Publikované: 18.11.2015

Exhaust gases

Exhaust gases
Air pollution is still increasing due to industrial emissions, exhaust, smoke from heating appliances and secondary dust, which causes the vehicles, wind, etc. works. Gas, liquid and solid particles of substances that contaminate air, precipitation, and sedimentation is coming back to earth, where significantly alter the soil and water. All air pollutants, gaseous and solid, we call air pollutants. We distinguish in these emissions and air pollutants.
Emissions are emissions produced by the specific source (a plant the hutou, ..).
Emissions of harmful impurities in the atmosphere can be divided into three groups
1. additives to prevent the penetration of direct sunlight on the Earth’s surface – aerosols (sulphate, nitrate, carbon black, volcanic ash, desert sands).
2. ozonosphere toxic ingredients – especially halogenated hydrocarbons, namely chlorofluorocarbons and the like (freons, halons) .In the stratosphere decomposition to components of destroying the ozonosphere and results in a potentiation of the of UV light on the surface.
3. additives enhancing the greenhouse effect of the atmosphere called. greenhouse gases (H2O, CO2, CH4, N2O, O3, CFCs, halons, perfluorocarbons), ie gases that absorb long-wave radiation of the Earth and cause amplification of the natural greenhouse effect of the atmosphere, ie global warming ground layer of atmosphere.
All the pollutants present in the air, regardless of their origin, for example. in cities they form the exhaust fumes of cars, smoke from heating systems, air pollutants and plants. Solids were evaluated as SPM.
Impact of air pollution on organisms manifests itself directly and indirectly.
The primary damage imminent irritants and toxic effects of air pollution on organisms. Clog vents plant in animals produce catarrh of the mucous membranes, allergic reactions, poisoning, etc.
Secondary damage consisting in environmental degradation, for example. smoke and dust reduce solar radiation, aerosols become condensation nuclei for the formation of fog and smog.
To the right
One of the areas which seriously affects the quality of the environment gaseous pollutants is right. Transport has a number of negative impacts on the health of humans, animals, the plants and the quality of the environment at all. These impacts: air pollution exhaust emissions, carbon dioxide emissions, ground and water pollution, noise, accidents, land and energy consumption.
It is estimated that the global impact of exhaust emissions from motor vehicles up to 10 billion cubic meters annually. Transport has become the largest polluter of the environment in cities. Emissions from the combustion of gasoline and diesel fuel have an effect on all living organisms. Emissions also affect global climate change, the consequences of which will have repercussions for many years.
Air pollution contributes the most. Produces 91-97% of harmful emissions from all modes of transport. One car produces about one ton per year of harmful gases (carbon monoxide, hydrocarbons, nitrogen oxides, častice- benzopyrene, lead).
rail transport
By switching to diesel and electric traction particular significantly reduces the amount of harmful air pollutants. In terms of air protection, preferably as electric locomotives. Environmental and energy is very convenient.
Water transportation
Although it is a little difficult, but causes enormous interventions in aquatic ecosystems and the water flows. Make full use of diesel engines with large engine power. To air they can receive particular carbon monoxide, sulfur oxides, nitrogen oxides, aldehydes, unburnt hydrocarbons.
Air transport
In recent years it becomes a major air polluter. The major impurities are carbon monoxide, nitrogen oxides, unburnt hydrocarbons, the products of incomplete oxidation, aldehydes, carbon black.
Plume containing harmful pollutants at the start and landing lietadiel.Zápach kerosene accompanying runway of aviation on a large vzdialenosť.Hmla reducing visibility and maneuverability while piloting aircraft
Are there concerns about possible disruption of balance in the upper atmosphere. This is about the oxygen uptake and considerable production of harmful substances – carbon monoxide, nitrogen oxides, hydrocarbons, non-combustible, Incomplete oxygenation, aldehydes, carbon black. The combustion reaction engines of supersonic aircraft respond in the high layers of the atmosphere with ozone, thereby reducing the thickness of the layer of protective gas. The share of aviation on air pollution is still relatively small.
Exhaust fumes contain
Water, particulate matter, carbon monoxide (CO), carbon dioxide (CO 2), unburned hydrocarbons (HC), nitrogen oxides (NOx), sulfur dioxide (SO2), aldehydes, ketones, heavy metals (e.g. lead), carbon black ,. ..
Composition of exhaust gases depends
Kind of internal combustion engines
Spark ignition (gasoline), diesel (diesel) – has a higher sulfur content, there is an increased
the amount of sulfur dioxide
Type of fuel used
Knštrukcie engine and accessories
Precision manufacturing and setting internal combustion engine
Operating conditions (deceleration, acceleration, idle)
Overview exhaust
Carbon monoxide (CO)
The most harmful exhaust gas components. Formed by incomplete combustion of fuel in the engine when there is insufficient amount of oxygen. The main negative effects of CO through blocking the delivery of oxygen to the tissue. The classic symptoms of CO poisoning are headache and dizziness, heart problems and dizziness. In high concentrations may result in the death of the affected person.
Carbon dioxide (CO2)
Most CO2 produced in our road transport – almost 93.0%. Any motor vehicle burning petrol or diesel causes emissions of carbon dioxide into the atmosphere. CO2 is not toxic for organisms, but it has an impact on global climate change (greenhouse effect). Carbon dioxide is the most important so-called. greenhouse gases and is responsible for over 50% of emissions contributing to this is currently the most serious environmental problems. Transport to the global CO2 emissions accounts for almost 25%.
Unburned hydrocarbons
Unpleasant odor surroundings. The hydrocarbon emissions occur as a result of incomplete combustion of fuel molecules in the engine. Hydrocarbons can escape from the vehicle tank and evaporation, especially in summer, or during refueling. Some are carcinogenic (polyaromatic hydrocarbons – benzopyrene), which occur even at high temperatures (700-800 ° C). As for the polycyclic hydrocarbons as particles of the atmospheric concentration is very low.
Nitrogen oxides (NOx)
The most serious role in the issue of air pollution play:
Nitric oxide – NO, into the atmosphere gets a result of direct response merger molecular nitrogen and oxygen in the presence of high temperature (endothermic reaction) N2 + O2 → 2 NO
Nitrous oxide – NO2 (dimer – N2O4), formed by direct oxidation of NO (very slow) 2 NO + O2 → 2 NO2
By the formation of nitrogen oxides occurs each time the air being heated by the combustion of the fuel occurs. It is dependent on the temperature of the process – the higher the temperature, the higher the formation. NO2 acts as an irritant gas. Nitrogen oxides cause mild to severe bronchitis or lung. In Europe, about one third causing acidification of rainfall. Over 90% of the emitted nitrogen oxides as nitric oxide (NO). In the air, this gas is rapidly converted to carbon dioxide. NO2 is converted to acid, nitrogen dioxide, which is associated with moisture and leads to the formation of so-called. acid rain along with sulfur dioxide, which have a negative impact on organisms and materials. N2O emissions are destroying the ozone layer and are also called. greenhouse gas that causes climate change.
Sulphur dioxide (SO2)
Sulfur emissions in the transport sector comes mainly from the combustion of diesel fuel in trucks, tractors, locomotives, construction machinery and ships.
Sulphur dioxide is partially in the ambient air further oxidizes to sulfur trioxide and sulfuric acid. The compounds are carbon black, along the so-called component. Black (reducing) smog.
The effect on atmospheric pollution over other less harmful substances. This creates an incomplete oxidation of hydrocarbon combustion engines running. Acrolein (CH 2 CHCO) produces a pungent sensation in the eye, mucous membranes, feel it in the cabs of trucks.
Lead (Pb)
During the combustion of fuel in car engines are released into the air of heavy metals contained in petrol respectively. fuels such as arsenic, cadmium, mercury, lead and zinc. The amount of lead depends on fuel composition, engine speeds. It acts primarily on the nervous system. Influence the effects of lead in the air on the health of the population is reflected mainly in the reduction of IQ in children. The part of the lead, which is fixed in the body adversely affects erythrocytes production. The causes of excess body mental retardation, memory impairment, fatigue, difficulty sleeping, dizziness, low blood pressure.
Carbon Black
This creates imperfect combustion of rich mixtures. The basis of carbon black is carbon, the surface of which is adsorbed another pollutant, in particular carcinogenic polyaromatic hydrocarbons.
Some of these substances promote the formation of secondary pollutants: ozone, peracylnitrátov, singlet oxygen and solid aerosols in the atmosphere, which are components of the so-called. photochemical white (oxidation) smog.
The combustion of petrol and diesel in motor vehicles leads to the formation of nitrogen oxides and other chemical substances under the influence of sunlight leads to increased concentrations of ground level ozone atmosphere. The concentration of ozone is increased by an average of 2% per year.
The average residence times of certain components of the atmosphere One car produced annually
Constituents of the atmosphere approximate residence time of 800 kg carbon dioxide NO2 three days 100 kg of hydrocarbons 5 days SO2, NH3 7 days 70 kg of nitrogen oxides, 10days H2O, O3 2 years 10 kg of particulates, CO three years, four years CO2 1 kg of lead.
Options for reducing emissions
Efforts to reduce the amount of pollutants in the exhaust of motor vehicles and the impending shortage of liquid fuels is forcing both to look for another type of engine to drive passenger cars, such as the gasoline engine, and also improved the design of the engine. The main directions of structural modifications of the combustion engine in terms of reducing pollutants can be expected in the following areas:
Modification of the composition of fuel and new fuel (propane – butane, methanol, ethanol, hydrogen, ..)
The lean-burn gasoline engine in
Injection readily vaporizable fuel cartridge exchange management, program the combustion process and post-combustion carbon monoxide and hydrocarbons, destruction of nitrogen oxides in the exhaust gas
The ideal solution would be the so-called transition. clean fuels (zero emission vehicles). Technological measures: use as catalyst in passenger cars reduces exhaust emissions when engine is warm, depending on the driving speed as follows: CO by 80%, NOx by 85% and VOCs by 90%. On the other hand, increase the concentration of carbon uhličitého- greenhouse effect.
The value of air pollution can be reduced by motorists themselves by keeping the vehicle in good condition, driving in the right way and the right carburettor adjustment.

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