II.4.1 Agglomerations
With regard to the Communication of the Air Quality Protection Division of
the Ministry of Environment on delineating zones and agglomerations within the
territory of the Czech Republic, air quality assessment in the proposed
agglomerations (Prague, Brno and the Moravian-Silesian Region) has been treated
with more attention since 2005. In addition to the above agglomerations, special
attention is paid in this Yearbook also to the zone Ústí nad Labem Region due to
the concentration of industrial plants, higher population density and also due
to the recorded above-the-limit concentrations of pollutants.
II.4.1.1 Prague
The Capital City of Prague is the area in which a lot of people are exposed
to ambient air pollution. Most of the limit values exceedances are connected
with significant traffic loads ensuing from the fact that the main routes lead
directly through the city centre. In 2007 air pollution concentrations were
measured at 23 localities in the territory of Prague (15 CHMI, 8 ZÚ).
In 2007 the PM10 particles concentrations were monitored in Prague in 15 CHMI
localities and in 5 ZÚ localities. The most frequent exceedances of 24-hour PM10
limit value (50 μg.m-3) were recorded in the following localities: Prague
2-Legerova (132x), Prague 8-Karlín (74x) and Prague 5-Smíchov (61x). All three
cases are the localities with very heavy traffic loads. Of the total number of
22 localities with valid annual average 8 stations recorded 24-hour PM10 limit
value exceedances. The annual PM10 limit value (40 μg.m-3) was exceeded in two
localities: Prague 2-Legerova (46 μg.m-3) and Prague 5-Svornosti (46 μg.m-3).
The PM2.5 particles concentrations were measured in 5 CHMI localities and in 1
ZÚ locality in 2007. In spite of the fact the valid air pollution limit value
for PM2.5 has not been set in the Czech legislation so far, the comparison of
the measured concentrations with the target limit value for annual average
concentration set by the Directive of the European Parliament 2008/50/EC (25
μg.m-3) is very interesting. The highest average annual concentrations in Prague
localities were as follows: Prague 5-Smíchov 23.7 μg.m-3, Prague 10-Šrobárova
21.3 μg.m-3 and Prague 9-Vysočany 19.6 μg.m-3. It is quite evident that the
target limit value for PM2.5 fraction set by the Directive 2008/50/EC was not
exceeded at any Prague station.
The graphs in Fig. II.4.1.1 show the air pollution characteristics of PM10
concentrations at selected AMS in Prague for the winter periods (October–March)
in the years 2003/2004–2007/2008.
In the given periods the average winter PM10 concentration exceeded the value 40
μg.m-3 at several AMS. At the AMS Prague 5-Smíchov the exceedance of this value
was recorded in 4 of 5 monitored periods. More than 35 exceedances of the
24-hour air pollution limit value were recorded at the AMS Mlynářka, Vršovice
and Smíchov in all winter periods. The both above air pollution characteristics
show the marked decreasing trend at the AMS Kobylisy. The maximum measured
24-hour concentrations reached the highest values during the winter periods
2003/2004 and 2005/2006, when the lowest average temperature and wind velocity
were measured as well.
Fig. II.4.1.3 shows the dependence of the average daily PM10 concentrations in
Prague on dispersion conditions (according to the degrees of dispersion
conditions: good, partly deteriorated, deteriorated and unfavourable) in
2003–2007. The average daily PM10 concentrations from the stations in Prague in
individual years have been considered. The figure shows the seasonal course of
PM10 concentrations and dispersion conditions. During the winter parts of the
calendar year (January–March, October–December) there occur frequent several-day
deteriorated (3rd degree) and unfavourable (4th degree) dispersion conditions
and simultaneously also increased PM10 concentrations in the ambient air. The
most apparent confirmation of this dependence can be seen in winter periods of
2003, 2004 and 2006.
Fig. II.4.1.4 shows the number of days according to the degree of dispersion
conditions and the number of days with average daily PM10 concentration > 50
μg.m-3 and PM10 > 100 μg.m-3 in the years 2000–2007. Meteorological data were
processed from aerological outputs in Prague 4-Libuš. The graph shows the
decreasing trend in the number of days with unfavourable dispersion conditions
from 2002 (181) to 2004 (98). Similar decrease of the days with the above
mentioned PM10 concentrations was recorded in the period 2003–2005. In 2005 this
trend stopped and in 2006 the number of days with unfavourable dispersion
conditions increased (154) and there was a slight increase of the days with PM10
concentrations. In 2007 the number of days with unfavourable dispersion
conditions significantly dropped (88) and simultaneously, the number of days
with high PM10 concentrations decreased.
NO2 concentrations were measured in all 23 localities in Prague in 2007. The AMS
station Prague 2-Legerova which is located in the immediate vicinity of a
communication with heavy traffic, exceeded the hourly limit value plus the
margin of tolerance (200+40 μg.m-3). The value of 200 μg.m-3 was exceeded 254x,
the value of 240 μg.m-3 was exceeded 83x. The highest 19th hourly concentration
at this AMS reached 257μg.m-3. The hourly NO2 concentration 200 μg.m-3 was not
exceeded in 2007 in any other locality.
The annual air pollution limit value plus the margin of tolerance for NO2 (40+6
μg.m-3) was exceeded in the following localities: Svornosti in Prague 5 (84
μg.m-3), Legerova in Prague 2 (72 μg.m-3), Sokolovská in Prague 8 (59 μg.m-3), Národní muzeum in Prague 1 (52 μg.m-3) and Jasmínová in Prague 10 (47 μg.m-3).
It can be expected that the exceedance of air pollution limit values can occur
also in other localities exposed to traffic, where there are no measurements.
Fig. II.4.1.2 shows the graphs of annual courses of monthly NO2 concentrations
at selected AIM stations in Prague in 2007. Groups of AMS with similar courses
of NO2 concentrations are visible in the figure. They are related to the traffic
loads at individual AMS. The first group is represented by the AMS Prague
2-Legerova (traffic hot spot) at which high NO2 concentrations are dominating.
It is followed by the second group of AMS classified as traffic (Vysočany,
Karlín and Smíchov) and finally there is the group of urban and suburban
background AMS (Riegrovy sady, Stodůlky, Veleslavín and Libuš) which are also
influenced by traffic to a certain extent.
Another problem is caused again by above-the-limit benzo(a)pyrene concentrations
which, similarly as in two previous two years, exceeded the target value at all
(3) stations which measured it in Prague, and namely Prague 5-Smíchov, Prague
10-Šrobárova, Prague 4-Libuš.
The results of the measured concentrations of PM10, NO2 and benzo(a)pyrene
suggest the serious need to find the solution for the traffic situation within
the agglomeration.
In Prague, at the station Prague 5-Řeporyje, the target value for arsenic was
exceeded for the first time in 2007. During the recent 4 years the annual
average has increased gradually up to the first exceedance in 2007 (for the
recent 11 years) in spite of the fact that the concentration of PM10 to which
arsenic is bound, recorded the lowest levels in 2007 within the latest 4 years.
The exceedances of the target value for the ground-level ozone was also
recorded. It was exceeded in 4 of 8 localities in Prague, which have carried out
the measurements in the recent three years at least for the period of one year
(pursuant to the definition of the target value in the Government Order). The
exceedance was recorded in the following localities: Prague 6-Suchdol, Prague
4-Libuš, Prague 5-Stodůlky and Prague 6-Veleslavín.
Fig. II.4.1.1 PM10 air pollution characteristics for monitoring
stations and basic characteristics of meteorological conditions in the winter
periods (October–March), 2003–2008, Prague agglomeration
Fig. II.4.1.2 Annual course of monthly NO2 concentrations at
selected AMS stations, Prague 2007
Fig. II.4.1.3 Dependence of average daily PM10 concentrations in
Prague on dispersion conditions, 2003–2007
Fig. II.4.1.4 The number of days according to the degrees of dispersion
conditions with average daily PM10 concentrations exceeding 50 μg.m-3
and 100 μg.m-3, 2000–2007
Fig. II.4.1.5 Field of the annual concentration of NO2, Prague
agglomeration, 2007
Fig. II.4.1.6 Field of the annual concentration of benzo(a)pyrene, Prague
agglomeration, 2007
II.4.1.2 Brno
In the Brno agglomeration, similarly as in the Prague agglomeration, the most
serious air pollution problems are caused by high density of population
connected with ever increasing intensity of traffic. This results mainly in the
increased PM10 (PM2.5) particles and benzo(a)pyrene concentrations in the
ambient air.
In 2007 the ISKO database received the measured concentrations from 4 CHMI
stations, from 3 ZÚ stations, and from 5 stations of the Statutory City of Brno.
PM10 concentrations were measured in 6 localities in 2007. The exceedance of
the PM10 24-hour limit value was recorded at AMS Brno-střed which is located in
the city centre in the immediate vicinity of the crossroad of two frequented
communications. The tolerated number of exceedance of the value 50 μg.m-3 is 35x
in total; the measurements at this station, however, recorded 59 cases of exceedance. The limit value was further exceeded in the localities Brno-Masná
(48x) and Brno-Tuřany (40x). Air pollution limit value for the annual average
concentration was not exceeded at any monitoring station in Brno in 2007.
The only locality in Brno measuring the PM2.5 fraction concentration in 2007,
and namely Brno-Tuřany, recorded the annual average concentration 20.2 μg.m-3.
The NO2 annual limit value plus the margin of tolerance was exceeded in the
locality Brno-Svatoplukova (47.3 μg.m-3), the localities Brno-střed (42.4
μg.m-3), Brno-Zvonařka (41 μg.m-3) and Brno-Výstaviště (40.4 μg.m-3) recorded
the limit value exceedance. The hourly limit value was not exceeded at any
station.
In 2007 also the target limit value for benzo(a)pyrene was exceeded in the
locality Brno-Kroftova (1.2 μg.m-3), which as one of the two stations in Brno
measured this pollutant.
The concentrations of ground-level ozone were measured in 3 localities in 2007
of which Brno-Tuřany exceeded the target limit value for the three-year period
2005–2007.
The influence of temperature on the pollutants concentrations in the Brno
agglomeration and in the South Moravian Region
The meteorological conditions have significant impact on air quality, both
primary in physical-chemical processes occurring in the atmosphere, and
secondary when anthropogenic activities are the main source. The first category
could include temperature and temperature inversion (one of the sources of bad
dispersion conditions in winter period), rain (washing out the particles from
ambient air), processes leading to the creation of secondary atmospheric
aerosols etc. The second category is characterized mainly be the length of the
heating season depending on the length of winter and on the temperatures in the
winter period.
The influence of temperature on pollutants concentrations is demonstrated on
the results of measurements at the stations in the Brno agglomeration:
Brno-Kroftova (traffic station, type of zone urban, characteristic of zone
residential), Brno-Tuřany (background station, type of zone urban,
characteristic of zone residential) and in the zone South Moravian Region at the
station Mikulov-Sedlec (background station, type of zone rural, characteristic
of zone agricultural).
Particles
The monitored area (similarly as the remaining territory of the Czech Republic)
shows the most frequent exceedances in the limit values for 24-hour PM10
concentrations.
The graph in Fig. II.4.1.7 shows that the decreasing average annual
temperature results in the increase of the 36th highest 24-hour concentration.
This relation is much more obvious in the graphs in Fig. II.4.1.8, where the
relations between the monthly average concentration and temperature are
monitored.
The graphs show the inversion course of average monthly PM10 concentrations
with average monthly temperatures. Though the absolute levels of concentrations
in various localities are different, the influence of the temperature is obvious
in all cases. The graphs also show that the worst air pollution situation was
recorded in January 2006 with the average monthly PM10 concentrations ranging
between 60 and 80 μg.m-3 in the South Moravian Region. Simultaneously, January
2006 was the month with the lowest average monthly temperature (about –6 C).
Generally, the most frequent exceedances of air pollution limit value of 50
μg.m-3 for 24-hour PM10 concentration in the monitored area occur in the winter
period from October to March. The following Fig. II.4.1.9 shows the number of exceedances of 50 μg.m-3 in individual months of the winter periods and their
relation to the average temperature of the respective winter period in the
locality Brno-Tuřany.
And again, this figure confirms the correlation between temperature and air
pollution situation. Two high peaks – of March 2003 and especially of January
2006 – should be noted. The value of the limit value for 24-hour concentration
of PM10 was exceeded 18x, resp. 19x. The graph also shows that the given periods
were the coldest ones.
Further, very important is the comparison of air pollution situation of January
2006 and January 2007. January 2006 recorded 19 exceedances, the average monthly
PM10 concentration reached 77.4 μg.m-3 at the average monthly temperature –6.3
C. Only three exceedances occurred in this locality a year later, in January
2007, the average monthly PM10 concentration reached the value of 21.5 μg.m-3 at
the average monthly temperature 3.2 C.
Fig. II.4.1.10 shows the influence of the temperature drop in winter months
on the increased concentrations of particles in the ambient air, and namely on
the number of exceedances of the limit value for 24-hour PM10 concentrations in
the locality Mikulov-Sedlec. The locality Mikulov-Sedlec is classified as
background; the concentrations measured at this station are representative for
the large area of the South Moravian Region.
The graph in Fig. II.4.1.11 shows that the concentration of the fine PM2.5
fraction in PM10 increases with the declining temperature. The highest PM2.5
concentration was measured in January 2006 when the share of the fine fraction
in PM10 reached almost 85 %. As concerns the health risks, January 2006 can be
classified as the worst month in the previous 7 years; not only the highest PM10
concentrations were measured in the South Moravian Region, but these high
concentrations included also mainly fine PM2.5 fraction which infiltrates deeper
in human body and causes more serious problems.
Sulphur dioxide and nitrogen dioxide
Also in these two gaseous pollutants, the correlation between the concentration
and temperature was recorded. However, unlike the particles the concentrations
of SO2 and NO2 are low, and, consequently, their limit values are not exceeded.
To illustrate the situation, the graphs of courses of concentrations and
temperatures from the background station Mikulov-Sedlec are presented.
As results from Fig. II.4.1.12, in case of a background station the level of
the NO2 concentration has a very good correlation with the temperature. In urban
and especially traffic stations (e.g. Brno-Kroftova) the correlation is not
good, in spite of the fact that the overall trend can still be observed.
Ozone
Ozone concentrations have very good correlation with temperature. Unlike the
previous pollutants, ozone concentration does not increase with the decreasing
temperature, but vice versa. The concentration of O3 is significantly
influenced, in addition to the temperature (see Figs.
II.4.1.12 and II.4.1.13),
by solar radiation (see Fig. II.4.1.14).
Benzo(a)pyrene
Benzo(a)pyrene is another pollutant with concentrations exceeding the limit
value in the territory of the South Moravian Region. And, similarly as in PM10,
there is correlation between benzo(a)pyrene concentration and temperature, as is
obvious in Fig. II.4.1.15.
The worst air pollution situation as concerns benzo(a)pyrene occurred again in
January 2006, when the concentrations ranged around 9 ng.m-3; the target limit
value is 1 ng.m-3.
Fig. II.4.1.7 The development of the 36th highest 24-hour PM10
concentration and average annual temperature, 2000–2007
Fig. II.4.1.8 Dependence of PM10 on temperature, 2000–2007
Fig. II.4.1.9 Number of exceedances of the 24-hour PM10 limit
value in the winter months in relation with the average temperature of the
winter period in Brno-Tuřany locality
Fig. II.4.1.10 Influence of monthly temperature on the number of 24-hour PM10
limit value exceedances in the given month in Mikulov-Sedlec locality, 2004–2005
Fig. II.4.1.11 Influence of temperature on PM2.5 and PM10
concentrations, Brno-Tuřany, 2000–2007
Fig. II.4.1.12 Influence of temperature on SO2, NO2 and
O3 concentrations, Mikulov-Sedlec, 2000–2007
Fig. II.4.1.13 Influence of temperature on SO2, NO2 and
O3 concentrations, Brno-Kroftova, 2000–2007
Fig. II.4.1.14 Influence of temperature on O3 concentrations,
Mikulov-Sedlec, 2000–2007
Fig. II.4.1.15 Influence of temperature on benzo(a)pyrene concentration,
Brno-Kroftova, 2004–2007
Fig. II.4.1.16 Field of the annual concentration of NO2, Brno
agglomeration, 2007
Fig. II.4.1.17 Field of the annual concentration of benzo(a)pyrene, Brno
agglomeration, 2007
II.4.1.3 The Moravian-Silesian Region
The ambient air pollution in the agglomeration Moravian-Silesian Region is
connected, in addition to high population density, also with high concentration
of industry, and namely in the following cities: Ostrava, Karviná, Havířov,
Český Těšín and Třinec.
In 2007 PM10 concentrations were monitored in 24 localities (19 CHMI, 5 ZÚ) in
the agglomeration Moravian-Silesian Region. The exceedance of the PM10 24-hour
limit value was reached most frequently at the stations in the districts Karviná
and Ostrava-město, then in several parts of the districts Frýdek-Místek, Nový
Jičín and Opava. The highest number of exceedances of the value of 50 μg.m-3 was
recorded in the following localities: Ostrava-Bartovice (202x, in 2006 172x),
Bohumín (129x), Čěský Těšín (121x), Ostrava-Přívoz (116x),Věřnovice (112x),
Karviná (104x), Ostrava-Českobratrská hot spot (98x), Havířov (95x), Orlová
(93x), Ostrava-Fifejdy (90x) and Ostrava-Přívoz ZÚ (84x). In total, 20
localities with the valid annual average exceeded the PM10 24-hour limit value.
The exceedances of the PM10 annual limit value (40 μg.m-3) were recorded also
mostly in the above districts. The highest annual average was recorded in the
following localities: Ostrava-Bartovice (65.4 μg.m-3, higher than in 2006), Bohumín (49.5 μg.m-3), Věřnovice (47.2 μg.m-3), Ostrava-Přívoz (46 μg.m-3), Český Těšín (44.3 μg.m-3), Ostrava-Českobratrská hot spot (42.9
μg.m-3), Karviná (42
μg.m-3), Orlová (41.9 μg.m-3), Havířov (41.8 μg.m-3), Ostrava-Mariánské Hory
(41.5 μg.m-3) and Karviná-ZÚ (48 μg.m-3). The limit value for annual average was
exceeded in 11 above listed localities in this region.
The localities which measured PM2.5 fraction in 2007 in the Moravian-Silesian
Region, are the only ones in the Czech Republic, in which the average
concentrations exceeded the value 25 μg.m-3 (target value pursuant to the
Directive of the European Parliament 2008/50/EC). In the locality Bohumín the
annual average amounted to 35.9 μg.m-3, in Věřnovice 35 μg.m-3, in Ostrava-Přívoz
33.2 μg.m-3, in Ostrava-Zábřeh 29.5 μg.m-3 and Třinec-Kosmos 26.4 μg.m-3. It is
evident that all localities would markedly exceed the proposed limit value.
NO2 concentrations were measured in total in 27 localities in 2007 (20 CHMI, 4
ZÚ, 2 ČEZ and 1 MÚ Třinec). The highest annual average concentration in this
region was measured at the AMS Ostrava-Českobratrská hot spot (39.5 μg.m-3)
which is the concentration closely below the limit value.
Benzo(a)pyrene is measured in 6 localities in the Moravian-Silesian Region. All
localities exceeded the target value for the annual average concentration, the
highest benzo(a)pyrene concentration was measured again in Ostrava-Bartovice
(8.9 μg.m-3,) which is the highest level measured in the Czech Republic in 2007.
The persisting problem with high benzene concentrations in Ostrava resulted,
similarly as in the previous years, in the exceedance of the limit value for
annual average concentration. The limit value was exceeded in both monitoring
stations with high industrial loads, i.e. Ostrava-Přívoz (ZÚ and CHMI), as the
only localities in the Czech Republic. In 2007 benzene concentrations were
monitored in 9 localities of the Moravian-Silesian Region (5 CHMI and 4 ZÚ).
In 6 localities (of the total number of 7) the target limit value for
ground-level ozone was exceeded as well, and namely: Červená, Bílý kříž, Třinec
Kosmos, Ostrava-Fifejdy, Studénka and Karviná.
The target value for arsenic was also exceeded at 2 localities with the highest
air pollution loads (Ostrava-Bartovice 11.2 μg.m-3 and Ostrava-Mariánské Hory
9.5 μg.m-3). Arsenic concentrations were monitored in 11 localities in the
Moravian-Silesian Region in 2007.
Air pollution concentrations measured in 2007 in the Moravian-Silesian Region
were, owing to very favourable dispersion conditions of the pollutants in the
ambient air, lower than in the previous years for the most part of the year.
There was no marked episode of deteriorated dispersion conditions. The average
levels of air pollution are comparable with the level reached in the year 2000
for the last time (see Fig. II.4.1.32). Nevertheless, on the most part of the
regions territory the limit value concentrations pursuant to the Government
Order No. 597/2006 Coll. were exceeded, mostly in the localities with the
highest pollution, affected by local sources, and the year-on-year decline of
concentrations was less distinct. On the contrary, the station Ostrava-Bartovice
recorded the exceedance of the daily limit value 50 μg.m-3 on 220 days per year,
as compared with 172 cases in 2006.
The persistent problem is caused by suspended particles of PM2,5 and PM10
fractions, benzo(a)pyrene, benzene and ground-level ozone.
The average pollutants concentrations in individual months showed atypical
annual courses. In January and February the concentrations of basic pollutants
were low, below average. It is illustrated in the figure comparing the average
annual course of PM10 in 2007 from the localities of the Ostrava-Karviná area,
which shows that January concentrations, as compared with other years and with
the average annual course for the whole period with PM10 measurements
(2003–2007), were atypically low in 2007, even lower than in the summer months.
Very similar course of concentrations can be seen in SO2 and NO2 (see
Fig.
II.4.1.18).
Ambient air pollution caused by PM10 suspended particles in the dependence on
meteorological dispersion conditions in the territory of the city of Ostrava in
the winter period
The graphs depict the dependence of air pollution caused by suspended particles
PM10 on meteorological dispersion conditions in the territory of the city of
Ostrava in the winter period (the period of three winter months
December–February).
Fig. II.4.1.19 shows the latest seven winter periods from 2001/2002 to 2007/2008
with average concentrations of PM10 calculated for the whole period from
available daily concentrations measured on AMS of the state air pollution
network in the territory of the city of Ostrava. Further relative frequencies of
daily concentrations measured at these stations in the territory of the city of
Ostrava higher than the limit value of 50 μg.m-3 (% >50) and higher than 100, or
150 μg.m-3 (% > 100, % > 150) are presented. The comparison of the air pollution
characteristics in the assessed wither periods shows quite clearly that the
highest level of ambient air pollution in the territory of the city of Ostrava
was recorded in 2002/2003 and 2005/2006 winter periods, the most favourable
levels, on the contrary, were recorded in the last two assessed winter periods,
especially in winter 2006/2007.
Fig. II.4.1.20 shows the average winter values of selected basic characteristics
of meteorological dispersion conditions: the average air temperatures (Tavg)
according to the measurements of airborne meteorological service (Airborne
Meteorological Service Mošnov=LMS Mošnov) and the meteorological station
Ostrava-Poruba, the average values of vertical temperature pseudogradients (Gavg)
according to the measurements of the meteorological station Lysá hora and LMS
Mošnov, and the average wind velocity according to the meteorological pole in
Ostrava-Zábřeh and LMS Mošnov (Favg). Fig. II.4.1.21 shows the average winter
values of these characteristics in dependence on average winter PM10
concentrations. Both figures show quite clearly the dependence of the level of
air pollution on meteorological dispersion conditions. There is a good
correspondence of winters with relatively most favourable/most unfavourable
meteorological dispersion conditions with the whole air pollution situation.
In order to study the dependence of the level of air pollution caused by PM10 at
individual stations the so called daily flow types were derived, based on the
wind direction and wind velocity measurements from the meteorological slope in
Ostrava-Zábřeh in the level 36 m and from LMS Mošnov at 7:00, 14:00, 21:00 and
7:00 of the following day. Fig. II.4.1.22 shows the relative frequencies of
individual daily flow types. It is quite clear that in the Ostrava area there
are prevailing the days with the flows from the south-western octant (this type
occurred on 304 days of the basic package of 632 days, i.e. in 48.1 %); the
second most frequent type was represented by the days with calm weather (or with
low wind velocities max. 1 m.s-1) in the most of the terms, on 73 days, i.e.
11.6 %. The absolute frequencies above 15 days were recorded on the days with
the flows from the northern octant (55 days, i.e. 8.7 %) and from the
north-eastern octant (33 days, i.e. 5.2 %). It was not possible to determine the
daily flow type (a marked change of winter direction during a day, or variable
wind direction) on 154 days in total (24.4 %). The figure also shows the
relative frequencies of all days with the prevailing wind from the
south-western, or north-eastern half of the horizon (346 days, i.e. 54.7, % and
107 days, i.e. 16.9 % respectively).
Fig. II.4.1.23 illustrates the average values of meteorological characteristics Tavg, Favg and Gavg in dependence on the daily flow types and regardless the
daily flow types. It is for instance obvious that on the days with the flows
from the south-western octant and from the whole south-western half of the
horizon there are higher flow velocities and positive air temperatures; in the
flows from the northern and north-eastern octant and from the whole
north-eastern half of the horizon the flow velocities are, on the contrary,
lower and air temperatures are negative. On the average, the most stable thermal
stratification is on the calm days and on the days with the flows from the
north-east.
Again, there is good correlation between these results and results of the level
of ambient air pollution evaluation in individual daily flow types.
Fig.
II.4.1.24 shows, for individual AMS in Ostrava, the arithmetic means and
relative frequencies of daily concentrations of PM10 > 50 μg.m-3 on the days
with the given daily flow type. It is obvious that at all stations, with the
exception of the station ZÚ Bartovice, both assessed characteristics reach the
highest levels on the calm days and on the days with the flows from the
north-eastern octant. On the contrary, the station ZÚ Bartovice, which is, due
to the prevailing south-western winds, located on the lee side of the
significant emission source of the company Arcelor Mittal a.s., records the
highest average concentrations, besides the calm days, on the days with the
flows from the south-western octant and the frequencies of concentrations above
50 μg.m-3 are in these flow directions even higher than in calm weather.
Fig. II.4.1.18 Average monthly concentrations of PM10, NO2,
SO2, O3 and CO from the stations in the Ostrava-Karviná
area
Fig. II.4.1.19 Ambient air pollution caused by PM10 particles in
the city of Ostrava in winter periods 2001/2002–2007/2008
Fig. II.4.1.20 Average meteorological characteristics in winter periods
2001/2002–2007/2008
Fig. II.4.1.21 Dependence of average PM10 concentrations on
meteorological characteristics in winter period
Fig. II.4.1.22 Relative frequencies of the derived daily airflow types
Fig. II.4.1.23 Average values of meteorological characteristics in dependence
on daily airflow types
Fig. II.4.1.24 Average daily PM10 concentrations and relative
frequencies of PM10 daily concentrations >50 μg.m-3 in
winter period on the days with the respective daily airflow types
Fig. II.4.1.25 Field of the annual concentration of NO2,
Moravian-Silesian agglomeration, 2007
Fig. II.4.1.26 Field of the annual concentration of benzo(a)pyrene,
Moravian-Silesian agglomeration, 2007
II.4.1.4 Other areas with air pollution loads with higher density of
population
The Ústí nad Labem Zone
The Ústí nad Labem Region is defined as a zone. This area has high population
density and is highly industrialized, and thus a number of pollutants have
above-the-limit concentrations.
In 2007, pollutantss concentrations were measured in 40 localities (18 CHMI, 9
ČEZ, 11 ZÚ, 1 SŠZE Žatec, 1 FRANTSCHACH PULP@PAPER, a.s., Štětí) in the Ústí nad
Labem Region. At several localities the measuring programme was not complete.
PM10 concentrations were measured at 26 localities. The exceedances of the
24-hour limit value for PM10 occurred mostly in the Ústí nad Labem, Teplice and
Most districts. The highest numbers of exceedances of the value 50 μg.m-3 were
recorded in the following localities: Ústí n.L.-Všebořická (58x), Most (57x),
Ústí n.L.-město (53x), Lom (53x), Lovosice MÚ (47x), Teplice (45x), Děčín (36x)
and Děčín-ZÚ (36x). In total, 8 localities in the Ústí nad Labem Region exceeded
the PM10 24-hour limit value. The exceedance of the PM10 annual limit value was
not recorded at any station in the Ústí nad Labem Region in 2007.
The highest annual average PM2.5 concentration was measured in the locality
Teplice and reached the value of 18.8 μg.m-3. This value is below the target
limit value for the annual average concentration pursuant to the Directive
2008/50/EC.
In 2007 NO2 concentrations were monitored in 33 localities in total in the Ústí
nad Labem Region (out of which 18 CHMI). The station Ústí n.L.-Všebořická, which
is significantly influenced by traffic, exceeded the annual limit value of NO2
but not the limit value plus the margin of tolerance.
In 2007 the limit value for 24-hour SO2 concentration was exceeded only in
the Ústí nad Labem Region, and namely in the locality Teplice (2x), Blažim, Lom,
Ústí n.L.-město, Most, Krupky, Ústí n.L.-Kočkov, Kostomlaty pod M., Havraň and
Sněžník (1x).
The 1-hour limit value of SO2 was not exceeded. The first five positions in the
table showing the exceedances of 1-hour limit value for SO2 are occupied by the
localities in the Ústí nad Labem Region, with the highest 1-hour value (720,7
μg.m-3 ) measured at the station Blažim.
The target value for benzo(a)pyrene was exceeded at 3 localities (Teplice, Ústí
nad Labem-ZÚ, Pasteurova, Most).
The target value for ground-level ozone was markedly exceeded similarly as in
other parts of the Czech Republic, and mainly at the stations with lower traffic
loads. Totally the exceedances of the target limit value for the three-year
period 2005–2007 were recorded in 9 localities of the total number of 12
localities measuring ground-level ozone.
PM10 concentrations in the period 2003–2007
The foothills of the Krušné hory Mts. and the territory around the cities
Litoměřice and Louny belong to the areas with deteriorated air quality due to
the exceedance of the limit values for PM10 suspended particles. The comparison
of the measured PM10 concentrations at selected stations in the period 2003–2007
with regard to the limit values is shown in Figs. II.4.1.27 and
II.4.1.28.
However, there are considerable differences in the level of exceedance and
the size of the territory with limit values exceedances between individual
years. The influence of meteorological conditions, and namely meteorological
conditions for the dispersion of pollutants in the ambient air during the given
year is quite significant.
The foothills of the Krušné hory Mts. is ranked among the areas with frequent
occurrence of inversion situations which result in unfavourable dispersion
conditions. The frequency of occurrence of individual degrees of dispersion
conditions (four-degree classification) in the foothills of the Krušné hory Mts.
in the years 2003–2007 is presented in Fig. II.4.1.29.
Further significant deterioration of air pollution situation occurs during the
episodes with long-lasting (several days) slightly unfavourable (deteriorated)
or unfavourable dispersion conditions, and mainly if these situations are
accompanied by temperatures below zero (see Fig. II.4.1.31). This figure shows
that during the warmer winter 2006/2007 and warmer November and the first half
of December 2007 there were relatively lower PM10 concentrations which then
significantly influenced the overall more favourable situation in 2007.
Fig. II.4.1.27 Annual average PM10 concentration, Ústí nad
Labem Region, 2003–2007
Fig. II.4.1.28 36th highest 24-hour PM10 concentration
and number of LV exceedances, Ústí nad Labem Region, 2003–2007
Fig. II.4.1.29 Number of days per year divided according to four degrees of
dispersion conditions, Krušné hory Mts. area, 2003–2007
Fig. II.4.1.30 The number of episodes with deteriorated and unfavourable
conditions lasting four and more days and the total number of days within these
episodes
Fig. II.4.1.31 Average 24-hour PM10, concentrations, temperature
and dispersion conditions, Ústí nad Labem Region, 2003–2007
4.1.5 Trends of annual air pollution characteristics of SO2, PM10 and NO2 for
the period 1996–2006
Fig II.4.1.32 shows the trends of SO2, PM10, NO2 and CO annual air pollution
characteristics in 1996–2007 for the following agglomerations: Prague, Brno and
Moravian-Silesian Region and for the zone Ústí nad Labem Region.
Up to 1999 there was a significant decreasing trend in SO2 and PM10
concentrations in the agglomerations, the NO2 concentrations decreased only
slightly. In 2001 the decreasing trend was interrupted and, on the contrary, the
SO2 and NO2 concentrations slightly increased; PM10 concentrations increased
significantly, mainly in the Ostrava agglomeration. In 2004, on the contrary,
concentrations of all pollutants monitored in the agglomerations decreased, and
SO2 concentrations slightly increased in the Ústí nad Labem Region. Since 2005
NO2 air pollution has returned to the increasing trend, which was confirmed in
2006. As concerns PM10, there has been a similar characteristic increasing trend
since 2005, with the steepest progress in the Moravian-Silesian Region. In 2006,
however, this trend continued only in the Prague and Brno agglomerations. The
increase of the pollutants concentrations, and mainly of PM10 (PM2.5) in the
years 2005 and 2006 is given mainly by deteriorated dispersion conditions. In
2006 these unfavourable meteorological conditions occurred on the whole
territory of the Czech Republic. In the Ústí nad Labem Region and in the
Moravian-Silesian Region, on the contrary, a very slight decrease of 24-hour
PM10 concentrations and stagnation of annual PM10 concentrations were recorded.
CO concentrations have remained at similar level since 1999. The highest average
concentrations have been regularly measured in the Moravian-Silesian Region
since 2000. In 2007 there was a marked decrease of air pollution caused by SO2,
PM10, NO2 and CO in all agglomerations. The steepest decrease is apparent, after
the previous increase, in hourly NO2 concentrations in Brno. The decrease of
pollutants concentrations in the ambient air was influenced by more favourable
meteorological and dispersion conditions in 2007.
Fig. II.4.1.32 Trends of
SO2, PM10, NO2 and CO annual characteristics in
agglomerations, 1996–2007
