Patterson said light pollution affects animals, the environment and humans. Turtles, birds, bats and fireflies can be affected by excessive lights. Sea turtle hatchlings are disoriented by lights and may not make it out to sea, and birds can be confused by lights in migration and end up flying into buildings. Trees can bud at the wrong times, lose leaves later in the year, and can have shorter lifespans due to artificial lights, he said.

Human health, he said, can be affected in terms of circadian rhythm and melatonin creation, both impacting sleep.

“Another issue, which doesn’t often get acknowledged, is just the equity issue in terms of where the impact of artificial light falls most heavily is in cities,” Patterson said. “It’s often where you find areas of poverty. People then have no access to the night sky, just as part of their heritage, as mankind’s inheritance, and also suffer the health effects, as well.”

Color also matters, he said, as blue light scatters more than red light.

“It’s not too late for anyone if we dismantle everything, but it’s not too much that we have to reverse in order to get things better,” he said.