Subtitles section Play video Print subtitles volcanoes often conjure up images of lava and fire. But there's a lasting impact that's often ignored, called bog or volcanic smog. So what is Bog bog is a form of air pollution. It's made of carbon dioxide, water vapor and sulfur dioxide that last one being most important. That sulfur dioxide is released from the volcano and or Fisher events, and it reacts with the atmosphere. And within hours, today's. It converts toe very fine particles, which scatter sunlight, causing that visible hes is bogged dangerous. Vaud can be dangerous and can damage the environment. Humans and animals. It affects humans by damaging the lungs, triggering headaches, watery eyes, sore throats and even breathing difficulties. Even in people who have zero history of respiratory problems, what should you do if you encounter bog? It is advised to avoid bog by limiting your time outdoors. Additionally, if it rains and there is bog in the atmosphere, you need to be very careful. Bog can cause something called acid rain. If that does happen, please stay indoors and once again, avoid your exposure in the event you do come in contact with acid rain. Wash it off as soon as possible. What are the long term effects of bog? Depending on the volcano in the location of the bog, it could be present for several weeks, meaning it could spread to more populated cities even hundreds of miles away.