1. Abstract The alteration of the natural nighttime environment due to artificial light at night (ALAN) can disrupt ecological systems and affect human health. Inefficiencies in lighting use have downstream consequences for climate, economies and health. High resolution, regional-scale data of the nighttime environment is not readily available yet is necessary to address this issue. Mapping light emissions from a stratospheric balloon platform provides data of sufficient quality to further our understanding of the impacts and possible solutions to this health and environmental stressor. For this work, we designed and flew instrumentation on latex high altitude balloons for remote sensing of nighttime lights. We collected tens of thousands of images across an urban to rural footprint centered on the city of Indianapolis, Indiana (Fig. 1). Our results indicate land zoned for commercial use contributes 20.5% of all light emissions while only comprising 7% of land area. These results also corroborate an earlier study that road lighting contributes only an estimated 14% of total emissions, where our study shows a contribution of 24.3%, including other light sources on the roads. Comparing on-orbit observations from the VIIRS instrument to those collected with our method (Fig. 2), we can estimate the quantity of light unaccounted for due to the short (blue) wavelength insensitivity of the VIIRS sensor. This method can identify sources of light pollution on a regional scale. Our results indicate policy addressing commercial lighting may be the most efficient mitigation strategy in developed areas.
