ILOILO City – Lockdowns due to the coronavirus disease 2019 (COVID-19) pandemic have one unexpected but welcome effect here – an improved air quality.
With people restricted in their homes for quite some time, public and private transport stayed off the streets, too, or limited their operation, thereby reducing deleterious smoke emissions.
Air pollution in this southern city significantly decreased, according to Atty. Ramar Niel B. Pascua, director of the Environmental Management Bureau (EMB) in Region 6, an attached agency of the Department of Environment and Natural Resources (DENR).
“Considering the limited operations of both private and public utility vehicles during the quarantine period, a significant decrease in particulate matter emission was recorded in our ambient air monitoring station,” Pascua told Panay News, citing particularly their station in La Paz district.
Particulate matter (PM), according to the EMB, is a mixture of solid particles and liquid droplets in the air.
Based on EMB-6’s data obtained by Panay News, all sampling events were within the National Ambient Air Quality Guideline value which is 230 mass per unit volume (expressed as µg/NCM).
EMB-6 gathered data (between January and August this year) and monitored the air quality levels in Iloilo City with the total suspended particles (TSP) – a pollutant – as parameter.
TSP refers to all atmospheric particles with diameters equal to or less than 100 micrometers. These relatively “coarse” particles are mainly related to soiling and dust nuisance.
Based on the Air Quality Index (AQI) of 37 sampling events since January, the air quality in this city is “good,” according to Pascua.
The lowest result recorded between January and August this year was on Aug. 22 with two µg/NCM.
Meanwhile, in March 2019, the La Paz station logged the highest value with over 250 µg/NCM.
“(Year) 2021’s results showed the lowest concentration of pollutants comparing to 2020 and 2019. This is due to the limited movement of motor vehicles and operation of (establishments) with air pollution sources installation that affects the air quality,” Pascua explained.
The regional director cited three major sources of air pollutants: mobile, area and stationary.
Mobile sources are produced from motor vehicles moving on land, sea and air, Pascua said.
Meantime, air pollutants which are emitted from facilities with geographically-fixed location with Air Pollution Source Installation (APSI) like standby generator sets and boilers are referred to as stationary sources of air pollutants.
Area sources of air pollutants, on the other hand, include emissions through processes, such as the production of methane by decaying organic materials, grass fires, building construction, dry cleaning, unpaved roads, dumpsites/landfills, and the small scale burning combustible materials, like charcoal from households and commercial food preparations.
In Western Visayas, EMB-6 has five air quality monitoring stations:
* La Paz Ambient Air Quality Monitoring Station in La Paz plaza – uses manual method of sampling; monitors TSP
* Leganes Ambient Air Quality Monitoring Station (Leganes, Iloilo) – uses manual method of sampling; monitors PM10 and PM2.5 as parameters.
(According to EMB, PM with diameters less than 10 micrometers are specifically called PM10 while PM with diameters less than 2.5 micrometers are called PM2.5. These are of greater health concern as they can penetrate deep into the lungs.)
* University of San Agustin Ambient Air Quality Monitoring Station (City Proper) – uses manual method of sampling; monitors PM10 and PM2.5
* Oton Ambient Air Quality Monitoring Station (Oton, Iloilo) – uses manual method of sampling; monitors PM10
* Bacolod Ambient Air Quality Monitoring Station (New Government Center) – uses automatic method of sampling; monitors PM10 and PM2.5
Manual ambient air quality monitoring stations conduct air monitoring every six days, while automatic ones conduct it daily.
“Ambient air quality monitoring is an important step for taking corrective actions to reduce air pollution and let the public know of the quality of the air they breathe,” said Pascua./PN