According to China News Service 20 13, 10/0/0 9, since10, the smog weather in many places in Henan has intensified, and the air in Zhengzhou, the provincial capital, reappeared on the 9 th.

First, thermal power generation, mainly coal burning, will produce a lot of air pollution gas and dust in the process of coal burning; So, A is wrong; ?

B, automobile exhaust contains carbon monoxide, unburned hydrocarbons, nitrogen oxides, lead compounds and smoke. ; So, B is wrong;

C, fireworks will produce a lot of air pollutants such as CO, SO2, NO2 and dust; So, c is wrong;

D, afforestation can prevent wind and fix sand, and the fluff and mucus on the leaves can absorb harmful smoke and dust in the air, and can also absorb toxic gases such as sulfur dioxide, thus greatly reducing and reducing dust in the air; Therefore, d is correct;

So the answer is: D.