How can outdoor air quality affect indoor air quality?

Outdoor air quality significantly affects indoor air quality because outdoor pollutants can infiltrate indoor spaces through various pathways. Buildings are not totally isolated from the outdoors; they usually have natural ventilation openings, leaks, or are intentionally ventilated with outside air. This means that contaminants such as particulate matter, volatile organic compounds, carbon monoxide, and biological pollutants can enter indoor environments.

Moreover, during construction or renovation, outdoor pollutants can also accumulate or inadvertently impact indoor air quality through dust, mold spores, or chemicals used in building materials and practices. This interplay is particularly critical in urban areas, where outdoor pollution levels can vary greatly and directly impact residents' health when these pollutants find their way indoors.

The other options do not accurately reflect the dynamics of indoor and outdoor air quality interaction. For instance, the notion that outdoor air quality has no influence on indoor air quality misunderstands the fundamental principles of air exchange. While it's possible for certain circumstances to see an improvement indoors, it is not a blanket truth, as outdoor pollutants can often compromise indoor conditions rather than enhance them. The idea that only buildings with windows open are impacted overlooks the fact that many structures utilize mechanical ventilation systems that bring in outside air regardless of whether windows are open or not.