Do Rodents Affect Indoor Air Quality

Animal dander, bacteria, mildew, molds, viruses, pollen, mites, cockroaches, and house dust are biological contaminants. These pollutants come from various sources. Animal dander and saliva come from household pets, animals, people, plant and soil debris are sources of bacteria, plants produce pollen, while animals and people transmit viruses. So, do rodents affect indoor air quality?

Do Rodents Affect Indoor Air Quality
Do Rodents Affect Indoor Air Quality

One of the most potent biological pollutants is the protein in urine from mice and rats. The protein can become airborne once it dries up. Mildew and mold can breed in a contaminated central air system and be distributed throughout the home by other sources of biological contaminants.

The growth of some of these contaminants can be minimized by regulating a home's relative humidity (RH) level. The recommended relative humidity level for most homes is 30-50. Molds, bacteria, and insects find the perfect breeding ground in wet surfaces, water-damaged materials, and standing water.

Warm, damp environments are an ideal breeding ground for house dust mites which are the sources of some of the most potent biological allergens.

Biological Pollution
Biological Pollution

The Health Effects of Biological Contaminants

Allergic reactions such as allergic rhinitis, different asthma types, and hypersensitivity pneumonitis result from biological contamination. Chickenpox, influenza, and measles are infectious illnesses transmitted through the air. Some common biological pollution symptoms include digestive issues, lethargy, shortness of breath, sneezing, and dizziness.

Allergic reactions may become apparent after the repeated exposure to a particular biological pollutant. However, multiple exposure or re-exposure over time may lead to an immediate reaction. Consequently, people who have only experienced mild to no reactions may become sensitive to particular allergens.

Exposure to toxins from microorganisms that typically grow in ventilation systems in large buildings can lead to humidifier fever. Some microorganisms that thrive in humidifiers and home heating and cooling systems could also be responsible for such diseases. People that are more susceptible to these kinds of agents include older people and children.

Asthma can be triggered by pet dander, dust mites, mold, pest droppings, or body parts. A large number of the population suffer allergic reactions from biological contaminants such as pollens and molds.

Breeding Ground
Breeding Ground

How To Reduce Exposure To Biological Contaminants

It is essential to maintain the cleanliness of the home and heating and air conditioning equipment. Efficient air distribution and adequate ventilation are also vital. Moisture control is the key to mold control. Get rid of excess moisture and water, then get rid of the mold if it's causing issues.

To control cockroaches, mold, and dust mites, maintain RH at 30-60%. To control animal and insect allergens, seek the services of professional pest management.

Here are some ways to reduce exposure to biological contaminants.

– Ventilate crawl spaces and the attic to get rid of excess moisture. Water condensation on building materials can be prevented by keeping a humidity level of 50% in these areas.

– Bathrooms and kitchens should have exhaust fans vented to the outdoors. This ensures that most of the moisture present during day-to-day activities is dried up.

– Follow manufacturers' instructions when cleaning ultrasonic humidifiers or cooling mist. Make sure they are refilled with clean water every day. Humidifiers can cause diseases like humidifier fever and hypersensitivity pneumonitis since they can become ideal breeding grounds for biological contaminants.

– Remove, dry, or replace water-damaged carpets and other building materials. Bacteria and mold can find the perfect building ground in water-damaged building materials and carpets.


To avoid the risk of diseases caused by rodents, make sure you keep the house clean and take extra steps to reduce the risk of biological pollutants in your basement. Clean and disinfect your home and basement regularly.