How to deal with the reality of acid rain pollution?

In the current situation of serious acid rain pollution, it is a very important measure to screen and cultivate crops and tree species resistant to acid rain. Such as camellia, citrus, citrus, juniper and Platycladus orientalis in southwest China, are not only famous and special products in this area, but also cash crops and trees resistant to acid rain. Cinnamomum camphora is a perennial green broad-leaved tree species with strong acid rain resistance, which can be used to replace coniferous trees vulnerable to acid rain such as Pinus massoniana. In garden construction, more acid-resistant tree species such as osmanthus fragrans, camellia and Ligustrum lucidum can be planted.

Greening can purify the air in a large area for a long time and is an important way to control acid rain pollution. Trees, grasslands and flowers can regulate climate, conserve water, conserve water and soil, and absorb toxic gases, including sulfur dioxide and other gases. Some trees have a strong ability to absorb sulfur dioxide. For example, 1 square meter of silver fir can absorb 60 kilograms of sulfur dioxide. Other trees that can strongly absorb sulfur dioxide include kumquat, red orange, mulberry and camphor tree. Lagerstroemia indica and chrysanthemum in flowers also have strong ability to absorb sulfur dioxide.

For acidified lakes, alkaline substances such as limestone can be put into them to neutralize acidic substances, thus improving the living conditions of aquatic organisms. It was found that the number of juvenile fish in the lake increased obviously by this method. However, it is not clear whether this method will have adverse consequences. So far, this method has not found any disadvantages, and its negative impact on the ecosystem may not appear until many years later.

For acidified soil, the treatment method is similar to that of acidified lakes, that is, lime is added to the soil. Under the action of acid rain, aluminum ions will be dissolved from acidified soil, which will affect the healthy growth of crops. When alkaline lime is added, soil acidity is neutralized, dissolved aluminum ions are precipitated again, and the normal nutrient cycle between soil and crops is restored. But adding lime is only an auxiliary measure, and it can't cure the problem of acid rain pollution.

Acid rain is an international problem. Many countries in Europe and North America, where acid rain is the most serious in the world, finally realize that the atmosphere has no national boundaries and cannot solve the problem of acid rain pollution by one country alone. 1979165438+10. At the meeting of environment ministers of the United Nations Economic Commission for Europe held in Geneva, the Convention on the Control of Long-distance Transboundary Air Pollution was adopted, which came into effect in 1983 and began to control pollution gases such as sulfur dioxide. All contracting parties have strengthened the control of gas emissions that cause acid rain, and achieved some results. However, many human actions will still cause a large number of acidic substances to be discharged into the air, especially the war has a great impact on local air pollution. The following example is very illustrative.

199 1, a mountaineering team encountered heavy snow while climbing Mount Everest. To their surprise, the snowflakes floating in the sky turned out to be black. Black snowflakes swirl, leaving the earth and the sky shrouded in haze. The reason why scientists found black snow was the Gulf War that broke out in 1990. In this war, the participating parties * * * dispatched 6,543,800 sorties and threw 6,543,800 tons of explosives, which seriously polluted the atmosphere and discharged a lot of acid gas into the air. In this war, about 700 oil wells in Kuwait were destroyed, and the ignited oil wells have been burning for 8 months. At most, 800,000 tons of crude oil were burned in one day, with a value of more than $654.38 billion. The smoke from the burning oil wells covered the sky, making the day like night. People should turn on the lights when driving during the day and use flashlights when walking. Vegetation and soil are also affected by the decrease of sunshine. Combustion makes the content of sulfur dioxide and carbon dioxide in the air greatly exceed the normal value, and high-acid precipitation appears in many places, which has caused great harm to plants. Rain in some places is not even drinkable. A large amount of dust appeared after the spread of oil combustion. These black smoke moved eastward through the warm and humid airflow over the Indian Ocean and condensed into black snow when it floated across the Himalayas.

Link: China needs to strengthen the control of nitrogen oxide emissions.

In February, 2009, experts attending the symposium on atmospheric nitrogen oxide pollution control held by the Ministry of Environmental Protection pointed out that if effective measures are not taken further to control nitrogen oxide emissions, China's nitrogen oxide emissions will continue to increase in the future 15, and may reach more than 30 million tons by 2020. China's efforts to reduce sulfur dioxide by 65,438+00% during the 11th Five-Year Plan period will be attributed to the remarkable emission of nitrogen oxides. The research shows that the significant increase in nitrogen oxide emissions has transformed acid rain pollution in China from sulfuric acid to sulfuric acid and nitric acid, and the proportion of nitrate ions in acid rain has gradually increased from110 in the 1980s to 1/3 in recent years, which shows that nitrogen oxide emissions have become a very important pollutant in acid rain control in China.

Nitrogen oxides are harmful to human health. In recent years, the concentration of nitrogen dioxide in Beijing, Guangzhou, Shanghai, Shenzhen and other big cities is generally high, often exceeding the standard, and it is gradually increasing. Satellite remote sensing shows that the increase of nitrogen dioxide concentration in eastern China is obviously higher than that in other parts of the world, and the industrial intensive area between Beijing and Shanghai has become the most polluted area of nitrogen dioxide in the troposphere in the world.

At the same time, nitrogen oxides are important precursors of secondary pollution such as ozone and acid precipitation. Haze is a frequent word in weather forecast in recent years, and its formation is closely related to nitrogen oxides. This kind of foggy weather phenomenon has a great influence on people's life and health. According to statistics, in recent years, the atmospheric visibility in most parts of China, especially in the economically developed areas of the Pearl River Delta, has been declining and the number of haze days has increased. Take Shenzhen as an example. In the 1980s, the average annual number of haze days was about 6 days. Since 200 1 year, the annual average is about 122 days, and it increased to 177 days in 2004.

It is estimated that during the period from1995 to 2005, the annual growth rate of nitrogen oxide emissions in China was above 6%. In 2005, the total emission of nitrogen oxides in China was19.9 million tons, of which thermal power generation was the largest source, accounting for about 36%; Followed by the industrial and transportation sectors, which "contributed" 23% and 20% respectively. Relevant research results show that at present, except for power enterprises, most enterprises pay insufficient attention to nitrogen oxides. With the further growth of thermal power generation and car ownership, the phenomenon of concentrated emission of nitrogen oxides in these two industries will be further highlighted.

In terms of spatial distribution, nitrogen oxide emissions are mainly concentrated in the eastern region. According to estimates, more than 80% of the country's nitrogen oxide emissions come from the central and eastern regions with dense population, concentrated industries and rapid economic development, such as Guangdong, Liaoning, Hebei and Shandong. This has also caused serious nitrogen oxide pollution and secondary pollution problems in the Pearl River Delta, Yangtze River Delta and Beijing-Tianjin-Hebei urban agglomerations. From the perspective of emission intensity per unit area, the regions with the largest emissions are Shanghai, Tianjin and Beijing in turn.

There is a lack of monitoring standards for nitrogen oxides in China's environmental quality standards. At present, there are only secondary standards for nitrogen dioxide and particulate pollutants. There is a certain correlation between nitrogen dioxide and nitrogen oxides, and nitrogen dioxide reflects the pollution problem of nitrogen oxides to some extent. However, due to the unreasonable setting of monitoring points, the migration and transformation from nitric oxide to nitrogen dioxide can not be fully reflected, so the current monitoring results of nitrogen dioxide can not fully reflect the pollution status of nitrogen oxides in China.

The formulation of emission standards for nitrogen oxides industry in China started late. At present, there is still no emission limit of nitrogen oxides in the air pollution emission standards of industrial furnaces and coking furnaces. However, in the only emission standards of air pollutants from thermal power plants, cement plants and boilers, although the concentration limit of nitrogen oxides is stipulated, these standards are generally too loose.

Therefore, it is an urgent task to revise and improve the emission standards of nitrogen oxides in some industries. Only in this way can we promote the prevention and control of nitrogen oxide pollution in China.