In Manila, masks sold out quickly after residents were advised to wear them if they had to go out. Some wore handkerchiefs across their faces as they breathed air tainted by the smell of sulphur.
Streets that would normally be snarled with some of the world's worst traffic were largely empty in the city of 13 million people.
Schools and government offices were closed on official orders. The stock exchange suspended trading and many private businesses shut for the day too.
Classes in some cities in the capital will remain suspended on Tuesday, officials said.
Flight operations at Manila's international airport partially resumed, authorities said, after more than 500 flights were delayed or cancelled on Sunday.
One flight that did land carried President Rodrigo Duterte, who was coming back from his home city of Davao in the southern Philippines. He had been unable to fly on Sunday because visibility was so low.
One of the most active volcanoes in the Philippines, Taal has erupted more than 30 times in the past five centuries, most recently in 1977. An eruption in 1911 killed 1,500 people and one in 1754 lasted for a few months.
The island has been showing signs of restiveness since early last year.
The Philippines lies on the "Ring of Fire," a belt of volcanoes circling the Pacific Ocean that is also prone to earthquakes.
