How is acid rain formed? The reason for the formation of acid rain is the phenomenon of atmospheric chemistry and atmospheric physics. Acid rain contains a variety of inorganic acids and organic acids, most of which are sulfuric acid and nitric acid. 1. The main cause of the form

How is acid rain formed?

The reason for the formation of acid rain is the phenomenon of atmospheric chemistry and atmospheric physics. Acid rain contains a variety of inorganic acids and organic acids, most of which are sulfuric acid and nitric acid .

1. The main cause of the formation of acid rain - natural factors

marine fog, which will entrain some sulfuric acid into the air, and sulfuric acid is one of the main gases that cause acid rain.

Certain organisms in the soil, such as dead animals and dead plant leaves, can decompose certain sulfides under the action of bacteria, and then convert them into sulfur dioxide .

Volcanic eruptions spew considerable amounts of sulfur dioxide gas.

Forest fires caused by lightning and dry heat are also a natural source of sulfur oxides emissions, because trees also contain trace amounts of sulfur.

High-altitude rain cloud lightning has strong energy, which can partially combine nitrogen and oxygen in the air to form nitric oxide, which is then oxidized into nitrogen dioxide in the troposphere. N₂+O₂==Discharge==2NO 2NO+O₂======2NO₂ Nitrogen oxides are the sum of nitric oxide and nitrogen dioxide, which react with water vapor in the air to form nitric acid.

Bacteria decompose

Over-fertilized soil also contains trace amounts of nitrate. Soil nitrate can decompose gases such as nitric oxide, nitrogen dioxide and nitrogen with the help of soil bacteria.

2. The main reason for the formation of acid rain - human factors

such as car exhaust. In the engine, pistons frequently produce sparks, like lightning in the sky, and nitrogen turns into nitrogen dioxide. Different car models have different concentrations of nitrogen oxides, but in recent years, the number of various types of cars in our country has increased dramatically, and the contribution of their exhaust gas to acid rain is increasing year by year, so we cannot take it lightly.

Sulfur dioxide emitted from coal burning in industrial production and civilian life, nitrogen oxides emitted from burning petroleum and automobile exhaust, go through the "rain-forming process in the cloud", that is, water vapor condenses on sulfate radicals ht On the condensation nuclei such as ml4 and nitrate radicals, a liquid-phase oxidation reaction occurs, forming sulfuric acid raindrops and nitric acid raindrops; it also goes through the "undercloud washout process", that is, the acidic raindrops continuously merge and adsorb during the falling process, washing away other acidic raindrops and acidic gases, forming larger raindrops, and finally falling on the ground, forming acid rain. Since my country burns a lot of coal, the acid rain is sulfuric acid type acid rain. And in countries that burn more oil, it rains nitric acid.

Whether it is coal or petroleum, a large amount of sulfur dioxide will be generated during the combustion process. In addition, the high temperature during coal combustion causes nitrogen and oxygen in the air to combine into nitric oxide, which is then converted into nitrogen dioxide, causing acid rain.

Industrial processes, such as metal smelting : The ores of some non-ferrous metals are sulfides, copper, lead, and zinc. This is the case. During the reduction of copper, lead, and zinc sulfide ores into metals, a large amount of sulfur dioxide gas will overflow, part of which is recovered as sulfuric acid, and part of which enters the atmosphere. Another example is chemical production, especially sulfuric acid production and nitric acid production, which can produce considerable amounts of sulfur dioxide and nitrogen dioxide respectively. Another example is petroleum refining, which can also produce a certain amount of sulfur dioxide and nitrogen dioxide.

The main reason for the formation of acid rain is actually due to our continuous use of nature and continuous development. Industrial production and civil life burn coal to emit sulfur dioxide, burn oil and automobile exhaust to emit nitrogen oxides, and also emit acidic gas NOx. They are washed away by rain and snow at high altitudes, and combine with water to form a liquid with a pH value less than 7, forming acid rain.

1. Acid rain can cause soil acidification. The soil in southern my country is originally mostly acidic, but acid rain washes it off, accelerating the acidification process. The soil in northern my country is alkaline and has strong buffering and dilution capabilities against acid rain, so it cannot be acidified temporarily. Soil contains a large amount of aluminum hydroxide. After soil acidification, it can accelerate the weathering of primary and secondary minerals containing aluminum in the soil and release a large amount of aluminum ions, forming aluminum compounds that can be absorbed by plants. Long-term and excessive absorption of aluminum by plants can lead to poisoning and even death.

How is acid rain formed?

The reason for the formation of acid rain is the phenomenon of atmospheric chemistry and atmospheric physics. Acid rain contains a variety of inorganic acids and organic acids, most of which are sulfuric acid and nitric acid .

1. The main cause of the formation of acid rain - natural factors

marine fog, which will entrain some sulfuric acid into the air, and sulfuric acid is one of the main gases that cause acid rain.

Certain organisms in the soil, such as dead animals and dead plant leaves, can decompose certain sulfides under the action of bacteria, and then convert them into sulfur dioxide .

Volcanic eruptions spew considerable amounts of sulfur dioxide gas.

Forest fires caused by lightning and dry heat are also a natural source of sulfur oxides emissions, because trees also contain trace amounts of sulfur.

High-altitude rain cloud lightning has strong energy, which can partially combine nitrogen and oxygen in the air to form nitric oxide, which is then oxidized into nitrogen dioxide in the troposphere. N₂+O₂==Discharge==2NO 2NO+O₂======2NO₂ Nitrogen oxides are the sum of nitric oxide and nitrogen dioxide, which react with water vapor in the air to form nitric acid.

Bacteria decompose

Over-fertilized soil also contains trace amounts of nitrate. Soil nitrate can decompose gases such as nitric oxide, nitrogen dioxide and nitrogen with the help of soil bacteria.

2. The main reason for the formation of acid rain - human factors

such as car exhaust. In the engine, pistons frequently produce sparks, like lightning in the sky, and nitrogen turns into nitrogen dioxide. Different car models have different concentrations of nitrogen oxides, but in recent years, the number of various types of cars in our country has increased dramatically, and the contribution of their exhaust gas to acid rain is increasing year by year, so we cannot take it lightly.

Sulfur dioxide emitted from coal burning in industrial production and civilian life, nitrogen oxides emitted from burning petroleum and automobile exhaust, go through the "rain-forming process in the cloud", that is, water vapor condenses on sulfate radicals ht On the condensation nuclei such as ml4 and nitrate radicals, a liquid-phase oxidation reaction occurs, forming sulfuric acid raindrops and nitric acid raindrops; it also goes through the "undercloud washout process", that is, the acidic raindrops continuously merge and adsorb during the falling process, washing away other acidic raindrops and acidic gases, forming larger raindrops, and finally falling on the ground, forming acid rain. Since my country burns a lot of coal, the acid rain is sulfuric acid type acid rain. And in countries that burn more oil, it rains nitric acid.

Whether it is coal or petroleum, a large amount of sulfur dioxide will be generated during the combustion process. In addition, the high temperature during coal combustion causes nitrogen and oxygen in the air to combine into nitric oxide, which is then converted into nitrogen dioxide, causing acid rain.

Industrial processes, such as metal smelting : The ores of some non-ferrous metals are sulfides, copper, lead, and zinc. This is the case. During the reduction of copper, lead, and zinc sulfide ores into metals, a large amount of sulfur dioxide gas will overflow, part of which is recovered as sulfuric acid, and part of which enters the atmosphere. Another example is chemical production, especially sulfuric acid production and nitric acid production, which can produce considerable amounts of sulfur dioxide and nitrogen dioxide respectively. Another example is petroleum refining, which can also produce a certain amount of sulfur dioxide and nitrogen dioxide.

The main reason for the formation of acid rain is actually due to our continuous use of nature and continuous development. Industrial production and civil life burn coal to emit sulfur dioxide, burn oil and automobile exhaust to emit nitrogen oxides, and also emit acidic gas NOx. They are washed away by rain and snow at high altitudes, and combine with water to form a liquid with a pH value less than 7, forming acid rain.

1. Acid rain can cause soil acidification. The soil in southern my country is originally mostly acidic, but acid rain washes it off, accelerating the acidification process. The soil in northern my country is alkaline and has strong buffering and dilution capabilities against acid rain, so it cannot be acidified temporarily. Soil contains a large amount of aluminum hydroxide. After soil acidification, it can accelerate the weathering of primary and secondary minerals containing aluminum in the soil and release a large amount of aluminum ions, forming aluminum compounds that can be absorbed by plants. Long-term and excessive absorption of aluminum by plants can lead to poisoning and even death.

Acid rain can accelerate the loss of soil mineral nutrients; change the soil structure, lead to soil impoverishment, and affect the normal development of plants; acid rain can also induce plant diseases and insect pests, causing a significant reduction in crop yields, especially wheat. Under the influence of acid rain, the yield can be reduced by 13% to 34%. Soybeans and vegetables are also susceptible to acid rain, leading to a decrease in protein content and yield. The impact of acid rain on forests is largely caused by the deterioration of the physical and chemical properties of soil.

Under the action of acid rain, the nutrients potassium, sodium, calcium, and magnesium in the soil will be lost and leached away with the rain. Therefore, long-term acid rain will cause a large amount of nutrients in the soil to be leached, causing a serious shortage of nutrients in the soil, thus making the soil infertile. In addition, acid rain can release aluminum in the soil from its stable state, causing an increase in active aluminum and a decrease in organic complex aluminum. The increase of active aluminum in the soil can seriously inhibit the growth of forest trees. Acid rain can inhibit the reproduction of some soil microorganisms and reduce enzyme activity. Nitrogen-fixing bacteria, bacteria and actinomycetes in the soil will all be significantly inhibited by acid rain.

2. Acid rain can cause great harm to forest plants. According to domestic simulation experiments on the impact of on 105 species of woody plants, when the pH value of precipitation is less than 3.0, it can cause direct damage to plant leaves, causing the leaves to become chlorotic, turn yellow and begin to fall off. The longer the leaves are exposed to acid rain, the more severe the damage will be. Field surveys show that in areas where the precipitation pH value is less than 4.5, a large number of yellow leaves appear and fall off in masson pine forests, Huashan pine forests, and fir forests, and the forests decline in large areas.

For example, in areas where the precipitation pH value is less than 4.3 in Fengjie County, Chongqing, the annual average high growth of 20-year-old Masson pine forests is reduced by 50%. Acid rain can also significantly increase forest pests and diseases. In Sichuan, the disease index of masson pine forests in heavy acid rain areas is 2.5 times that of areas without acid rain. The harm caused by acid rain to China's forests is mainly in the provinces south of the Yangtze River. According to preliminary survey statistics, the Sichuan Basin has the largest forest area harmed by acid rain, accounting for approximately 280,000 hectares, accounting for 32% of the forest area. The affected forest area in Guizhou is approximately 140,000 hectares. According to some research results, a total of 6.3 million cubic meters of wood was lost due to the decline in forest productivity caused by acid rain in the southwest region alone, with direct economic losses reaching 3 billion yuan (calculated based on 1988 market prices). It is estimated that the direct economic losses caused by acid rain in 11 southern provinces can reach 4.4 billion yuan.

Most experts believe that the ecological value of forests far exceeds its economic value. Although there is still some controversy over the calculation method of the ecological value of the forest, and the calculated figures are not yet universally recognized by society, it is almost unanimous that the ecological value of the forest exceeds its economic value. According to these calculations, the ecological value of a forest is 2-8 times greater than its economic value. If calculated according to this ratio, the economic losses caused by acid rain to forests are extremely huge.

3. Acid rain can dissolve the hardened cement on the surface of non-metal building materials (concrete, mortar and lime sand bricks), causing voids and cracks, resulting in a reduction in strength and thus damaging the building. Building materials become dirty and black, affecting the quality of urban appearance and urban landscape, which is called the "black shell" effect.

Acid rain is spreading in my country, which is the third largest acid rain area in the world after Europe and North America. In the 1980s, acid rain in my country mainly occurred in Sichuan, Guizhou and Guangxi, represented by Chongqing, Guiyang and Liuzhou. The acid rain area covered an area of ​​1.7 million square kilometers. By the mid-1990s, acid rain had spread to a vast area south of the Yangtze River, east of the Tibetan Plateau and the Sichuan Basin, with the acid rain area expanding by more than 1 million square kilometers. The acid rain areas in Central China, represented by Changsha, Ganzhou, Nanchang, and Huaihua, have now become the areas with the most serious acid rain pollution in the country. The annual acid rain frequency in the central area is higher than 90%, almost to the extent that it is always acidic when it rains. The coastal areas of East China, represented by Nanjing, Shanghai, Hangzhou, Fuzhou, Qingdao and Xiamen, have also become the main acid rain areas in my country. Acidic precipitation also occurred in some areas of North China and Northeast China.In 1998, more than half of the cities in the country, including more than 70% of the southern cities and the northern cities of Xi'an, Tongchuan, Tumen and Qingdao, suffered from acid rain. Acid rain has become a prairie fire in my country, covering more than 30% of the country's land area.

The harm of acid rain is multifaceted, including direct and potential harm to human health, ecosystems and building facilities. Acid rain can reduce the immune function of children, increase the incidence of chronic pharyngitis and bronchial asthma, and increase the incidence of eye and respiratory tract diseases in the elderly. Over the past decade, the problem of acid rain has become increasingly prominent due to increasing emissions of sulfur dioxide and nitrogen oxides. China is already the third largest acid rain area after Europe and North America. The main distribution areas of acid rain in my country are the Sichuan Basin south of the Yangtze River, Guizhou, Hunan, Hubei, Jiangxi, and coastal provinces such as Fujian and Guangdong. In North China, acid rain deposition is rarely observed, which may be due to low precipitation, low air humidity, and low soil acidity in the north.

The anions in acid rain are mainly nitrate and sulfate ions. Based on their concentrations in acid rain samples, it can be determined whether the main influencing factor of precipitation is sulfur dioxide or nitrogen oxides. Sulfur dioxide mainly comes from the combustion of fossil fuels (such as coal), and nitrogen oxides mainly come from pollution sources such as vehicle exhaust. In relevant literature, the types of acid rain are divided into three categories based on the concentration ratio of sulfate and nitrate ions, as follows:

(1) Sulfate type or coal-fired type: sulfate/nitrate 3

(2) Mixed type: 0.5 sulfate/nitrate = 3

(3) Nitric acid type or fuel type: sulfate/nitrate = 0.5.

From this, the main influencing factors of acid rain can be preliminarily determined based on the type of acid rain in a place. Of course, acid rain in most places may be covered by these three types, which requires further analysis of the influencing factors of acid rain in each time period.

In 1998, more than half of the cities in the country, including more than 70% of the southern cities and the northern cities of Xi'an, Tongchuan, Tumen and Qingdao, suffered from acid rain. Acid rain has become a prairie fire in my country, covering more than 30% of the country's land area.

The harm of acid rain is multifaceted, including direct and potential harm to human health, ecosystems and building facilities. Acid rain can reduce the immune function of children, increase the incidence of chronic pharyngitis and bronchial asthma, and increase the incidence of eye and respiratory tract diseases in the elderly. Over the past decade, the problem of acid rain has become increasingly prominent due to increasing emissions of sulfur dioxide and nitrogen oxides. China is already the third largest acid rain area after Europe and North America. The main distribution areas of acid rain in my country are the Sichuan Basin south of the Yangtze River, Guizhou, Hunan, Hubei, Jiangxi, and coastal provinces such as Fujian and Guangdong. In North China, acid rain deposition is rarely observed, which may be due to low precipitation, low air humidity, and low soil acidity in the north.

The anions in acid rain are mainly nitrate and sulfate ions. Based on their concentrations in acid rain samples, it can be determined whether the main influencing factor of precipitation is sulfur dioxide or nitrogen oxides. Sulfur dioxide mainly comes from the combustion of fossil fuels (such as coal), and nitrogen oxides mainly come from pollution sources such as vehicle exhaust. In relevant literature, the types of acid rain are divided into three categories based on the concentration ratio of sulfate and nitrate ions, as follows:

(1) Sulfate type or coal-fired type: sulfate/nitrate 3

(2) Mixed type: 0.5 sulfate/nitrate = 3

(3) Nitric acid type or fuel type: sulfate/nitrate = 0.5.

From this, the main influencing factors of acid rain can be preliminarily determined based on the type of acid rain in a place. Of course, acid rain in most places may be covered by these three types, which requires further analysis of the influencing factors of acid rain in each time period.