tools. However, the use of these tools is only slowly evolving because public health communities do not routinely use spectral or spatial data and information in their daily work flows. There are two reasons for this. Users need assurance that: (a) these new and (to them) exotic inputs are accurate and reliable for use in health decisions; and, (b) data and information can be provided in timely electronic form without demanding additional processing for a work environment that is already overloaded. To address these issues, the Public Health Applications in Remote Sensing (PHAiRS) project is developing an application framework to enhance existing public health decision support systems. 1 Jointly executed by the University of New Mexico’s Earth Data Analysis Center, the University of Arizona’s Institute for Atmospheric Physics, and the University of Malta’s DREAM modeling team. Erice International Seminars on Planetary Emergencies, 40 Session, Aug. 19-24, 2008 5 ENVIROMENTAL/HEALTH MONITORING: A Description of PHAiRS