Which option correctly pairs a pollutant with its medium and a corresponding health or environmental impact?

• A. Nitrates and heavy metals in water cause eutrophication and poisoning
• B. CO2 and PM2.5 in air cause climate change and respiratory diseases
• C. Pesticides in soil cause food contamination
• D. Heavy metals in soil cause water poisoning

Answer: (B)

Pollutants have a specific medium they affect and produce particular health or environmental effects. In the air, carbon dioxide acts as a greenhouse gas that traps heat and drives climate change, while fine particulate matter (PM2.5) can be inhaled deep into the lungs, causing respiratory and related health problems. This combination—pollutants in a given medium (air) with clearly linked impacts (climate change from CO2 and respiratory diseases from PM2.5)—best represents a correct pairing of pollutant, medium, and outcome.