AIR QUALITY & AIR QUALITY AIR QUALITY & AIR QUALITY INDICESINDICES

A WORLD APART?A WORLD APART?

Frank de Leeuw

AQ EIONET workshop

17-18 October 2005, Vilnius

AQ Indices, Frank de Leeuw 210th AQ EIONET, Vilnius, 17/18-10-2005

AQ Indices, Frank de Leeuw 310th AQ EIONET, Vilnius, 17/18-10-2005

What is an Air Quality Index??What is an Air Quality Index??

Index (according to the Concise Oxford Dictionary):

• forefinger• list of books forbidden to Roman Catholics,

or to be read by them only in expurgated editions

• quantity indicating relative level of prices or wages at a particular date compared with that at a date taken as standard

AQ Indices, Frank de Leeuw 410th AQ EIONET, Vilnius, 17/18-10-2005

What is an Air Quality Index??What is an Air Quality Index??

A numerical relation expressing the relative levels of air quality in a region derived from air quality measurements at specific locations in that region, frequently used to inform the public on air quality.

It is as old as “automatic” measurements: – Paris, daily bulletin on ozone levels at 12 stations (Sainte-

Claire Deville Ch. Comptes Rendus 69, 99-101, 1869);– Ontario (Shenfield L., J. Air Pollution Control Assoc. 20,

612,1970)

AQ Indices, Frank de Leeuw 510th AQ EIONET, Vilnius, 17/18-10-2005

Comparing different approachesComparing different approaches

index 1 2 3 4 5 6 7 8 9 10

rating exellent very good

good fairly good

Moderate

poor very poor

bad very bad horrible

Index

1. sehr gut

2. gut

3. befriedigend

4. ausreichend

5. slecht

6. sehr slecht

Banding I ndex

1

2 Low

3

4

5 Moderate

6

7

8 High

9

Very High 10

AQ Indices, Frank de Leeuw 610th AQ EIONET, Vilnius, 17/18-10-2005

The common principles:The common principles:

• based on short-term health-related targets and/or information and alert levels

• the worst wins (TSP)

• (near) on-line information; hourly/daily update

• applicable in forecast mode

AQ Indices, Frank de Leeuw 710th AQ EIONET, Vilnius, 17/18-10-2005

DrawbacksDrawbacks

• No relation between AQI-value and pollutant mix

• Health effects of pollutants not comparable

• Long-term health effects not considered

• Assessment of long-term changes in air quality

AQ Indices, Frank de Leeuw 810th AQ EIONET, Vilnius, 17/18-10-2005

Classes, colours, namesClasses, colours, names

index 1 2 3 4 5 6 7 8 9 10

rating exellent very good

good fairly good

Moderate

poor very poor

bad very bad horrible

Index

1. sehr gut

2. gut

3. befriedigend

4. ausreichend

5. slecht

6. sehr slecht

Banding I ndex

1

2 Low

3

4

5 Moderate

6

7

8 High

9

Very High 10

AQ Indices, Frank de Leeuw 910th AQ EIONET, Vilnius, 17/18-10-2005

Overview of AQIsOverview of AQIs

Belgium France Germany UK Citeair # numerical levels, (scale)

10 (1-10) 10 (1-10) 6 (1-6) 10 (1-10) 5 (0- >100)

# colours 10 3 6 4 5 # verbal classes1 10 6 6 4 5

component PM10 PM10 PM10 PM10 PM10 averaging time 24h mean 24h mean 24h mean daily max of

24h running means

daily max of 1h means or24h

mean

component O3 O3 O3 O3 O3 averaging time daily max of

8h running means

daily max of 1h means

daily max of 1h means

daily max of 1h means or of 8h running means

daily max of 1h means

component NO2 NO2 NO2 NO2 NO2 averaging time daily max of 1h

means daily max of 1h

means daily max of 1h

means daily max of 1h

means daily max of 1h

means

component SO2 SO2 SO2 SO2 SO2

averaging time 24h mean daily max of 1h means

daily max of 1h means

15 minute means4

daily max of 1h means

component CO CO CO

averaging time daily max of 8h running

means

daily max of 8h running

means

daily max of 8h running

means

AQ Indices, Frank de Leeuw 1010th AQ EIONET, Vilnius, 17/18-10-2005

Class boundaries ozoneClass boundaries ozone

ozone concentration (ug/m3)

0

50

100

150

200

250

300

350

400

index class

BE FR UK Citeair DE

1 2 3 4 5 6 7 8 9 10

AQ Indices, Frank de Leeuw 1110th AQ EIONET, Vilnius, 17/18-10-2005

Class boundaries PM10Class boundaries PM10

PM10 concentration (ug/m3)

0

50

100

150

200

250

index class

BE FR UK Citeair DE

1 2 3 4 5 6 7 8 9 10

AQ Indices, Frank de Leeuw 1210th AQ EIONET, Vilnius, 17/18-10-2005

Class boundaries NO2Class boundaries NO2

NO2 concentration (ug/m3)

0

100

200

300

400

500

600

700

800

900

index class

BE FR UK Citeair DE

1 2 3 4 5 6 7 8 9 10

AQ Indices, Frank de Leeuw 1310th AQ EIONET, Vilnius, 17/18-10-2005

Comparing the AQIsComparing the AQIs

• 10 station from AirBase, 2003 data

• 4 + 1 traffic• 4 (sub)urban

background• 1 rural background

traff ic

urban

rural

AQ Indices, Frank de Leeuw 1410th AQ EIONET, Vilnius, 17/18-10-2005

Madrid, traffic stationMadrid, traffic station

ES0125A

0

5

10

15

20

25

30

35

1-1-03 01 10-2-03 01 22-3-03 01 1-5-03 01 10-6-03 01 20-7-03 01 29-8-03 01 8-10-03 01 17-11-03 01 27-12-03 01

Citair

UK

AQ Indices, Frank de Leeuw 1510th AQ EIONET, Vilnius, 17/18-10-2005

Prague-traffic; London backgroundPrague-traffic; London background

0

10

20

30

40

0 2 4 6 8 10

CZ0065A - UK index

Cit

air

inde

x

0

4

8

12

16

20

0 2 4 6 8 10

GB0620A - UK index

Cit

air

inde

x

AQ Indices, Frank de Leeuw 1610th AQ EIONET, Vilnius, 17/18-10-2005

Comparison at daily baseComparison at daily base

0

1

2

3

4

5

6

7

8

CZ0065A ES0125A ES1426A GB0682A GR0035A GB0566A GB0620A NL0204A NL0248A NL0249A

UK

Citair

FR

BE

DE

AQ Indices, Frank de Leeuw 1710th AQ EIONET, Vilnius, 17/18-10-2005

ConclusionsConclusions

• Similar concepts but widely different implementation

• resulting sometimes in conflicting information• while blaming different pollutants• although correlation is good.• Index values sensitive for choice of PM10

correction factors?• CO and SO2 of minor importance

AQ Indices, Frank de Leeuw 1810th AQ EIONET, Vilnius, 17/18-10-2005