Common Causes of Poor Indoor Air Quality

Causes of Unhealthy Air Quality and Allergies Indoors


Pests, including mice and cockroaches, are almost constantly leaving droppings of feces and urine wherever they go. Mice urine in particular can transmit hantavirus to humans - learn more about hantavirus from the CDC website here.  Mice can live anywhere in the home, but attics are a common spot. The insulation provides warmth and rodents love to chew on it. If there are mice present in the attic, it's likely the insulation is contaminated with droppings and has been damaged. Damaged insulation cannot properly condition a space, therefore rooms under or above spaces with rodent infestations are prone to humid and hot conditions in the summer - conditions that are favorable for dust mites and mold. 

Dust Mites

Dust mites are microscopic pests that thrive in humid conditions. They live in bedding, mattresses, furniture, carpets, curtains, and anything upholstered. Most every home has them and they go unnoticed, but their propensity for high humidity means that their population will explode if those conditions are met. Dust mites droppings cause allergy symptoms in humans and can exacerbate underlying respiratory issues. If dust mites are the culprit for in-home allergies, it's likely the real issue lies either in the attic or crawl space/basement - humid air is leaking in and cooled air is escaping from somewhere and until that is sealed or insulated, the conditions for dust mite growth will remain. 


Like dust mites, mold thrives in warm, humid conditions. Mold spores, depending on the strain, can cause varying degrees of allergic reactions. Kitchens, bathrooms, and damp basements are common places due to their uses but attics, especially in the summer, are excellent homes as well. When these spores float around in the air due to excess mold growth, they can compromise the quality of the indoor air and cause allergic reactions such as sneezing, coughing, headaches, and a runny nose. The spores of some mold strains can actually cause neurological and cognitive problems if left unaddressed. 

The common causes of indoor air quality problems and allergy symptoms are usually by-products of underlying building science problems. If these problems exist in your home, schedule a home inspection with Comfenergy. We diagnose the root cause of the problem and provide a permanent solution.

Here is the CDC's indoor air quality checklist.