Particulate matter concentration in Davao City airshed and its trend over the years

Davao City airshed was selected for air quality mapping using particulate matter (PM) concentrations. PM data were taken from the regulatory office, Environmental Management Bureau XI, from 2016 to 2021 to understand annual variation and determine trends that may be attributed to seasonal changes in the region. PM concentrations were spatially interpolated using Inverse distance weighting (IDW) feature, an interpolation technique of ArcGIS. PM concentration and distribution over the years showed no similar patterns, both for PM10 and PM2.5. No annual similarities of PM concentration were observed, and distribution varies yearly. No seasonal trends were shown on the interpolated maps for PM. However, there was an overall PM concentration decrease and distribution covered fewer affected areas over time. PM concentration in 2016 were generally at a level within the defined limit of NAAQGV except for some AQMS locations and years but sparingly exceeding the NAAQGV limit over time. Results show that PM emissions were lower suggesting a possible success on the regulation policies in the Davao City airshed through reduction or better management of air pollutant emissions.