Analisis Konsentrasi Pencemar SO2 dan NO2 Dari Kegiatan Transportasi dengan Pendekatan Model Delhi Finite Line Source (DFLS) (Studi Kasus: Jalan Gatot Subroto Kota Medan)

Abstract

The rapid development of the city led to the increase of population in Medan, followed by an increase in the number of motor vehicles. The increase in the number of vehicles has led to an increase in traffic density and an increase in the amount of emissions in the air. The pollutants generated from motor vehicles are sulfur dioxide (SO2) and nitrogen dioxide (NO2). This study aims to determine the concentration and emissions rate of SO2 and NO2 from transportation activities by using the model of Delhi Finite Line Source (DFLS), to compare the SO2 and NO2 concentrations of model result and the SO2 and NO2 concentrations of sampling result, as well as the suitability of the model to be applied in Gatot Subroto Street, Medan. Field measurements such as the number and type of vehicles that pass through Gatot Subroto Street, the concentrations of SO2 and NO2 and meteorology factors in the form of temperature, humidity, wind speed and direction were conducted during three (3) days, on Tuesday, Wednesday and Thursday with the measurement time in the morning and afternoon at each research location. Based on the observation, the type of vehicles that dominate on Gatot Subroto Street is the type of vehicle motorcycle amounted 31.996 vehicles. Based on calculation by DFLS, the highest concentration of SO2 was on Thursday in point 6 (TB. Simatupang intersection) amounted to 1.546 μg/m3 and the lowest was on Tuesday in point 2 (Iskandar Muda intersection) amounted to 470 μg/m3. Meanwhile, the highest concentration of NO2 was on Tuesday in point 1 (Bundaran SIB intersection) amounted to 249 μg/m3 and the lowest was on Tuesday in point 2 (Iskandar Muda intersection) amounted to 77 μg/m3. Meanwhile, based on the direct, the highest concentration of SO2 was on Thursday in point 6 (TB. Simatupang intersection) amounted to 84,17 μg/m3 dan the lowest was on Thursday in point 5 (Gagak Hitam intersection) amounted to 70,24 μg/m3. The highest concentration of NO2 was on Thursday in point 6 (TB. Simatupang intersection) amounted to 101,51 μg/m3 and the lowest was on Wednesday in point 3 (Darussalam intersection) amounted to 77,14 μg/m3. The observation results of SO2 and NO2 concentrations, none of which exceeded quality standards of ambient air. Validation results by using Index of Agreement (IOA) equation obtained d=0.01 for SO2 concentration and d=0.14 for NO2 concentration. The value of d <0.7 indicates that DFLS model does not correspond to be applied in Gatot Subroto Street, Medan.

Perkembangan kota yang pesat menyebabkan meningkatnya jumlah penduduk di Kota Medan yang diikuti dengan peningkatan jumlah kendaraan bermotor. Peningkatan jumlah kendaraan bermotor menyebabkan peningkatan kepadatan lalulintas dan peningkatan jumlah emisi di udara. Salah satu polutan yang dihasilkan dari kendaraan bermotor adalah sulfur dioksida (SO2) dan nitrogen dioksida (NO2). Penelitian ini bertujuan untuk mengetahui konsentrasi dan laju emisi SO2 dan NO2 dari kegiatan transportasi menggunakan model Delhi Finite Line Source (DFLS), membandingkan konsentrasi SO2 dan NO2 hasil model dengan konsentrasi SO2 dan NO2 hasil sampling, serta kesesuaian model untuk di terapkan di Jalan Gatot Subroto Kota Medan. Pengukuran di lapangan berupa jumlah dan jenis kendaraan yang melewati Jalan Gatot Subroto, konsentrasi SO2 dan NO2 dan faktor meteorologi berupa suhu, kelembaban, arah dan kecepatan angin yang dilakukan selama 3 (tiga) hari yaitu pada hari Selasa, Rabu dan Kamis dengan waktu pengukuran pagi dan siang hari di masing-masing lokasi penelitian. Berdasarkan hasil pengamatan, jenis kendaraan yang mendominasi di Jalan Gatot Subroto adalah jenis kendaraan sepeda motor yaitu sebesar 31.996 unit kendaraan. Berdasarkan perhitungan dengan DFLS, konsentrasi SO2 tertinggi pada hari Kamis di titik 6 (Simpang Jalan TB. Simatupang) sebesar 1.546 μg/m3 dan terendah pada hari Selasa di titik 2 (Simpang Jalan Iskandar Muda) sebesar 470 μg/m3. Sementara itu konsentrasi NO2 tertinggi pada hari Selasa di titik 1 (Simpang Bundaran SIB) sebesar 249 μg/m3 dan terendah pada hari Selasa di titik 2 (Simpang Jalan Iskandar Muda) sebesar 77 μg/m3. Sedangkan, berdasarkan pengamatan langsung konsentrasi SO2 tertinggi pada hari Kamis di titik 6 (Simpang Jalan TB. Simatupang) sebesar 84,17 μg/m3 dan terendah pada hari Kamis di titik 5 (Simpang Jalan Gagak Hitam) sebesar 70,24 μg/m3. Sementara itu konsentrasi NO2 tertinggi pada hari Kamis di titik 6 (Simpang Jalan TB. Simatupang) sebesar 101,51 μg/m3 dan terendah pada hari Rabu di titik 3 (Simpang Jalan Darussalam) sebesar 77,14 μg/m3. Hasil pengamatan konsentrasi SO2 dan NO2 tidak ada yang melebihi baku mutu udara ambien. Hasil validasi dengan Persamaan Index of Agreement (IOA) diperoleh nilai d = 0,01 untuk konsentrasi SO2 dan d = 0,14 untuk konsentrasi NO2. Nilai d < 0,7 menandakan bahwa model DFLS tidak sesuai diterapkan di Jalan Gatot Subroto Kota Medan.