07-02-2017, 11:19 PM
10-02-2017, 12:12 PM
The vast majority of today's cars and trucks travel using internal combustion engines that burn gasoline or other fossil fuels. The process of burning gasoline to fuel cars and trucks contributes to air pollution by releasing a variety of emissions into the atmosphere. Emissions released directly into the atmosphere from the exhaust pipes of cars and trucks are the main source of vehicular contamination. But motor vehicles also pollute the air during manufacturing processes, refueling, and emissions associated with oil refining and the fuel distribution they burn.
Primary pollution of motor vehicles is pollution that is emitted directly into the atmosphere, while secondary pollution is the result of chemical reactions between pollutants after being released into the air.
Despite decades of efforts to control air pollution, at least 92 million Americans still live in areas with chronic smog problems. The US Environmental Protection Agency (EPA) predicts that by 2010, even with the benefit of current and planned pollution control programs, more than 93 million people live in areas that Violate ozone standards and more than 55 million Americans will suffer from unhealthy levels of fine particle pollution, which is especially harmful to children and senior citizens.
While new cars and light trucks emit 90 percent fewer pollutants than three decades ago, the annual total of miles per vehicle has increased more than 140 percent since 1970 and is expected to increase another 25 percent for the year 2010. Emissions reductions Vehicles have not kept pace with increased miles driven and the market trend towards more polluting light trucks, a category that includes sport utility vehicles (SUVs). As a result, automobiles and light trucks continue to be the main source of air pollution in most urban areas, accounting for a quarter of smog-forming pollutant emissions across the country.
Cars and Air Pollution
The main air pollutant emissions from gasoline, diesel and alternative fuel engines are carbon monoxide, nitrogen oxides, unburned hydrocarbons and particulates. They are the emissions of these pollutants that are regulated by the Euro emission standards. Modern automobiles, if kept in good condition, produce only very small amounts of air quality pollutants, but emissions from a large number of cars add up to a significant air quality problem. Carbon monoxide, nitrogen oxides, and unburned hydrocarbons are gases and are generally invisible. The particles are usually invisible although under certain operating conditions diesel engines produce visible particles, which appear as smoke. Gasoline engines will also produce visible particles if they are burning engine oil or operating "rich", for example, after a cold start. Fine particles can also be produced by tire wear and braking. Emission levels of pollutants are more dependent on vehicle technology and vehicle maintenance status. Unlike CO2 emissions, the emission of pollutants from air quality depends less on fuel consumption. Other factors, such as driving style, driving conditions and ambient temperature also affect them. However, as a starting point, all new passenger cars must comply with the EU minimum emission standards.
The ingredients of air pollution
Cars and trucks produce air pollution throughout their lives, including pollution emitted during vehicle operation, refueling, manufacturing and disposal. Additional emissions are associated with refining and fuel distribution of the vehicle.
Air pollution from cars and trucks is divided into primary and secondary pollution. Primary pollution is emitted directly into the atmosphere; Secondary pollution is the result of chemical reactions between pollutants in the atmosphere. The following are the main pollutants of motor vehicles:
Particles (PM). These particles of soot and metals give smog their cloudy color. Fine particles - less than a tenth the diameter of a human hair - represent the most serious threat to human health, as they can penetrate deep into the lungs. PM is a direct (primary) pollution and a secondary contamination by hydrocarbons, nitrogen oxides and sulfur dioxides. Diesel exhaust gas is a major contributor to PM contamination.
Hydrocarbons (HC). These pollutants react with nitrogen oxides in the presence of sunlight to form ozone at ground level, a primary ingredient in smog. Although it is beneficial in the upper atmosphere, at ground level this gas irritates the respiratory system, causing coughing, choking and reduced lung capacity.
Nitrogen Oxides (NOx). These contaminants cause lung irritation and weaken the body's defenses against respiratory infections such as pneumonia and the flu. In addition, they help in the formation of ground-level ozone and particles.
Carbon monoxide (CO). This odorless, colorless and poisonous gas is formed by the combustion of fossil fuels like gasoline and is emitted mainly from cars and trucks. When inhaled, CO blocks oxygen from the brain, heart and other vital organs. Fetuses, newborns and people with chronic diseases are especially susceptible to the effects of CO.
Sulfur dioxide (SO2). Power plants and motor vehicles create this pollutant by burning sulfur-containing fuels, especially diesel. Sulfur dioxide can react in the atmosphere to form fine particles and represents the greatest health risk to young children and asthmatics.
Hazardous (toxic) air pollutants. These chemicals have been linked to birth defects, cancer and other serious diseases. The Environmental Protection Agency estimates that atmospheric toxicants emitted by cars and trucks - which include benzene, acetaldehyde and 1,3-butadiene - account for half of all cancers caused by air pollution.
Greenhouse gases. Motor vehicles also emit pollutants, such as carbon dioxide, that contribute to global climate change. In fact, automobiles and trucks account for more than a fifth of the total pollution of global warming in the United States; Transportation, which includes freight, trains and airplanes, accounts for about thirty percent of all gas emissions that trap heat.
Primary pollution of motor vehicles is pollution that is emitted directly into the atmosphere, while secondary pollution is the result of chemical reactions between pollutants after being released into the air.
Despite decades of efforts to control air pollution, at least 92 million Americans still live in areas with chronic smog problems. The US Environmental Protection Agency (EPA) predicts that by 2010, even with the benefit of current and planned pollution control programs, more than 93 million people live in areas that Violate ozone standards and more than 55 million Americans will suffer from unhealthy levels of fine particle pollution, which is especially harmful to children and senior citizens.
While new cars and light trucks emit 90 percent fewer pollutants than three decades ago, the annual total of miles per vehicle has increased more than 140 percent since 1970 and is expected to increase another 25 percent for the year 2010. Emissions reductions Vehicles have not kept pace with increased miles driven and the market trend towards more polluting light trucks, a category that includes sport utility vehicles (SUVs). As a result, automobiles and light trucks continue to be the main source of air pollution in most urban areas, accounting for a quarter of smog-forming pollutant emissions across the country.
Cars and Air Pollution
The main air pollutant emissions from gasoline, diesel and alternative fuel engines are carbon monoxide, nitrogen oxides, unburned hydrocarbons and particulates. They are the emissions of these pollutants that are regulated by the Euro emission standards. Modern automobiles, if kept in good condition, produce only very small amounts of air quality pollutants, but emissions from a large number of cars add up to a significant air quality problem. Carbon monoxide, nitrogen oxides, and unburned hydrocarbons are gases and are generally invisible. The particles are usually invisible although under certain operating conditions diesel engines produce visible particles, which appear as smoke. Gasoline engines will also produce visible particles if they are burning engine oil or operating "rich", for example, after a cold start. Fine particles can also be produced by tire wear and braking. Emission levels of pollutants are more dependent on vehicle technology and vehicle maintenance status. Unlike CO2 emissions, the emission of pollutants from air quality depends less on fuel consumption. Other factors, such as driving style, driving conditions and ambient temperature also affect them. However, as a starting point, all new passenger cars must comply with the EU minimum emission standards.
The ingredients of air pollution
Cars and trucks produce air pollution throughout their lives, including pollution emitted during vehicle operation, refueling, manufacturing and disposal. Additional emissions are associated with refining and fuel distribution of the vehicle.
Air pollution from cars and trucks is divided into primary and secondary pollution. Primary pollution is emitted directly into the atmosphere; Secondary pollution is the result of chemical reactions between pollutants in the atmosphere. The following are the main pollutants of motor vehicles:
Particles (PM). These particles of soot and metals give smog their cloudy color. Fine particles - less than a tenth the diameter of a human hair - represent the most serious threat to human health, as they can penetrate deep into the lungs. PM is a direct (primary) pollution and a secondary contamination by hydrocarbons, nitrogen oxides and sulfur dioxides. Diesel exhaust gas is a major contributor to PM contamination.
Hydrocarbons (HC). These pollutants react with nitrogen oxides in the presence of sunlight to form ozone at ground level, a primary ingredient in smog. Although it is beneficial in the upper atmosphere, at ground level this gas irritates the respiratory system, causing coughing, choking and reduced lung capacity.
Nitrogen Oxides (NOx). These contaminants cause lung irritation and weaken the body's defenses against respiratory infections such as pneumonia and the flu. In addition, they help in the formation of ground-level ozone and particles.
Carbon monoxide (CO). This odorless, colorless and poisonous gas is formed by the combustion of fossil fuels like gasoline and is emitted mainly from cars and trucks. When inhaled, CO blocks oxygen from the brain, heart and other vital organs. Fetuses, newborns and people with chronic diseases are especially susceptible to the effects of CO.
Sulfur dioxide (SO2). Power plants and motor vehicles create this pollutant by burning sulfur-containing fuels, especially diesel. Sulfur dioxide can react in the atmosphere to form fine particles and represents the greatest health risk to young children and asthmatics.
Hazardous (toxic) air pollutants. These chemicals have been linked to birth defects, cancer and other serious diseases. The Environmental Protection Agency estimates that atmospheric toxicants emitted by cars and trucks - which include benzene, acetaldehyde and 1,3-butadiene - account for half of all cancers caused by air pollution.
Greenhouse gases. Motor vehicles also emit pollutants, such as carbon dioxide, that contribute to global climate change. In fact, automobiles and trucks account for more than a fifth of the total pollution of global warming in the United States; Transportation, which includes freight, trains and airplanes, accounts for about thirty percent of all gas emissions that trap heat.