Linking Nitrogen Oxide Emissions and Future Urban Growth: How Present Day Land Use Development ChoicesInfluence Future Emissions

Abstract

The world’s population is becoming increasingly urbanized, with 66% of the global population expected to reside in urban areas by 2050. City planners and policy makers must consider how cities can accommodate such growth to minimize the city’s contribution to climate change through greenhouse gas emissions and the consumption of ecologically valuable and agriculturally productive lands. On a regional scale, the horizontal expansion of urban areas creates fragmentation of agricultural lands and endangers vulnerable plants and animals by encroaching upon natural habits and biodiversity corridors The concentration of transportation networks and industry in heavily urbanized areas cause cities to point sources of pollution on a global scale. Numerous polluting gases that can lead to climate change are produced in cities: sulphur dioxide, carbon dioxide, volatile organic carbons, and nitrogen oxides. Nitrogen oxides, produced largely through the combustion of fossil fuels in automobiles, are of particular concern as they lead to a host of other gases that pose significant risk to human and environmental health. The projected growth of cities has already been modeled with consideration for agriculture lands, urban sprawl and biodiversity, but the emissions associated with the changes in land use associated with such growth have not been thoroughly investigated. A land-use regression (LUR) model can be utilized to calculate future NO2 emissions associated with changes in land use in an urban setting. For Los Angeles County, nine predictor variables on five spatial scales were selected to be correlated to the two-week average NO2 concentrations. The developed LUR model was used to calculate NO2 emissions for five future growth scenarios for Los Angeles County. The Smart Growth scenario demonstrated the lowest average NO2 concentration, suggesting that city development constrained to already urban areas will preserve green spaces that reduce emissions and restricts the urban sprawl associated with higher NO2 emissions. However, urban density was not included in this study and could play a vital role in determining NO2 emissions on a finer spatial scale.