[en] The anthropogenic emissions of mercury to air is considered to contribute by 50-75 % of the total, and is thus responsible for elevated mercury concentration in the global atmosphere. These elevated atmospheric levels may be a serious threat to terrestrial and aquatic ecosystems due to wet or dry deposition. Hence, measures must be taken in controlling the anthropogenic emissions of mercury. A fundamental step of a global mercury control is realistic mapping of anthropogenic and natural emissions. Today, reasonably well documented mercury emission inventories of anthropogenic point sources exist in Europe and North America. The amount of anthropogenic emissions in other parts of the world is quite uncertain, as well as world-wide diffuse emissions (anthropogenic and natural). Guizhou is situated on a plateau with a mean altitude of about 1000 m. Its climate is a typical subtropical humid monsoon with an average annual temperature of 15 dec C and a precipitation of 1100-1400 mm. The province accounts for about 2.8% of the total population in China. (orig.)

[en] Short communication

[en] The emission of sulfurous gases including SO₂ from stationary power generation remains to be a serious environmental and ecological problem. Sulfurous gases are almost entirely produced from the combustion of sulfur-containing fuels. While fuel desulfurization and flue gas scrubbing is a viable solution, in the developing countries it remains to be an economical challenge to implement these SO_x reduction technologies. The oxidation of methane in presence of sulfurous gas (SO₂) addition was studied experimentally. Te experiments were conducted in a static reactor at temperature of 728-786 K, and for mixture of C₄/O₂ ≡ 1/2 at a pressure of 117 Torr with varying amount of SO₂ addition. It was observed that SO₂ addition accelerated the oxidation process, reduced the induction period and increased the extent of methane consumption. At the relatively short resident time (less than 50 sec) SO₃ was detected, but at longer residence time SO₃ was reduced spontaneously to SO₂

[en] During the last twenty years, wide studies on dioxins and furans, the micropollutants responsible of toxic effects towards human health and ecotoxicity, have been performed. State of the art concerning the principal sources of emission, in particular the industrial sources, as well as the homogeneous and heterogeneous mechanisms of formation from the main recognized precursors, is presented. Emphasis is done to problems arising from combustion processes

[en] Short communication

[en] The pollutant emission of the thermal power stations may have an important contribution to the local pollution as well as to regional (transfrontier) and global pollution. Due to the impossibility at present of making continuous monitoring of the emission of pollutants it is necessary to use computational models for obtaining inventories of the pollutant sources and for studying their dispersion into atmosphere. The computational code used to simulate the pollutant diffusion in the atmosphere is a climatologic model giving the annual average concentration and the evaluation of the maximum SO₂ concentration. The paper presents the analyses for the case of 14 thermal power stations of Romania

[en] A charge on NO_x emissions from energy production at stationary combustion units was introduced in Sweden 1992. The main reason for reducing NO_x emissions was to combat acidification. In 2001 the charge covered some 250 combustion facilities, with a total of just under 400 production units for electricity and heat production, having emissions of just over 14,000 tonnes of nitrogen oxides. Specific emissions from the plants subject to the charge have fallen by around 40 per cent since it was introduced. The charge is paid on emissions of nitrogen oxides (NO_x) from boilers, stationary combustion engines and gas turbines having a recorded useful energy production of at least 25 GWh a year. Production units generating steam, hot water, warm water, or hot oil are subject to the charge, as are gas turbines and stationary combustion engines. Liability to the charge also presupposes that the energy generated is used to heat buildings, electricity generation or in industrial processes. Emissions from direct process combustion, eg, combustion in furnaces for direct heating and melting of raw materials and intermediate products, are not covered by the charge system. Also exempt are recovery boilers and sulphite liquor boilers in the pulp and paper industry. The charge is SEK 40 per kilo of emitted nitrogen oxides (NO_x), calculated as nitrogen dioxide (NO₂), regardless of the fuel used. The total NO_x charge is repaid to the charge payers in proportion to each production unit's share of total useful energy production. Sweden is committed to achieving an emissions target of 148,000 tonnes of nitrogen oxides to air by 2010 under the EC Air Quality Directive (NEC). This would mean a reduction of about 56 per cent compared with the level in 1990. NO_x emissions in Sweden were approximately 250,000 tonnes in 2001. On the basis of instruments already decided, annual NO_x emissions are expected to fall to 160,000 tonnes by 2010. Most of this reduction is expected to come from automobiles and machines as a consequence of more stringent exhaust standards. It may therefore be considered reasonable for part of the additional emission reduction needed to reach the emission target to come from stationary emission sources such as energy production and industrial processes. Studies have shown that the NO_x charge system is a cost-effective complement to emission permit conditions. In relation to the quantity of energy produced, emissions from plants subject to the charge have fallen by about 40 per cent since the charge was introduced. At the current level and scope of the charge, emissions will remain low and will also continue to fall by around one per cent a year. The charge also influences investment in new production units and conversion of existing ones. It has also had an impact in encouraging the development of better technologies for emission reduction and continual monitoring of emissions. To achieve a cost-effective reduction in emissions of nitrogen oxides using the NO_x charge system, the Swedish EPA proposes that: the charge system be expanded to cover recovery boilers and sulphite liquor boilers used in the pulp and paper industry; the charge system be expanded to cover combustion in industrial processes; the threshold for liability to the charge should be retained at 25 GWh per year; the charge should be raised to SEK 50 during an initial phase; and an evaluation of the effect of expanding the NO_x charge system and raising the charge should be carried out two years after the change has taken effect. At that time a further increase in the level of the charge should be considered on the basis of the evaluation. It is not certain whether the financial consequences of the environmental charge may be unduly onerous for certain plants in relation to the emission reductions that can be expected. The Swedish EPA considers that this particularly applies to the cement industry, the lime industry, the mining industry, the glass industry and the fibreboard and chipboard manufacturing industry. For example, the cement industry and the mining industry would have to pay a net charge in the region of SEK 70-100 million per year assuming a charge of SEK 50. However, it should be stressed that the actual outcome depends on the action the plants in question are able to take to reduce their emissions. The cement industry has taken extensive measures to reduce NO_x emissions from cement kilns, and the scope for further emissions reductions is considered to be very limited. The Swedish EPA therefore considers it reasonable to exempt the cement industry from the charge. The Swedish EPA proposes that tradable emission rights for nitrogen oxides should not be introduced at present. The possibility of replacing the NO_x charge system with a trading system should be considered once trading schemes for nitrogen oxides have been introduced in other countries and the introduction of the carbon dioxide emission rights trading scheme in Sweden has been evaluated. The Agency sees no theoretical obstacles to introducing a system of tradable emission rights as an alternative to the NO_x charge system. However, complementing the NO_x charge system with a trading scheme for emission sources other than those currently covered by the NO_x charge is not considered an effective option. International regulations such as the IPCC Directive may present certain obstacles to an effective market. Amendment of the IPPC Directive as has already been done to facilitate the EU system of trading in greenhouse gas emission rights, would make for a more effective market in tradable emission rights

[en] The paper discusses results from a July 1991 workshop and the progress that has been made in advancing the technology of surface-coating-free materials (SCFMs). The workshop identified opportunities for the development of SCFMs being used by industries and recommended ways for increasing the use of SCFMs by other industries. In addition, the workshop offered the opportunity for the exchange and the development of innovative concepts related to SCFMs. Coating operations release about 15% of stationary area source volatile organic compound (VOC) emissions. Many of these sources cannot be impacted by add-on controls at a reasonable cost due to their small size and/or the difficulty of capturing emissions. In addition, not only do emissions occur during initial coating, they occur each time the surface is recoated. If materials or products could be developed which do not need coating during either manufacture or use (SCFMs), VOC emissions could be reduced significantly. The U.S. ambient air quality standard for ozone (0.12 ppm) is exceeded in over 100 areas in the country. Extensive reduction of VOC emissions is required for attainment. The difficulty of dealing with stationary area sources has been a major obstacle to attaining these reductions. Area sources may contribute as much as 50% of U.S. VOC emissions

[en] It is well known that the radiation effect of nuclear enterprises on the environment is due mainly to gas-aerosol emissions which emanate from the object in the form of a jet flow. A characteristic feature of the propagation of radioactive impurities near such structures is that they depend on the local thermal and wind conditions at the location of the source of contamination. Transferring directly the results of laboratory investigations of the propagation and diffusion of fluxes to objects in the environment and neglecting the peculiarities of the wind and thermal interference with the underlying surface and other buildings can lead to incorrect conclusions. In this paper, we examine two examples: (1) emissions through the plant stack or other ventilation system openings, and (2) leakage of radioactive pollutants into the reactor building and from there to the atmosphere. A mathematical description on each example is provided, and data on the Archimedes number for a convective jet is given as a function of the deflecting wind velocity

[en] This project is one of Austria's contributions to international efforts within the framework for the target oriented reductions of sulfur- and nitrogen emissions. Within the project the critical loads of sulfur and nitrogen for forest soils, bogs and alpine ecosystems of Austria were calculated. For more than 11,000 reference areas the critical loads were calculated with a steady state mass balance model. It can be derived from the results that large areas of Austria are covered by ecosystems sensitive to acidification and eutrophication. In comparison with deposition calculations it can guessed that the highest risk can also exists in specific areas with lower sensitivities. (author)