FIGURE 5-2 Steps in the atmospheric oxidation of methane to carbon dioxide.

Combustion of C-containing substances ,

S in coal or oil

Nj in air via combustion

(Other nitrates)

FIGURE 5-3 Stable species (i.e., nontransients) and their additional sources during sequential atmospheric oxidation processes.

oxidation, and the increasing amounts of the gas released from the surface of the Earth, have led to an increase in the atmospheric concentration of CH4 in recent times, as discussed further in Chapter 6.

Under conditions of low nitrogen oxide concentration, such as occur over oceans, the mechanism of methane oxidation differs in some of the steps. In particular, instead of oxidizing NO", the peroxy radicals often react with each other, combining to produce a (nonradical) peroxide:

Coping with Asthma

Coping with Asthma

If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.

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