Free Guide · 2026
The Homeowner's Guide

What Are You
Breathing
Inside Your Home?

Most Los Angeles homeowners have never measured their indoor air quality, even though the air inside their homes is often more polluted than the air outside. This guide explains what's really in your air, why it matters, and what to do about it.

Indoor air can be more polluted than outdoor air
90%
Of our time is spent indoors
0
Times most families have measured their indoor air
The Problem

The air in your home is working against you. Silently..

You track your steps, filter your water, and buy organic produce. But the one thing you cannot avoid is the air you breathe 15,000 times a day inside your home, and it has almost certainly never been tested.

Indoor air quality is the overlooked health issue of the modern home. The science has been clear for decades: the air inside a typical home contains a mixture of fine particles, chemical gases, combustion byproducts, and potentially radioactive radon, at levels that accumulate quietly over years of daily exposure.

In Los Angeles, the problem is compounded by two opposing forces. Outdoor air quality is genuinely poor. LA is consistently ranked the most ozone-polluted city in America, which leads homeowners to keep windows closed and rely entirely on their HVAC system to manage air. But a sealed home with an older or under-maintained HVAC system simply recirculates and concentrates whatever is already inside, while blocking the ventilation that would otherwise dilute it.

"In study after study, indoor air quality is found to be significantly worse than outdoor air, even in cities with notoriously polluted outdoor environments."

U.S. Environmental Protection Agency, Introduction to Indoor Air Quality

The symptoms of poor indoor air quality are easy to misattribute: chronic fatigue, morning headaches, persistent congestion, poor sleep, difficulty concentrating, and frequent respiratory illness. These are not dramatic or sudden. They are gradual, low-grade, and easy to explain away. Which is exactly why the problem persists unaddressed in so many homes.

The Threats

Four pollutants hiding in almost every home.

Your home generates air quality threats from multiple sources simultaneously: cooking, cleaning products, furniture, building materials, your HVAC system itself, and infiltration from outside. These are the four categories that matter most.

Threat 01 · Particles
Fine Particulate Matter (PM2.5)

Particles smaller than 2.5 microns, including cooking smoke, candles, wildfire infiltration, and HVAC dust, bypass your nose and throat entirely and lodge deep in lung tissue. LA homes during wildfire season regularly measure indoor PM2.5 levels that exceed EPA outdoor air quality limits, even with windows closed.

Threat 02 · Chemicals
VOCs & Formaldehyde

Volatile organic compounds off-gas continuously from flooring, cabinetry, paints, cleaning sprays, scented candles, personal care products, and new furniture. Formaldehyde, a Group 1 carcinogen, is found in pressed-wood products in virtually every home. New construction and recent remodels carry the highest concentrations.

Threat 03 · Gases
CO₂ & Carbon Monoxide

Elevated CO₂ from poor ventilation causes measurable cognitive decline, reduces sleep quality, and creates chronic fatigue, often well below the level where you feel acutely unwell. CO from gas ranges, attached garages, and aging appliances presents an acute safety risk that standard CO detectors often miss until levels are already dangerous.

Threat 04 · Radioactive
Radon

Radon is a colorless, odorless radioactive gas that seeps through foundation materials from the soil below. It is the second leading cause of lung cancer in the US, responsible for an estimated 21,000 deaths per year. It has no smell, no taste, and no immediate symptoms. The only way to know if your home has a radon problem is to measure it properly.

1 in 15
US homes have elevated radon levels above EPA action threshold
500+
VOC-emitting products in a typical American home
21,000
Lung cancer deaths per year linked to residential radon (EPA)
Warning Signs

Signs your home's air quality may be affecting your family.

Because indoor air quality issues accumulate slowly, the symptoms are often subtle enough to be attributed to other causes: stress, allergies, aging, or just "how things are." These are the warning signs that warrant a professional assessment.

Any one of these can have other explanations. But if two or more are present, your home's air quality deserves to be ruled out, not assumed to be fine.

What To Measure

A professional assessment goes far beyond a $30 sensor.

Consumer air quality monitors sold at hardware stores and online can detect some pollutants in real time, but they offer no context, no interpretation, and no path to action. A professional indoor air quality assessment measures the full picture and connects what it finds to specific, actionable solutions.

What We Measure Why It Matters Safe Range
PM2.5 Fine particles that reach deep lung tissue; elevated during cooking, candles, wildfire events < 12 μg/m³ annual avg
Total VOCs Chemical gases from furniture, finishes, cleaning products, and building materials < 220 μg/m³
CO₂ Ventilation indicator; elevated levels reduce cognitive performance and sleep quality < 1,000 ppm
Carbon Monoxide Colorless combustion gas; acute exposure risk from gas appliances and attached garages < 9 ppm (8-hr)
Relative Humidity Drives mold growth, dust mite proliferation, and respiratory discomfort 30 to 50% RH
Temperature / Dew Point Comfort and condensation risk indicator; linked to moisture and mold conditions 68 to 76 degrees F
Radon Radioactive soil gas; second leading cause of lung cancer; varies significantly by home < 4 pCi/L (EPA action level)

A note on radon testing: most home tests are unreliable.

The standard 48-hour charcoal canister test, available at most hardware stores, produces a number. But that number is shaped almost entirely by variables that were never controlled: whether your HVAC was running, whether windows were open, what the weather was doing, and what type of foundation your home has.

Foundation type is the single most important variable in radon testing. A home with a raised pier-and-beam foundation requires a 10-day dwell period for a reliable reading. A home with a finished basement requires 7 to 10 days. A crawlspace foundation needs up to 14 days. A 48-hour test in any of these homes produces data that cannot be used to make defensible decisions.

Baseline Home uses professional-grade continuous monitors with foundation-specific dwell periods, controlled for HVAC runtime, outdoor temperature, and barometric pressure trends, so the reading you get is actually meaningful.

Taking Action

Five things every homeowner can do right now.

Before scheduling a professional assessment, there are meaningful steps you can take immediately to reduce the most common indoor air quality risks in your home.

1
Upgrade your HVAC filter. And actually change it.
Most homes run on MERV-8 or lower filters, which catch large particles but allow fine PM2.5 and many allergens to pass through freely. Upgrading to a MERV-13 filter (compatible with most residential systems) significantly improves fine particle capture. Change it every 60 to 90 days, or every 30 days during wildfire season in LA.
2
Ventilate when you cook.
Cooking is one of the highest-impact indoor air quality events in most homes. Gas burners produce nitrogen dioxide and CO. Any cooking produces fine particles. Run your range hood on high and open a window while cooking, and for 15 minutes after. If your range hood doesn't vent to the outside, it is recirculating, not helping.
3
Switch to fragrance-free cleaning products.
Conventional cleaning products, including many "natural" ones, contain a significant load of VOCs in their fragrance compounds. Fragrance-free or certified low-VOC cleaners substantially reduce chemical exposure. The same applies to scented candles and air fresheners, which are among the highest VOC sources in residential environments.
4
Keep indoor humidity between 30 and 50 percent.
Relative humidity below 30 percent dries mucous membranes and increases respiratory vulnerability. Above 50 percent, mold and dust mite populations begin to thrive. A basic hygrometer (around $20) tells you where you are. A whole-home humidifier or dehumidifier, installed and balanced correctly, keeps you in the healthy range year-round.
5
Get your home professionally assessed.
The steps above reduce risk. They don't measure it. The only way to know what is actually in your air, and whether any of the invisible threats above are present at meaningful levels, is to have them professionally measured. An assessment gives you a data-backed baseline, a prioritized action plan, and the specific knowledge to make informed decisions about your family's health environment.

Ready to know what you're actually breathing?

Baseline Home offers professional indoor air quality assessments for homeowners in the greater Los Angeles area, with a full data report and a personalized action plan.

Schedule Your Assessment · $195
Serving Woodland Hills · Calabasas · Westlake Village · Agoura Hills · West San Fernando Valley