Delineating Urbanicity\nand Rurality: Impact on Environmental\nExposure Assessment

Environmental exposures and their health impacts can\nvary substantially\nbetween urban and rural areas. However, different methods for classifying\nthese areas could lead to inconsistencies in environmental exposure\nand health studies, which are often overlooked. We constructed different\nurban/rural classification systems based on multiple population-based\n(e.g., total population, population density, and commuting) and built-environment-based\n(e.g., nighttime light intensity, building density, road density,\ndistance to urban centers, point of interest density, and urban area\ncoverage) indicators and various classification schemes. These classification\nsystems were applied to Virginia and West Virginia, United States.\nWe compared differences in urban/rural spatial patterns, demographic\ncompositions, and exposures of particulate matter (PM<sub>2.5</sub>), greenspace, and land surface temperature using these urban/rural\nclassification systems to understand their impacts on environmental\nexposure and health research. Our findings reveal clear differences\nin spatial patterns and demographic compositions across various systems.\nWe also observed that different systems can lead to changes in the\nmagnitude and direction of urban/rural disparities in environmental\nexposure assessment. Addressing the complexities in delineating urbanicity\nand rurality may include careful consideration of classification systems\nto reflect those aspects of urbanicity and rurality that are relevant\nto the research question or the use of multiple, complementary systems.