Particulates in the atmosphere can be pollutants and carcinogens. Which statement is true?

• A. They are always harmless to human health
• B. They are never inhaled by people
• C. They can contribute to health risks and are made of materials like metals, acids, soil, and dust
• D. They only occur as water droplets

Answer: (C)

Particulates in the atmosphere come from many sources and vary in size and composition. They can be inhaled and, even at low concentrations, contribute to health risks such as respiratory irritation, asthma flares, and heart problems, with long-term exposure linked to increased cancer risk. Their makeup is diverse, including metals (like lead or nickel), acidic compounds, soil and dust, and various organic and carbon-based substances. This mix means particulates can be pollutants and carry carcinogenic components, so the statement that they can contribute to health risks and are made of materials like metals, acids, soil, and dust is true. They aren’t always harmless, they aren’t never inhaled, and they aren’t limited to water droplets—airborne particles can be solid or liquid and small enough to breach the lungs’ defenses.