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Asthma and the Environment

There is increasing evidence and awareness about the relationship between asthma and the environment. Since there are many non-environmental factors that contribute to asthma, there have been efforts to estimate what proportion of the asthma burden is related to the environment. In a study conducted by the World Health Organization, it is estimated that 44% of the asthma burden worldwide is due to the environment.

While there is some evidence that environmental factors can cause asthma, we know much more about indoor and outdoor environmental factors that can exacerbate asthma symptoms or trigger asthma attacks. Indoor air quality in the home and workplace is a concern for people with asthma.

In the home, some indoor air pollutants, also known as asthma triggers, are associated with both the development and exacerbation of asthma, including:

In the U.S., an expert panel estimated that 30% of asthma exacerbations among children were related to the environment-- this was associated with an annual cost of $2.0 billion. Likewise in California, we estimated that 30% (20-41%) of asthma was attributable to the environment -- with associated costs of $200 million per year.