How the way we build cities and communities affects the quality of the air that we breathe.
Poor air quality is still a major issue affecting a large number of Americans. In new research, Nikhil Kaza and Josh McCarty write that how urban areas are laid out can make a difference to local air quality.
Using remote sensing data for continental United States, they find that both sprawling cities and mixed urban and rural counties are more associated with poor air quality. The more fragmented communities are, the worse the local air quality. They argue that increasing the amount of forest cover near to these areas will help to improve air quality.
More than 40 percent of Americans live in parts of the country where air pollution levels are dangerously high. But what determines where is the most affected by air pollution? A location’s air quality depends on a number of factors including pollutant sources, meteorology and landscape features such as basins. Different pollutants have different spatial spillovers and have differential effects on human health. Thus it is useful to understand the impact of various factors in air quality. The configuration and composition of urban area is an important determinant of air quality. In recent research, we demonstrate how patterns such as leapfrog development and the mixing of urban and forest land uses have an impact on air quality.
We expect the urban form to influence air quality in a number of ways. A sprawling urban spatial structure is associated with larger amount of travel, especially by car, which in turn has an effect on particulate matter emissions and pre cursors compounds to Ozone. Building configurations and tree cover in an urban area in turn influence atmospheric chemistry and affect local pollutant levels. Impervious cover impacts Ozone formation. However, very few studies have established the relationship between urban form and air quality for different levels of urbanisation.
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How the way we build cities and communities affects the quality of the air that we breathe
About the authors
Nikhil Kaza – University of North Carolina at Chapel Hill
Nikhil Kaza is an Associate Professor in the Department of City and Regional Planning at the University of North Carolina at Chapel Hill. He studies the phenomena of plans and their uses in public and private decision-making. Of particular interest are urban development processes, energy planning and land use impacts. His research seeks to analyse the motivations and plans of multiple intentional actors endowed with limited capabilities, imperfect foresight and distributed authority in urban settings.
Josh McCarty – Urban3
Josh McCarty is Urban3’s Chief Analytics Researcher and resident Geo-Accountant. Geo-Accounting, a portmanteau of geography and accounting, is inspired by the foundational geodesign work of those such as Ian McHarg. Just as geodesign seeks to improve design through spatial awareness, Josh’s work focuses on new ways to visualize local finance. His work focuses on the relationship between patterns of development and economics.
This article is based on the paper “Urban Form and Air Quality in the United States” in Landscape and Urban Planning.