Why Does an Air Purifier Filter Develop a Sour Odor?

A sour odor from an air purifier filter is usually caused by the activated-carbon layer. There are two common causes:

1. The activated-carbon filter has reached saturation.

2. The activated-carbon filter has absorbed moisture.

Either condition can cause the filter to develop a sour smell.

Activated-carbon filters on the market generally use either carbon-coated fabric or pelletized activated carbon. Carbon-coated fabric is more likely to absorb moisture and develop an odor because it usually contains less activated carbon. Its service life is therefore generally shorter than that of a pelletized activated-carbon filter.

When choosing an air purifier, consider a model equipped with a pelletized activated-carbon filter.