Heavy Smog in Shanghai

In the past few days, we had a heavy smog in Shanghai. In the morning, when I looked out of my window, I could literally see nothing. If you walk outside for more than 10 mins, you may feel uncomfortable. Actually, I had a sore throat for over a week.
I once thought it was just fog, some kind of tiny drops of water in the air. But recently, it turned out that the smog was a phenomenon of pollution, which contains a high concentrations of PM 2.5 dust. And these tiny dusts will adhere to your lungs once you breath them in. It's very bad for your health.
Ironically, this smog bringed a new fashion accessory for Shanghai people, the dust mask. My company even gave each of us a dust mask. Most people were wearing a mask when they were going out. The whole city looked like a set of some science fiction. At first, I didn't care about the smog. But as the increasing of PM 2.5 level, I decided to buy some masks for my family. Then I was astonished that most online shops were sold out all kinds of dust mask.
The news said the smog in shanghai was expected to disperse today. Hope tomorrow will be a nice day!