Like many homecare routines, ensuring healthy indoor air quality requires regular maintenance and monitoring. HVAC filters are changed, smoke detectors are retested and heating ducts are cleaned regularly. Many environmental factors will affect mold and allergen concentration levels in homes as seasons change. In colder winter months, thereâs an increase in water pipes breaking, spring brings heavy rainfall in summer, humidity levels increase and during autumn, falling leaves exacerbate outdoor mold that can move inside when we begin to spend more time indoors. For this reason, we recommend testing four times a year, or when you see or smell mold.