The Impact of Atmospheric Stability Affected by Peat Forest Fire on Surface PM2.5 Concentration in Pontianak Urban Area during La Nina Events 2022

Abstract

Pontianak is the capital city of West Kalimantan province, which is affected by forest fires, especially forests on peatlands that also burn peat. The forest and peatland fires produce a lot of smoke-content particulates because of incomplete combustion of underground biomass. This paper investigates the PM2.5 concentration in 2021 coinciding with moderate La Nina when the effect of a short dry season does not support the occurrence of fires. PM2.5 concentration is analyzed by considering the air quality standard, atmospheric stability, and hotspot account observed by the SNPP satellite in the area with a radius of less than 0.5, 1 and 2. Analysis of the hotspot counts shows a good relationship with the dry season pattern in equatorial rainfall-type regions. Forest fires at locations less than 0.5 and strong inversion layers created heavy pollution in Pontianak, where the air environment is at dangerous levels, with daily concentrations exceeding the National Ambient Air Quality Standards and WHO air quality guidelines. Seasonal analysis shows a very high concentration difference in day and night in the December, January Febturay (DJF) and March, April, May (MAM) periods. This is related to the inversion event at 07:00, where there were many double inversions during the DJF and MAM periods, namely surface inversion and subsidence inversion, causing particulate matter to settle on the earth's surface.