Trace Contaminants Control Subassembly Methane is produced in the intestines. Ammonia is created by the breakdown of urea in sweat. People also emit acetone, methyl alcohol, and carbon monoxide in their urine and their breath. Some of these gaseous compounds cause unwanted odors; others are extremely poisonous and must be removed quickly from the atmosphere in Space Station Alpha or they will make the crew sick. Activated Charcoal Filters are the primary method for removing these chemicals from the air. The filters are located in the Atmosphere Control and Supply Subsystem and the gases are removed as the air circulates through the system. Go Back