Nitrogen oxides, from automobile

An economic externality exists whenever the wellbeing of some individual is affected by the economic activities of others without particular attention to the welfare of that individual. For example, smog-related illnesses such as bronchitis and exacerbated cases of childhood asthma have been blamed, to some extent, on the emissions of nitrogen oxides from automobiles and large fossil-fuel-burning power plants. These illnesses have high treatment costs that are not... 

In the stratosphere, the region of the atmosphere from 10 up to 50 km, ozone is synthesized from dioxygen in a complex cycle of reactions. Thanks to its strong absorption of ultraviolet radiation in the range between 232 and 290 nm, ozone provides a protective shield for the plant and animal life on the earth s surface. Because no other atmospheric species can absorb the intense radiation in this range, the ozone layer is absolutely critical to the earth s inhabitants and has been the focus of numerous investigations. A major concern is the possible depletion of the ozone layer by nitrogen oxides from automobile exhausts and by Freons from aerosal sprays. 

Photochemical smog, an infamous example being Los Angeles smog, is a combination of unburned hydrocarbons, carbon monoxide, and nitrogen oxides from automobile exhaust that reacts under the influence of sunlight to produce a variety... 

The reaction chambers used to remove nitrogen oxides from power station flue gases constitute the largest type of fixed-bed reactors as regards reactor volume and throughput, while automobile exhaust purification... 

The most widespread and persistent urban pollution problem is ozone. The causes of this and the lesser problem of CO and PMjq pollution in our urban areas are largely due to the diversity and number of urban air pollution sources. One component of urban smog, hydrocarbons, comes from automobile emissions, petroleum refineries, chemical plants, dry cleaners, gasoline stations, house painting, and printing shops. Another key component, nitrogen oxides, comes from the combustion of fuel for transportation, utilities, and industries. 

The Clean Air Act of 1990 establishes tighter pollution standards for emissions from automobiles and trucks. These standards will reduce tailpipe emissions of hydrocarbons, carbon monoxide, and nitrogen oxides on a phased-in basis beginning in model year 1994. Automobile manufacturers will also be required to reduce vehicle emissions resulting from the evaporation of gasoline during refueling. 

An example of a set of emission limits based on the rollback approach is the limits adopted by the United States for carbon monoxide, hydrocarbons, and oxides of nitrogen emissions from new automobiles (Table 25-2). 

The exhaust gas from an average automobile contains 206 ppm of the pollutant nitrogen oxide, NO. If an automobile emits 125 L of exhaust gas at 1.00 atm and 350 K, what mass of NO has been added to the atmosphere ... 

Acid rain is actually a catchall phrase for any kind of acidic precipitation, including snow, sleet, mist, and fog. Acid rain begins when water comes into contact with sulfur and nitrogen oxides in the atmosphere. These oxides can come from natural sources such as volcanic emissions or decaying plants. But there are man-made sources as well, such as power plant and automobile emissions. In the United States, two-thirds of all the sulfur dioxide and one-fourth of the nitrogen oxides in the atmosphere are produced by coal-burning power plants. 

The best way to prevent these problems is to prevent acid rain at the start. Reducing emissions from automobiles and power plants would help reduce acid-rain levels. This means conserving energy and driving less. The less energy people use, the less coal needs to be burned to produce electricity. These measures help decrease the sulfur and nitrogen oxides in the atmosphere and, therefore, decrease the amount of acid rain. 

With the advance of three-way catalysis for pollution control, used mainly in automobile catalytic conversion but also for the purification of gas exhausts from stationary sources, a need has arisen to develop a basic understanding of the reactions associated with the reduction of nitrogen oxides on transition metal catalytic surfaces [1,2]. That conversion is typically carried out by using rhodium-based catalysts [3], which makes the process quite expensive. Consequently, extensive effort has been placed on trying to minimize the amount of the metal needed and/or to replace it with an alternatively cheaper and more durable active phase. However, there is still ample room for improvement in this direction. By building a molecular-level picture of theprocesses involved,... 

Because wholesale bans of this type will not occur, then another approach to achieving safety, at least for pollutants, might be suggested. Why not seek the goal of no detectable chemicals in the media of human exposure If automobiles emit various nitrogen oxides, simply ensure that emission rates are sufficiently low so that these noxious chemicals cannot be found in air. If PCBs are migrating from a hazardous waste site, impose limits on that migration so that no detectable PCBs are found in the off-site environment. Control afla-toxin contamination of raw food commodities to ensure none can be found in finished foods. Why not apply this approach to all pollutants (it obviously is not applicable to products) ... 

Automobile accidents, oxidant concentration and, 427 Automotive exhaust aerosol formation from, 60 chemiluminescence associated with. 48 diolefins in, 101 hydrocarbons in, 1,95-%, 97 nitrogen oxides in. 1... 

Nitric oxide was discovered by Van Helmont in 1620. It occurs in the exhaust gases from automobiles along with other oxides of nitrogen, at trace concentrations. It also is found in minute quantities in the upper atmos-... 

Combustion products from automobiles and factories include nitrogen oxides and sulfur dioxide, which react with water in the atmosphere to produce acids.17... 

Transportation sources, particularly automobiles, are a major source of air pollution and include smoke, lead particles from tetraethyl lead additives, CO, nitrogen oxides, and hydrocarbons. Since the mid-1960s there has been significant progress in reducing exhaust emissions, particularly with the use of low-lead or no-lead gasoline as well as... 

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