What is the difference between AHAM AC-1 and GB/T 18801 CADR?

AHAM AC-1 is the US standard: it reports CADR in cubic feet per minute (CFM) for smoke, dust and pollen only. GB/T 18801 is the Chinese standard: it reports CADR in cubic metres per hour (m3/h), covers both particulate and formaldehyde, and adds a CCM filter-life grade that AHAM does not measure.

How do I convert CADR from m3/h to CFM?

Divide the m3/h value by 1.699 to get CFM (1 CFM equals 1.699 m3/h). For example, a GB/T CADR of 400 m3/h is about 235 CFM. Always confirm which standard a number was tested under before comparing two suppliers.

What is CCM on a Chinese air purifier test report?

CCM (Cumulative Clean Mass) is the filter-life metric in GB/T 18801. It is the mass of pollutant a filter holds before CADR drops to half. Particulate CCM is graded P1 to P4 (P4 is highest, at least 12,000 mg) and formaldehyde CCM is graded F1 to F4. Higher grades mean longer filter life.

Which CADR standard should I ask my factory for?

For the US and AHAM-driven retail or Amazon listings, request AHAM AC-1 CADR in CFM. For China and many Asian and Middle East markets, GB/T 18801 in m3/h with CCM and formaldehyde data is standard. LYL Clean Air can provide model test data in the format your market requires.

Standards Literacy

AHAM AC-1 vs GB/T 18801: How to Read an Air Purifier’s CADR Report

Two factories quote “CADR 400” and the numbers are not comparable. Here is how to decode a CADR test report before you buy — for importers, distributors and private-label brands.

Quick answer ANSI/AHAM AC-1 is the US standard: it reports CADR in CFM for smoke, dust and pollen only. GB/T 18801 is the Chinese standard: it reports CADR in m³/h, covers particulate and formaldehyde, and adds a CCM filter-life grade that AHAM does not measure. To compare two suppliers, first confirm which standard each number came from, then convert to the same unit (1 CFM = 1.699 m³/h).

CADR — Clean Air Delivery Rate — is the headline number on almost every air purifier spec sheet. But “CADR 400” from a Chinese factory and “CADR 240” from a US-targeted datasheet can describe the same machine. The difference is the standard and the unit behind the number. Reading the report correctly is what separates a confident sourcing decision from a returns problem.

Side-by-Side: AHAM AC-1 vs GB/T 18801

	ANSI/AHAM AC-1 (US)	GB/T 18801 (China)
CADR unit	CFM (cubic feet/min)	m³/h (cubic metres/hour)
Pollutants	Smoke, dust, pollen (particulate only)	Particulate + formaldehyde (gaseous)
Filter life	Not measured	CCM grade (P1–P4 / F1–F4)
Test chamber	~28.3 m³ (1008 ft³)	30 m³
Certification	AHAM Verifide (third-party, voluntary)	National standard; tested by CMA/CNAS labs
Primary markets	US, Canada, AHAM-driven retail	China, much of Asia & Middle East

Sources: AHAM Verifide — air filtration standards; GB/T 18801-2022, Air cleaner; Smart Air — CADR test standards.

AHAM AC-1, in Plain Terms

ANSI/AHAM AC-1 became a US national standard in 1988 and was last revised in 2020. It uses a sealed-chamber decay method and reports three CADR numbers by particle size:

Smoke CADR — particles 0.09–1.0 microns (the smallest and hardest to capture)
Dust CADR — particles 0.5–3.0 microns
Pollen CADR — particles 5.0–11.0 microns (the largest)

If a model carries the AHAM Verifide seal, those three numbers and a recommended room size have been independently verified — which is what US retailers and Amazon buyers expect to see.

GB/T 18801, and Why CCM Matters

GB/T 18801 (current edition GB/T 18801-2022; the widely-cited GB/T 18801-2015 took effect in March 2016) reports CADR in m³/h and goes further than AHAM in two ways that matter to buyers:

Formaldehyde CADR — a separate gaseous-pollutant number, important for new-home and Asian markets where formaldehyde claims sell.
CCM (Cumulative Clean Mass) — the filter-life grade. It is the mass of pollutant captured before CADR falls to half of the new-filter value. Particulate CCM is graded P1–P4 (P4 is the highest, at least 12,000 mg) and formaldehyde CCM is graded F1–F4. A high CADR with a low CCM means strong airflow but a filter that fades fast — a hidden cost-of-ownership trap.

GB/T also defines an applicable area, derived as roughly CADR × 0.07 to 0.12 for a 2.4 m ceiling (the higher factor assumes a better-sealed room).

The Conversion Every Buyer Needs

Because the units differ, never compare a CFM number to an m³/h number directly:

1 CFM = 1.699 m³/h (to go from m³/h to CFM, divide by 1.699).
Example: a GB/T particulate CADR of 400 m³/h is about 235 CFM — not 400 CFM.

So a factory quoting “CADR 400” (m³/h) and another quoting “CADR 235” (CFM) may be selling equally capable machines. Always normalise to one unit and one standard first.

What to Ask For, by Market

US / Canada / AHAM-driven retail: request AHAM AC-1 CADR in CFM (smoke/dust/pollen), ideally AHAM Verifide.
China / Asia / Middle East: request GB/T 18801 in m³/h with the CCM grade and, where relevant, the formaldehyde CADR.
Every market: ask whether the number is the tested value for the exact SKU, and get the test report — not a marketing figure.

Need CADR data in the right format for your market?

Tell us your target country and we will provide model test data — AHAM-style CFM or GB/T m³/h with CCM — for the exact SKU.

Request Model Test Data

Related Sourcing Guides

CADR and room size — how to match a CADR number to the room it is sold for.
HEPA H13 vs H14 — filter grade and its effect on positioning.
Replacement filter cost — why CCM and filter life drive total cost of ownership.
Air purifier models — browse the OEM/ODM range and request test data.

This guide is general sourcing information. Standard editions and test methods are updated periodically — confirm the current standard version and the SKU-specific test report with your supplier.