Dust Rate and Attrition Rate: The Two Numbers That Tell You How a Litter Will Behave

Two small percentages, two very different stories about life with a cat.

Most cat litter is sold on what it does in the tray. The numbers we find most telling are the ones that describe what it does in the air, and what it does over time.

Dust rate and attrition rate are the two we keep coming back to. They sit on most technical specifications, rarely make it onto the bag, and between them they explain almost everything about whether a litter will feel pleasant or quietly grating to live with.

What dust rate actually measures

Dust rate is the proportion of a litter that becomes airborne when it's poured under standard conditions. It's expressed as a percentage of the total weight, and it's measured in a sealed chamber so the result is comparable from one product to the next.

A litter at 0.5% dust rate releases five grams of airborne particles for every kilogram you pour. A litter at 0.09% releases less than a gram. The difference is the visible cloud that hangs above the tray for a few seconds after a refill, and the fine film that settles on the floor a metre out.

Snow sits at 0.09%. Below 0.2% is generally considered ultra-low dust territory, so Snow comes in at less than half of that threshold.

Why the number matters for the room, not just the tray

Airborne dust doesn't stay around the tray. It drifts on the air currents that move through any house, settling on skirting boards, bookshelves, the cat's coat, and the cushions where they sleep afterwards.

For a cat, the more immediate concern is what travels into the respiratory tract while they dig and cover. Cats have small lungs and they put their faces directly into the material several times a day. Fine particles below about 10 micrometres are small enough to reach the lower airways, and a portion of any litter's dust falls into that range.

For the human at the other end of the room, it's the cumulative version of the same problem. Less dust in the air means less to breathe in, less to clean up, and less that gradually coats the surfaces around the tray.

A litter you can't see in the air is a litter you're not breathing in across the room.

What attrition rate measures, and why it matters more than people realise

Attrition rate is durability under friction. A sample of the litter is tumbled under controlled conditions, and the proportion that breaks down into fine powder is weighed. The lower the number, the more the granules hold their shape through the rough handling of being poured, scooped, scratched, and shifted.

This is the number that decides what your tray looks like a week into the bag, not a minute. A litter can start out low-dust on day one and still generate clouds by day five if its granules crumble every time the cat digs.

Snow's attrition rate is 0.02%. The benchmark for robust granules is below 1.0%, and typical clay litters sit in the 1.0% to 3.0% range. At 0.02%, Snow is roughly one fiftieth of where the typical clay floor begins.

How the two numbers work together

Dust rate is the snapshot. Attrition rate is the slow reveal.

A litter with low dust and high attrition tests beautifully in a lab and disappoints in a living room, because the dust you didn't see on day one is being manufactured under the cat's paws every day after. A litter with low attrition but high initial dust is the opposite story — a rough first pour that settles into something more tolerable, but never quite clean.

Snow is engineered to be low on both, which is what makes the air around the tray stay quiet through the life of the bag, not just the first ten minutes of it. The cassava starch and baking soda are processed into granules that hold together under the kind of force a cat actually applies, and that's the part you feel in the room.

What to look for on a spec sheet

When a litter publishes its dust rate, look for a figure under 0.2% for ultra-low dust. Anything above 1.0% is producing visible airborne particles every time it's poured.

When it publishes its attrition rate, look for a figure under 1.0% for robust granules. Many products don't publish this number at all, which is itself a signal worth noticing.

The two together are a more honest description of a litter than any adjective on the front of the bag. They're the closest thing the category has to a quiet promise about how the next eight weeks in your home are going to feel.