Graphic Yearbook 2013
IV.9 POLLUTANTS WITHOUT THE LIMIT VALUE
IV.9.1 Volatile organic compounds (VOC)
Volatile organic compounds (VOC) play an important role in
the chemistry of the atmosphere and, consequently, in the
oxidation capacity of the atmosphere, which has its influence on
the ambient air quality and its state. Along with nitrogen
oxides VOC participate significantly in the process of formation
of ground-level ozone and other photooxidative pollutants.
Transformation and degradation of VOC are usually started by the
reaction with the hydroxyl radical (Víden 2005). Pursuant to the
Air Protection Act, the volatile organic compound means any
organic compound or mixture of organic compounds, with the
exception of methane, which has a vapour pressure of 0.01 kPa or
higher at a temperature of 20 °C or has corresponding volatility
under the specific conditions of its use. With regard to the
range of different reactivity lengths in individual VOC and
their amount, no limit value has been set for these pollutants.
The monitoring of VOC was integrated into the EMEP programme on
the basis of the decision of the EMEP Workshop on Measurements
of Hydrocarbons/VOC in Lindau 1989 (EMEP, 1990). The
measurements carried out by CHMI in the Observatory Košetice (OBK)
were launched during the year 1992, and three years later
identical measuring programme was implemented at the station
Prague-Libuš. Within EMEP monitoring was carried out first at
five stations but during 20 years the number of stations and the
range of the measured hydrocarbons changed several times. OBK
succeeded in maintaining the homogenous series of measurements
up to the present time. Since 2011 the OBK has participated in
the project ACTRIS, realized within the EU 7th
Framework Programme INFRA-2010-1-1.1.16: Research
Infrastructures for Atmospheric Research. The problems connected
with VOC are solved in the group WP4 (Trace gases networking:
Volatile organic carbon and nitrogen oxides) aimed at the
improvement and harmonization of VOC measurements in Europe.
Standard operation procedures are developed within the project
tasks and the best measuring instruments for quality assurance
are tested. CHMI laboratory participated in the round robin
test, and the results of VOC analysis carried out in CHMI
confirm that the laboratory meets the recommended parameters of
GC-system and complies with the required uncertainties both in
the standards and samples in most pollutants.
The average annual concentrations of most VOC at the stations in
OBK and Prague-Libuš have shown a statistically significant
downward trend over the recent 20 years, which reflects the
decrease of VOC emissions both in the CR and throughout central
Europe (Table IV.9.1.1). The trend of ethane concentrations is
more marked at the suburban station than at the background
station (Fig. IV.9.1.1). There is only one exception, and namely
isoprene (natural origin, produced by deciduous trees). At the
OBK station there was not recorded any trend of the average
annual concentrations of isoprene and at the station Prague-Libuš
even a slight increase of concentrations was recorded. The
annual course of most VOC reflects the emission levels, i.e. the
maximum values in winter and the minimum values in summer; in
isoprene, however, the opposite is true. Generally, it can be
stated that concentrations of the main VOC in the 90s of the
last century were by approx. 150–200 % higher at the suburban
level than at the background station. In the recent decade the
differences between both stations have had a significantly
decreasing trend.
The latest report on VOC measurements within EMEP (NILU 2013)
concludes that the evaluation of the long-term trends uses, in
addition to the data from OBK also data from further 9 stations
(5 in Germany, 2 in France, one in Finland and one in
Switzerland). The level of concentrations recorded in OBK is
comparable with the German and French stations. As concerns
ethane, the Czech station is characterized by lower annual
averages in the long term. The values of most VOC measured in
winter are usually very similar to those measured at the German
stations, while the summer values from the OBK are markedly
lower.
The Geneva Protocol concerning the control of emissions of VOC
or their transboundary fluxes was adopted in November 1991
entered into force in September 1997 (UN-ECE 1991). The Protocol
specified three options for emission reduction targets:
- 30% reduction in emissions of VOC by 1999 using a year between 1984 and 1990 as a basis;
- The same reduction as for (1) and ensuring that by 1999 total national emissions do not exceed 1988 levels;
- Where emissions in 1988 do not exceed the specified levels, parties may opt as emission ceiling the level of 1999 emissions.
In 1999 the Göthenburg Protocol to abate acidification,
eutrophication and ground-level ozone was adopted and it came
into force on 17 May 2005 (UN-ECE 1999). The protocol sets the
emission ceilings for 2010 for four pollutants incl. VOC. The
protocol sets that Europe’s emissions of VOC should be cut by at
least 40 % compared to 1990. The CR, similarly as most of
central European countries (with the exception of Poland), has
met this limit; VOC emissions in the CR for the period 1990–2010
decreased by 51 % (EEA 2013d).
The most significant sources of VOC emissions in the CR are
found in the sector of organic solvent use and application (NFR
3A-D); its share in air pollution caused by these substances in
2012 amounted to
52.6 % (Fig. IV.9.1.2). This sector includes the activities
connected with coating applications (22.9 %), decreasing and dry
cleaning (6.2 %), production and processing of chemical products
(9.0 %), solvent use in the printing industry, households etc.
(14.5 %). The release of VOC emissions is partly regulated, but
most of these pollutants are released in the form of fugitive
emissions, and their reduction is difficult. VOC emissions are
also produced by insufficient combustion of fossil fuels. The
largest amount of VOC emissions from combustion processes is
produced in the sector of local household heating (20.5 %),
passenger car transport (4.4 %), road freight transport over 3.5
t (5.4 %) and in the sector public electricity and heat
production (3.8 %). In connection with transport, VOC emissions
are released into air also as vapour from fuel tanks (4.5 %).
In the period 2007–2012 the total VOC emissions had a downward
trend (Fig. IV.9.1.3) caused by the application of products with
lower content of VOC, e.g. of water-based paints or powder
coating. As concerns paints packed for the retailers there is
applied the legislative regulation limiting the maximum content
of solvents in the products supplied to the market. Owing to the
constant renewal of the car fleet traffic emissions of VOC have
a decreasing trend.
Tab. IV.9.1.1 Stations with average annual concentrations of VOC in the ambient air
Fig. IV.9.1.1 Annual average concentrations of ethane and
isoprene in the ambient air at selected stations, 1997–2013
Fig. IV.9.1.2 Emissions of VOC sorted out by NFR sectors, 2012
Fig. IV.9.1.3 The development of VOC emissions, 2007–2012
IV.9.2 Elemental and organic carbon
Elemental carbon (EC) and organic carbon (OC) are important
components of atmospheric aerosols. EC gets into the atmosphere
mainly due to incomplete combustion of fossil fuels during
traffic, heating, energy production, wood and biomass burning
and also agricultural activities. Emissions of OC originate, in
addition to incomplete combustion, also from resuspension of
biological objects (fungi, spores) or from the abrasion of tyres
or plastic materials (Kuhlbusch et al. 2009).
The main reasons for the monitoring and research of EC and OC
behaviour in the atmosphere are the impacts on human health and
global climate. The negative impact of EC and OC on human health
was confirmed in various toxicological and epidemiological
studies (Highwood et al., 2006; Adar, Kaufman 2007). As a
consequence, the requirement for the measuring of EC and OC in
PM at regional stations was set by the European Commission
Directive (EC 2008).
Recently the scientists have aimed their attention also to the
role of carbonaceous aerosols in the process of global climate
change (e.g. Ramanathan, Carmichael 2008). EC is one of a few
aerosols with a strong ability to absorb solar radiation, while
OC, similarly as further aerosols, contributes mainly to its
scattering.
The EC-OC have been measured regularly within the EUSAAR project
and later the ACTRIS project in the Observatory Košetice since
February 2009. The sampling is carried out every sixth day in
PM2.5 fraction. Within the EUSAAR project the standardized
protocol for sampling and analysis of measurements was developed
and is further elaborated within the ACTRIS network. This
protocol should form the basis for the development of the
European or worldwide reference method and should be implemented
in national and international monitoring networks (such as EMEP)
to ensure the consistent measurement within Europe.
The average concentration of total carbon (TC) in PM2.5 in the
Observatory Košetice in the period 2009–2013 reached 4.01
µg.m-3, and the respective value for EC was 0.51 µg.m-3, which
represents the average share of 12.5 % in TC. Within the ACTRIS
network the data from the Observatory Košetice characterize,
together with the German station (Melpitz) and the Italian
station (Ispra), the continental part of Europe. Data obtained
in the Observatory Košetice are highly similar to the results
measured at the German station, while the Italian station has
recorded the highest concentrations both of TC (about 8 µg.m-3)
and EC (closely below 2 µg.m-3) in the long term within the
whole ACTRIS network. The concentration levels measured at
Scandinavian and mountainous stations are significantly lower (approx.
one third of the central European level.
Table IV.9.2.1 does not
show any marked year-toyear variability. The annual course of
concentrations corresponds with the annual course of their
emissions, i.e. the maximum levels are recorded in winter and
the minimum levels in summer (Fig. IV.9.2.1). The share of EC in
TC has continuously decreased during the monitored period from
14.5 % in the year 2009 to 10.4 % in the year 2013 (Fig.
IV.9.2.2). TC contributed to total concentrations of PM2.5 fraction in average by 20 %, out of which EC by 3.3 %.
Fig.
IV.9.2.3 shows the apparently higher share of EC in the cold
part of the year. The share of total carbon in PM in the ACTRIS
network corresponds with the results achieved in the Observatory
Košetice and it ranges around 20 %. There is the only exception,
and namely the Ispra station with the share amounting to almost
40 %.
Fig. IV.9.2.1 Average monthly concentrations of elemental
carbon and organic carbon in the
Observatory Košetice, 2009–2013
Fig. IV.9.2.2 Average monthly shares of elemental carbon in
total carbon in the Observatory Košetice, 2009–2013
Fig. IV.9.2.3 Average monthly shares of elemental carbon in PM2.5 concentrations in the Observatory Košetice, 2009–2013
IV.9.3 Ammonia (NH3)
Concentrations of NH3 in the year 2013
The measurement of NH3 concentrations in 2013 was carried out
only in two localities. This low number or localities was caused
by the fact that no limit value is set for NH3 and the
obligation to monitor its concentrations is not set by
legislation. The legislation is focused mainly at the reduction
of NH3 emissions (i.e. the maintenance of good agricultural
practice and the prevention of serious accidents). In the CR NH3 is measured at the stations Most and Pardubice-Dukla in
connection with emissions from industrial sources. In both cases
these are the stations classified as urban background.
The highest annual average concentration was measured similarly
as in 2012 at the station Pardubice-Dukla (Table IV.9.3.1). In comparison with the previous year (2012) this level decreased to
4.2 µg.m-3 (from 5.1 µg.m-3). The concentration
measured in the locality Most remained at similar level as in
2012 (i.e. 2 µg.m-3). Most and Pardubice were chosen for
monitoring NH3 concentrations in connection with emissions from
chemical industry located in the respective areas.
The average annual concentrations measured in the CR are
comparable with the concentrations measured abroad. In Ontario,
Canada, the annual average concentrations of NH3 range from 0.1
to 3.0 µg.m-3 (Zbieranowsky, Aherne, 2012), in the areas with
intensive agricultural activity this concentration amounts to
3.6 µg.m-3 (Zbieranowsky, Aherne, 2013). In southern Scotland
there were measured the average annual concentrations of NH3 in the range 0.40–22.9 µg.m-3, depending on the sampling site (Vogt
et al., 2013). The highest values were reached in the locality
70 meters up the wind from the poultry farm. It is thus evident
that NH3 concentrations show a marked spatial and time
variability (with regard to the main air pollution source).
The spatial variability is influenced by the distance from the
source of emissions. The time variability of NH3 concentrations
in agricultural areas is caused by the seasonal character of the
application of fertilizers within the respective year.
Consequently, higher concentrations are reached mainly in spring
and autumn (Zbieranowski, Aherne, 2013).
NH3 concentrations are also significantly influenced by higher
temperature which, due to increased volatility, results in
higher emissions of NH3 from the sources.
Emissions of NH3
Ammonia emissions are produced by decomposition of urea from
animal biological waste or during some chemical-technological
processes.
Farm animal breeding is the main source of NH3; its share in
total emissions of NH3 in 2012 amounted to 69.6 % (Fig.
IV.9.3.1). Further significant sources result from the sector of
application of mineral nitrogen-containing fertilizers with the
share of
26.5 % of total NH3 emissions. The remaining 3.9 % of NH3 emissions are produced by mobile sources equipped with catalytic
converters where NH3 is formed by the reduction of nitrogen
oxides, and further technological sources. Ammonia is emitted to
the atmosphere during the chemical production of fertilizers,
during the production of mineral fibres with the use or organic
binding agents, in the production of nitric acid etc.
The downward trend in the development of total emissions is
connected with the decrease of the number of farm animals,
mainly pigs, and in 2012 also poultry, as a consequence of
agricultural policy and market economy (Fig. IV.9.3.2). Further
reason for emission reduction is the legislation connected with
the issuing of integrated permits, within which there were
approved and consequently implemented the so called good
agricultural practice plans in the largest livestock groups.
Fig. IV.9.3.1 Emissions of NH3 sorted out by NFR
sectors, 2012
Fig. IV.9.3.2 The development of NH3 emissions, 2007–2012
