If you noticed a haze over Oahu today, it could be vog — or it could be pollution.

“It’s not out of the question that it’s vog,” said National Weather Service Senior Forecaster Tom Birchard. “The winds did turn a little bit southeasterly at cloud level over the past 24 hours. But the winds will be switching to the northwest overnight, so the haze should flush out.”

While it could be vog from Halemaumau, it could be from vehicle exhaust or pollution, he said.

In a tweet this afternoon, the weather service in Honolulu, said, “We have received several reports of hazy conditions in Honolulu today. Sensors around the state do show lower air quality which could cause some breathing issues for seniors, children, and immunocompromised individuals.”