What Are Bioaerosols?

By Anne Fonda

Bioaerosols are microorganisms, particles, or fragments of biological origin, meaning they are either alive or came from a living organism that are in the air. Bioaerosols are everywhere in the environment. 

Measured in microns, they range from .05-100 microns (symbol µ). They are small enough to be inhaled. Examples of household bioaerosols include:

• Bacteria
• Fungal spores
• Mold spores
• Viruses (including influenza and Coronavirus)
• Algae
• Pollen
• Animal dander
• Dust mite particles

These bioaerosols, or contaminants, affect your indoor air quality (IAQ) and can affect your health.

Health Effects of Bioaerosols

How do bioaerosols affect human health? In a nutshell, they can cause both hypersensitivity illnesses and Infectious diseases. 

Hypersensitivity Illnesses

These are more commonly known as allergic illnesses or allergic responses. Some people are more sensitive to certain allergens, which can trigger the body’s autoimmune response. 

Examples and associated symptoms include:

• Building-related asthma with wheezing, coughing, shortness of breath, and chest tightness. Bioaerosols such as fungi, ragweed pollen, dust mites, and pet dander can trigger an asthma attack. 
• Allergic rhinitis with nasal congestion, itchy nose, itchy eyes, and sneezing. Post-nasal drip may irritate the throat and be especially noticeable in the morning. Symptoms may clear while you’re away from home at work or school, and recur when you come home. Fungi, pollen, pet dander, and dust mites can trigger an allergic reaction.
• Hypersensitivity pneumonitis is an acute and recurrent pneumonia with cough, fever, chest tightness, and shortness of breath. It can be caused by fungi and bacteria.

Infectious Diseases

While less commonly occurring in a residential environment, certain bioaerosols can cause infectious diseases. Examples include:

• Legionnaire’s disease is a bacterial pneumonia that can lead to hospitalization. It’s caused by bioaerosols from contaminated evaporative condensers, whirlpools, shower heads, faucets, and hot water tanks.

Pontiac fever is marked by fever, body aches, headache, cough, and shortness of breath without pneumonia. It’s caused by the same bacteria that causes Legionnaire’s disease.

How Can HVAC Help with Bioaerosols?

Your home’s HVAC system can provide a defense against bioaerosols. A standard 1” HVAC air filter can filter out some contaminants but to capture smaller particles and to flush contaminants out of your home, you may want to consider additional HVAC equipment.

Beneficial systems include:

• An air purifier
• A ventilation system
• A dehumidifier.

Whole-House Air Purification

Whole-house air cleaners/air purifiers such as the Trane CleanEffects® Whole-House Air Cleaner and QuikBox® Air Cleaner use advanced filtration technology to capture bioaerosols and other allergens and particulate matter as small as .3-1 microns. Learn more about each of these systems in our Trane’s Best Air Purifiers article.  

While the systems can greatly reduce contaminants such as fungi, viruses, and bacteria, they cannot completely remove them. 

Whole-House Ventilators

Some contaminants/bioaerosols, such as bacteria, can thrive in conditions with inadequate ventilation. Your central heating and air conditioning units alone don’t mechanically bring fresh air in from the outdoors – they simply recirculate the indoor air. However, ventilation systems such as a whole-house ventilator bring fresh air in and remove stale indoor air. They circulate air to help remove some bioaerosols.

Whole-House Dehumidifiers

Bioaerosols such as mold and dust mites thrive in high-humidity environments. High humidity is considered to be anything at or above 60% relative humidity. While bathroom exhaust fans can help regulate the humidity in your bathroom, if you have high humidity in your whole house, you need a whole-house solution.
A whole-house dehumidifier can be a great solution if you live in a humid climate or have a single-stage AC unit that sometimes has a hard time removing moisture from the air.

Breathe Easier with Trane IAQ Products

Contact your local Trane Comfort Specialist for a consultation and product recommendations tailored to your home and family.

Anne Fonda, Content Writer

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A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.

She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.

When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.

Expert review by Jennie Bergman, Senior Product Manager, Indoor Air Quality