Question

The adverse effects of air pollutants on lung does not depend on which of the following factor ?

• A. Total dose of exposure
• B. Duration of exposure
• C. Particle size
• D. Colour

Hint:

Some of the most dangerous and deadly respiratory toxins (like Carbon Monoxide and Radon gas) are completely invisible and colorless. Biological damage is entirely based on chemistry and physics (dose, time, size), never optics.

Answer 1

The Correct Option is D

Step 1: Concept:
This question tests basic principles of environmental toxicology and respiratory pathology, specifically identifying which physical or chemical parameters dictate how much damage an inhaled pollutant will cause.

Step 2: Step-by-step Explanation:

• The toxicity and adverse physiological effects of any inhaled airborne pollutant are governed by several strict physical and biological factors:

• Total dose of exposure (A): Toxicology dictates that "the dose makes the poison." Inhaling a massive concentration of a chemical causes more severe and rapid damage than a tiny amount.

• Duration of exposure (B): Chronic (long-term) exposure, even at lower doses, leads to cumulative lung damage (like pneumoconiosis or COPD) compared to brief, transient exposures.

• Particle size (C): This is a critical aerodynamic factor. Large particles ($>10 \mu m$) get trapped in the nose and throat. Fine particles (PM 2.5) bypass upper defenses and lodge deep in the pulmonary alveoli, causing severe systemic damage. Thus, particle size is highly relevant.

• Colour (D): The visual color of a gas or particulate cloud (whether it is white smoke, black soot, or a colorless gas like Carbon Monoxide) has absolutely zero biological bearing on its chemical toxicity or its physical mechanism of damaging lung tissue.

Step 3: Final Answer:
The adverse effects do not depend on the colour of the pollutant.