Geological Agency: Red SO2 Map Does Not Mean Jakarta's Air Is Dangerous
The Geological Agency of the Ministry of Energy and Mineral Resources (ESDM) has explained that the red colour shown on a satellite map indicating sulphur dioxide (SO2) content over the Jakarta area is a result of the eruption of Mount Anak Krakatau. The agency stressed that the red SO2 map does not automatically mean that the air in Jakarta is dangerous.
“Besides volcanic ash and incandescent rock ejections, the eruption of Mount Anak Krakatau in the Sunda Strait also released SO2 gas. Information circulating on social media regarding SO2 has caused concern among the public,” the Geological Agency said in a statement on its official Instagram account on Monday (7/9/2026).
The uploaded SO2 map shows dark red patches over the Jakarta and West Java regions. The red colour on the SO2 map also extends over Lampung and towards the Indian Ocean.
“SO2, or sulphur dioxide, is a chemical compound in the form of a toxic gas that is colourless but has a very pungent smell. However, the danger of SO2 depends on its altitude in the troposphere, because if it is at a certain height, it is not directly inhaled by the public,” the agency wrote.
The Geological Agency explained that the satellite map shows the total amount of SO2 across the entire atmospheric column at a certain altitude, not the concentration of gas at the surface that people breathe. It emphasised that the red map does not mean Jakarta’s air is dangerous.
“This red-coloured map does not mean the air in Jakarta is dangerous. The red colour means an SO2 anomaly at concentrations higher than normal air in the atmospheric layer, not a surface air quality figure,” the agency said.
Nevertheless, the government has urged residents to remain alert to the smell of sulphur or SO2 caused by Mount Anak Krakatau’s activity. People are advised to limit outdoor activities and to wear masks.
“If you smell SO2 resembling sulphur due to volcanic activity, you are advised to use a mask, stay indoors to reduce exposure, and do not drink rainwater because it will become acidic and harmful to the body,” it added.