Volcanic Smog (vog) is produced from SO2 gas and is a hazard in Haw...

Gases emerge from the Halema‘uma‘u crater, located within the much larger summit caldera of Kīlauea in the Hawaii Volcanoes National Park. Scientists use miniature spectrometers to measure the absorption of light as it passes through a volcanic plume to determine the concentration and emission rate of gases. Monitoring gases is important for understanding volcano behavior and determining volcanic hazards. The view is to the northwest, with Mauna Loa in the background.