Filters & Ratings · explainer
What Is PM10, and Does It Matter?
the particle class the pollen CADR sits in
Pollen and dust class. The visible half of the reading.
PM10 is the coarse half of the particulate story, the fraction you can often see, and the one your nose and curtains notice first. It gets fewer headlines than PM2.5 and keeps most of the pollen.
Here is what it covers, which rating on the box speaks to it, and how to use that honestly.
What PM10 actually means#
PM10 is the fraction of airborne particles up to 10 microns across, the coarse end, sitting above the PM2.5 fine fraction. The number in the name is the size, as with its smaller sibling.
This is the class where pollen, much household dust and the visibly floating material of daily life live. It is the part of the air that announces itself.
Where it appears in the ratings#
The standard CADR test measures three particle types, and the pollen test particle sits in the coarse, PM10-class range. So the pollen CADR is the figure on the box that speaks to this fraction.
EPA's published minimums by room area apply to the CADR you choose; if coarse particles are your concern, the pollen CADR is the number to set against them.
Suggested next step
Compare what the table asks for
Search listings for the published minimum your room needs, then check the smoke CADR on the shortlist before anything else.
Does it matter?#
Yes, as the visible, sneeze-inducing half of the problem, and as the fraction most units handle well. Coarse particles are the easier catch for real HEPA media, which is why pollen seasons are survivable with a correctly sized unit.
The honest read: match the fraction to the figure. Pollen problems are a pollen-CADR decision; fine smoke is a smoke-CADR decision. Neither is decided by the largest number on the front of the box.
What to check on the box#
- The pollen CADR, printed separately if the box gives three figures.
- A pollen CADR at or above the published minimum for your room area, rounded up between sizes.
- The distinction between coarse (PM10-class) and fine (PM2.5-class) claims, different fractions, different figures.
- A filter that is actually in stock for the model, because pollen season does not pause for backorders.
Questions people actually ask
Sources
- U.S. Environmental Protection Agency, Guide to Air Cleaners in the Home (2nd edition), retrieved 2026-08-30
Quoted and transcribed, never paraphrased into new numbers. This site does not interpolate between published figures.
Suggested next step
One more angle before you decide
The minimum is settled, spend the rest of the decision on noise, filter cost and the smoke CADR.
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Printed from https://roomandfilter.com/filters/what-is-pm10, “What Is PM10, and Does It Matter?”. Figures from U.S. Environmental Protection Agency, Guide to Air Cleaners in the Home (2nd edition), retrieved 2026-08-30. No prices are shown on this site, by policy.