Public advised to monitor air quality index
Fair weather and cloudy skies were observed in Metro Manila, seen from Pasig City on Friday, 4 April 2025. Areas with temperatures between 33°C and 41°C fall under the “extreme caution” category. PAGASA said heat cramps and heat exhaustion are likely risks under this heat index level. The weather bureau advises the public to limit outdoor activity, stay hydrated, and wear light clothing to avoid heat-related illnesses. In Metro Manila, a heat index as high as 38°C is expected in NAIA, Pasay City, while Science Garden, Quezon City, could reach 40°C.
The Department of Health (DOH) on Tuesday advised the public to monitor the air quality index (AQI) in their areas to help avoid exposure to polluted air.
This came after the Quezon City government on Monday identified 11 areas with unhealthy air quality for sensitive groups, while five areas had very unhealthy levels.
According to the Department of Environment and Natural Resources (DENR), the "hazy skies" on Monday may have been caused by the fire at the Sanitary Landfill in Montalban, Rizal, and two warehouse fires in Commonwealth, Quezon City.
In an advisory, DOH Secretary Ted Herbosa said there are two commonly used indicators for AQI: Particulate Matter 10 micrometers (PM 10) and PM 2.5. Both commonly come from sources like vehicle emissions, burning of trash, wildfires, or fire incidents.
PM 10 irritates the upper respiratory tract, like the sinuses and throat, Herbosa explained.
Meanwhile, PM 2.5 can go deep into the lungs and cause asthma attacks, and can also cross over into the blood, posing problems to our cardiovascular system.
Herbosa advised individuals sensitive to air pollution, such as those with asthma, emphysema, chronic obstructive pulmonary disease (COPD), and similar conditions, to always have their rescue medications on standby (example: Salbutamol, etc.) for use as prescribed by their doctors.
He added that both sensitive individuals and the general public should avoid or minimize exposure to haze or polluted outdoor air by staying indoors.
If going outdoors is necessary, wear a face mask—preferably an N95 mask—the Health chief furthered.
"Our President Marcos ordered to ensure the safety of the public, especially patients with lung conditions, during times like these with haze," Herbosa said.
"Always find out from the DENR or your local government what the air quality index of your area is to be guided on what to do," he added.
The AQI data are gathered by the Environmental Management Bureau (EMB) of the DENR and are often displayed online or in user-friendly weather or AQI apps.