It’s hard to make a blanket statement about whether outdoor air quality is better or worse than indoor air quality. It depends on factors like location, weather, time of year, and specific indoor environments being compare to. In some cases, outdoor air may be cleaner, while in others, indoor air may be the better option.
In general, factors like traffic emissions, industrial pollution, pollen, and wildfire smoke affect outdoor air quality. However, in some places and conditions, outdoor air may still be cleaner than indoor air.
A range of sources can impact indoor air quality. These include cooking, smoking, cleaning products, building materials, and off-gassing from furniture and electronics. Poorly ventilated indoor spaces can build up higher levels of pollutants. This sometimes leads to indoor air quality being worse than outdoor air.
In areas with high levels of outdoor pollution (e.g., urban), outdoor air quality may be worse than indoor air quality. This is especially true if measures are taken to improve indoor air quality. These might include using air purifiers and maintaining proper air flow. In contrast, in areas with lower outdoor pollution levels (e.g., rural or suburban), outdoor air quality may be better than indoor air quality.
In the end, it is key to monitor and assess both outdoor and indoor air quality on a fixed schedule. This helps make informed decisions and take useful measures to ensure healthy air quality.