The report also finds that a variety of strategies, such as removing a pet, intensive cleaning, prohibiting smoking and controlling indoor humidity, may help alleviate asthma symptoms. In addition, exposure to these allergens, as well as those produced by cats and cockroaches, can aggravate symptoms in some asthma sufferers. The condition of asthmatic preschoolers also can be worsened by contact with secondhand tobacco smoke. People spend most of their time inside, and it's vital that we understand how the indoor environment may contribute to the disease. Fortunately, there are actions people can take to limit their exposure and ease symptoms.
Scientists think that some people are genetically predisposed to develop the disease.
For example, dust mites are present in most indoor environments, so their mere existence is not the sole factor that determines whether a person will develop asthma. The committee evaluated a broad body of research on asthma and indoor air, including population studies, clinical research and studies on air flow and humidity in buildings. The committee found varying degrees of evidence for some of the allergens and irritants. For example, secondhand tobacco smoke was very strongly linked to worsening asthma symptoms in preschoolers, but the evidence was unclear in the case of older children. Evidence in this category is strong enough to conclude that an allergen or irritant causes symptoms to develop in predisposed individuals or to worsen in known asthmatics.