Preserving Natural Skies in Alachua County: Light Pollution Mitigation and Economic Impact

Artificial light at night (ALAN) is an accelerating environmental stressor in Alachua County, Florida, with measurable growth in skyglow and expanding illuminated areas. This presentation summarizes an independent, citizen-science assessment that combines satellite remote sensing, local sky-quality context, and a policy-and-economics roadmap for mitigation. Using AI-assisted comparison of 2012–2024 VIIRS nighttime imagery, overall brightness is estimated to have increased by 19%, while the area above a fixed brightness threshold expanded from 16% to 21%, indicating a wider skyglow footprint; estimated glow increases include Gainesville (+6%), Alachua (+10%), and the Paynes Prairie vicinity (+15%). Current conditions place Gainesville’s urban core near Bortle 7 (Milky Way largely invisible), while Paynes Prairie and Rosemary Hill Observatory are approximately Bortle 4, with prominent light domes threatening ecological and educational assets. The impacts of ALAN are framed across ecology (including fireflies, moths, frogs, bats, and migratory birds), human health (circadian disruption), economical effects of ALAN (crops such as soybeans and corn, beef cattle, and equine breeding) and public safety through disability glare. Mitigation is organized around Dark Sky International’s five principles (useful, targeted, low level, controlled, warm-colored) and implementable policy levers (full-cutoff fixtures, warmer CCT limits, adaptive dimming/curfews, and intensity reduction).

A scenario model “Dark Sky Simulator” estimates that comprehensive county-wide mitigations could improve Paynes Prairie from Bortle 4 to 2 and Gainesville urban areas from Bortle 7 to 3, with an estimated 15 million initial investment and 480k annual maintenance, yielding 2.4M/year energy savings (1.9M net) and ROI in 7-8 years. The presentation concludes with recommended first steps for Alachua County Environmental Protection Advisory Committee (EPAC) in 2026: initiate a county dark-sky program, complete a lighting inventory, draft model ordinance language, deploy public education, and launch pilot retrofit zones.

Keywords: light pollution; ALAN; skyglow; dark-sky policy; outdoor lighting standards; urban planning; Paynes Prairie; Alachua County; energy savings; glare; astro-tourism