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Instruments & method

How we measure — and where measuring stops.

This page exists for the person in your household who reads spec sheets. Welcome. Here's the kit, the benchmarks, and — because it's rarer than it should be in this industry — the limits, in writing.

The kit

Professional‑grade instruments, listed in every report

We publish the exact models and check dates in each report's appendix. By class:

PM2.5

Laser particle counters

Optical instruments that count fine particles in real time — the same sensing principle used in research‑grade nephelometers. We cross‑check units against each other every visit and log side‑by‑side readings.

CO₂

NDIR CO₂ loggers

Nondispersive infrared sensors — the reference method for CO₂ — in silent, battery‑powered loggers we can leave in a bedroom overnight. No camera, no microphone, no Wi‑Fi required.

TEMP · RH

Calibrated thermo‑hygrometers

Placed in pairs so a single flaky sensor can't write your report. Overnight placement captures the swings a one‑time reading misses.

WATER

NYS ELAP‑certified laboratories

We collect first‑draw and flush samples; the analysis happens at a New York State ELAP‑certified lab, and the lab's own report comes to you alongside ours. We interpret; the certified lab measures. More: the water panel →

The yardsticks

Benchmarks we read against

A number without a benchmark is decoration. Every reading in your report sits next to one of these:

PM2.5 · fine particles

WHO guidelines: 15 µg/m³ (24‑hour), 5 (annual). EPA annual standard: 9. We annotate both, because “meets the standard” and “as good as it can be” are different sentences.

CO₂ · ventilation proxy

~1,000 ppm is the widely used convention for well‑ventilated occupied rooms (outdoors sits near 420). CO₂ at these levels isn't toxic — it's a tracer that tells you how much everyone's exhaled air is being replaced with fresh.

Relative humidity

30–50% is the comfort‑and‑allergen band: dry enough that dust mites lose, humid enough that sleep and skin win.

Water lead

No amount is considered safe, so lower is always better. For context: NYC schools act at 5 ppb; the federal action level for water systems is 10. Your ELAP lab report states the measured value to the decimal.

The limits, in writing

What a screening can't see

Inside walls and building systems. We measure the air you breathe, not the cavities behind it. Where readings or observations suggest something structural deserves attention, we say so and refer.

Specialist domains. Asbestos, lead paint, radon, and similar areas are licensed specialist territory with their own certified methods. We don't perform them, we don't pretend to, and when one is indicated we put the referral in writing — with no referral fee changing hands in either direction.

VOC speciation. Consumer “VOC” sensors produce numbers we wouldn't stake a report on, so we don't. You get honest source‑and‑ventilation guidance instead, and a straight answer about when lab‑grade specialist testing is actually worth the money.

A screening is not a certification. We give you carefully measured readings, benchmarks, and a prioritized plan — not a stamp. Anyone selling a residential air “certification” is selling the stamp.

A note on microplastics

Why we don't sell a microplastics test (yet)

You can pay for a residential microplastics water test today. We won't sell you one, and here's the reasoning, since it explains how this whole practice works.

There is currently no federal standard method and no health‑based benchmark for microplastics in drinking water. Exactly one jurisdiction on earth — California — has standardized a methodology, built for water utilities, using spectroscopy that runs on the order of a thousand dollars per sample. Consumer kits exist, but results vary between labs, the smallest particles (which are the most abundant) are the hardest to detect, and above all: a particle count with no benchmark is a number that can't tell you anything except to worry.

What we do instead: fold microplastics literacy into the water consult — where exposure actually comes from (bottled water, notably, runs far higher than tap; plastic kettles and packaging matter more than your faucet), and which filtration approaches (reverse osmosis, NSF/ANSI‑401‑listed carbon) address it if you want to act anyway. The day a validated method and a meaningful benchmark exist, we'll add the test. Until then, we'd rather decline revenue than sell you a number that means nothing.

That's the practice in one sentence: if a measurement can't change a decision, we won't charge you for it.

Founding cohort · September

Measured. Benchmarked. Explained.

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