Which term is used for tiny particles smaller than 10 micrometers suspended in the air?

• A. Volatile Organic Compound
• B. NO2
• C. Particulate Matter
• D. SO2

Answer: (C)

Tiny particles suspended in air are described as Particulate Matter. When those particles are smaller than about 10 micrometers in diameter, they fall into the PM10 category, which means they are small enough to be inhaled and potentially reach the lungs. Particulate Matter is a mix of solid and liquid particles—dust, soot, pollen, salts, and aerosols from combustion and other processes. This size threshold (10 μm) is important because it relates to how deeply particles can penetrate the respiratory system and influence health and air quality metrics. The other terms refer to gases rather than particles: volatile organic compounds are vapors of organic chemicals, while NO2 and SO2 are gaseous pollutants formed from burning fuels. So, the term that specifically describes tiny particles under 10 micrometers suspended in air is Particulate Matter.