Effect of land cover change on future air Quality in Atlanta

Atmospheric modeling systems (i.e., meteorological, air quality and emissions models) are being extensively used to study air pollution problems over urban and regional domains. Federal, state, and local agencies use these systems to develop and analyze emission control strategies aimed at improving air quality in regions of interest. Generally, meteorological conditions are held constant as mass emission rates are adjusted to reflect future changes in emissions. While this strategy is probably well suited for predicting relative change in air quality over shorter planning periods, land use/land cover changes that occur over longer time frames (i.e., 10 years or more) can have a significant effect on local meteorology, and our assessment of future air quality. We analyze the effect of land cover change on air quality in the metropolitan Atlanta area. Land cover changes up to year 2030 are predicted using a Spatial Growth Model (SGM). A rule-based model, SGM simulates growth around a region using population, employment and travel demand forecasts. Atmospheric modeling simulations were conducted using both current and future land cover. Meteorological modeling simulations indicate a 0.5 °C increase in surface temperatures and enhanced vertical mixing. Air quality modeling simulations show substantial differences in relative contribution of individual atmospheric processes as a result of land cover change. Enhanced mixing tends to offset the increase in ozone concentration expected due to higher surface temperatures as a result of urbanization. Land cover induced changes in meteorological and air quality fields were substantial enough to necessitate emission sensitivity simulations for some major sources and source categories located in the region.