B1.2 EMISSIONS (AIR POLLUTION SOURCES)

B1.2.1 Categorisation of air pollution sources

Sources generating atmospheric pollutants are monitored nation-wide within the so-called Air Pollution Sources Register (the corresponding Czech acronym is REZZO). Sources are classified into respective categories depending on the level of their effects on air quality. Stationary air pollution sources are registered in the databases of REZZO 1–3, the fourth category (REZZO 4) includes mobile sources.

Tab. B1.2.1 Categorization of air pollution sources

REZZO – Air Pollution Sources Register
Pursuant to Section 13 (1) of the Act No. 86/2002 Code on air pollution control.

B1.2.2 Stationary air pollution sources

B1.2.2.1 Number of sources

The number of extremely large and large pollution sources (category REZZO 1) is based on data of the Summary Operation Register, verified by the Czech Environmental Inspection (ČIŽP). Such emission sources are distributed unevenly across the territory of Prague. The step up increase in between the years 1985 and 1992 was mostly caused by the construction of block heating stations on new Prague housing estates. The increase in the number of sources in 2002 was due to changes to the classification of sources to respective categories according to executive regulations of the Act No. 86/2002 Code, on air pollution control, in which originally mid-sized sources were reclassified to belong to the category of large sources (in the City of Prague these first of all are dry cleaning facilities). On the other hand, the decrease in the number of large pollution sources in 1998 to 2002 is a result of the implementation of the largest co-generation project in the whole Europe – the interconnection of heating systems of Mělník and Prague.

This system supplies heat to majority of buildings on the right riverbank in the Capital City. The gradual development of the system enabled stand-alone sources and local heating rooms with combustion of heavy oil or coal were decommissioned. In recent years, an important change to more environmentally friendly situation in the Capital City happened in the Jižní Město District as well, where in total 33 block heating stations were connected to the system Mělník - Prague and were retrofitted to heat exchange stations. In the areas of Krč and Modřany where 6 existing gas-fired block boiler units and in the area Lhotka - Libuš were converted into exchange stations and the block boiler unit Modřany was decommissioned (the boiler unit Krč was transferred from year-round operation to the regime of peak consumption support). In the course of 2004 the heat network the natural gas-fired steam boiler unit Invalidovna was connected to the heating systems of Mělník and Prague and the boiler unit Invalidovna was decommissioned.

The number of mid-sized sources (category REZZO 2) is based on data collected by the Department of the Environment of the Prague City Hall (OOP MHMP). The total number of sources has been stagnating in recent years. The highest numbers of mid-sized sources are located in older buildings in the City centre. A relatively high number of sources in the class “Others including technologies” comprises either technological sources with no fuel combustion (petrol stations, printing houses, painting shops, dry cleaning facilities, etc.), and boiler units under reconstruction. Small pollution sources (category REZZO 3) are not registered individually (only selected types of boiler units).

Tab. B1.2.2 Number of registered air pollution sources in Prague, 1995–2004

Source: ČHMÚ, ČIŽP, MHMP

B1.2.2.2 Emissions

The quantity of emissions from stationary pollution sources (Categories REZZO 1–3) is nation-wide monitored for fundamental pollutants as follows: particulate matter, sulphur dioxide (SO₂), nitrogen oxides (NO_x), carbon monoxide (CO), volatile organic compounds (VOCs – replaced the originally monitored emissions of C_xH_y), ammonia (NH₃), and certain other selected pollutants as heavy metals (HMs) and persistent organic pollutants (POPs). Territorial balances are as usual developed only for fundamental pollutants while territorial distribution of NH₃ emissions and VOCs emissions from small sources and in households can be merely estimated.

The amount of emissions from large and mid-sized pollution sources was determined using the data of the REZZO 1 and REZZO 2 registers. Data on the small pollution sources of REZZO 3 were determined by model calculations employing updated figures from the census carried out in 2001. These data have been continuously updated in co-operation with major fuel and energy suppliers (Prague Gas Utility Company, Prague Energy Utility Company (PRE), and Prague Heat Utility Company). The quantity of pollutants emissions furthermore depends on heat consumption and therefore it is influenced by weather conditions in respective heating periods. The usage of new methodology for the calculations of REZZO 3 sources, employing data from the 2001 census, is the reason why small sources emissions demonstrate a relatively significant annual drop in between years 2001 and 2002.

The tables and charts document the long-term emission reduction in particulate matter, sulphur dioxide, and nitrogen oxides from stationary sources. This favourable trend results partly from the decrease in fuel consumption (higher utilisation of heat from the heat supply mains Mělník - Prague, heat savings at end consumers, decrease in industrial production output after 1990, etc.), and partly from the change in fired fuel structure (replacing solid fuels by gaseous fuels) and efficient operations (reconstruction and modernisation of boilers). Furthermore, other reason is the pressure of economic and legislative measures aimed at emission reduction from these sources.

In 2003 the largest stationary emission source located on the territory of the City of Prague was the Prague Heat Utility Company – the Malešice Co-Generation Plant. Its dominant share in total emissions has been maintained despite the fact that two low-rank coal boilers were retrofitted to be able to burn a high quality, low-sulphur hard coal in 1997–1999, including the installation of new electric precipitators and a covered fuel stock and so the volume of SO₂ emissions as well as particulate matter emissions were substantially reduced.

Due to high stacks of large emission sources (REZZO 1) their contribution to air pollution is manifested over much larger territory than that of mid-sized sources and small ones, which exert pollution load to their very surroundings. The main share of emissions is accounted, apart from the Radotín Cement Plant, Malešice Incineration Facility, and several industrial sources generating smaller emission volume, to the plants of the Prague Heat Utility Company.

Tab. B1.2.3 Emissions of selected principal pollutants generated by stationary sources in Prague in the 1975–2004 period [t.year^-1]

Source: ČHMÚ, ČIŽP, MHMP

Tab. B1.2.4 Emissions of principal pollutants (total and share in %) generated by stationary sources, Prague 2004

Source: ČHMÚ, ČIŽP, MHMP

Tab. B1.2.5 Comparison of total specific emissions generated by stationary sources, Prague – Czech Republic, 2004

Source: ČHMÚ, ČIŽP, MHMP

Tab. B1.2.6 Major large air pollution sources (REZZO 1), Prague, 2004

Source: ČHMÚ, ČIŽP

B1.2.2.3 Fuel consumption

For the purpose of the comparison of fuel consumption in stationary sources of REZZO 1 and 2 the consumption of fuels in physical units (tons, 1,000 m³) was converted, using appropriate calorific values, to the consumption of heat contained in the fuel (expressed in TJ). There are no input data on small sources of REZZO 3. The development trend of fuel consumption structure, i.e. increase in gaseous fuels at the expense of solid fuels, results from the changes in the boilers used. The total heat consumption from fuel in the monitored years was also influenced by various weather conditions, higher efficiency of the natural gas combustion, and by the utilisation of heat from the heat supply mains Mělník - Prague. The total decrease in fuel consumption has also been influenced by lower energy consumption by end customers, lower output of production, change in customers’ behaviour adequate to the environmental development, social conditions etc., both in companies and in households.

In recent years the largest share of the decrease in fuel consumption in stationary sources on the territory of Prague went to the account of the retrofitting and reconnecting of 33 block boiler units in Jižní Město and connecting of Krč (incl. the area of Novodvorská) and 6 block boiler units in the area Lhotka - Libuš and the heating plant Modřany to the heat mains Mělník - Prague. The stepwise increase in solid fuel consumption in 1999 is the consequence of the completed retrofitting of boilers of the Co-Generation Plant Malešice. The slightly increasing consumption of solid fuels in the last three years was caused by the increasing volume of municipal waste incinerated in the Malešice Incineration Facility and the increased hard coal consumption of the Co-Generation Plant Malešice.

Tab. B1.2.7 Fuel consumption [TJ]

Source: ČHMÚ, IMIP, MHMP

Fig. B1.2.1 Major stationary air pollution sources, Prague, 2004

Source: ČHMÚ, ČIŽP, MHMP

Fig. B1.2.2 Emissions of pollutants produced by stationary sources (REZZO 1–3), Prague 2004

Source: ČHMÚ, MHMP, ČSÚ, PT, a. s., PP, a. s., O. Hrubý

Fig. B1.2.3 Total and specific emissions generated by stationary sources, Prague, 1984–2004

Source: ČHMÚ, ČIŽP, MHMP

Fig. B1.2.4 Fuel consumption trend in REZZO 1 and 2 boiler units, Prague, 1994–2004

Source: ČHMÚ, MHMP, ČSÚ, PT, a. s., PP, a. s., O. Hrubý

B1.2.3 Mobile air pollution sources (REZZO 4 – transport)

Input data for emission calculations

At present the automotive traffic is the most important source of air pollution on the territory of Prague. The emission balance of automotive traffic has been carried out within the regular two-year cycles of the ATEM project “Model air quality assessment on the territory of the City of Prague”. Traffic emissions were calculated for:

• line sources (sections of roads);
• crossroads;
• special sources (bus depots, public transport system terminals and pump stations).

The major source of pollutants emissions from the automotive traffic is urban roads – line sources. The determination of the line sources network is given by the traffic census, which is carried out by the Institute of Transportation Engineering of the City of Prague (ÚDI). In the last period the ÚDI census was expanded for certain roads and the network of line sources employed for model calculations in appropriate manner. Furthermore new roads – a section of the ring road Zlíchov–Radlická Street were added.

For the calculations of traffic emissions the methodology, developed by the Institute of Chemical Technology, Prague and ATEM – Studio of Ecological Modelling within the Project sponsored by the Ministry of the Environment of the Czech Republic in 2000–2002, was employed. The emission model, developed on the basis of the methodology, enables, in the emission calculations, to take into account effects of respective factors (type of vehicle, composition of traffic flow, speed, slope, etc.) by means of a system of mutually interrelated equations. The model is designed for a wide spectrum of emission calculations within the extent from a detailed modelling of respective subjects (garages, parking facilities, bus terminals and depots) through areas of medium size (City parts, larger transport structures), down to vast territories of cities or regions. The methodology employed was under the name of MEFA-02 published in October 2002 as a binding methodology of the Ministry of the Environment of the Czech Republic pursuant to the Annex No. 9 to the Order of the Government of the Czech Republic No. 350/2002.

Similarly as in the previous phase the traffic emissions calculations included also increased emissions generated at the cold start of vehicle engine. In the travelling on the first approx. 5 km after the vehicle start-up there is increased production of emissions compared to the standard operation thereof. Therefore taking the contribution from cold starts into account is significant in emission assessment and immission load from automotive traffic in cities where automobiles are often used for relatively short trips.

Within the Update A5 – 2004 the evaluation of the amount of stirred up suspended particulates generated by the passing vehicles – so-called secondary dust from automotive traffic was carried out for the first time ever. The emission calculation was carried out for particles up to 10 mm in size, so-called fraction PM₁₀. It follows from the methodology employed that the amount of stirred-up particles increases substantially with growing vehicle weight which is reflected in significantly higher dust on roads where there is high intensity of heavy cargo traffic.

On the basis of input data given calculations were carried out on the traffic emission production for the following pollutants: emissions of solids fraction PM₁₀, sulphur dioxide, nitrogen oxides, carbon monoxide, sum of hydrocarbons, and benzene. Basic information on the locations of respective pollution sources and sizes of their emissions can be found in the Figure below.

Emission balances of respective groups of sources (line sources, tunnels, crossroads, and special sources) are summarised in Tables and Figures below.

Tab. B1.2.8 Traffic emissions on the Prague territory [t.year^-1]

* Including the secondary dust generation

Source: ATEM

Tab. B1.2.9 Shares of respective groups of sources on total traffic emission in Prague [%]

Source: ATEM

Results of emission calculations on the territory of Prague demonstrate that:

• the total traffic emissions of PM₁₀ are by the decisive portion caused by so-called secondary dust (over 90 %) The amount of stirred-up dust increases with the increasing weight of passing vehicles, which is reflected in the high share of heavy trucks, lorries, and buses on the total emissions;
• automotive transport produces a relatively small portion of the total emission of sulphur dioxide in Prague (merely 133 t.year^-1), the overwhelming part of this pollutant emissions goes to stationary sources;
• the total amount of emissions of nitrogen oxides produced by automotive transport accounts for over 19 kt.year^-1, this way transport is the major source of NO_x emissions in Prague as the previous years. Passenger cars contribute by approximately one half to the to NO_x emissions, heavy trucks create 31 % of the total emissions;
• concerning carbon monoxide passenger cars are the major producer thereof (79 %). This fact is caused namely by the increased CO production at cold engine starts. A relatively important share of the emissions (over 7 %) is formed in the area of crossroads due to the high increase in the CO production under adverse regimes of ride;
• Hydrocarbon emissions, namely benzene ones, are produced at significantly higher level in petrol combustion than in diesel fuel combustion, which is demonstrated in a high share of passenger cars. The total emissions of C_xH_y from transport reaches over 18 kt.year^-1, out of that volatile organic compounds account for approx. 17 kt.year^-1.

Fig. B1.2.5 Benzene – course of average yearly concentration, 2002, 2004

Source: ATEM

Fig. B1.2.6 NO₂ – course of average yearly concentration, 2002, 2004

Source: ATEM

Fig. B1.2.7 Nitrogen dioxide – course of average yearly concentration, 1994, 2004

Source: ATEM

Fig. B1.2.8 Sulphur dioxide – course of average yearly concentration, 1994, 2004

Source: ATEM

CONTENTS AUTHORS ABBREVIATIONS

AIR

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