Plants respond to, and affect, their atmospheric environment. We use integrated measurements obtained at single leaf, single plant, and canopy scales to study these interactions in crops. Plant responses to light and humidity, and developmental control of plant hydraulic conductance, interact with air pollutants to control water use, pollutant uptake, and emission of greenhouse gases. We study the impacts of ozone, fugitive dust, and biofuel production on control of temperature and greenhouse gases.