Environmental Health – Which radioactive pollutant has recently drawn public attention due to its occurrence in building materials?

Introduction / Context:
Indoor air quality can be affected by naturally occurring radioactive materials. Radon (Rn), a noble gas produced from the decay of radium in the uranium-238 series, can seep from soil and certain building materials (like some granites, phosphogypsum, or fly-ash based products) into homes, contributing to long-term radiation exposure.

Given Data / Assumptions:

• The focus is on a pollutant linked specifically to building materials and indoor environments.
• Public awareness has risen due to measurements of radon exhalation from materials and entry through foundations.
• We must select the most relevant pollutant.

Concept / Approach:
Radon is colorless, odorless, and radioactive. It can accumulate indoors, especially in poorly ventilated spaces. Unlike metals like plutonium (industrial/weapon-related) or thorium/radium in bulk form, radon as a gas readily migrates and is directly inhaled, making it a primary indoor radiation concern.

Step-by-Step Solution:
Identify pollutant with indoor relevance and linkage to building materials: radon gas.Recognize source: decay of radium/uranium in rocks, soil, and certain construction materials.Choose the option that names the gas directly affecting indoor air.

Verification / Alternative check:
Health advisories often recommend radon testing in basements/ground floors and improving ventilation or sealing entry pathways where levels are high.

Why Other Options Are Wrong:

• Thorium: present in monazite sands and some materials but not the main indoor gas hazard.
• Radium: parent of radon; the gas is the immediate indoor air concern.
• Plutonium: not a typical residential building-material contaminant.

Common Pitfalls:
Confusing parent radionuclides with the airborne daughter product. Radon’s gaseous nature makes it uniquely problematic indoors.

Final Answer:
Radon