People move from room to room during the day, so exposures may not be constant. Because air carrying the pollutants is heated, it rises, and the pollutant concentrations may increase with height above the floor. Symptoms of some pollutants are listed below. Note that given symptoms may be caused by more than one pollutant. At still higher concentrations, headaches, dizziness, and nausea can occur.
Likely sources are poorly ventilated natural gas furnaces and appliances.
Symptoms of high CO concentrations include headaches, drowsiness, fatigue, and nausea. A fireplace or furnace is a likely source. When the humidity is too low, the eyes, nose, throat, and mucous membranes will feel dry and irritated. Skin may become dry or scaly. Asthma symptoms may become worse.