Foul atmospheres can be described as miasmas, which is a term used to refer to an unpleasant or unhealthy atmosphere. Miasmas are typically caused by the presence of pollutants in the air, such as smoke, dust, and other airborne particles. These pollutants can cause a variety of health problems, including respiratory illnesses, headaches, and eye irritation. In addition, miasmas can also create an unpleasant smell, making it difficult to breathe.