Indoor Air Quality in Boise: What's Really in Your Home's Air

When people think about air quality in Boise, they usually think about wildfire smoke. And for good reason — the Treasure Valley has seen some brutal smoke seasons in recent years.

But here's something that surprises most homeowners: the air inside your home is often 2 to 5 times more polluted than the air outside — even on a smoky day.

The EPA has been saying this for decades. Yet most of us spend 90% of our time indoors, breathing air we never think to question. Understanding what's in your home's air — and what to do about it — is one of the most impactful things you can do for your family's health.

Your home's air is a complex mixture of particles, gases, and biological contaminants. Here's what's typically present:

Household dust is a mixture of dead skin cells, fabric fibers, soil tracked in from outside, and dozens of other materials. Fine particulate matter — particles small enough to be inhaled deep into the lungs — is the most concerning from a health standpoint.

Your HVAC system circulates air through your home continuously. Every particle that gets pulled into the return air vents gets deposited somewhere in your duct system — and eventually blown back out. This is why professional air duct cleaning is so effective at reducing household dust.

• Dust mites — microscopic organisms that thrive in warm, humid environments and are a leading trigger for asthma and allergies
• Mold spores — present in virtually every home; become a problem when moisture allows them to colonize duct surfaces
• Pet dander — proteins from pet skin, saliva, and urine that remain airborne for hours
• Pollen — enters through doors, windows, and your HVAC system's fresh air intake

VOCs are gases emitted by common household products: paints, cleaning supplies, furniture, flooring, and even air fresheners. Many VOCs are harmless at low concentrations, but some — like formaldehyde — are known carcinogens.

During smoke events, fine particles from wildfire smoke infiltrate homes through gaps in the building envelope and through HVAC systems. These particles are small enough to penetrate deep into lung tissue and have been linked to cardiovascular and respiratory health effects.

Your HVAC ductwork is the circulatory system of your home. Air passes through it dozens of times per day.

When ducts are clean, they do their job: distribute conditioned air efficiently. When they're dirty, they become a reservoir for everything listed above — and your system blows it through your home every time it runs.

A few specific ways dirty ducts degrade air quality:

Mold growth. Condensation inside ductwork — especially near the evaporator coil — creates conditions where mold can establish itself. Once mold is in your ducts, spores are distributed throughout your home with every cycle.

Accumulated allergens. Dust mite debris, pet dander, and pollen settle in ductwork and get re-aerosolized when airflow increases. People with allergies often notice symptoms are worse when the HVAC system runs — this is one of the key signs your air ducts need cleaning.

Reduced filter effectiveness. When ducts are heavily contaminated, your air filter has to work harder — and often can't keep up. Particles bypass or overwhelm the filter and recirculate.

Living in the Treasure Valley adds some unique considerations:

Wildfire smoke infiltration. During smoke events, running your HVAC on recirculation mode helps — but fine particles still accumulate in your duct system over time. After a heavy smoke season, it's worth having your ducts inspected.

High desert dust. The dry climate means more airborne dust year-round. Homes in the Treasure Valley tend to accumulate dust faster than homes in wetter climates — which is one reason we recommend cleaning your air ducts every 3 years rather than the standard 5.

New construction dust. The Boise metro has been one of the fastest-growing areas in the country. If you're near active construction — or if your home was recently built — construction dust is a significant contributor to indoor air quality problems.

Irrigation season. Agricultural activity in the surrounding area contributes to elevated particulate levels during irrigation season, which can infiltrate homes.

You don't have to accept poor indoor air quality. Here's what actually makes a difference:

This is the single most impactful thing most homeowners can do. A thorough cleaning removes accumulated dust, allergens, and biological contaminants from the entire duct system — not just the accessible portions.

Our $249 air duct cleaning special covers up to 10 vents, all returns, the furnace, evaporator coil, and includes an air quality test before and after so you can see the measurable improvement.

Most homeowners focus on HVAC ducts and overlook the dryer vent — but a clogged dryer vent pushes lint, moisture, and heat back into your laundry room. It's also a leading cause of house fires. Our $129 dryer vent cleaning service is a quick add-on that covers both systems in one visit.

A clogged filter doesn't just reduce airflow — it stops capturing particles effectively. Check your filter monthly and replace it at least every 90 days. If you have pets or allergies, every 30–60 days is better.

Use a filter with a MERV rating of 8–11 for a good balance of filtration and airflow. Higher isn't always better — very high MERV filters can restrict airflow enough to strain your system.

Dust mites and mold both thrive in humid conditions. Keep indoor humidity between 30–50% using a dehumidifier if needed. In Boise's dry climate, this is less of an issue in summer — but can be a concern in basements year-round.

On days when outdoor air quality is good (check AirNow.gov for Boise's current AQI), open windows to flush stale indoor air. Avoid this during smoke events or high-pollen days.

Standard vacuum cleaners can exhaust fine particles back into the air. A vacuum with a true HEPA filter captures particles down to 0.3 microns — the size range that matters most for respiratory health.

Choose low-VOC paints and finishes, store chemicals in a garage or shed rather than inside, and ventilate well when using cleaning products.

Consider scheduling a professional air duct cleaning if:

• You've never had your ducts cleaned (or it's been more than 3 years)
• You've recently moved into a home
• You've completed a renovation
• Someone in your household has allergies, asthma, or respiratory issues
• You notice increased dust, musty odors, or worsening allergy symptoms
• You went through a heavy wildfire smoke season

Not sure if you're due? Read how often you should clean your air ducts for a complete guide.

We serve Boise, Meridian, Nampa, Caldwell, Eagle, Kuna, and the surrounding Treasure Valley. Call (208) 504-0230 or get a free estimate today.