Paicle size which is inhaled by lung and causes damage is:
**Core Concept**
The question is testing the understanding of the relationship between particle size and lung damage. In respiratory medicine, the size of inhaled particles determines their fate in the lungs, with smaller particles penetrating deeper into the lung tissue and causing damage. The lungs are lined with cilia and mucus, which trap larger particles, but smaller particles can reach the alveoli and cause inflammation and damage.
**Why the Correct Answer is Right**
The correct answer is related to the concept of aerodynamic diameter, which is the diameter of a particle that has the same settling velocity as the particle in question. Particles with an aerodynamic diameter of less than 10 micrometers (PM10) can penetrate deep into the lungs and cause damage. This is because particles of this size can be inhaled deeply into the lungs, where they can cause inflammation and damage to the alveoli.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the question, as it does not specify a particle size.
* **Option B:** This option may be related to particle size, but it is not the correct answer. Particles with an aerodynamic diameter of less than 5 micrometers (PM5) are even smaller and can cause more damage, but the question specifically mentions the lungs.
* **Option D:** This option is incorrect because it does not specify a particle size, and even if it did, it would not be relevant to the question.
**Clinical Pearl / High-Yield Fact**
The size of inhaled particles is critical in determining their fate in the lungs. Particles with an aerodynamic diameter of less than 10 micrometers (PM10) can penetrate deep into the lungs and cause damage, while larger particles are trapped in the upper respiratory tract.
**Correct Answer:** C.