KAZALCI OKOLJA

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Key message
Bad

In recent years, the level of air pollution with ozone has been above the target value in most locations, including rural areas and higher altitudes, while (due to less sunny and cooler summers) the action value has been exceeded only in the Primorska region and in some places at higher altitudes. The highest ozone concentrations have been recorded in the Primorska region due to weather patterns that are favourable for ozone formation and the transport of ozone and its precursors from northern Italy.


This indicator shows the number of days with exceeded ozone target value and the number of hours with exceeded information value within a calendar year.

Tropospheric ozone differs from some other pollutants, as it is a product of photochemical reactions. Ozone precursors, especially nitrogen oxides and hydrocarbons, are substances from which ozone is formed in photochemical reactions. Consequently, high ozone concentrations do not occur in the immediate vicinity of large sources of precursors but in their wider surroundings. Under stable weather conditions during anticyclones, ozone clouds with high ozone concentrations can have a diameter of hundreds of kilometres and can be several kilometres high. Ozone concentrations above the information value may cause health problems (chest pain, coughing, vomiting, irritated eyes) in children and in people with chronic respiratory and cardio-vascular diseases. Repeated exposure to high ozone concentrations may cause permanent lung damage.


Charts

Figure ZR07-1: Number of days with exceeded target value for ozone in Slovenian urban areas with highest average 8-hour floating value > 120 μg/m3 (annual limit value 25 days)in the period of 2004-2016
Sources: 
Air quality monitoring database (DMKZ), Slovenian Environment Agency (2018)
Show data

Urban background

Ljubljana Bežigrad

Hrastnik

Celje

Nova Gorica

Koper

Suburban background

Trbovlje

Rural background

Iskrba

Otlica

Urban-traffic type

Maribor center

Zagorje

Rural/Agricultural type

Murska Sobota - Rakican

permitted exceedance

2004

43

42

31

40

59

0

25

25

47

47

0

11

8

14

50

50

25

2005

46.25

47

32

45

61

0

26

26

59

59

0

11.50

6

17

48

48

25

2006

35.25

37

25

33

46

0

16

16

53

53

0

7.50

3

12

24

24

25

2007

39

41

29

38

48

55

20

20

61

61

0

8.50

3

14

30

30

25

2008

32.75

35

26

28

42

60

18

18

65.50

53

78

6.50

3

10

23

23

25

2009

26.25

29

20

22

34

55

15

15

59.50

47

72

3

2

4

19

19

25

2010

23.75

22

22

19

32

57

17

17

48

39

57

3

2

4

15

15

25

2011

33

30

29

27

46

65

22

22

53

40

66

9

2

9

27

27

25

2012

40.25

37

34

33

57

66

22

22

55

42

68

8

3

13

38

38

25

2013

41.25

40

32

33

60

69

19

19

41

41

69

14

0

14

39

39

25

2014

31

28

25

23

48

56

15

15

37

37

54

9

0

9

27

27

25

2015

29.50

26

24

20

48

62

14

14

31

31

48

9

0

9

22

22

25

2016

24.25

21

18

15

43

57

12

12

32

25

39

5

0

5

16

16

25

Figure ZR07-2: Number of days with exceeded warning value for ozone in Slovenian urban areas (highest 1-hour value > 180 μg/m3) in the period of 1995-2016
Sources: 
Air quality monitoring database (DMKZ), Slovenian Environment Agency (2018)
Show data

Urban background

Ljubljana Bežigrad

Hrastnik

Celje

Maribor Vrbanski plato

Nova Gorica

Koper

Suburban background

Trbovlje

Rural background

Iskrba

Otlica

Urban-traffic type

Maribor center

Zagorje

Rural/Agricultural type

Murska Sobota - Rakican

1995

4

4

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1996

20

20

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1997

2.67

7

0

1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1998

1.33

2

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1999

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2000

1.67

3

2

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2001

1.33

1

0

3

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2002

7.50

4

0

0

0

26

0

0

0

0

0

0

0

0

0

0

0

0

0

2003

30.25

18

1

2

0

100

0

6

6

11

11

0

0

0

0

6

6

0

0

2004

7.25

4

0

0

0

25

0

0

0

1

1

0

0

0

0

0

0

0

0

2005

11.60

11

0

0

0

31

16

0

0

0

0

0

0

0

0

1

1

0

0

2006

17

9

4

3

0

33

36

1

1

34

1

67

0

0

0

0

0

0

0

2007

6.80

7

0

0

0

18

9

0

0

25

7

43

0

0

0

0

0

0

0

2008

0

0

0

0

0

0

0

0

0

2.50

0

5

0

0

0

0

0

0

0

2009

0.60

0

0

0

0

0

3

0

0

1

0

2

0

0

0

0

0

0

0

2010

0.40

0

0

0

0

0

2

0

0

1.50

0

3

0

0

0

0

0

0

0

2011

1.20

0

0

0

0

2

4

0

0

0.50

0

1

0

0

0

0

0

0

0

2012

7.20

3

1

1

0

18

13

1

1

6

0

12

0

0

0

0

0

0

0

2013

8.60

1

0

0

0

20

22

0

0

0

0

33

0

0

0

0

0

0

0

2014

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2015

2.50

0

0

0

0

6

9

0

0

0

0

0

0

0

0

0

0

0

0

2016

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0


Goals

  • Meeting the ozone target value for human health protection: the maximum daily 8-hour mean value for ozone (120 µg/m3) must not be exceeded more than 25 days within a calendar year (calculated as the average for the last three years);
  • meeting long-term goals as regards ozone values for human health protection: the maximum daily 8-hour mean value for ozone (120 µg/m3) must not be exceeded;
  • the information value of hourly ozone concentration for human health protection is 180 µg/m3, while the alert value is 240 μg/m3.

Ozone concentrations have a distinct annual cycle, which is associated with the way in which ozone is formed, requiring sufficient sunlight. The level of outdoor air pollution with ozone is significantly affected by transboundary transport of ozone concentrations. This is particularly characteristic of the Primorska region. Lowlands in northern Italy are among the areas in Europe where the largest amounts of ozone are formed. Thus, the highest concentrations occur during the summer along the coast and in the Primorska region, generally during periods of moderate westerly and south-westerly winds. The measurements of ground-level ozone show overages at almost all measurement sites in Slovenia except at those exposed to emissions of nitrogen oxides from traffic. At those measurement sites, ozone decomposes to O2 oxygen molecules. The lowest ozone concentrations were measured at the Maribor centre and Zagorje measurement sites, where the volume of traffic is high. The largest number of target value overages was recorded at the rural measuring sites of Iskrba and Otlica, where emissions of ozone precursors are low, which reduces the possibilities of reactions with ozone.

A multi-year data series does not reveal a discernible trend. Ozone concentrations depend on emissions of ozone precursors and, most of all, weather conditions during the summer months. Weather dependence is also evident from the number of overages of information values by year. The Slovenian Environment Agency forecasts ozone concentrations for all of Slovenia two days in advance. When an hourly information value is exceeded, the public is informed thereof on the ARSO website and the notification is sent to various addresses (hospitals, health clinics, the media, rescue centres, municipalities, schools, kindergartens). Along with the notification, information on potential effects on health, recommendations for the general population and the predicted duration of elevated concentrations is provided.