LOOK: Data show less polluted air in Metro Manila amid lockdown

Kristine Sabillo, ABS-CBN News

Posted at Mar 25 2020 10:34 PM

MANILA—Various groups on Wednesday confirmed that the air quality in Metro Manila has improved after the government imposed an enhanced community quarantine in Luzon.

The Department of Environment and Natural Resources, the Institute of Environmental Science & Meteorology (IESM) at the University of the Philippines Diliman, and Airtoday.ph all released data on Wednesday showing how air pollution decreased in the metropolis.

In a news release, the Environmental Pollution Studies Laboratory of IESM-CS-UP Diliman said that Airtoday.ph stations recorded a “180% decrease in PM2.5 since the enhanced community quarantine was imposed in Metro Manila in March 16, 2020.”

AIR POLLUTANTS

PM, or particulate matter, refers to the mixture of solid particles or liquid droplets in the atmosphere. These include water, dust and salt particles. PM2.5 refers to particulate matters that have a diameter of less than 2.5 micrometers or just 3 percent of the diameter of a human hair. High levels of fine particulate matter in the air can reduce visibility or make the sky look hazy. 

According to the Environmental Pollution Studies Laboratory, PM2.5 is airborne dust particles that can enter the lungs, aggravate pre-existing respiratory conditions and cause shortness of breath.

It said a comparison of pre-ECQ and current air quality levels show the best improvement during evenings and early mornings. During this time, PM2.5 is reduced from 80% to 180% at the Lung Center of the Philippines, one of the partners of Airtoday.ph, an initiative of the Rotary Club of Makati.

From Airtoday.ph and the Environmental Pollution Studies Laboratory of IESM-CS-UP Diliman

Meanwhile, PM2.5 was also reduced by 70% to 90% along EDSA Munoz.

The same trend was observed in another Airtoday.ph station along EDSA Munoz, at 70-90% reduction in PM2.5 since the ECQ (Figure s 1&2). 

From Airtoday.ph and the Environmental Pollution Studies Laboratory of IESM-CS-UP Diliman

Dr. Mylene Cayetano, technical adviser of Airtoday.ph and head of the UP Environmental Pollution Studies Laboratory, said majority of air pollution in the area comes from vehicle emissions. 

“Cordoning off East Ave. and Quezon Ave., both hospital zones, brings positive feedback of cleaning the air,” Cayetano said, referring to the road restrictions imposed because of the Luzon lockdown. 

“The COVID-19 patients and the rest of the patients presenting in these QC hospital zone have either obstructive or restrictive breathing, thus, are in much need of clean air.”

SATELLITE IMAGES

The IESM, UP Diliman also shared data from the Himawari satellite, which is used by the PAGASA for weather monitoring.

It shows the Atmospheric Optical Depth (AOD) or how sunlight is reflected from the Earth as it is blocked or scattered by particulate matter or air pollutants.

A lower AOD at 0.01 means the air is clean in that area while a 0.5 value means hazy conditions.

Satellite data from March 16 to 25 show a reduction in AOD compared to the same period in 2018 and 2019.

The IESM said it means Metro Manila’s air quality is better and there is less air pollution. The same can be said for Southern Tagalog but not for Central Luzon and Cagayan Valley where agricultural burning continues.

Satellite image from the Institute of Environmental Science & Meteorology, UP Diliman

The DENR also released that air quality improved based on data from their various monitoring stations in Metro Manila.
 
“On March 22, 2020, the 24-hour average level for PM10 in Las Piñas and Marikina went down to 31.67 and 27.21 micrograms per normal cubic meter (ug/Ncm) from a high 57.81 and 31.28 ug/Ncm, respectively, on March 9, 2020,” DENR said in a statement. “The acceptable threshold standard level of PM 10 is 60 ug/Ncm.”

DENR said that PM 2.5 levels in In Muntinlupa and Paranaque on March 22, 2020 were recorded at 10.78 and 14.29 ug/Ncm, respectively - “much lower when they were recorded at 28.75 and 27.23 ug/Ncm, respectively, on March 10, 2020.”
 
“This explains why our sky now is clear and looks clean,” said DENR Undersecretary Benny Antiporda.
 
DENR Secretary Roy A. Cimatu said the lockdown imposed in countries around the world due to COVID-19 has allowed “the earth to heal from environmental degradation.”

“The major cause of climate change- air pollution, due mainly by mass transport energy emissions, is being abated. In the same way, there is lesser trash in public places because people are in strict home quarantine and restaurants are closed,” he said.