A weather phenomenon that Thursday morning triggered several carbon monoxide detectors in the city's East End neighborhoods could repeat Friday morning.
Rihaan Gangat of the National Weather Service confirmed that conditions are right for an inversion, a thin layer of the atmosphere that forms when warm air near the ground that gets cooler as it rises then increases in temperature.
Pittsburgh fire and emergency services responded to some 20 calls in the East End on Thursday morning for carbon monoxide detection, the earliest at 2 a.m. and the last around 10:30 a.m., said Frank Large, deputy fire chief. The alarms were going off in homes with open windows, apparently because the gas and other pollutants were trapped closer to the ground than normal and entering homes.
"What we're surmising is that it basically blocked any real air flow in the East End for whatever reason," Chief Large said.
Chief Large said firefighters attributed the gas to the inversion in so many cases, because fire department equipment oddly registered a greater presence of carbon monoxide outside, as opposed to inside, "backward from what we would normally expect."
For a while, they thought their equipment was broken.
"It's a reminder that sometimes Mother Nature can play some pretty nasty games on you," he said.
None of the levels detected was immediately dangerous, Chief Large said. An Allegheny County dispatch supervisor said no one was treated for carbon monoxide poisoning.
Ron Voorhees, acting director of the Allegheny County Health Department, said people should take a warning from a carbon monoxide detector seriously. Carbon monoxide is an odorless, colorless gas that in high concentrations can cause serious health problems, including death.
"People still need to make sure they don't have a real reason for their CO detectors going off," he said.
The Health Department issued a general air quality advisory Thursday for Pittsburgh, recommending no strenuous work outside, but included nothing specifically related to carbon monoxide.
Molly Born: firstname.lastname@example.org or 412-263-1944.