The energy crises of the 1970s and real estate building boom of the early 1980s led to an increased inventory of homes with "energy efficiency" features. This usually means less air exchange between indoors and outdoors (weathersealants used wherever air might leak in), more insulation materials (which outgas pollutants) and woodwork comprised of composite woods (particleboard and plywood, which has gas-emitting glues, instead of solid woods).

Various studies suggest that people are spending longer hours at work (probably to pay the higher housing costs that have risen faster than income), so the longer hours indoors could be the reason for increased exposure times to indoor air pollution.