What pollutes the air in the city? What substances pollute the air?

The change in the gas composition of the atmosphere is the result of a combination of natural phenomena in nature and human activity. But which of these processes is prevailing at the present time? In order to find out, we first clarify that it pollutes the air. Its relatively constant composition over the past years is subject to significant fluctuations. Let us consider the main problems of controlling emissions and protecting the purity of the air basin by the example of this work in the cities.

Does the composition of the atmosphere change?

Pollution of air ecologists consider change of its average indicators collected for long time of supervision. They occur as a result of many types of social impact on the environment, as well as due to natural processes. For example, substances that pollute the air and change the gas composition of the atmosphere are formed as a result of respiration, photo- and chemosynthesis in cells of living organisms.

In addition to natural, there is anthropogenic pollution. Its sources can be the emissions of any production facilities, gaseous waste from the domestic utility industry, and emissions from transport. This is exactly what pollutes the air, threatens the health and well-being of a person, the state of the entire environment. The main indicators of the composition of the atmosphere should remain unchanged, such as in the diagram below.

The content of some components in the atmosphere is insignificant, but it is taken into account when deciding which substances pollute the air and which are harmless to living organisms. In the table, located just below, except for the main ones, constant components of the air medium are also included, the content of which increases during volcanism, economic activity of the population (carbon dioxide and nitrogen, methane).

What does not pollute the air?

The gas composition of the atmosphere over the oceans, seas, forests and meadows, biosphere reserves is changing less than in cities. Of course, on Wednesday above the above-mentioned natural objects, too, substances come. Gas exchange in the biosphere is constantly. But in ecosystems, the process prevails that does not pollute the air. For example, in the forests - photosynthesis, over water objects - evaporation. Bacteria fix nitrogen from the air, plants secrete and absorb carbon dioxide. The atmosphere over the oceans and seas is saturated with water vapor, iodine, bromine, chlorine.

What pollutes the air?

Dangerous for living organisms are very diverse, there are more than 20,000 pollutants in the biosphere. In an atmosphere of megacities, industrial and transport centers, simple and complex gaseous substances, aerosols, small solid particles are present. Let's list what substances pollute the air:

• Carbon monoxide and carbon dioxide (mono- and carbon dioxide);
• Sulfuric and sulfurous anhydrides (di- and sulfur trioxide);
• Nitrogen compounds (oxides and ammonia);
• Methane and other gaseous hydrocarbons;
• Dust, soot and suspended particles, for example, ores in mining areas.

What are the sources of emissions?

Harmful, air polluting substances enter the atmosphere not only in the gas and vapor state, but also in the form of tiny droplets, solid particles of different sizes. Accounting for the pollution coming from enterprises and transport lead to specific compounds, their groups (solid, gaseous, liquid).

The concentration of constant and variable air components changes during the day, at times of the year. When calculating the content of pollutants take into account the atmospheric pressure, temperature, wind direction, because meteorological conditions affect the composition of the surface layer of the atmosphere. Changes in the concentration of most components, for example, carbon dioxide, occur not only during the year. An increase in the amount of CO ₂ in the last hundred years (greenhouse effect) has been noted. In some cases, the changes in the concentration of substances are due to natural phenomena. These can be volcanic eruptions, spontaneous exits of poisonous compounds from under the ground or water in certain areas. But more often the unfavorable changes in the composition of the atmosphere are caused by human activity.

What pollutes the air on Earth? Natural and anthropogenic sources of emissions of harmful compounds. The latter are stationary (pipes of enterprises, boiler houses, fuel dispensers of filling stations) and mobile (different types of transport). Let's list the main objects from which substances that pollute the air come:

• Operating enterprises of many industries;
• Career, where the extraction of minerals is conducted;
• Cars (pollute the air when burning fuels derived from oil, gas and other carbonaceous substances);
• Filling stations for gaseous and liquid fuels;
• Boiler houses using combustible fossil fuels and products of their processing;
• Polygons and garbage dumps where substances polluting the atmospheric air are formed as a result of decay, decomposition of industrial and domestic waste.

Agricultural land, such as fields, orchards, vegetable gardens, also contribute to a negative change in the composition of the atmosphere. This is due to the operation of machinery, the introduction of fertilizers, spraying pesticides.

What is the main source of air pollution?

Many harmful compounds enter the atmosphere during missile launches, waste incineration, fires in populated areas, forests, fields and steppes. In heavily populated regions, the most significant contribution to the change in the composition of the surface layer of the atmosphere is made by motor transport. According to various estimates, it accounts for 60 to 95% of all gaseous emissions.

What pollutes the air in the city? The population of urbanized countries is particularly affected by toxic products of burning fuel and fuel. As part of harmful emissions there are solid particles, for example, soot and lead, liquid and gaseous compounds: sulfur dioxide, carbon monoxide, nitrogen oxides, hydrocarbons and their derivatives.

Plants pollute the air in industrial regions, where industries that process metal ores, salts, oil, coal and natural gas are developed. The composition of emissions varies depending on the set of industries in this or that region of the country. Contaminated air in cities often contains combustion products, among them there are many carcinogens, for example, dioxin. Smoke appears due to forest, steppe and peat fires, burning leaves and debris. Woods and waste are often burnt in the vicinity of cities, but it happens that even directly on the streets, people are burning leaves and grass.

What substances contain emissions from industry and transport?

What pollutes the air in the city? Industrial centers, transport, communal and construction enterprises operate in industrial centers. Each object separately and all together have anthropogenic impact on the environment. Pollutants often interact with each other. Most often, dissolution of oxides of non-metals in droplets of water - this is how "acid" fog and rain form. They cause irreparable damage to nature, human health and architectural masterpieces.

Gross emissions of pollutants in cities reach hundreds and thousands of tons. The greatest volume of toxic compounds comes from the enterprises of metallurgical, fuel-energy, chemical, transport industry. Factories pollute the air with toxic substances: ammonia, benzapyrene, sulfur dioxide, formaldehyde, mercaptan, phenol. The emissions of a large industrial enterprise contain from 20 to 120 types of compounds. To a lesser degree, harmful compounds are formed at the food and light industries, in educational, health and cultural institutions.

Are burning products of organic debris dangerous?

In cities, it is prohibited to burn fallen leaves, grass, cuttings, packaging, building materials and other industrial and domestic waste. Corrosive smoke contains substances that pollute the atmosphere. They damage the health of people, generally worsen the quality of the environment.

It is alarming that some citizens and employees of enterprises do not understand that they violate the rules of improvement, exacerbating the already unfavorable ecological situation, when garbage heaps and manure are burned in their plots, in the courtyards of multi-storey houses, they burn containers in containers. Very often in the garbage there are plastic bottles, a film. This smoke is particularly harmful due to the products of thermal decomposition of polymers. In the Russian Federation, firing incineration within the boundaries of the settlement is subject to penalties.

When burning parts of plants, bones, animal skins, polymers and other products of organic synthesis, carbon oxides, water vapor, and a few nitrogen compounds are released. But these are not all substances that pollute the air, which are formed during the burning or smoldering of waste, domestic garbage. If leaves, branches, grass and other materials are damp, then more toxic substances are released than harmless water vapor. For example, at a smearing of 1 ton of moist foliage, about 30 kg of carbon monoxide (carbon monoxide) is released.

Standing next to a smoldering garbage heap is the same as being on the most gassed traffic road of a metropolis. The danger of carbon monoxide lies in the fact that it binds hemoglobin of the blood. The resulting carboxyhemoglobin can no longer deliver oxygen into the cells. Other substances that pollute the atmospheric air can cause disruption of the bronchi and lungs, poisoning, exacerbation of chronic diseases. For example, if you inhale carbon monoxide, the heart works with increased pressure, as oxygen is not enough to enter the tissues. In this case cardiovascular diseases can become aggravated. Even more dangerous is the combination of carbon monoxide with pollutants in industrial emissions, transport emissions.

Concentration of pollutants

Harmful emissions come from metallurgical, coal, oil and gas processing plants, energy facilities, construction and utilities. Radioactive contamination from explosions at the Chernobyl nuclear power plant and nuclear power plants in Japan has spread globally. There is an increase in the content of carbon oxides, sulfur, nitrogen, freons, radioactive and other dangerous emissions in different parts of our planet. Sometimes toxins are found far from the place where air polluting enterprises are located. The situation that has arisen is disturbing and difficult to solve by the global problem of mankind.

As early as in 1973, the profile committee of the World Health Organization (WHO) proposed criteria for assessing the quality of atmospheric air in cities. Experts found that the health of people by 15-20% depends on environmental conditions. Based on many studies in the XX century, permissible levels of the main pollutants, harmless to the population, were determined. For example, the average annual concentration in air of suspended particles should be 40 μg / m ^₃ . The content of sulfur oxides should not exceed 60 μg / m ^₃ per year. For carbon monoxide, the corresponding average value is 10 mg / m ^₃ for 8 hours.

What is the maximum permissible concentration (MPC)?

By the decision of the Chief State Sanitary Doctor of the Russian Federation, a hygienic standard for the maintenance of almost 600 harmful compounds in the atmosphere of settlements was approved. This MPC of pollutants in the air, compliance with which indicates the absence of adverse effects on people and sanitation. The norm specifies the hazard classes of compounds, the values of their content in air (mg / m ^₃ ). These indicators are refined when new data on the toxicity of certain substances appear. But that's not all. The document contains a list of 38 substances for which a ban on ejection has been introduced because of their high biological activity.

How is state control in the field of atmospheric air protection carried out?

Anthropogenic changes in air composition lead to negative consequences in the economy, health deteriorates and people's life expectancy decreases. The problems of increasing the flow of harmful compounds into the atmosphere are disturbing both by governments, state and municipal authorities, and the public, ordinary people.

Legislation of many countries provides for engineering and environmental research before the start of construction, reconstruction, modernization of almost all objects of the economy. Normalization of pollutants in the air is carried out, measures are being taken to protect the atmosphere. The problems of reducing the anthropogenic load on the environment, reducing emissions and discharges of pollutants are being addressed. In Russia, federal laws on the protection of the environment, atmospheric air, and other legislative and regulatory acts regulating activities in the environmental sphere have been adopted. State environmental control is carried out, pollutants are limited, emissions are regulated.

What is MPE?

Enterprises that pollute the air should make an inventory of the sources of harmful compounds entering the air. Usually this work finds its logical continuation in determining maximum permissible emissions (MPE). The necessity of obtaining this document is connected with the normalization of the technogenic load on atmospheric air. Based on the information that is included in the MPE volume, the company receives permission to release pollutants into the atmosphere. Data on regulatory emissions are used to calculate payments for adverse environmental effects.

If there is no volume of MPE and no permit, then for the emissions from sources of pollution located on the territory of an industrial or other industry object, enterprises pay 2, 5, 10 times more. The normalization of pollutants in the air leads to a reduction in the negative impact on the atmosphere. There is an economic incentive for carrying out measures to protect nature from foreign compounds entering it.

Payments for environmental pollution from enterprises are accumulated by local and federal authorities in specially created budget environmental funds. Funds are spent on environmental activities.

How do they clean and protect air in industrial and other facilities?

Purification of polluted air is carried out by different methods. Filters are installed on the pipes of boiler-houses and processing enterprises, there are dust and gas catching installations. Through the use of thermal decomposition and oxidation, some toxic substances are converted into harmless compounds. The capture of harmful gases in emissions is carried out by condensation methods, sorbents are used to absorb impurities, catalysts for purification.

Prospects for activities in the field of air protection are related to work to reduce the flow of pollutants into the atmosphere. It is necessary to develop laboratory monitoring of harmful emissions in cities, on busy transport routes. Work should continue on the introduction of systems for collecting particulate matter from gaseous mixtures in enterprises. We need cheap modern devices for cleaning emissions from toxic aerosols and gases. In the field of state control it is required to increase the number of posts for testing and adjusting the toxicity of automobile exhausts. Enterprises of the energy sector and motor transport should be transferred to less harmful, in terms of ecology, types of fuel (say, natural gas, biofuel). At their combustion less solid and liquid pollutants are released.

What role does green planting play in clearing atmospheric air?

It is difficult to overestimate the contribution of plants to the replenishment of oxygen reserves on Earth, the trapping of pollution. Forests are called "green gold", "lungs of the planet" for the ability of leaves to photosynthesis. This process consists in the absorption of carbon dioxide and water, the formation of oxygen and starch in the light. Plants release into the air phytoncides - substances that are destructive to pathogenic microbes.

The increase in the area of green spaces in cities is one of the most important environmental measures. Plant trees, bushes, grasses and flowers in the courtyards of houses, parks, squares and along roads. Green areas of schools and hospitals, industrial enterprises.

Scientists have found that it is best to absorb dust and harmful gaseous substances from emissions of enterprises, transport emissions such plants as poplar, linden, sunflower. The most of the phytoncides are coniferous plantations. The air in pine, fir, juniper forests is very clean and healing.