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Direct-reading instruments log the fine particles, chemical vapors, formaldehyde and combustion gases in the rooms you live in, over one visit of about an hour or two, with a written report graded against EPA and WHO guidance. Serving Northern Virginia, Maryland and Washington DC. Book online in a couple of minutes, or ask for a price first.
Americans spend about 90 percent of their time indoors, where the EPA says some pollutants run two to five times higher than outside. The difference is the house: the range, the furnace, the new cabinets, the closed bedroom, the damp basement, the garage. This test reads each of them where it happens. Tap a marker.
Outside gets in too. Wildfire smoke put the region under Code Purple air in June 2023 and again in July 2026. Both times the advice was to stay in with the windows shut; how much smoke got in depended on the house.
Raised by cooking, candles, fireplaces, unvented heaters, smoking, and smoke or traffic from outside. High means particles small enough to reach deep into the lungs; a range without a vented hood is the usual culprit.
Raised by paints, varnishes, cleaning and disinfecting products, cosmetics, hobby supplies, and new furniture, carpet and flooring as they off-gas. High means irritated eyes, nose and throat, headaches, nausea. Indoors runs up to ten times outdoors, per the EPA.
Raised by the resins in composite wood: plywood, particleboard and MDF, which is most cabinets, shelving, laminate flooring and flat-pack furniture. High means irritation now and, at high long-term exposure, a cancer risk the EPA names. New builds and renovations are where it shows up.
Raised by people and pets breathing in a room that is not exchanging air: tight new construction, a bedroom with the door shut. High means under-ventilation, not poison. Outdoor air sits near 400 ppm; under about 1,000 is the usual benchmark.
Raised by gas stoves, furnaces and water heaters, fireplaces, generators, and exhaust from an attached garage; leaking chimneys and a back-drafting furnace are the ones nobody sees. High means a combustion or venting fault, and it gets fixed first.
Raised by the season, the basement, the bathroom, a house that does not dehumidify. High means the EPA's mold-risk zone above 60 percent; a persistently damp reading is where an air quality question becomes a mold question.
Sources: EPA, Indoor Air Quality, Volatile Organic Compounds' Impact on Indoor Air Quality, Indoor Particulate Matter, Carbon Monoxide's Impact on Indoor Air Quality and A Brief Guide to Mold, Moisture and Your Home; Minnesota Department of Health, Carbon Dioxide.
One price covers the visit, every reading and the written report. What a test comes to depends on the home, so this is where it starts. Ask for a price on your home and we will send you the number.
Starting from$425
What the price covers
The visit, every reading and the written report. No laboratory fee, because nothing is mailed to one, and no charge for the walk-through that finds the sources.
Same price in Virginia, Maryland and Washington DC.
Same price added to a home inspection, on the same order.
Want mold sampling on the same visit? Ask for a combined price.
We test. We never sell the fix. NextDay Inspect sells no air purifiers, no duct cleaning, no HVAC work and no remediation, so there is no reading that pays us better than another. If something comes back high, you take the report to whoever fixes that kind of problem, and we come back to re-test independently once it is done.
12hours before
Close the house. Windows and exterior doors shut from the evening before until the visit is over; normal coming and going through the doors is fine. This is the one rule the test depends on.
People search for "air quality" with three different problems in mind. Here is the sorting, by what you have noticed rather than by what the test is called.
Headaches, irritated eyes or a heavy head that ease when you leave the house
Air quality testingthis page
A chemical, painty or "new" smellFresh paint, new floors, new cabinets, a room full of new furniture.
Air quality testingVOCs and formaldehyde
A gas range, a fireplace or an attached garage, and a wish to know what it puts in the air
Air quality testingparticles, CO and gas
A stuffy bedroom and foggy mornings in a tightly built house
Air quality testingcarbon dioxide
A musty or earthy smell, a stain that came back, a leak you rememberOr allergy symptoms that live in one room, or anything visibly growing.
Mold testingair and swab samples, laboratory analyzed
Buying or selling, or someone sleeps in the basementRadon has no smell and no symptoms; only a monitor finds it.
Radon testing48-hour continuous monitor, $185
The tap water tastes, smells or looks wrong
Water testinglaboratory analyzed
Two of them at once? Mold sampling can ride the same visit as the air quality test; ask for a combined price. Not sure which? Call (703) 450-6398 and describe what you have noticed; the office books the right one. Lead and asbestos testing are on the environmental services page.
Northern Virginia, the Maryland suburbs and the District, at the same price by property type everywhere. The house decides the air, not the county, so there is no map of risk to show, only the list of where we drive.
Northern Virginia
Maryland
Washington DC
The whole District, river to river. Every neighborhood, from Georgetown to Anacostia. See our Washington DC page
Somewhere nearby but not on the list? Call (703) 450-6398 and ask. The rest of what we test for is on the environmental services page.
The questions people ask us first, answered in the first sentence.
Air quality testing starts at $425. What a test comes to depends on the home, so ask for a price on yours and we will send you the number. It covers the visit, every reading and the written report, it is the same price in Virginia, Maryland and Washington DC, and it does not change when the test is added to a home inspection.
Plan on about an hour or two, and it helps to be there, though it is not required. The instruments need time to log, and the technician walks the house while they do. Someone who can say where the smell is, which room is worst and when helps the visit land where it should.
If nobody can be there, lockbox or agent access arranged when you book works the same way it does for an inspection.
No. Mold is a separate test with a separate method. Air quality testing reads particles, chemical vapors, formaldehyde, carbon dioxide and combustion gases with direct-reading instruments during the visit. A mold test collects air and swab samples that go to an accredited laboratory to identify and count the spores. A particle count can tell you the air is dusty; it cannot tell you what the dust is.
If the trigger is a musty smell, a stain that came back or a leak, book the mold test. If you want both, we can do them in the same visit; ask for a combined price.
Six things, in each area we set up in: fine and coarse particles (PM2.5 and PM10), total volatile organic compounds, formaldehyde, carbon dioxide, carbon monoxide and combustible gas, plus temperature and humidity as context. Not included, because each needs its own method: mold spores, radon, asbestos, lead, allergens and pet dander.
One row per measurement, per area, with the average, the peak and a status against published guidance. The reference points are the ones public health agencies use: the EPA's 24-hour standard of 35 µg/m³ for fine particles and the WHO's stricter 15, the WHO's indoor guideline of 0.1 mg/m³ for formaldehyde, about 1,000 ppm of carbon dioxide as the point where a room is under-ventilated, and any sustained carbon monoxide at all.
Those standards are written for long averages and a visit is a snapshot, so the report shows both the number and its peak and says in plain words what each one means for your house.
The report tells you what is high, where, and what usually causes it, and then the fix is yours to choose. Most high readings have ordinary causes: a range hood that vents nowhere, a bedroom that never gets fresh air, new cabinets still off-gassing, a damp basement, a furnace that needs service.
Carbon monoxide or combustible gas is the exception. A sustained reading means a venting or appliance fault, and the technician tells you during the visit rather than in a report days later. We sell no purifiers, duct cleaning or HVAC work, so the report is not a sales pitch, and we can come back and re-test once you have made a change.
Not with this test. The particle counter tells you how much fine dust is in the air, not what it is made of, and identifying allergens needs laboratory analysis of a collected sample. If the concern is mold specifically, the mold test does exactly that, indoors against an outdoor control.
Yes, and it is one of the best times to. Composite wood, adhesives, paint and new flooring off-gas most when they are new, and a tightly built house holds what it makes. Testing a few weeks after moving in, with the house closed up for the twelve hours before, tells you whether the new-house smell is a number worth acting on or just a smell.
If it is high, the fix is usually more ventilation and time, and a re-test shows the curve coming down.
