Pomps Pond closed and every outdoor youth sports program in Andover moved indoors Thursday, as wildfire smoke drifting down from Ontario pushed air quality into unhealthy territory across the Merrimack Valley. In North Andover, the Recreation Department kept early-morning summer programs running but shifted youth sporting events inside as conditions worsened through the day.

Andover Recreation Director Joe Connelly spent Wednesday at the pond, where about 50 people turned out for a youth concert and others paddle boarded under what he called a "weird orange glow." Residents weren't rattled by the haze itself, Connelly told the Eagle-Tribune — they just wanted to know what it meant for the schedule. "Most people are looking up at the sky right now and seeing that orange haze, wondering what is going on," said Caitlyn Mensch, a meteorologist with the National Weather Service in Norton, describing the scene that day.

Throughout Wednesday, Connelly fielded a steady stream of parent emails and calls about the evening concert and Thursday's lineup. The Wednesday concert went on as planned — Connelly left it to residents to decide whether they felt comfortable attending. By Thursday morning, though, the town made the call: Pomps Pond closed, outdoor programming at Rec Park and the pond moved indoors, and anything that couldn't be relocated was canceled outright. Connelly said it echoed a similar disruption during Canadian wildfires a few years back, when the town delayed evening activities and moved what it could inside.

More than 835 wildfires were burning across Canada as of Thursday, with 112 considered out of control, according to Reuters. Massive blazes in western Ontario sent smoke plumes drifting south through the Great Lakes and into New England. The Massachusetts Department of Environmental Protection issued a statewide air quality alert Wednesday morning, warning of elevated fine particles unhealthy for children, teens, older adults and anyone active outdoors — an alert that stayed in effect through noon Thursday. Andover officials advised residents to keep windows and vehicle vents closed and rely on air conditioning or filtration indoors.

Mensch said Wednesday was likely the worst day of the smoke event, with relief expected by Friday as the smoke keeps moving south. Saturday's forecast calls for scattered showers and possible thunderstorms that could help clear the air completely.

The next scheduled children's performance at Pomps Pond is Wednesday, July 22, featuring Matt Heaton & The Outside Toys at 10 a.m. Andover Recreation's Concerts in the Park series continues Wednesday evenings through Aug. 26, with Thursdays as rain dates. Questions can go to the department at 978-623-8340.