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Air at the Koper station

Koper, Slovenia

Network: Slovenian Environment Agency · Station code: SI0038A

This year, up to yesterday (October 6)

102 days

with an 8-hour average of ozone (O₃) above the target value of 120 µg/m³.

The target value allows 25 such days a year, averaged over three years.

In 2025: 47 days above the limit, the target value allows 25 as a three-year average.

2 days

with a daily average of particulate matter PM10 above the EU limit of 50 µg/m³.

35 days are allowed in the whole year.

Worst day: August 6, 2026, O₃ 181 µg/m³ as a daily average, 1.5 times the limit.

Daily average for 273 of 279 days · data for 2026 not yet finally verified · Yardstick: EU limits (Directive 2008/50/EC)

All figures by year and month

Moderate

Air now · Measured at 21:00

Latest values

Latest value: 21:00

Readings
PollutantValueLevel
PM1017.5 µg/m³Fair
NO₂32.9 µg/m³Moderate
O₃42.2 µg/m³Good

How the air is changing

Over the last seven days there was more PM10, PM2.5, NO₂, and O₃ in the air than the week before.

  • PM10: average 14.2 µg/m³, week before 8.2 µg/m³
  • PM2.5: average 7.8 µg/m³, week before 4.8 µg/m³
  • NO₂: average 11.3 µg/m³, week before 9 µg/m³
  • O₃: average 96.9 µg/m³, week before 82.1 µg/m³

Last month there was less PM10, PM2.5, NO₂, and O₃ in the air than the month before.

  • PM10: average 8.2 µg/m³, month before 14.4 µg/m³
  • PM2.5: average 4.3 µg/m³, month before 7.6 µg/m³
  • NO₂: average 9.7 µg/m³, month before 12.4 µg/m³
  • O₃: average 86.8 µg/m³, month before 114.2 µg/m³

Show

Ozone O₃

42.2

Nowµg/m³

Measured at 21:00

80.6

Last 24 hoursµg/m³

measured in 96 % of hours · provisional

96.9

Last 7 daysµg/m³

measured in 100 % of hours · provisional

85.2

Last 30 daysµg/m³

measured in 100 % of hours · provisional

76.3

Last 12 monthsµg/m³

measured in 97 % of hours · provisional

Days in 2023: O₃, 8-hour average above 120 µg/m³

59 days above the limit.

1102031JanFebMarAprMayMay 6: 129 µg/m³, above the limitMay 7: 127 µg/m³, above the limitMay 22: 124 µg/m³, above the limitMay 23: 141 µg/m³, above the limitJunJun 1: 120 µg/m³, above the limitJun 10: 122 µg/m³, above the limitJun 17: 143 µg/m³, above the limitJun 18: 143 µg/m³, above the limitJun 19: 142 µg/m³, above the limitJun 20: 138 µg/m³, above the limitJun 21: 183 µg/m³, above the limitJun 22: 192 µg/m³, above the limitJun 23: 157 µg/m³, above the limitJun 24: 131 µg/m³, above the limitJun 25: 129 µg/m³, above the limitJun 26: 141 µg/m³, above the limitJun 27: 168 µg/m³, above the limitJun 29: 129 µg/m³, above the limitJun 30: 132 µg/m³, above the limitJulJul 1: 138 µg/m³, above the limitJul 2: 132 µg/m³, above the limitJul 5: 127 µg/m³, above the limitJul 8: 130 µg/m³, above the limitJul 9: 138 µg/m³, above the limitJul 10: 159 µg/m³, above the limitJul 11: 146 µg/m³, above the limitJul 12: 131 µg/m³, above the limitJul 15: 143 µg/m³, above the limitJul 16: 125 µg/m³, above the limitJul 17: 124 µg/m³, above the limitJul 18: 155 µg/m³, above the limitJul 19: 133 µg/m³, above the limitJul 20: 130 µg/m³, above the limitJul 23: 129 µg/m³, above the limitJul 28: 122 µg/m³, above the limitJul 29: 134 µg/m³, above the limitJul 30: 128 µg/m³, above the limitAugAug 1: 127 µg/m³, above the limitAug 12: 123 µg/m³, above the limitAug 14: 125 µg/m³, above the limitAug 15: 136 µg/m³, above the limitAug 16: 125 µg/m³, above the limitAug 17: 132 µg/m³, above the limitAug 19: 120 µg/m³, above the limitAug 21: 130 µg/m³, above the limitAug 22: 135 µg/m³, above the limitAug 23: 135 µg/m³, above the limitAug 24: 132 µg/m³, above the limitAug 25: 148 µg/m³, above the limitAug 26: 137 µg/m³, above the limitAug 27: 123 µg/m³, above the limitSepSep 2: 141 µg/m³, above the limitSep 3: 131 µg/m³, above the limitSep 10: 123 µg/m³, above the limitSep 11: 124 µg/m³, above the limitSep 12: 129 µg/m³, above the limitSep 13: 123 µg/m³, above the limitOctOct 3: 131 µg/m³, above the limitOct 8: 126 µg/m³, above the limitNovDec
  • above the limit
  • below the limit
  • too few readings for the day
Days above the limit with values (59)
  1. May 6 129
  2. May 7 127
  3. May 22 124
  4. May 23 141
  5. Jun 1 120
  6. Jun 10 122
  7. Jun 17 143
  8. Jun 18 143
  9. Jun 19 142
  10. Jun 20 138
  11. Jun 21 183
  12. Jun 22 192
  13. Jun 23 157
  14. Jun 24 131
  15. Jun 25 129
  16. Jun 26 141
  17. Jun 27 168
  18. Jun 29 129
  19. Jun 30 132
  20. Jul 1 138
  21. Jul 2 132
  22. Jul 5 127
  23. Jul 8 130
  24. Jul 9 138
  25. Jul 10 159
  26. Jul 11 146
  27. Jul 12 131
  28. Jul 15 143
  29. Jul 16 125
  30. Jul 17 124
  31. Jul 18 155
  32. Jul 19 133
  33. Jul 20 130
  34. Jul 23 129
  35. Jul 28 122
  36. Jul 29 134
  37. Jul 30 128
  38. Aug 1 127
  39. Aug 12 123
  40. Aug 14 125
  41. Aug 15 136
  42. Aug 16 125
  43. Aug 17 132
  44. Aug 19 120
  45. Aug 21 130
  46. Aug 22 135
  47. Aug 23 135
  48. Aug 24 132
  49. Aug 25 148
  50. Aug 26 137
  51. Aug 27 123
  52. Sep 2 141
  53. Sep 3 131
  54. Sep 10 123
  55. Sep 11 124
  56. Sep 12 129
  57. Sep 13 123
  58. Oct 3 131
  59. Oct 8 126

Values in µg/m³, limit 120 µg/m³.

Months of 2023

MonthDays above 120Highest 8 hNo readings
January0810
February0920
March01090
April01180
May4 above the number allowed1410
June15 above the number allowed1920
July18 above the number allowed1590
August14 above the number allowed1480
September6 above the number allowed1410
October2 above the number allowed1310
November0900
December0780

Values in µg/m³. ■ marks a month with at least one day above the limit; the number allowed applies to the whole year. “No readings”: days on which not a single reading came from the station.

Last 7 days, every hour: O₃ in µg/m³highest 138 µg/m³, latest 25 µg/m³ (21:00)0100200ThuFriSatSunMonTueWedlatest 25 (21:00)
measured
Last 7 days, every hour: O₃ in µg/m³
Values as a table
Hour toµg/m³Note
Wednesday, 10/7
21:0024.7
20:0013.9
19:0056.7
18:0058.3
17:0061
16:0071
15:0077.8
14:00100.8
13:0082.4
12:0091.3
11:0065.9
10:0083.5
09:0079.9
08:0089.5
07:0098.3
06:00111.3
05:0090.2
04:0096.2
03:00106.9
02:0098.9
01:00105.6
Tuesday, 10/6
00:0095
23:0095.6
22:00102.8
21:00102.8
20:0094
19:00123.7
18:00133.7
17:00138.1
16:00136.2
15:00128.3
14:00114.8
13:0099
12:0084.4
11:0059.6
10:0054.1
09:0064.4
08:0053.3
07:0064.3
06:0076.3
05:0066.4
04:0076.6
03:0066.4
02:0081.5
01:0075.8
Monday, 10/5
00:0074.2
23:0080.1
22:0069.6
21:0089.7
20:0091.8
19:0090.5
18:00106.8
17:0099.4
16:0095.1
15:00109.7
14:0099.4
13:0085.8
12:0084.4
11:0068.5
10:0052.4
09:0059.7
08:0063.6
07:0073.6
06:0088.4
05:0083.8
04:0076.5
03:0090
02:0098.4
01:00109.4
Sunday, 10/4
00:00108.5
23:00105.5
22:00109.4
21:00111.9
20:00109.2
19:00116.5
18:00130.4
17:00132.5
16:00135.2
15:00130.8
14:00131.9
13:00125.5
12:00119
11:0098.3
10:0089.8
09:0091.8
08:00101.2
07:00101.5
06:00104.7
05:00104.7
04:00105.4
03:00103.2
02:00103.2
01:00102.3
Saturday, 10/3
00:00101.7
23:0086.4
22:0090.1
21:00100
20:0093.3
19:00112.5
18:00115.7
17:00119.1
16:00120.7
15:00121.9
14:00116.3
13:0097.3
12:0089.1
11:0095.4
10:0088.5
09:0096.2
08:0099.7
07:00100.5
06:00102
05:00103.4
04:00104.5
03:00103.5
02:00103.2
01:00102.1
Friday, 10/2
00:00102.9
23:00100.7
22:0099.1
21:0095.2
20:0086.4
19:0084.3
18:0087.1
17:0084.4
16:0080.2
15:0092.6
14:0092.2
13:0089.5
12:0096.4
11:0090.1
10:0094
09:0095.5
08:0095.3
07:0097.2
06:00100.4
05:00102
04:00101.2
03:00101
02:00102.2
01:00100.7
Thursday, 10/1
00:00100
23:00101.1
22:0095.5
21:0091
20:0084
19:0083.2
18:00111.5
17:00117.9
16:00119.8
15:00118.6
14:00113.9
13:0097.5
12:0088.1
11:0082.7
10:0081.6
09:0090.4
08:0094.3
07:00100
06:0099.6
05:00101.9
04:00101.1
03:00100.3
02:0099.5
01:0088.4
Wednesday, 9/30
00:0089.9
Last 30 days, highest 8-hour average of the day: O₃ in µg/m³ · 4 days above the limithighest 139 µg/m³, latest 121 µg/m³0501001509/99/169/239/30highest 139latest 121
day above the limittarget value, 120 µg/m³
Last 30 days, highest 8-hour average of the day: O₃ in µg/m³ · 4 days above the limit
Values as a table
Dayµg/m³Note
Tue, 10/6121.4above the limit · provisional
Mon, 10/5112.6provisional
Sun, 10/4127.7above the limit · provisional
Sat, 10/3112.4provisional
Fri, 10/2101.1provisional
Thu, 10/1106.3provisional
Wed, 9/30110.1provisional
Tue, 9/29110.2provisional
Mon, 9/28102.3provisional
Sun, 9/27103.8provisional
Sat, 9/2699.5provisional
Fri, 9/2580.7provisional
Thu, 9/2475.9provisional
Wed, 9/2391.2provisional
Tue, 9/2286.7provisional
Mon, 9/2181.6provisional
Sun, 9/20101.9provisional
Sat, 9/1980provisional
Fri, 9/1889.5provisional
Thu, 9/17100.8provisional
Wed, 9/16115.3provisional
Tue, 9/1599.7provisional
Mon, 9/14123above the limit · provisional
Sun, 9/13110.1provisional
Sat, 9/1287.8provisional
Fri, 9/1166provisional
Thu, 9/1091.7provisional
Wed, 9/9117.3provisional
Tue, 9/8138.7above the limit · provisional
Mon, 9/7117.3provisional
Last 12 months, monthly average: O₃ in µg/m³highest 114 µg/m³, latest 97 µg/m³050100150DecFebAprJunAugOcthighest 114latest 97
Last 12 monthsthis month so fara year earlier
Last 12 months, monthly average: O₃ in µg/m³
Values as a table
Monthµg/m³a year earlierNote
October 2026 so far97.260.9measured in 100 % of hours · provisional · year before: same days
September 202686.869measured in 100 % of hours · provisional
August 2026114.287.2measured in 92 % of hours · provisional
July 2026110.990.6measured in 100 % of hours · provisional
June 202696.5101.6measured in 97 % of hours · provisional
May 202695.585.6measured in 97 % of hours · provisional
April 202690.679measured in 98 % of hours · provisional
March 202670.671.6measured in 96 % of hours · provisional
February 202649.253.1measured in 97 % of hours · provisional
January 202645.446.8measured in 98 % of hours · provisional
December 202536.144.3measured in 96 % of hours · verified
November 202552.845.6measured in 96 % of hours · verified

O₃ by year

Yardstick: EU limits (Directive 2008/50/EC)

Measure2026*20252024
Days with 8-hour average above 120 µg/m³ (target value 25)1024756
Annual average, µg/m³85*69.369
Highest 8-hour average, µg/m³181August 6163June 19160August 24
Hours measured97 %96 %96 %
Days without any reading from the station000

* 2026 up to October 6; the average since the start of the year is not yet an annual average.

The monitoring networks have not yet finally verified this year’s data. The EEA publishes verified values once a year.

■ and a figure in red: more than is allowed for the whole year.

The column for 2023 is shown on wider screens.

The worst days of 2023

DayHighest 8 hTimes the limit
Jun 22, 20231921.6 ×
Jun 21, 20231831.5 ×
Jun 27, 20231681.4 ×
Jul 10, 20231591.3 ×
Jun 23, 20231571.3 ×

Daily average in µg/m³, daily limit 120 µg/m³. Days with the same unverified value over many hours are not on this list.

Outages in the last 12 months

Every period of at least 24 hours in which no reading arrived from this station.

Days without a reading: 0

Timeline of outages from October 7, 2025 to today

In the last 12 months this station had no outage of 24 hours or longer.

Calculated from the hourly values the EEA publishes. If late values arrive afterwards, an outage gets shorter or disappears.

Where the data comes from

Measured by Slovenian Environment Agency. We take the values from the European Environment Agency (EEA) under the CC BY 4.0 licence.

Values marked provisional have not been fully checked by the network yet. The EEA publishes verified data for the previous year once a year, usually by the end of September.

An hourly value is the average of one hour. We show the end of the hour: the value to 18:00 was measured from 17:00 to 18:00.

A day runs from midnight to midnight local time.

We only show an average when at least three out of four hours in the period have a reading. The EU air quality directive requires this for daily averages, and we apply the same rule to longer periods. We compare an annual average with the EU limit only once 90 % of hours are measured, as the directive requires. For 12 months and for a year we ask for more: if less than 90 % of hours are measured, every full calendar month needs readings for at least half of its hours. Otherwise a whole season could be missing from the average, such as summer, when ozone is highest.

We do not call a difference of up to 10 % a change, nor one of up to 1 µg/m³ at low levels, because weather and measurement uncertainty alone cause differences that size.

When a station sends no reading, the EEA sometimes fills the hour with a model estimate. We draw those hours dashed and leave them out of every average.

The EU limits come from Directive 2008/50/EC. Here they serve as a yardstick for comparison. When more than a tenth of the days or hours are missing, the number of exceedances can only be higher, so we write “at least” in front of it.

How we measure

samoEKO is a brand of samoLabs, Juelich.