A survey conducted by the United States Environmental Protection Agency (EPA) found that people in the United States spend 87 percent of their time in an indoor environment. Of this, 69 percent of their time was spent at home, and 18 percent was spent in some other type of indoor venue, such as at a place of work. The survey results were based on responses by 9,000 people in the continental United States.
More facts about indoor time:
A 2011 poll in the United Kingdom indicated that UK citizens spent an average of 17 minutes of each day outdoors. Factors such as inclement weather, security concerns, lack of gardens and working out in gymnasiums rather than in the open air all contributed to the results.
According to the EPA, indoor levels of pollutants might be as much as 100 times the levels found outside.
Air pollution indoors might be caused by various factors, including furnishings, choice of building materials, household cleaning, personal care and the lack of proper maintenance for air conditioning and heating systems.