The Department of Health (DOH) has advised the public to monitor the Air Quality Index (AQI) in their areas and avoid exposure to polluted air following reports of haze in parts of Quezon City and Rizal.

Earlier, the Department of Environment and Natural Resources - Environmental Management Bureau (DENR-EMB) said the fires that broke out in Montalban, Rizal, and Commonwealth, Quezon City, were responsible for the haze that covered Metro Manila on Monday, April 28.

“There are two commonly used indicators for AQI: Particulate Matter 10 micrometers (PM10) and PM2.5. Both commonly come from sources like vehicle emissions, burning of trash, wildfires, or fire incidents,” the DOH said in a public health advisory.

The health department explained that PM10 can cause irritation of the upper respiratory tract, such as the sinuses and throat, while PM2.5 can penetrate deep into the lungs, potentially triggering asthma attacks and crossing into the bloodstream, posing risks to the cardiovascular system.

Individuals with asthma, emphysema, chronic obstructive pulmonary disease (COPD), and similar conditions are advised to always have their rescue medications on hand, such as salbutamol, as prescribed by their doctors, the agency said.

The DOH also recommended that both sensitive individuals and the general public avoid or minimize outdoor exposure during hazy conditions. 

“If going outdoor is necessary, wear a face mask, preferably an N95 mask,” it said.

“Laging alamin mula sa DENR o inyong local government kung ano ang air quality index ng inyong lugar para magabayan sa dapat gawin (Always check with the DENR or your local government what the air quality index of your area is so you can be guided on what to do),” DOH Secretary Ted Herbosa said.

AQI data are gathered by the DENR-EMB and are often available online or through weather and AQI monitoring apps.