Environmental time-activity patterns from 2019 to 2025: changing patterns of exposure to different environments...

A major determinant of a person's health is how they split their time between environments with variable health risks such as indoor air quality. Such environmental 'time-activity patterns' are required to estimate toxicant dosimetries and, as these patterns change over time, are important to assess continually. Here, we report the age- and gender-standardized, population-weighted time-activity patterns for n = 6443 adults in Canada of varied demographics from 2019 to 2025. People in Canada spent 67.6% of time (5921 h/y) in their primary house, 4.6% (393 h/y) in a different residential building, 14.0% (1223 h/y) in a non-residential building, and 13.9% (1218 h/y) outside or in a vehicle. On average, Canadians spent 86.1% of life indoors. Most people experienced major time-activity pattern shifts during the 2020-2023 COVID-19 pandemic response period, with 611.0 h/y more time in primary houses and 442.4 h/y less time in non-residential buildings versus 2019-2020. From 2023 to 2025, patterns returned to (pre-pandemic) baselines for people who were retired, unemployed, or on leave, while changes persisted for workers. The largest persisting changes are experienced by people working jobs in management, administration, government, insurance, community service, and professions such as law, finance, information technology, science, and engineering, spending +774.0 h/y at home in 2025 versus 2019. People in full-time, 100% telecommuting jobs now spend 80.5% of time in their primary residence, contrasting with 58.4% of time for workers who never telecommute. Our work supports understanding demographic and temporal differences in environmental time-activity patterns to inform exposure duration data needed for toxicological evaluation of health risks.