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The first-principles method based on density functional theory has been used to investigate the adsorption performance of NO/NO₂ molecules on intrinsic, Ag-doped, Pt-doped and Au-doped graphene. Results show that graphene doped with Ag/Pt/Au has shorter final adsorption distance, larger adsorption energy and charge transfer amount with NO/NO₂ molecules than intrinsic graphene, and the charge densities of doped graphene and NO/NO₂ molecules overlap effectively. Therefore, doping graphene with noble metals can greatly enhance the adsorption between graphene and NO/NO₂ molecules. Analysis also reveals that Au-doped graphene has the strongest adsorption effect on NO/NO₂ molecules, followed by Ag-doped graphene, while Pt-doped graphene has the weakest role on the adsorption of NO/NO₂ molecules. The work conducted in this research provides a theoretical guidance for the application of NO/NO₂ gas sensors based on graphene.

The adsorption of N₂O on Ir(110) was investigated with high-resolution resonant photoemission at 135 K. The results obtained show evidence of molecular adsorption of N₂O, along with some dissociation. It is found that the nitrogen photoemission spectra measured at the terminal and central nitrogen energy positions of the N₂O/Ir(110) system are equivalent to those of N₂O in the gas phase. In contrast, the oxygen spectrum shows little resemblance to the gas phase oxygen spectrum of N₂O. In the nitrogen resonant photoemission spectra one can only discover resonant behavior with constant binding energy peaks. In contrast, the oxygen resonant photoemission spectra shows dominantly Auger behavior with peaks at constant kinetic energies. Both observations reveal that the oxygen is bonded to the Ir surface. A systematic study as a function of coverage and temperature and a comparison with other surfaces differing in structure and composition is needed to understand the variations in the adsorption behavior of N₂O on metal surfaces.

The gas-phase reaction mechanism of NO₂ with NH₂ on the singlet potential energy surface is investigated at the B3LYP, MP2, CCSD(T) and G3B3 levels of calculation in connection with the 6-311$++$G(3df, 3pd) basis sets. Seven different kinds of products have been obtained. The results reveal that P7 [N₂$\text{O}+\text{H}$₂O] is the main product in thermodynamic viewpoint with the Gibbs free energy of $\mathrm{\Delta }{G}^{\circ }=-62.1$kcal/mol. The product P2 due to less number of transition states and low level barrier height of transition states is introduced as the kinetic product. The calculation of rate constants in different temperatures confirms our predication for P7 adduct in comparison with other products. In the first step, the reactions without catalytic effects are considered. All of these reactions begin with pre-reactive collision complex CR [NO₂–NH₂]. This complex has been produced from barrier-less process via collision of reactants. From variation of bond lengths and angles or dissociation of this complex, other species are produced. In the second step, the catalytic effect of water and water dimer molecules on the reaction rate of kinetic path, P2, have been attended. Calculation of the rate constant was done in the temperature range from 500K to 3000K. Our results showed that the rate constant of path P2 increases with temperature and the number of water molecules. So, we can conclude that the number of water molecules corresponding to relative humidity of atmosphere has catalytic effect on the mentioned reaction rate.

Acid rain is formed when sulfur dioxide and nitrogen oxides reach the air and are transformed into sulfate or nitrate particles. When combined with water vapor, they are converted into sulfuric or nitric acids. Acid rain can adversely affect aquatic life, erode stone buildings and marble statues, and seriously threaten trees and crops. Power plants that burn coal to generate electricity are a chief cause of acid rain. The US Congress and US Environmental Protection Agency (US EPA) have worked to reduce acid rain by restricting the amount of sulfur allowed in the coal burned by power plants and other industrial sources. In some areas, where pollution is concentrated, plants may burn only coal with 1% sulfur or less. In rural locations, a maximum sulfur content of 2% is allowed. Nitrogen oxide emissions from cars also contribute to acid rain. These emissions are being reduced by new car emissions standards that have been established by the US EPA. Acid rain monitoring stations are built to determine the long-term effects of acid deposition. The 1990 Federal Clean Air Act Amendments required power plants across the nation to reduce sulfur dioxide and nitrogen oxide emissions. These measures have significantly reduced the pollutants that contribute to acid rain formation.

Aquatic life at all levels of the food chain can be harmed by acid rain. Destruction begins at the lowest level of the food chain, when the tiny microorganisms that are food for minnows and other small organisms die. As food sources dwindle, more and larger fish die. Acid in the water may also interfere with oxygen circulation, harm fish gills and cause heart problems in fish. Even though acid rain is a complex global problem, there are things that each of us can do to help control it. Conserving energy helps by reducing electricity demands on our power plants. Carpooling also helps, by reducing emissions of nitrogen oxides. And widespread recycling will also help control acid rain. By minimizing the volume of waste we generate, we are contributing to reductions of nitrogen oxide emissions from waste incinerators. These are a few ways that, with enough individuals acting on behalf of the environment, each of us can make a difference.

Urbanization is often associated with natural resource exploitation, largely characterized by fossil fuel combustion for energy generation. Increasing demand for energy releases acidic gases into the atmosphere, thus increasing the acidity of natural rain with debilitating consequences to the environment and public health. Therefore, this chapter aims to simplify the complex interactions guiding acid rain formation and its projected impacts on the ecosystem, and to reveal the urgent need for mitigation measures particularly by acid rain–stricken developing countries.

This chapter describes how economic models are used to answer questions about policy changes, specifically in the context of a carbon fee-and-dividend system. A carbon fee-and-dividend is a price on carbon dioxide emissions that returns the revenues gained to ordinary households in the form of a monthly check. The chapter describes, in nontechnical terms, the economic models and modeling processes involved and how they are similar and different from climate models…

Outdoor air pollution can be serious enough to cause human illness. Because of this, protection of the public health has been the driving force behind the laws and regulations put in place to clean up the air in and around our cities. While these efforts have been generally successful in reducing emissions from stationary sources, they have had less effect on reducing emissions from mobile sources such as automobiles. The health effects of motor vehicle exhaust are well documented and most indoor environments offer only moderate protection for those with increased sensitivities. As cities become more crowded and vehicular traffic increases, the number of IAQ complaints and the number of people affected by this type of air pollution will increase as well. Past research has shown that an air cleaning system using a single gas-phase (or dry-scrubbing) air filtration media is not adequate for the control of the major chemical components found in automobile exhaust. Recent testing has shown that at least three different media are required and two promising new chemical filter technologies have been developed and evaluated with respect to their application for the control of one of the primary components of motor vehicle exhaust – nitrogen oxides. One is an adsorbent-loaded nonwoven fiber medium which provides for flexible filter design with removal efficiencies and service life comparable to many granular media systems. The second is a gas-phase air filtration medium in the form of an extruded monolithic block composed of essentially 100% adsorbent materials which allows the entire composite structure to function as a chemical filter. Both of these chemical filters can be produced with integral particulate filtration that can effectively address all of the air cleaning requirements – both chemical and particulate – for motor vehicle exhaust. This paper will present information and comparative test data on these new air cleaning technologies, how they may be integrated into existing HVAC systems, and the relative effectiveness of each against motor vehicle exhaust.