| Among all the air pollution problems in China, acid rain is | | | | harms to forest plants. Under this effect, nutrients in soil |
| the biggest one. Acid rain is rainfall that has been | | | | will be released, and leached out with the rain. As a |
| acidified. It usually has a pH lower than 5.6. It is formed | | | | result, the soil will become barren. In addition, it can |
| when pollutants called oxides of sulfur and nitrogen, | | | | make the aluminum elements in the soil released out |
| contained in power plant smoke, factory smoke, and | | | | from the stable state, so that the activated aluminum in |
| car exhaust, react with the moisture in the | | | | the soil will be increased, which could seriously inhibit |
| atmosphere. Dry deposition, such as soot and ash, | | | | the growth of trees. When acid rain falls on trees, it will |
| sleet, hail, snow, smog and low level ozone are forms | | | | make their leaves turn brownish-yellow and the tree |
| that acid rain can take. As the emission of sulfur | | | | can no longer carry out photosynthesis properly. |
| dioxide and nitrogen oxide keeps increasing, the | | | | The main areas affected by acid rain in China are the |
| problem has becomes more and more serious. Now | | | | areas in the south of the Yangtze River, such as |
| China is the third largest acid rain area, only next to | | | | Sichuan Basin, Guizhou, Hunan, Hubei, Jiangxi, and some |
| Europe and North America. | | | | coastal provinces such as Fujian and Guangdong. |
| There are many problems and effects caused by acid | | | | According to preliminary survey, the forests in Sichuan |
| rain. It can cause buildings, statues and bridges to | | | | Basin is the largest area damaged, which is about 28 |
| deteriorate faster than usual, and will pollute thousands | | | | million hectares, accounting for 32% of the woodland |
| of lakes, rivers, and streams worldwide. It will damage | | | | area. |
| the ecosystems of the lakes and kills wildlife in these | | | | China has made great efforts on researches about |
| affected lakes, rivers and streams. It can also damage | | | | acid rain for nearly 30 years. However, it is still quite |
| soil and the tree roots in it. When soil is acidified, tree | | | | limited in the funding, size and depth of the research. |
| roots are damaged, leaving them not able to draw in | | | | As a result, China still has a lot to do to solve the |
| enough nutrients to support the tree. It will bring great | | | | problems brought it. |