Pengaruh Variabilitas Iklim dan Karhutla terhadap Dinamika Konsentrasi PM 2.5 Kota Pontianak Tahun 2022-2023

Abstract

Pontianak City, as the capital of West Kalimantan Province, faces serious challenges related to air quality, making air quality monitoring essential. Air quality deterioration frequently occurs, particularly during forest and land fire (FLF) events in surrounding areas. Forest and land fires in West Kalimantan are often triggered by human activities and are further exacerbated by local climatic and weather conditions. These fires generate smoke containing particulate pollutants such as PM2.5. Due to its small diameter (= 2.5 µm), PM_2.5 can be easily inhaled and deposited in the respiratory system (Sompornrattanaphan et al. 2020). In addition to emission sources, meteorological conditions such as air temperature, rainfall, and wind speed play an important role in the dynamics of PM_2.5 concentrations (Wark et al. 1998). Climate variability, particularly ENSO, can influence rainfall patterns, air temperature, and atmospheric circulation, potentially intensifying dry or wet seasons and increasing the risk of forest and land fires. This study aims to describe the concentration condition of temperature, rainfall, and wind speed play an important role in the dynamics of PM_2.5 in Pontianak City during 2022-2023, examining the influence of climate variability and meteorological factors, and evaluating the contribution of forest and land fire events to fluctuations in temperature, rainfall, and wind speed play an important role in the dynamics of PM_2.5 concentrations. The study period of 2022–2023 was selected to represent two contrasting climate conditions, allowing for a comparative analysis of PM_2.5dynamics. Cross-Correlation Function (CCF) analysis was employed to identify time lags between forest and land fire occurrences and subsequent increases in PM_2.5 concentrations. Air mass trajectory analysis using the HYSPLIT model was conducted to examine the direction and pathways of pollutant transport, providing insight into potential source regions and the contribution of surrounding areas to PM_2.5 fluctuations in Pontianak City. The data used in this study include daily PM_2.5 concentrations obtained from the Ministry of Environment and Forestry (KLH) of Pontianak City, along with daily meteorological parameters rainfall, air temperature, wind speed, and wind direction from the Pontianak Maritime Meteorological Station (BMKG). Climate variability was analyzed using the Niño 3.4 index as an indicator of ENSO (El Niño–Southern Oscillation) to describe climate anomalies during the study period. Forest and land fire events were assessed using daily hotspot data and burned area information obtained from SIPONGI (KLH). The results of the analysis showed that the concentration of PM_2.5 in Pontianak City in 2022–2023 showed a diurnal pattern with an increase in morning and evening and a decrease during the day, with the maximum daily value still below the 24-hour BMUA, but the annual average has exceeded the annual BMUA. Climatic conditions play a role in the PM_2.5 variation, where weak La Niña conditions in the 2022 MAM season are related to lower concentrations, while El Niño is medium-strong in the 2023 JJA season along with an increase in PM_2.5 resulting in a decrease in air quality. A significant increase in forest and land fire hotspots in 2023 contributed substantially to elevated PM_2.5concentrations, with responses occurring at lags of 0 to +4 days. Meteorological factors showed relatively weak influences and acted as supporting factors, while PM_2.5 dynamics were governed by a combination of local emission sources, long-range transport, and regional atmospheric conditions, as corroborated by HYSPLIT model results.