Board of Health urges lighting controls in data center ordinance; accountability group proposes 0.1 foot-candle limit

Kathy Dolter, chair of the Dubuque County Board of Health, summarized recent observational studies linking artificial night light to suppressed melatonin and associated health conditions. "Does light pollution impact health? I think the general consensus is yes, it does impact health," she said while reviewing model ordinances and evidence.

Steve Peek, representing the data center accountability group, explained the group’s proposed nighttime standard and the epidemiology behind it. "So our allowed level, in the draft ordinance is about 5 times a bright moonlit night," he said, describing the draft's 0.1 foot-candle allowance and noting cohort studies that associated that ambient level with a relative increase in heart-disease risk over a follow-up period. Speakers discussed practical controls—full-cutoff fixtures, motion sensors, timers, limits on luminous color temperature (Kelvin) such as 2,400–3,000 K, and the need for photometric plans and property-line monitoring or continuous dashboards funded by developers.

Board members signaled support for including lighting language from the accountability group's draft in the zoning commission's review. Supervisors and health staff agreed the ordinance language could be used as a working draft, with tracked changes and revisions before formal adoption.