uk air quality indicators janet dixon air and environment quality division, department of...
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UK Air Quality Indicators
Janet Dixon
Air and Environment Quality Division, Department of Environment, food and
Rural Affairs, UK
Air quality monitoring network
UK Air Pollution Index
• Used for providing a public summary of current and forecast air pollution
• 1-10 scale in 4 bands for 5 pollutants - ozone, PM10, SO2, NO2, CO
• Produced for all 16 UK zones and largest 16 of the 28 UK agglomerations
• Levels reported = highest for any single pollutant
• Has health advice associated with each band
• Mainly driven by PM10 and O3
• Further information: www.airquality.co.uk/archive/standards.php#band
UK Air Pollution Index
O3 NO2 PM10 SO2 CO
µg m-3
(mg m-3 for CO)
8hr running mean or hourly mean
Hourly mean 24 hour running mean
15 minute mean
8 hour running mean
Low
(1-3)
0 – 99 0 - 286 0 – 49 0 – 265 0 – 11.5
Moderate (4-6)
100 – 179 287 – 572 50 – 74 266 – 531 11.5 – 17.3
High
(7-9)
180 – 359 573 – 763 75 – 99 532 – 1063
17.4 – 23.1
Very high (10)
> 360 > 764 > 100 > 1063 > 23.2
UK Air Quality Headline Indicator
• UK Sustainable Development Strategy • One of 15 headline indicators• Developed in 1998, reviewed in 2002• Captures ‘acute’ air quality issues• Counts number of days of moderate or higher (from AP Index)
pollution for 5 ‘acute’ pollutants – ozone, PM10, SO2, NO2, CO
• Does not correspond directly to UK Air Quality Strategy objectives
Headline indicator
• Maximum number of sites used is fixed • Pre-1998 – up to 34 urban and 14 rural/remote• 1998 – 34 urban and 14 rural/remote• 2002 – 49 urban and 16 rural/remote
• To be included sites need minimum range of pollutants and data capture (>75%)
• Rural – at least O3
• Roadside/kerbside – at least PM10
• Other urban – at least O3, PM10 and SO2
• Fairly robust to changes in network• Urban sites cover 26 of the 28 UK agglomerations
0
10
20
30
40
50
60
70
1987 1989 1991 1993 1995 1997 1999 2001 2003
Days when air pollution is moderate or higher: 1987-2003
Urban sites
Rural sites
Final 2003 indicator
0
10
20
30
40
50
60
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Causes of air pollution at urban sites
total urban
0
10
20
30
40
50
60
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
particles
sulphur dioxide
Causes of air pollution at urban sites
total urban
0
10
20
30
40
50
60
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
ozone
particles
sulphur dioxide
Causes of air pollution at urban sites
total urban
The main episodes driving 2003
• Exceptionally hot summer – • high ozone
• Particulate episodes in spring, including • UK and European element• Saharan dust storm
9
10
11
12
13
14
15
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
Su
mm
er T
emp
erat
ure
0
10
20
30
40
50
60
70
80
Ozo
ne
Da
ys
Urban
Rural
• high secondary particulates (SO2 & NO2 gas converted to particulate sulphates & nitrates)
0
5
10
15
20
25
30
35
40
45
50
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
Co
nc
en
tra
tio
ns
(m g/m
3)
Average
Range
40 ug/m3 objective
20 ug/m3 prov. objective
PM100
10
20
30
40
50
60
70
80
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
Co
nc
en
tra
tio
ns
(m g/m
3)
Average
Range
40 ug/m3 objective NO2
0
10
20
30
40
50
60
70
80
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
Co
nc
en
tra
tio
ns
(m g/m
3)
Average
Range
20 ug/m3 vegetationprotection
SO2
•Indicator picks up peaks – what about long-term trends?
but….
….for ozone:
0
10
20
30
40
50
60
70
1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
Year
Co
nce
ntr
atio
ns
(mg/m
3)
Average
Range
• 2003 was an exceptional year.
• Headline Indicator accurately reflects poor air quality in 2003 (but not every aspect).
• Headline indicator is currently being reviewed
For the future:
Conclusions
long-term trend downwards for most pollutants.
ozone increasing - global ozone precursor emissions, (?) global warming