The effect of human activities on Bali’s Silent Day (Nyepi) in 2022

Indonesian Agency for Meteorology, Climatology, and Geophysics (BMKG), Jl Angkasa I No 2, Kemayoran, Jakarta Pusat 10610, Indonesia

^* Corresponding author: danang.eko@bmkg.go.id

Abstract

During Nyepi, all activities are eliminated, including public services, such as closing access to land, sea, and air transportation routes that transit to Bali for one day. In 2022, the BMKG Research and Development Center observed air quality in Nyepi. The measurement aims to determine the relative reduction level of greenhouse gas (GHG) and particulate emissions on Nyepi Day compared to before and after. Greenhouse gases and particulates were measured for seven days, February 28 - March 6, 2022. The measurement locations were over 3 points: Denpasar Regional Office III, Karangasem Geophysics Post, and Jembrana Climatology Station. The results of this field measurement show that daily human activities significantly influence the concentration of pollutant gases and particulates in the air. During Nyepi Day, air concentration improves when all human actions are reduced. This is marked by a decrease in the air’s concentration of pollutant gases (CO, NO2) and dust particles. The reduction in the concentration of pollutant gases and dust particles did vary at each observation location; this was due to the sensitivity of the equipment, the character of each observation location, and the placement of measuring devices. Urban areas filled with community activities have experienced the greatest improvement in air quality compared to suburban areas. Order of measuring instruments close to the location of pollutant sources, even in suburban areas, will decrease the concentration of pollutant gases, similar to that in urban areas. The difference between PM25 data during Nyepi 2022 and the average PM25 for 2020 - 2022 shows a decrease in PM25 concentrations of around 47%, with the highest drop at night.