Air quality map thresholds

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Classification of the air quality levels for the EEA air quality reports and viewers (mandatory pollutants).

Air quality levels in Europe

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This is the first draft documentation on standardised categories for visualising the air quality situation in Europe within EEA viewers and reports (based on the Air Quality in Europe – 2012 report).

Particulate matter (PM10)

The reference levels

20 µg/m3 (WHO[2], reference level for the annual mean)

40 µg/m3 (EU[1], limit value for human health, annual mean)

50 µg/m3 (EU[1], limit value for human health & WHO[2], reference level for the daily mean, exceeded <= 35 days/y)

31 µg/m3 (proxy for the daily LV when translated into annual mean, source: communication with Valentin Foltescu and Frank de Leeuw)

35 (EU[1], allowed nr of days with exceedance of 50 µg/m3 daily mean)

Annual statistics

90.41 percentile corresponding with the 36th highest daily value if 100% data is available [µg/m3]:

<= 20
> 20 <= 40
> 40 <= 50 (EU[1], limit value for human health & WHO[2], reference level for the daily mean)
> 50 <= 75 (nonattainment)
> 75 (nonattainment)

(the classes can be used also for presenting the 8th highest value – this AQ statistics is specified in the http://acm.eionet.europa.eu/databases/airbase/aggregation_statistics.html as included in the ‘AirBase’ statistics)

(AQ Report 2012 [6]: ‘distance-to-target’ graphs ref. to Fig. 2.2, attainment situation ref. to Fig. 2.3)

Nr of days with exceedance (with PM10 > 50 µg/m3):

= 0
> 0 <= 10
> 10 <= 35 (EU[1], allowed nr of days with exceedance of 50 µg/m3 daily mean)
> 35 <= 50 (nonattainment)
> 50 (nonattainment)

(AQ Report 2012 [6]: ref. to Fig. 2.8)

Annual mean [µg/m3]:

<= 20 (WHO[2], reference level for the annual mean)
> 20 <= 31 (proxy for the daily LV when translated into annual mean, source: communication with Valentin Foltescu and Frank de Leeuw)
> 31 <= 40 (EU[1], limit value for human health, annual mean)
> 40 <= 50 (nonattainment)
> 50 (nonattainment)

(AQ Report 2012 [6]: ref. to Map 2.1)

Short term statistics (UNDER DISCUSSION)

Daily mean or 24h run for UTD [µg/m3]:

Option 1:

<= 20
> 20 <= 35
> 35 <= 50 (EU[1], limit value for human health & WHO[2], reference level for the daily mean)
> 50 <= 65 (nonattainment)
> 65 (nonattainment)

(following the thresholds used in the EEA’s UTD viewer: http://www.eea.europa.eu/themes/air/air-quality/map/real-time-map)

Option 2:

<= 15
> 15 <= 30
> 30 <= 50 (EU[1], limit value for human health & WHO[2], reference level for the daily mean)
> 50 <= 100 (nonattainment)
> 100 (nonattainment)

(following the thresholds used in the CAQI: http://www.obsairve.eu/index.php?option=com_content&view=article&id=7&Itemid=129&lang=en)

Option 3:

<= 20
> 20 <= 35
> 35 <= 50 (EU[1], limit value for human health & WHO[2], reference level for the daily mean)
> 50 <= 75 (nonattainment)
> 75 (nonattainment)

(following the thresholds used in the ETC/ACM draft document: EEA’s short-term Air Quality Indicator for UTD data at Station & City level, not published)

Particulate matter (PM2.5)

(& AEI calculated from urban background stations as 3-calendar year running annual mean)

The reference levels

10 µg/m3 (WHO[2], reference level for the annual mean)

20 µg/m3 (EU[1], limit value for human health, annual mean – to be met by 1st Jan 2020)

25 µg/m3 (EU[1], target value for human health, annual mean – to be met by 1st Jan 2015 & WHO[2], reference level for the daily mean)

Annual statistics

Annual mean [µg/m3]:

<= 10 (WHO[2], reference level for the annual mean)
> 10 <= 20 (EU[1], limit value for human health, annual mean – to be met by 1st Jan 2020)
> 20 <= 25 (EU[1], target value for human health annual mean – to be met by 1st Jan 2015)
> 25 <= 30 (nonattainment)
> 30 (nonattainment)

(AQ report 2012 [6]: ref. to Map 2.2, ‘distance-to-target’ graphs ref. to Fig. 2.2, attainment situation ref. to Fig. 2.4)

Short term statistics (UNDER DISCUSSION)

Daily mean or 24h run for UTD [µg/m3]:

No reference to the WHO[2], level for the daily mean (25 µg/m3)!

Option 1:

<= 15
> 15 <= 30
> 30 <= 50
> 50 <= 100
> 100

(following the thresholds used in the CAQI: http://www.obsairve.eu/index.php?option=com_content&view=article&id=7&Itemid=129&lang=en)

Option 2:

<= 10
> 10 <= 20
> 20 <= 35
> 35 <= 50
> 50

(following the thresholds used in the ETC/ACM draft document: EEA’s short-term Air Quality Indicator for UTD data at Station & City level, not published)

Ozone (O3)

The reference levels

100 µg/m3 (WHO[2], reference level for the 8 hour mean)

120 µg/m3 (EU[1], limit value for human health, maximum daily eight-hour mean, exceeded <= 25 days/y, nr of days with exceedance averaged over 3 years)

120 µg/m3 (EU[1], long term objective, human health, maximum daily eight-hour mean within a calendar year)

180 µg/m3 (EU[1], information threshold)

240 µg/m3 (EU[1], alert threshold)

25 (EU[1], allowed nr of days with exceedance of 120 µg/m3 daily mean, nr of days with exceedance averaged over 3 years)

18000 µg*h/m3 (EU[1], target value of AOT40, protection of vegetation, May-July, averaged over 5 years)

6000 µg*h/m3 (EU[1], long term objective of AOT40, protection of vegetation, May-July)

10000 µg*h/m3 (Mapping Manual 2004[3], AOT40, critical level for protection of forests, April-September)

Annual statistics

93.15 percentile corresponding with the 26th highest daily value (daily maximum 8-hour mean) if 100% data is available [µg/m3]:

<= 80
> 80 <= 100 (WHO[2], reference level for the 8 hour mean)
> 100 <= 120 (EU[1], limit value for human health, maximum daily eight-hour mean, exceeded <= 25 days/y, nr of days with exceedance averaged over 3 years)
> 120 <= 140 (nonattainment)
> 140 (nonattainment)

(AQ report 2012 [6]: ref. to Map 3.1, ‘distance-to-target’ graphs – ref. to Fig. 3.1, attainment situation ref. to Fig. 3.2)

Nr of days with exceedance (with O3 > 120 µg/m3):

= 0
> 0 <= 10
> 10 <= 25 (EU[1], allowed nr of days with exceedance of 120 µg/m3 maximum daily eight-hour mean, nr of days with exceedance averaged over 3 years)
> 25 <= 50 (nonattainment)
> 50 (nonattainment)

(AQ report 2012 [6]: ref. to Fig .3.4)

AOT40 – protection of vegetation & protection of forests, both 1 year and 5 years averages [µg*h/m3]:

<= 6000 (EU[1], long term objective of AOT40, protection of vegetation, May-July)
> 6000 <= 10000 (Mapping Manual 2004[3], AOT40, critical level for protection of forests, April-September)
> 10000 <= 18000 (EU[1], target value of AOT40, protection of vegetation, May-July, averaged over 5 years)
> 18000 <= 30000
> 30000

(AQ report 2012 [6]: ref. to Map 3.3 and 3.4, ‘distance-to-target’ graphs – ref. to Fig. 3.1 and 3.5)

SOMO35 (year, corrected) [µg*d/m3]:

<= 3000
> 3000 <= 6000
> 6000 <= 10000
> 10000 <= 15000
> 15000

(classification follows the one used on the map http://www.eea.europa.eu/data-and-maps/figures/ozone-somo35-2007)

Short term statistics (UNDER DISCUSSION)

1h or 1h daily max for UTD [µg/m3]:

<= 60 (the threshold of 60 follows the lowest threshold used in the EEA’s UTD viewer, CAQI and ETC document)
> 60 <= 120
> 120 <= 180 (EU[1], information threshold)
> 180 <= 240 (EU[1], alert threshold)
> 240

(all of the documents in agreement: EEA’s UTD viewer: http://www.eea.europa.eu/themes/air/air-quality/map/real-time-map, CAQI: http://www.obsairve.eu/index.php?option=com_content&view=article&id=7&Itemid=129&lang=en, the ETC/ACM draft document: EEA’s short-term Air Quality Indicator for UTD data at Station & City level, not published)

Nitrogen dioxide (NO2)

The reference levels

40 µg/m3 (EU[1], limit value for human health & WHO[2], reference level for annual mean)

200 µg/m3 (EU[1], limit value for human health & WHO[2], reference level for hourly mean)

400 µg/m3 (EU[1], alert threshold)

18 (EU[1], allowed nr of days with exceedance of 200 µg/m3 hourly mean)

30 µg/m3 (EU[1], critical level for vegetation, annual mean, NOx expressed as µg NO2/m3)

Annual statistics

99.78 percentile corresponding with the 19th highest hourly value if 100% data is available [µg/m3]:

<= 50
> 50 <= 100
> 100 <= 200 (EU[1], limit value for human health & WHO[2], reference level for hourly mean)
> 200 <= 400 (nonattainment, EU[1], alert threshold)
> 400 (nonattainment)

(AQ report 2012 [6]: ‘distance-to-target’ graphs – ref. to Fig. 4.1)

Nr of hours with exceedance (with NO2 > 200 µg/m3):

= 0
> 0 <= 9
> 9 <= 18 (EU[1], allowed nr of days with exceedance of 200 µg/m3 hourly mean)
> 18 <= 27 (nonattainment)
> 27 (nonattainment)

Annual mean [µg/m3]:

<= 20
> 20 <= 30
> 30 <= 40 (EU[1], limit value for human health & WHO[2], reference level for annual mean)
> 40 <= 50 (nonattainment)
> 50 (nonattainment)

(AQ report 2012 [6]: ref. to Map 4.1, ‘distance-to-target’ graphs – ref. to Fig. 4.1 and 4.4, attainment situation ref. to Fig. 4.2)

Short term statistics (UNDER DISCUSSION)

1 h for UTD [µg/m3]:

<= 50
> 50 <= 100
> 100 <= 200 (EU[1], limit value for human health & WHO[2], reference level for hourly mean)
> 200 <= 400 (nonattainment, EU[1], alert threshold)
> 400 (nonattainment)

Sulphur dioxide (SO2)

The reference levels

20 µg/m3 (EU[1], critical level for vegetation, winter & WHO[2], reference level for daily mean)

125 µg/m3 (EU[1], limit value for human health, daily mean, exceeded <= 3 days/y)

350 µg/m3 (EU[1], limit value for human health, hourly mean, exceeded <= 24 hours/y)

500 µg/m3 (EU[1], alert threshold, 3 consecutive hours & WHO[2], reference level for 10’ mean)

24 (EU[1], allowed nr of days with exceedance of 350 µg/m3 hourly mean)

3 (EU[1], allowed nr of days with exceedance of 125 µg/m3 daily mean)

Annual statistics

99.73 percentile corresponding with the 25th highest hourly value if 100% data is available [µg/m3]:

<= 100
> 100 <= 200
> 200 <= 350 (EU[1], limit value for human health, hourly mean, exceeded <= 24 hours/y)
> 350 <= 500 (nonattainment, EU[1], alert threshold, 3 consecutive hours)
> 500 (nonattainment)

(AQ report 2012 [6]: ‘distance-to-target’ graphs – ref. to Fig. 5.1)

Nr of hours with exceedance (with SO2 > 350 µg/m3):

= 0
> 0 <= 10
> 10 <= 24 (EU[1], allowed nr of days with exceedance of 350 µg/m3 hourly mean)
> 24 <= 50 (nonattainment)
> 50 (nonattainment)

99.18 percentile corresponding with the 4th highest daily value if 100% data is available [µg/m3]:

<= 20 (WHO[2], reference level for daily mean)
> 20 <= 60
> 60 <= 125 (EU[1], limit value for human health, daily mean, exceeded <= 3 days/y)
> 125 <= 200 (nonattainment)
> 200 (nonattainment)

(AQ report 2012 [6]: ‘distance-to-target’ graphs – ref. to Fig. 5.1, attainment situation ref. to Fig. 5.2)

Nr of days with exceedance (with SO2 > 125 µg/m3):

= 0
> 0 <= 1
> 1 <= 3 (EU[1], allowed nr of days with exceedance of 125 µg/m3 daily mean)
> 3 <= 5 (nonattainment)
> 5 (nonattainment)

(AQ report 2012 [6]: ref. to Fig. 5.4)

Annual mean [µg/m3]:

<= 5
> 5 <= 10
> 10 <= 20
> 20 <= 25
> 25

(AQ report 2012 [6]: ref. to Map 5.1)

Short term statistics (UNDER DISCUSSION)

1h or 1h daily max for UTD [µg/m3]:

Option 1:

attainment ambivalence in the 4th class !

<= 50
>50 <= 100
> 100 <= 300
> 300 <= 500 (EU[1], alert threshold, 3 consecutive hours & WHO[2], reference level for 10’ mean)
> 500 (nonattainment)

(following the thresholds used in the EEA’s UTD viewer: http://www.eea.europa.eu/themes/air/air-quality/map/real-time-map)

Option 2:

<= 50
>50 <= 100
> 100 <= 350 (EU[1], limit value for human health, hourly mean, exceeded <= 24 hours/y)
> 350 <= 500 (nonattainment, EU[1], alert threshold, 3 consecutive hours & WHO[2], reference level for 10’ mean)
> 500 (nonattainment)

(following the thresholds used in the CAQI: http://www.obsairve.eu/index.php?option=com_content&view=article&id=7&Itemid=129&lang=en)

Option 3:

<= 100
> 100 <= 200
> 200 <= 350 (EU[1], limit value for human health, hourly mean, exceeded <= 24 hours/y)
> 350 <= 500 (nonattainment, EU[1], alert threshold, 3 consecutive hours & WHO[2], reference level for 10’ mean)
> 500 (nonattainment)

(following the thresholds used in the ETC/ACM draft document: EEA’s short-term Air Quality Indicator for UTD data at Station & City level, not published)

Carbon monoxide (CO)

The reference levels

10 mg/m3 (EU[1], limit value, human health, maximum daily eight-hour mean within a calendar year)

Annual statistics

The highest daily maximum of running 8-hour mean [mg/m3]:

<= 1
> 1 <= 5
> 5 <= 10 (EU[1], limit value, human health, maximum daily eight-hour mean within a calendar year)
> 10 <= 15 (nonattainment)
> 15 (nonattainment)

statistics confirmed by ETC/ACM, email from Frank de Leeuw, 16/04/2013, ETC/ACM[7], page 41

(AQ report 2012 [6]: ‘distance-to-target’ graphs – ref. to Fig. 6.1, attainment situation ref. to Fig. 6.2)

Annual mean based on daily maximum 8-hour mean [mg/m3]:

<= 0.5
> 0.5 <= 1.0
> 1.0 <= 2.0
> 2.0 <= 2.5
> 2.5

(AQ report 2012 [6]: ref. to Map 6.1)

Short term statistics (UNDER DISCUSSION)

Daily maximum 8-hour mean and 8h run for UTD [mg/m3]:

Option 1:

<= 5
> 5 <= 7.5
> 7.5 <= 10 (EU[1], limit value, human health, maximum daily eight-hour mean within a calendar year)
> 10 <= 20 (nonattainment)
> 20 (nonattainment)

(following the thresholds used in the CAQI: http://www.obsairve.eu/index.php?option=com_content&view=article&id=7&Itemid=129&lang=en)

Option 2:

<= 5
> 5 <= 7.5
> 7.5 <= 10 (EU[1], limit value, human health, maximum daily eight-hour mean within a calendar year)
> 10 <= 15 (nonattainment)
> 15 (nonattainment)

(following the thresholds used in the ETC/ACM draft document: EEA’s short-term Air Quality Indicator for UTD data at Station & City level, not published)

Benzene (C6H6)

The reference levels

5 µg/m3 (EU[1], limit value, human health, annual mean)

Annual statistics

Annual mean [µg/m3]:

<= 1.7 (WHO reference, as specified by ETC/ACM[5], calculated for excess lifetime risk level of 10-5)
> 1.7 <= 2 (lower assessment threshold in AQD)
> 2 <= 3.5 (upper assessment threshold in AQD)
> 3.5 <= 5 (EU[1], limit value, human health, annual mean)
> 5 (nonattainment)

(AQ report 2012 [6]: ref. to Map 8.1, ‘distance-to-target’ graphs ref. to Fig. 8.1, attainment situation ref. to Fig. 8.2), recommended by the ETC/ACM (Cristina Guerreiro, Frank de Leeuw, email correspondence from 11/04/2013)

Heavy metals (As, Cd, Ni and Pb)

The reference levels

As: 6 ng/m3 (EU[4], limit value, human health, annual mean)

Cd: 5 ng/m3 (EU[4], limit value, human health, annual mean & WHO[2], reference level)

Ni: 20 ng/m3 (EU[4], limit value, human health, annual mean)

Pb: 500 ng/m3 (EU[4], limit value, human health, annual mean & WHO[2], reference level)

Annual statistics

Annual mean [ng/m3], As:

<= 1
> 1 <= 3
> 3 <= 6 (EU[4], limit value, human health, annual mean)
> 6 <= 9 (nonattainment)
> 9 (nonattainment)

Annual mean [ng/m3], Cd:

<= 1
> 1 <= 2
> 2 <= 5 (EU[4], limit value, human health, annual mean & WHO[2], reference level)
> 5 <= 8 (nonattainment)
> 8 (nonattainment)

Annual mean [ng/m3], Ni:

<= 5
> 5 <= 10
> 10 <= 20 (EU[4], limit value, human health, annual mean)
> 20 <= 30 (nonattainment)
> 30 (nonattainment)

Annual mean [ng/m3], Pb:

<= 20
> 20 <= 100
> 100 <= 500 (EU[4], limit value, human health, annual mean & WHO[2], reference level)
> 500 <= 1000 (nonattainment)
> 1000 (nonattainment)

(AQ report 2012 [6]: ref. to Map 7.1)

Benzo(a)pyrene (BaP)

The reference levels

1 ng/m3 (EU[4], target value, human health, annual mean)

Annual statistics

Annual mean [ng/m3]:

<= 0.12 (WHO reference, as specified by ETC/ACM[5], calculated for excess lifetime risk level of 10-5)
> 0.12 <= 0.4 (lower assessment threshold in AQD)
> 0.4 <= 0.6 (upper assessment threshold in AQD)
> 0.6 <= 1.0 (EU[4], target value, human health, annual mean)
> 1.0 (nonattainment)

(AQ report 2012 [6]: ref. to Map 8.2, ‘distance-to-target’ graphs ref. to Fig. 8.4, attainment situation ref. to Fig. 8.5), recommended by the ETC/ACM (Cristina Guerreiro, Frank de Leeuw, email correspondence from 11/04/2013)

Sources

1. EU, 2008, Directive 2008/50/EC of the European Parliament and of the Council of 21 May 2008 on ambient air quality and cleaner air for Europe (OJ L 152, 11.6.2008, p. 1–44).

2. WHO, 2008, Air quality and health — Fact sheet no 313 — Updated August 2008 (http://www.WHO.int/mediacentre/factsheets/fs313/en/), accessed 9 January 2013.

3. Mapping Manual 2004, Chapter III Mapping Critical Levels for Vegetation (http://icpvegetation.ceh.ac.uk/manuals/documents/Ch%203%20revised%20summer%202010,%20updated%20June%202011.pdf), accessed 30 April 2013

4. EU, 2004, Directive 2004/107/EC of the European Parliament and of the Council of 15 December 2004 relating to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in ambient air (OJ L 23, 26.1.2005, p. 3–16).

5. ETC/ACM Technical Paper 2011/3 (http://acm.eionet.europa.eu/docs/ETCACM_TP_2011_3_evaluation_AQ_LT_TV.pdf), accessed 15 May 2013

6. Air Quality in Europe - 2012 report, EEA Report No4/2012 (http://www.eea.europa.eu/publications/air-quality-in-europe-2012), accessed 17 June 2013

7. ETC/ACM Technical Paper 2011/1, (http://acm.eionet.europa.eu/docs/ETCACM_TP_2011_1_eoi2010_2009aqdata.pdf), accessed 17 June 2013