Population patterns

The modeling package, delivered to the EPA, includes nationwide data bases for emissions, dispersion meteorology, and population patterns. These data are used as input for a Gaussian plume model for point sources and a box model for urbanwide area sources. Prototype modeling is used for point sources that are too numerous to define individually. Building wake effects and atmospheric chemical decay are addressed. 

Each of the main risk analysis elements consists of three interactive studies. Exposure estimates result from the integration of pollutant dispersion patterns and human population patterns. The dispersion patterns, in turn, result from the joint action of emissions and dispersion processes. 

The appropriate time and space scales are imposed by estimated health effects functions, source and population patterns, data quality and availability, and by the user s information needs. These constraints have led to a wide range of analytical approaches. 

In many risk analyses standard dispersion models, available from the EPA for regulatory compliance purposes, are used to compute concentration patterns for prototypes of a class of sources, and the patterns are convolved with population patterns that are characteristic of the source sites (5, 6). A similar level of analysis detail that relies on measured pollutant (ozone) concentration in each county of the Northeast Corridor rather than on modeled concentrations was used by Johnson and Capel ( 7). 

Estimation of the population pattern over the area of each computed concentration pattern. 

Computation of sums of products of the concentration and population patterns to provide exposure/dosage... 

For major point sources, site-specific population patterns were extracted from U.S. Census Bureau files using data at the Enumeration District/Block Group (ED/BG) level. These data provide the finest resolution of population patterns available. The data were scaled from 1970 to a base year of 1978 using county growth factors published by the Census Bureau. Interpolations of population and concentration patterns were used to develop patterns of exposure/dosage that were then summed to produce source-specific exposure/dosage totals. 

Anderson, T.J.C., Romero-Abal, M.E. and Jaenike, J. (1993) Genetic structure and epidemiology of Ascaris populations patterns of host affiliation in Guatemala. Parasitology 107, 319-334. 

On the basis of maternal hair concentration, the third study (conducted in the Seychelles) did not find any association between prenatal methylmercury exposure and adverse neuro-psychologic effects (Myers et al. 2003). Reasons for the discrepancies are not known but have been suggested to include differences in the child s age at testing, genetic susceptibilities of the populations, patterns of exposure (episodic vs continuous), and coexposure to polychlorinated biphenyls in the Faroes but not Seychelles populations (Rice et al. 2003). 

Many of the insects have a cyclical population pattern. 

M.B. Schenker of Institute of Toxicology, University of California Davis in Davis, California is leading a multidisciplinary study supported by National Cancer Institute (NCI). This study will examine whether environmental asbestos deposits in California are associated with increased rates of mesothelioma. The study will address geological occurrence of asbestos and potential human exposure based on population patterns and known occupational exposure, and epidemiological characteristics of the disease in the state. The project will plan a case-control study to rigorously test the hypothesis that mesothelioma in California is independently associated with environmental asbestos exposure. 

INTERACTIONS AMONG CONIFER TERPENOIDS AND BARK BEETLES ACROSS MULTIPLE LEVELS OF SCALE AN ATTEMPT TO UNDERSTAND LINKS BETWEEN POPULATION PATTERNS AND PHYSIOLOGICAL PROCESSES... 

Nevo, E. 1978 Genetic variation in natural populations patterns and theory. Theoret, Pop, Biol, 13, 121-177. 

Rowland, R. H. (2001). Regional population change in Kazakhstan during the 1990s and the impact of nationality population patterns Results from the recent census of Kazakhstan. Post-Soviet Geography and Economics, 42( ), 571-614. 

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