Anthropogenic emissions atmosphere

Antarctic air, hydrogen peroxide determination, 648 Anthocyanins, TEARS assay, 667 Anthracene, primary ozonides, 723-4 Anthropogenic emissions atmosphere, 604, 605 hydrogen peroxide, 626 Antibodies, hydrogen peroxide determination, 1315... 

Stratospheric distribution of NjO Atmospheric accumulation of NjO (0.25% yr ) Natural emissions (largely from tropical soils) Anthropogenic emissions cultivated soils (-h industry and combustion) 40 8.0 (. 1 sources... 

Forests can act as sources of some of the trace gases in the atmosphere, such as hydrocarbons, hydrogen sulfide, NO, and NH3. Forests have been identified as emitters of terpene hydrocarbons. In 1960, Went (10) estimated that hydrocarbon releases to the atmosphere were on the order of 108 tons per year. Later work by Rasmussen (11) suggested that the release of terpenes from forest systems is 2 x 10 tons of reactive materials per year on a global basis. This is several times the anthropogenic input. Yet, it is important to remember that forest emissions are much more widely dispersed and less concentrated than anthropogenic emissions. Table 8-2 shows terpene emissions from different types of forest systems in the United States. 

Anthropogenic Emissions and Climate Variability. Journal of Geophysical Research 103(DI 3) 15979-15993. Fkickinger, J., ct al. (1999). Variations in Atmospheric NjO Concentration During Abrupt Climate Changes. Science 285 227-230. 

Clean and Polluted Air. In the development of atmospheric chemistry, there has been an historic separation between those studying processes in the natural or unpolluted atmosphere, and those more concerned with air pollution chemistry. As the field has matured, these distinctions have begun to disappear, and with this disappearance has come the realization that few regions of the troposphere are completely unaffected by anthropogenic emissions. An operational definition of clean air could be based upon either the NMHC concentration, or upon the NOjj concentration. 

The ratio of anthropogenic emissions to total natural emissions is highest for the atmophilic elements Sn, Cu, Cd, Zn, As, Se, Mo, Hg, and Pb (Lantzy and Mackenzie, 1979). In the case of lead, atmospheric concentrations are primarily the consequence of the combustion of leaded gasoline. For many years, lead was used as a gasoline additive, in the form of an organometal compound, tetraethyl lead. When the fuel was... 

Indeed, the most important factor that affects the future estimates of climate is the (anthropogenic) emissions of greenhouse gases and all kind of aerosols. The amount of these products released into the atmosphere depends upon the socio-economical and technological development of humankind. Thus, different hypotheses about these evolutions are assumed, resulting in several emission scenarios. The scenarios used in the IPCC AR4 derive from a Special Report on Emission Scenarios (SRES) published earlier [2]. All these scenarios can be grouped in four families (storylines) that are named Al, A2, Bl, and B2. 

FIGURE 1.4 Change of global anthropogenic emissions of total mercury to the atmosphere from 1990-2000 (metric tons). (Reprinted from Pacyna et al. 2006, with permission from Elsevier.)... 

Jackson TA. 1997. Long-range atmospheric transport of mercury to ecosystems, and the importance of anthropogenic emissions — a critical review and evaluation of the published evidence. Environ Rev 5 99-120. 

The primary source of lead in the environment has historically been anthropogenic emissions to the atmosphere. In 1984, combustion of leaded gasoline was responsible for approximately 90% of all anthropogenic lead emissions. EPA phased out the use of lead alkyls in gasoline, however, and by 1990, auto emissions accounted for only 33% of the annual lead emissions (EPA 1996h). Use of lead additives in motor fuels was totally banned after December 31, 1995 (EPA 1996f). The ban went into effect on February 2, 1996. Atmospheric deposition is the largest source of lead found in soils. Lead is transferred... 

Nriagu J O. Global inventory of natural and anthropogenic emissions of trace metals to the atmosphere. Nature 1979 279 409M11. 

F —mobilization factor as a ratio of anthropogenic emission into the atmosphere to the natural one... 

Apart from anthropogenic emissions, heavy metals enter the atmosphere of Europe due to re-emission of previously deposited substances and from natural sources. These types of sources are taken into account on the basis of expert estimates made in MSC-E (Ryaboshapko and Ilyin, 2001 Travnikov and Ryaboshapko, 2002). 

A significant amount of lead emitted in a country is transported beyond the national borders contributing to the trans-boundary transport. In 2002 as much as 4.8 kt (around 60% of total anthropogenic emission) of atmospheric lead, emitted in Europe were involved in transport across state borders. Absolute magnitudes of lead transported outside countries vary substantially from country to country. It was calculated as difference between national emission and deposition to the country. This magnitude depends on national emission, size of the territory, climatic conditions and spatial distribution of emission sources within the country. 

Kato, N., Akimoto, H. (1992). Anthropogenic emissions of SO2 and NO in Asia emission inventories. Atmospheric Environment, 26a, 2997-3017... 

Pacyna, J. M., Pacyna, E. G., Steenhuisen, F., Wilson, S. (2003). Mapping 1995 global anthropogenic emissions of mercury. Atmospheric Environment, 37, Supplement 1, pp. S109-S117. 

Mercury is a naturally occurring element. Natural emissions of mercury, e.g. from ore deposits and from volcanic activity, are variously estimated at amounts between 2500 and 5500 tonnes/year and are thus similar in magnitude to anthropogenic emissions, which are currently estimated at some 3600-4100 tonnes/year world-wide. Some 30000 tonnes of mercury are readily available in the environment, i.e. in the atmosphere or in the mixing zone of the oceans, with tens of millions of tonnes in the upper layers of the continental masses and still more in the deep oceans (see Table 2.1). 

As developed in more detail in Chapter 6, the NO concentration at which other reactions such as (11), (12), and (29) occur at approximately the same rate as the H02/R02 + NO reaction is in the 10-50 ppt range. These concentrations are sufficiently low that they are encountered only in remote atmospheres, where the influence of anthropogenic emissions is minimized. 

Friedrich, R., and A. Obermeier, Anthropogenic Emissions of Volatile Organic Compounds, in Reactive Hydrocarbons in the Atmosphere (C. N. Hewitt, Ed.), Chap. 1, Academic Press, San Diego, 1999. 

To compare the relative importance of these potential atmospheric fates of R02 under typical polluted conditions, and particularly the relative importance of the NO reaction, let us take the C2H502 radical as an example. The lifetime of C2H,02 with respect to reaction with NO, H02, or C2H,02 at peak concentrations of 20 ppb, 40 ppt, and 40 ppt, respectively, can then be calculated from r= l/k[X] as 0.2, 1.3 X 102 s and 1.6 X 104 s, respectively. (Note that the NO and H02/R02 peaks will not occur simultaneously.) At night, with an NO-, concentration of 100 ppt, the lifetime would be 135 s, assuming a rate constant of 3 X 10-12 cnv1 molecule-1 s-1. In short, in areas impacted by anthropogenic emissions, the reaction of R02 with NO will predominate. 

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