Combustion particles, organic compounds, and metals are all PM__.

Combustion particles, organic compounds, and metals are all PM__.

• A. PM2.5
• B. PM10
• C. PM1
• D. PM0.1

Answer: (A)

Particles from combustion, organic compounds, and metals are all classified as PM2.5, the fine-particle fraction. PM2.5 refers to particles with a diameter of 2.5 micrometers or smaller. These tiny particles come from combustion processes like engines, power plants, and industrial activities, and they can carry adsorbed organic compounds and trace metals. Because of their small size, they can travel deep into the lungs and even enter the bloodstream, contributing to serious health effects. In contrast, PM10 includes larger coarse particles such as dust and pollen, which are not solely tied to combustion. PM1 and PM0.1 denote even smaller fractions, but PM2.5 is the standard category that encompasses combustion particles, organics, and metals together.

Particles from combustion, organic compounds, and metals are all classified as PM2.5, the fine-particle fraction. PM2.5 refers to particles with a diameter of 2.5 micrometers or smaller. These tiny particles come from combustion processes like engines, power plants, and industrial activities, and they can carry adsorbed organic compounds and trace metals. Because of their small size, they can travel deep into the lungs and even enter the bloodstream, contributing to serious health effects. In contrast, PM10 includes larger coarse particles such as dust and pollen, which are not solely tied to combustion. PM1 and PM0.1 denote even smaller fractions, but PM2.5 is the standard category that encompasses combustion particles, organics, and metals together.