Bulusan volcano spewed a huge ash column on Monday, sending thousands of people fleeing their homes. More than 700 remained at evacuation centres Wednesday awaiting advice on when it is safe to return, aid officials said.
The National Disaster Risk Reduction and Management Council said it handed out some 6,000 dust masks to residents of Irosin, one of three towns affected by the ashfall, including nearly 500 people at an evacuation centre there.
The health ministry meanwhile distributed face masks in the nearby town of Bulan, where a two-year-old boy died from an asthma attack aggravated by ashfalls caused by the eruption, it said in a statement.
Government doctors are checking the medical condition of people in affected areas, it added.
Volcanic ash can cause nose, throat, eye and skin irritation as well as contaminate tap water, while prolonged exposure can cause lung disease, according to the health ministry.
Government volcanologists said they had recorded one volcanic quake in the 1,559-metre (5,115-foot) volcano in the past 24 hours, but thick clouds hampered visual observations of further steam and ash emissions.
The government said human activity has been banned within four kilometres (2.5 miles) of its crater as a precaution.
Bulusan is among 23 active volcanoes in the Philippines, which is located in the so-called Ring of Fire of volcanic activity around the Pacific.
Bulusan, 360 kilometres southeast of Manila, last erupted between March and June of 2006.
The volcano also shot ash into the air in November last year, forcing hundreds of people to evacuate their homes.
However volcanologists said this was not an eruption, but heated ash deposits near the crater mouth that exploded and burst out on contact with rainwater.