Most people have never had their indoor air measured. Not once. They know the square footage of their home, the age of their roof, what their electricity costs in August. But the air inside — the thing they breathe 15,000 times a day — has never been quantified.
That is starting to change in Los Angeles. More homeowners are asking what is actually in their air, and the answer is rarely what they expect.
What an IAQ Assessment Measures
An indoor air quality assessment is not an inspection. There is no checklist of pass/fail items and no one trying to sell you a system while they are still in your house. It is a measurement session. Data in, report out.
At Baseline, we measure six parameters in every assessment.
PM2.5 (fine particulate matter). These are particles small enough to bypass your nose and throat and settle deep in lung tissue. The EPA's 2024 annual standard is 9 micrograms per cubic meter. The WHO's 24-hour guideline is 15. Most Los Angeles homes we assess test between 8 and 25, depending on filtration quality and what is happening outside.
CO2 (carbon dioxide). Not a pollutant in the traditional sense, but the most reliable indicator of whether your home is getting enough fresh air. We use 800 ppm as our action threshold, which comes from the WELL Building Standard. ASHRAE's minimum is 1,000 ppm, but by that point, cognitive performance is already measurably affected. Sealed homes regularly hit 1,200 to 1,800 ppm overnight when bedroom doors are closed.
VOCs (volatile organic compounds). Off-gassing from flooring, paint, furniture, cleaning products, and just about anything that was manufactured. New construction and recent renovations produce the highest readings. There is no single safe threshold, but we track trends against the home's ventilation rate.
Humidity. Target range is 40 to 60% relative humidity. LA homes frequently drop below 30% during Santa Ana winds and heavy AC months. Low humidity dries out mucous membranes, increases static, and accelerates cracking in wood finishes. High humidity feeds mold.
Temperature. Straightforward, but we measure it room by room to identify dead zones and distribution problems.
Ventilation rate. How much outside air is actually making it into the house. This one ties all the other readings together. A home with low ventilation will accumulate whatever it produces: CO2 from breathing, VOCs from materials, moisture from cooking and showers.
What the Data Actually Reveals
Every assessment produces a Baseline Score — a weighted composite of all six parameters. PM2.5 carries 30% of the weight, CO2 carries 25%, and the rest is distributed across VOCs, humidity, temperature, and NOx.
Most homes score between 40 and 60. The national average sits around 55. That is not catastrophic, but it is not great either. It means there are specific, identifiable things working against the air in most homes.
The patterns we see in LA are consistent. Filtration is the most common issue. We recommend MERV 13 as a standard, but the filter rating matters less than the filter fit. Gaps around the filter frame bypass filtration entirely. Air takes the path of least resistance. We find this problem in roughly half the homes we assess, including homes with expensive HVAC systems.
Ventilation is the second pattern. Tight-envelope homes — especially newer construction and renovated properties — are built to be energy efficient. That means less air exchange. Less air exchange means CO2 and VOC levels climb. The home does not smell different. The readings just show it.
What Happens After the Assessment
You get a scored report with your numbers for each parameter, your composite Baseline Score, and a prioritized list of recommendations. The recommendations are ranked by impact: what will move your score the most for the least cost and complexity.
Some fixes are immediate. Adjusting your HVAC fan schedule from "auto" to "on" during occupied hours can meaningfully improve air mixing. Sealing filter gaps costs nothing. Running exhaust fans for 15 minutes after cooking vents particulate before it settles.
Other fixes take planning. Adding mechanical ventilation, upgrading to a MERV 13 filter system that actually fits, or installing standalone air purifiers in high-use rooms.
Ongoing Management vs. One-Time Testing
A single assessment gives you a snapshot. It tells you where your home stands on one day, under one set of conditions. That is valuable, but air quality is not static. It changes with seasons, occupancy, outdoor conditions, and equipment wear.
Baseline's membership tiers are designed around this reality. Monitoring plans include continuous sensors that track your key parameters over time. Managed plans add regular filter service, equipment checks, and seasonal adjustments. The idea is that your air quality should be something that is maintained, not just something that gets tested when there is a problem.
What an Assessment Costs
A Baseline assessment is $195. It takes about 90 minutes. Bryan personally conducts every assessment. You get a scored report within a few days.
There is no upsell during the visit. The data speaks for itself. If your numbers are fine, we will tell you that. If there are issues, the report ranks them so you know where to start.
Our free IAQ guide covers the basics of what these numbers mean and what the thresholds are. If you want to know exactly where your home stands, the assessment is the next step.