2.4.1 Sizes of Particles & their Properties

What are Nanoparticles?

Comparing Particle Sizes:

• Nanoparticles: 1 - 100 nm
• Fine particles: 100 – 2,500 nm (also known as PM2.5)
• Coarse particles: 2,500 – 10,000 nm (often referred to as dust)

Surface Area to Volume Ratio:

• Nanoparticles have a very high surface area-to-volume ratio compared to larger particles. This means that even though they are tiny, they have a lot of surface area relative to their size.
• Why is this important? Because the larger surface area allows nanoparticles to be more reactive or more effective at doing things like acting as catalysts or being absorbed by the body.