An opening big enough that it only lets in subatomic particles, but nothing else?

Breathing in tiny airborne particles that come from rodent urine.

Breathing in too many alpha particles can cause serious health consequences, including cancer.

Radioactive materials give off a form of energy that travels in waves or particles.

Cilia on the inside of the tentacles create a feeding current and draw in particles.

To pose a health risk, plutonium-238 has to be taken into the lungs in very small particles.

Every piece of china from the antique cabinet lay in particles on the carpet.

Radiation is a form of energy released in particles or waves.

Many organisms are transported in small particles of water collectively called moisture.

The purpose of dewatering is to remove water contained in particles.