International conference joke

The polluted acid gas exists in the atmosphere, and its pH value is less than 5.65, which is called acid rain. What is acid? Pure water is neutral, tasteless, lemonade, orange juice, sweet and sour taste and sour taste of vinegar. They are alkaline baking soda powder and water with weak acidity and slightly astringent taste, which are more astringent than caustic soda, which is alkaline, but baking soda is alkaline. Scientists have found that the acidity is related to the concentration of hydrogen ions in aqueous solution; The flavor involved and the concentration of hydroxyl ions in alkaline aqueous solution, and then create an index: hydrogen ion concentration, and the pH value is mentioned as negative. So the pH value of pure water (distilled water) is 7; Reduce more acidic pH value; The higher the alkalinity, the higher the pH value. Pollution-free sleet (the PH value is usually between 0- 14) is close to neutral pH value to 7, slightly acidic (saturated with water and carbon dioxide as carbonate), and the pH value is 5.65. Rain with pH less than 5.65 is called acid rain, snow with pH less than 5.65 is called acid snow, and the air is filled with clouds. In high-altitude mountainous areas, such as Mount Emei, when the pH value is less than 5.65, it is called acid fog.

Generally, various tools can be used to test the PH value of water: litmus test solution \ phenolphthalein test solution \ PH test paper (with high accuracy, which can test the PH value) \ PH meter (to measure the pH value more accurately).

What is the acid rain rate?

There will be several showers and a lot of acid rain this year, and some of them are not acid rain, which is commonly called fields. What is the acid rain rate in this area? Total acid rain divided by rainfall. The minimum value is 0% to the maximum value 100%. If it depends on rainfall and snowfall.

Sometimes, a rain may last for several days, so the acid rain rate should be divided by the total number of people in the whole precipitation process and the annual acid rain precipitation process.

The average annual precipitation pH value and acid rain rate are another important index to distinguish the acid rain area.

What is an acid rain area?

The acid rain samples collected can't be regarded as acid rain areas, because there are dozens of them. The annual rainfall, rain acid rain and rainwater are not necessarily acid rain, and they are averaged annually. Does acid rain mean the pH value of annual average precipitation? Is the current scientific standard still under discussion? Above 5.65, the acid rain rate is 0-20%. Compared with the value in the non-acid rain area, the pH value is 5.30-5.60 10-40%. In the mild acid rain area? Acid rain, pH 5.00-5.30, acid rain rate 30%-60%, moderate acid rain, pH 4.70-5.00, rainfall 50%-80%, pH less than 4.70, acid rain with acid rain rate 70%- 100%. These are the so-called five standards. Beijing, Xining, Lanzhou and Urumqi actually collect acid rain, but the annual average pH value and acid rain rate are within the standards of acid rain areas and belong to non-acid rain areas.

Three major acid rain areas, including: sulfuric acid rain

1。 Southwest acid rain area: regional precipitation, serious acid rain pollution in Central China.

2。 Central China Acid Rain Area: It has become the regional center with the largest acid rain pollution range and the highest acid rain pollution intensity.

3。 The pollution intensity of acid rain area in eastern coastal areas of China is lower than that in central and southwest areas.

[Edit this paragraph] Acid rain,

In the modern industrial revolution, coal combustion produces steam from steam engines, boilers, propellers, lacquered cloth and thermal power plants, and the amount of coal combustion has soared. Unfortunately, coal contains sulfur impurities, and about 65438 0% sulfur dioxide in the high-temperature combustion gas produced by acid combustion can promote the chemical changes of some combustion air, oxygen and nitrogen compounds, as well as the emission of acid gas and nitrogen oxides. Rain, snow, soil erosion, acid rain and rainwater in high altitude areas, these acidic gases dissolve impurities sulfate, nitrate and ammonium ions in rainwater. 1872, the British scientist Smith analyzed whether the rainwater in the rural areas of London is acidic, the rainwater in the suburbs contains ammonium sulfate, and the slightly acidic urban rainwater contains sulfuric acid or acidic sulfate, which is acidic. Therefore, Smith was the first to study the chemical climatology of "acid rain" air and precipitation during his tenure.

[Edit this paragraph] The causes of acid rain

Acid rain is a complex atmospheric chemical and physical phenomenon. Most acid rain contains various organic and inorganic acids, sulfuric acid and nitric acid. Nitrogen oxides emitted by nuclear sulfuric acid, sulfur dioxide and automobile exhaust condense from clouds during the combustion of coal and oil, which leads to the liquid phase oxidation reaction of nitric acid in industrial production and civil life, forming sulfuric acid raindrops and nitric acid raindrops; Acid gas containing acid rain drops continuously combines adsorption, erosion and acid rain in the falling process, forming a larger process of rain drops and cloud erosion, and finally falls to the ground to form acid rain, which is sulfuric acid rain.

Acid rain burns fossil fuels and:

(1) sulfur → sulfuric acid (bright) sulfur+oxygen → sulfur dioxide

SO2+H2O → H2SO4 (sulfuric acid)

The chemical reaction equation of 2H2SO4+O2 is: (sulfuric acid)

S+O2 (ignition) = SO2-2SO2+2h2o+O2 = 2h2SO4

A.NO→HNO3 (nitric acid)

2NO+O2 = 2 NO2·3no 2+H2O = 2 HNO 3+NO

The chemical reaction equation is as follows:

4NO +2 H2O +3 O2 = 4HNO3

B NO2→ nitric acid

Total chemical reaction equation:

4 NO2+2 H2O+O2→4 HNO 3 & lt； BR /(* Note: The number after the subscript of this element is the stoichiometric number of the previous chemical formula).

[Edit this paragraph] Influencing factors of acid rain formation

Discharge and transfer conditions of acidic pollutants

Generally speaking, sulfur dioxide pollution is serious, and high concentration of sulfate ions is deposited in sediments, resulting in low pH value.

It is very important that acid rain forms ammonia and ammonia (NH3) in the atmosphere. Ammonia is a common gaseous alkali metal in the atmosphere. Ammonia in the atmosphere is decomposed by organic matter and volatilized from farmland. Reduce acidity because of its water-soluble acid aerosol or rain, the main source of nitrogen fertilizer. The soil with ammonia volatilization increased the pH value of the soil, which increased the pH value of the soil by 7? On the 8th, in Beijing, Tianjin, Chongqing and Guiyang, it is usually 5-6, which is an important reason why the ammonia level in the atmosphere is from north to south and the buffering capacity of soil acidity is low. These two factors can explain, at least in China, the buffering capacity of acid rain distribution in the south.

three

The acidity of atmospheric particles, acid gases SO2 and NO2, and an important member are very complicated-the sources of particles, dust and sand dust. It is estimated that there are about one-third in the north and one-third in the south. Inhalable particulate matter can form acid rain, and SO2 oxidation can catalyze metal acid. Acid and particulate matter are acidic, which can't play a role and will become acid sources. Usually, the high concentration of particulate matter is several times to ten times that of foreign atmosphere. The study of natural acid rain can not be ignored.

weather conditions

If the weather and terrain conditions are conducive to the diffusion of pollutants and reduce the concentration of atmospheric pollutants, acid rain will be seriously weakened (such as inversion), and vice versa.

[Edit this paragraph] The harm of acid rain

Sulfur and nitrogen nutrients and soluble minerals, if the acidity is too high and the pH value drops below 5.6, will cause serious harm to terrestrial plants. In a large area of forest, crops wither and die directly, which also inhibits the decomposition, nitrogen fixation and leaching of organic matter in soil, as well as nutrients such as calcium, magnesium and potassium in soil. The soil is barren and can be acidified in lakes and rivers. Dissolved heavy metals combine with soil and sediments in water to poison fish and accelerate the corrosion and weathering process of buildings and historic sites. May endanger human health.

Perhaps the most obvious impact is acid rain in Europe and the northeastern United States, which is highly publicized, but in threatened areas, including Canada, Sierra Leone, California Rocky Mountains and China, the occasional rain is as sour as vinegar. The influence of acid rain is a controversial topic. Living in lakes and rivers is harmful to aquatic organisms. At first, it was a key issue, but now it is recognized as dangerous buildings, bridges and equipment on the spot. The expensive consequences of acid rain and air pollution on human health are the most difficult to determine quantitatively.

Poor buffering capacity is the most harmful lake. Natural alkaline buffer, acid rain? However, the acidic compounds (mainly sulfuric acid, nitric acid and a small amount of organic acids) formed in granite lakes are easily damaged directly, because the dissolved metal ions (acids) of aluminum and manganese are caused by acid rain, which may lead to the decrease of the growth of plants and algae, and in some lakes, it may also lead to the decrease or disappearance of fish. The harmful effects of this form of pollution damage plants, including the fine roots of leaves, until they are destroyed.

The object of reducing pollutants is coal-fired power plants with high sulfur content in the northeast of the United States to prevent pollutant discharge. Chemical scrubber is a possible remedy. Chemical scrubbers are used to treat waste gas, or to dissolve or precipitate or eliminate fixed and moving sources of pollutants, another example of chemical action to improve air quality, methods to reduce nitrogen oxide emissions, and the amount of catalyst in the device.

Acid rain profit or

Analysis and formula

D = DH + DA + DF + DB + DC + DT

D- Total loss caused by air pollution

DH- air pollution

DA- the loss caused by air pollution and the loss caused by agriculture to human health.

DF- forest loss

D b- Air pollution caused by air pollution of building materials

DC- Increase the cost of cleaning up air pollution

DT- acid fog influence, visibility traffic loss

Estimated loss of air pollution to human body BR />DH, DHM+,DMT+DHD.

Among them,

DHM- respiratory diseases, medical expenses production

lose

DMT-DHD- Causes of premature death loss of lung cancer patients with respiratory diseases Estimation of forest loss caused by air pollution

DA = DAV + DAG

DAV- The loss caused by air pollution is caused by cutting vegetables.

DAG- The loss caused by air pollution destroyed the loss of forest ecological food production.

It is estimated that air pollutes forests.

DF = DFW + DFE

this

DFW- Forest Kiriko with economic losses < BR/DFE- Economic losses of welfare (non-forest products)

Estimation of air pollution loss of building materials

DB = DBS + DBP

Economic loss of DBS- galvanized steel plate damage

DBP- paint damage

Economic loss estimation, increased cleaning costs, air pollution

DC = DCH + DCR

DCH- Household cleaning expenses

DCR- city appearance cleaning fee

Visibility, reduce transportation loss estimation

DT = DTH + DTW

DTH- acid fog land transportation

DTW- Acid fog water transportation caused by economic loss

[Edit this paragraph], acid rain control measures

The fundamental measure to control acid rain is to reduce the emission of sulfur dioxide and nitrogen oxides.

Control measures, the worst acid rain in the world has been harmed by acid rain in many countries in Europe and North America for many years, and finally realized that there is no national border and atmosphere. After repeated consultations, the United States United Nations Environment Ministers' Meeting concluded that preventing acid rain is an international environmental problem, which cannot be solved by one country alone. Measures must be taken together to reduce the emissions of sulfur oxides and nitrogen oxides. According to the provisions of the Geneva Convention on the Control of Long-distance Transboundary Air Pollution of the Economic Commission for Europe (1979 1 1, adopted), the Convention came into force in 1983, and by the end of 1993, the contracting parties must reduce their sulfur dioxide emissions by 70%. 1980 Thirty-two countries in Europe and North America (including the United States and Canada) have signed the Convention, and most countries have taken active measures to fulfill their commitments and formulated laws and regulations to reduce emissions. For example, the acid rain of this law stipulates that the emission of sulfur dioxide in the east of the Mississippi River is1200,000 tons/year in 983. After 10, it will be reduced to 654.38+10,000 tons/year, sulfur Canada will be reduced to 1983 and 4.7 million tons/year, and carbon dioxide emissions will be reduced from 1994 to 2.3 million tons/year, and so on. At present, the main measures to reduce sulfur dioxide emissions in the world are:

1, raw coal desulfurization technology can remove about 40% ~ 60% inorganic sulfur from coal.

Use low-sulfur fuels, such as low-sulfur high-quality coal and natural gas.

3. Improve coal burning technology to reduce the emission of sulfur dioxide and nitrogen oxides during coal burning. For example, coal liquefaction technology is one of the new technologies in all countries, mainly the reaction of sulfur dioxide and calcium sulfate ash with limestone and dolomite.

As shown in fig. 4, the formed flue gas is desulfurized before being discharged into the atmosphere. 85% and 90% of sulfur dioxide gas in flue gas can be removed in the night afterburning of coal and quicklime. But the effect is good, but desulfurization is expensive. For example, the installation of flue gas desulfurization devices in thermal power plants accounts for 25% of the total investment cost of power plants. One of the main difficulties in controlling acid rain.

& gt5。 Develop new energy sources, such as solar energy, wind energy, nuclear energy and combustible ice, but the technology is not mature enough, and the cost of pollution and consumption will be high if it is used.

Acid rain, the manifestation of air pollution, is the earliest acid rain that is concerned, called acid rain, and carbonic acid is dissolved in it.

In pure rain and snow, there is carbon dioxide in the air, so it is slightly acidic. The concentration of carbon dioxide in the air is usually a normal phenomenon that the pH value of precipitation is around 3 16ppm to 5.6, and it is not what we usually call acid rain.

We are talking about acid rain. Due to the influence of human activities, the acid precipitation with pH below 5.6 decreased. With the development of modern industrialization, precipitation began to appear and showed an upward trend year by year. It has begun to affect human survival and human living environment.

The acidity of ancient rain and snow is not recorded. About 180 years ago, the ice accumulation experiment in Greenland showed that when the pH value of snowfall was 6? 7.6。

In 1950s, the pH value of precipitation in the world was generally greater than 5, and acid rain appeared in some industrial areas. Since 1960s, China's industrial development and fossil fuel consumption, as well as the pH value of precipitation in some industrialized areas in the world (such as declining northern Europe and eastern North America)? Add five and expand the scope to destroy the ecosystem.

1872, chemist Smith used "acid rain" for the first time in Air and Rainfall: The Beginning of the Chemical Climate School Year. This book pointed out the chemical characteristics of coal and organic matter that decompose precipitation, and also pointed out the harm of acid rain to plants and substances.

In the mid-1950s, Gorham, an American aquatic ecologist, did a series of research work, revealing the relationship between acidity of acidic precipitation in lake water and soil. The acidity of precipitation is caused by sulfur dioxide emitted from burning fossil fuels and metal smelting. However, their work has not attracted people's attention.

In 1960s, Swedish soil scientist greg oden first recorded limnology, agronomy, chemistry and atmospheric chemistry. Through comprehensive research, it was found that acidic precipitation was a common phenomenon in Europe, and ground precipitation increased the migration of acidic water, sulfur and nitrogen pollutants in Europe for thousands of kilometers.

1972, Swedish government, report submitted by the United Nations Conference on Human Environment: Impact of cross-border air pollution on the atmosphere and precipitation on the environment, knocking at the door. Since then, more and more countries have begun to pay attention to acid rain, and the scale of research has to be expanded.

The 1st International Symposium on Acid Rain and Forest Ecosystem, Ohio State University, May, 1975. 1982 In June, the international conference on environmental acidification was held in Stockholm, Sweden. Acid rain has become one of the main problems of global environmental pollution.

The formation of acid rain is a complex atmospheric chemical and physical phenomenon. Acid rain contained in various inorganic acids and organic acids must convert most of sulfuric acid, nitric acid, sulfuric acid and nitric acid into the amount of sulfur dioxide and nitrogen oxides discharged locally, but it also migrates from far away/>; In industrial activities, such as the combustion of coal and oil, sulfur dioxide produced by metal smelting is released into the air, and sulfuric acid is generated by gas-phase or liquid-phase oxidation reaction, which will generate high-temperature combustion air, nitrogen oxide and nitric oxide, which will continue to react with oxygen in the atmosphere, and most of them will be converted into nitrogen dioxide, nitric acid and nitrite to generate water or steam.

Due to human activities and natural processes, gas or solid substances entering the atmosphere will also form acid rain, which will affect the iron, copper and magnesium acid catalysts of atmospheric particles. Ozone and hydrogen peroxide are used as oxidants to oxidize sulfur dioxide; Fly ash, calcium oxide, calcium carbonate in soil, natural and artificial sources, ammonia and other alkaline substances react with acid, leaving acid.

In fact, the acidity of precipitation is mainly the balance of dry-cloudy and cationic precipitation. Atmospheric, precipitation acidity, sulfur dioxide and nitric oxide concentrations; Yang, the representative of several main alkaline substances, will have a high precipitation acidity in a hurry, and may even appear alkaline and alkaline earth areas, or the concentration of particulate matter in the atmosphere is very high, which is often the case. On the contrary, even if the concentration of sulfur dioxide and nitric oxide in the atmosphere is not high, there are few alkaline substances and they are still very acidic. The tall chimney-shaped sulfur and carbon dioxide in industrial areas will spread far away, which also reduces acid rain in many mountainous and wilderness areas.

Sulfur and nitrogen are indispensable nutrients for plant growth, and dissolved mineral precipitates are absorbed by weak acidic shells of plants and animals. For example, if the acidity is too high and the pH value drops below 5, the ecosystem will be destroyed.

The base saturation of soil is low and the soil layer is thin. Acid rain will make soil, lakes,

When the pH value of a lake or river is less than 5:00, the metal (such as aluminum) deposited in the basin of soil and water will acidify the river and dissolve it into the water, thus poisoning the fish. Changes in the composition and structure of aquatic organisms that are seriously acidified in reproduction and development will also lead to the increase and decrease of acid-resistant algae, fungi and bacteria in plant roots and invertebrates, and reduce the decomposition rate of organic matter. Therefore, reducing the acidification of lakes, rivers and fish, many lakes in southern Sweden and Norway, as well as the northeastern United States, have become dead fish in lakes.

Lake Adirondack in the United States is 700 meters above sea level, which is the pH value of more than half of the lakes in the east. Below 5,90%, there are no fish between 1929 and 1937, and only 4% of the lakes have a pH of 5 or lower, or there are no fish. More than 18000 large and medium-sized lakes in Sweden are acidified, about 4000 are seriously acidified, and aquatic organisms are seriously harmed.

Acid rain can also inhibit the fixation and leaching of nitrogen, soil particles, calcium, magnesium, potassium and other nutrient elements in the soil, and inhibit soil poverty and decomposition of organic matter in plants.

Acid rain will hurt new bamboo shoots, thus affecting the combination of growth and development; Acid rain corrodes the acidification of building materials, metal structures, paints, ancient buildings and statues, lakes and groundwater, because dissolved metals will affect the health of consumers.

The fundamental measure to control acid rain and reduce man-made emissions is another experiment of alkaline lime in acidified soil and water in Sweden and other countries, which has achieved good results.

How to reduce acid rain in a short time?

Acid rain, sulfur dioxide and nitric oxide. Important air quality is one of the problems we are facing today. The acidic substances in burning fossil fuels and power generation transmission are mainly compounds formed by acidic substances of sulfur oxides and nitrogen oxides in acids. These compounds come from some natural sources, such as lightning, volcanoes, biomass, combustion and microbial activities, but apart from rare volcanic eruptions, these natural gas vehicles are emitted by power plants and smelters, which is a relatively small amount.

Different strategic countermeasures to reduce acid rain, you may need to invest billions of dollars every year, because such a huge and very important understanding of atmospheric processes involves the migration of chemical pollutants and the change of cost and fate.

Acid deposition includes two parts, namely "wet" deposition (rain and snow) and dry deposition (aerosol or gaseous form trapped on the surface, such as acid compounds in soil particles and plant leaves). As of the settlement, are the materials regular? In an atmosphere with completely different chemical forms, for example, sulfur in coal is oxidized to sulfur dioxide, which is gaseous and discharged from the chimney, because they move slowly in the oxidized atmosphere and react with water to generate sulfate-possibly in a dissolved form hundreds of kilometers downwind.

The formation, route and final removal of nitrogen oxides from the atmosphere in the reaction are very complicated. When power plants are heated at the high temperature of nitrogen and oxygen, nitric oxide (NO) and nitrogen dioxide (NO 2) are produced at the high temperature of civil stoves and automobile engines, it is still quite uncertain for them and their leaders to quantitatively estimate the global nitrogen oxides with the balanced oxidant nitric acid (HNO3).

It was difficult to deeply understand the origin of biogeochemical cycles of different chemical forms of nitrogen, sulfur and carbon before, and finally it was easy to see the world of these chemicals. You can safely choose air pollution control strategies to achieve cleaner atmospheric chemistry, environmental chemistry and the core of a healthy environment. Reliable measurement can be used to track the chemical substances in the air, the most important atmospheric chemical reaction kinetics, and reduce the emission of pollutants. This is a new and more effective chemical process and must be carried out in the next 10 year.

[Edit this paragraph] Biological control of acid rain

Observation and research on the world, recently released 1994 Global? Trend Report 1994 Vital Features: Generally speaking, not all indicators can measure the health of the earth well. We have only successfully reversed the deterioration indicator-air Freon ozone layer reduces carbon dioxide emissions, but has not reduced the increasingly serious air pollution. According to statistics, SO2 1. 15 tons of NO2 are discharged into the atmosphere every year. About 5010.2 million tons, about half of the world's urban population lives in SO2 atmosphere, and 654.38 billion people live in the environment where particulate air pollution exceeds the standard, becoming hidden killers. The culprit of SO2. Twenty-six countries in Europe and Canada recently signed a new proposal to reduce sulfur dioxide emissions by 87%. According to the agreement of the United Nations Economic Commission for Europe, the United States promises to reduce 80% of sulfur dioxide emissions by 20 10. European countries and Canada praised the new agreement as a milestone in preventing and controlling air pollution. SO2 not only pollutes the air and harms human health, but also is the main raw material for acid rain. SO2 and NO2 in the air are dissolved in rainwater. In the air, measure meteor shower, sleet, snow, hail and other oxidants, such as pH less than 5.6. According to the statistics of acid rain of American authoritative organizations, sulfuric acid rain accounts for 60%, nitric acid accounts for 33%, hydrochloric acid accounts for 6%, and the rest is carbonic acid and a small amount of organic acids.

Severe acid rain has a negative impact on the earth's ecological environment, causing socio-economic and man-made destruction. Acid rain acidifies the soil, reduces soil fertility, and absorbs many toxic substances from toxic roots, thus killing root hairs, making plants unable to absorb water, soil and nutrients, and inhibiting plant growth and development. Acid rain acidifies rivers, lakes and water bodies, inhibits the growth and reproduction of aquatic organisms, and even leads to suffocation and death of fry. Acid rain also kills plankton in water, reduces the food source of fish, aquatic ecosystem diseases, and pollutes rivers, lakes and groundwater, directly or indirectly endangering human health. Acid rain directly damages plants (leaves and stems) on the surface or indirectly damages soil, and promotes deforestation. Acid rain also led to the outbreak of pests and diseases, leading to the death of large forests in Europe. In China and Sichuan, large areas of forests were destroyed. Acid rain is very corrosive. There are many ancient buildings and stone carvings in metal, stone, wood, cement and other building materials, which are corroded and destroyed all over the world. The parliament building in Leshan, Canada has been formed all over the world, and acid rain also directly damages wires, rails, bridges and houses.

The three major acid rain areas centered on Germany, France, Britain and other countries involve more than half of the Nordic acid rain areas in Europe. In the late 1950s, acid rain areas were formed in North America, including the United States and Canada. The total area of the two kinds of acid rain reached more than 6,543,800 square kilometers? The pH value of less precipitation is less than 5.0, and some even less than 4.0. In some cities and regions in China, such as Sichuan, Guizhou, Guangdong, Guangxi, Hunan, Hubei, Jiangxi, Zhejiang, Jiangsu and Qingdao. A million square kilometers acid rain area began to form in the mid-1970s, making it the third largest acid rain area in the world. The area of acid rain in China is small, but the acidification rate of precipitation caused by air pollution, which is rare in the world, is rapidly increasing and expanding, and there is no national boundary. "