The air quality of some cities in Metro Manila reached an "unhealthy" level for persons with respiratory conditions on Monday amid the ash fall from Taal Volcano's activity, according to a bureau of the Department of Environment and Natural Resources (DENR).
In an advisory, the DENR's Environmental Management Bureau said that the air quality in Las Piñas, Mandaluyong, and Taguig as of 11 a.m. on Monday reached a level considered "unhealthy for sensitive groups" due to the significant presence of particulates with diameters of 10 microns or less (PM10).
However, Environment Undersecretary Benny Antiporda said in a later press conference, the PM10 concentration in these three cities went down after it rained, with the conditions upgrading to "moderate/fair."
"As of 2 p.m., maganda naman at naging moderate/fair siya dahil umulan, most probably bumagsak na siya sa lupa, but still 'yung necessary precautionary measures should be taken dahil kapag natuyo po 'yung tubig at bumagsak sa lupa ang PM10 na 'yan pwede itong umakyat ulit at malanghap ng tao," he said.
The earlier recorded PM10 air quality index values from the monitoring stations in these cities were:
- CAA Road, Las Piñas - 108 micrograms of PM per cubic meter (μg/m³)
- Addition Hills in Mandaluyong - 118 micrograms of PM per cubic meter (μg/m³)
- TUP Campus in Taguig - 104 micrograms of PM per cubic meter (μg/m³)
All of these values fall within the EMB's "unhealthy for sensitive groups" category.
Particulates are tiny airborne particles or aerosols that come from sources that include soil; bacteria and viruses; fungi, molds and yeast; pollen; combustion products from space heating; industrial processes; power generation; and motor vehicle use.
According to the US Environmental Protection Agency, particulate matter (PM) small enough to be inhaled "can affect the heart and lungs and cause serious health effects."
PM10, which refer to particulates less than 10 micrometers in diameter, include both fine and dust particles and are inhalable.
Air quality remains "good" in Malabon City and San Juan City while that of Makati, Parañaque, and Pasig are still "moderate or fair," the EMB said.
Outside Metro Manila, the presence of PM2.5 or particles with diameters of 2.5 microns or less is also observed.
The AQI value in Antipolo, Rizal, considering the concentration of PM2.5, is already unhealthy for sensitive groups.
According to the World Health Organization, while PM10 can "penetrate and lodge deep inside the lungs," PM2.5 is even more health-damaging as it can "penetrate the lung barrier and enter the blood system."
"Chronic exposure to particles contributes to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer," it said.
A recent study by IQ AirVisual, a Swiss-based group that gathers air quality data globally, and Greenpeace, also said, "PM2.5 is widely regarded as the pollutant with the most health impact of all commonly measured air pollutants. Due to its small size, PM2.5 is able to penetrate deep into the human respiratory system and from there to the entire body, causing a wide range of short- and long-term health effects."
The Department of Health already advised the public to stay indoors as much as possible and wear protective masks when they have to go outdoors.
People with asthma, emphysema and chronic respiratory diseases were advised to take extra precaution.
"Hindi ibig sabihin na malinaw na 'yung ating nakikita sa kalye na parang wala nang smog ay malinis na, hindi po 'yun. We still need to be careful at 'yung recommendded na face mask ay gamitin po natin para masiguro ang ating kaligtasan," Antiporda said.
Ash fall has reached several areas in Metro Manila, Calabarzon and Central Luzon as authorities warned that a hazardous eruption in Taal Volcano is possible within hours or days. — Dona Magsino/BM, GMA News