What are the Trends in Indoor Air Quality And Their Effects On Human Health?

Americans, on average, spend approximately 90 percent of their time indoors, where the concentrations of some pollutants are often two to five times higher than typical outdoor concentrations.

People who are often most susceptible to the adverse effects of pollution (e.g., the very young, older adults, people with cardiovascular or respiratory disease) tend to spend even more time indoors.

Indoor concentrations of some pollutants have increased in recent decades due to such factors as energy-efficient building construction (when it lacks sufficient mechanical ventilation to ensure adequate air exchange) and increased use of synthetic building materials, furnishings, personal care products, pesticides, and household cleaners.

US EPA, 07 Sept. 2021