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Environmental Protection

6831 Dora 俞明瑾

Ladies and gentlemen, my name is Dora. My topic

is environmental protection. What is environmental

protection? Environmental protection is doing

something to protect the Earth. What will happen if we

don’t protect the Earth or nature?

PM2.5 or particulate matter is fine inhalable

particles, with diameters that are generally 2.5

micrometers and smaller. How small is 2.5

micrometers? Think about a single hair from your head.

The average human hair is about 70 micrometers in

diameter – making it 30 times larger than the largest

fine particle. These particles come in many sizes and

shapes and can be made up of hundreds of different

chemicals. Some are emitted directly from a source,

such as construction sites, unpaved roads, fields, or