Assessing the condition of
ambient air
DECEMBER 2011
PRODUCED BY Robert Joy
DECEMBER
2011
FOR the Department of Sustainability, Environment, Water, Population
and Communities
ON BEHALF OF the State of the Environment 2011 Committee
Citation
Joy R, Assessing the condition of ambient air. Report prepared for the Australian
Government Department of Sustainability, Environment, Water, Population and
Communities on behalf of the State of the Environment 2011 Committee. Canberra:
DSEWPaC, 2011.
© Commonwealth of Australia 2011
This work is copyright. Apart from any use as permitted under the Copyright Act
1968, no part may be reproduced by any process without prior written permission
from the Commonwealth. Requests and enquiries concerning reproduction and rights
should be addressed to Department of Sustainability, Environment, Water,
Populations and Communities, Public Affairs, GPO Box 787 Canberra ACT 2601 or
email public.affairs@environment.gov.au
Disclaimer
The views and opinions expressed in this publication are those of the author and do
not necessarily reflect those of the Australian Government or the Minister for
Sustainability, Environment, Water, Population and Communities.
While reasonable efforts have been made to ensure that the contents of this
publication are factually correct, the Commonwealth does not accept responsibility
for the accuracy or completeness of the contents, and shall not be liable for any loss or
damage that may be occasioned directly or indirectly through the use of, or reliance
on, the contents of this publication.
Cover image
Brisbane skyline, QLD
Photo by Paradise Ink & DSEWPaC
Australia ■ State of the Environment 2011 Supplementary information
i
Preface
This report was developed by the author as part of the Atmosphere chapter of the
Australia State of the Environment (SoE) 2011 report. It was removed from the main
report due to limitations of space and is presented here as supplementary information.
The Minister for Environment is required, under the Environment Protection and
Biodiversity Conservation Act 1999, to table a report in Parliament every five years
on the State of the Environment.
The Australia State of the Environment (SoE) 2011 report is a substantive, hardcopy
report compiled by an independent committee appointed by the Minister for
Environment. The report is an assessment of the current condition of the Australian
environment, the pressures on it and the drivers of those pressures. It details
management initiatives in place to address environmental concerns and the
effectiveness of those initiatives.
The main purpose of SoE 2011 is to provide relevant and useful information on
environmental issues to the public and decision-makers, in order to raise awareness
and support more informed environmental management decisions that lead to more
sustainable use and effective conservation of environmental assets.
The 2011 SoE report, commissioned technical reports and other supplementary
products are available online at www.environment.gov.au/soe
Australia ■ State of the Environment 2011 Supplementary information
ii
Assessing the condition of ambient air
List of Figures
Figure 1 Capital Cities - Air Quality Index - Percentage Frequency
Distributions – Ozone (4 hour NEPM Standard).......................................................................... 4-6
Figure 2 Capital Cities - Air Quality Index - Percentage Frequency
Distributions – Particles (PM10 24 hour NEPM Standard)........................................................ 7-10
Figure 3 Regional Cities - Air Quality Index - Percentage Frequency
Distributions – Ozone (4 hour NEPM Standard)........................................................................... 11
Figure 4 Regional Cities - Air Quality Index - Percentage Frequency
Distributions – Particles (PM10 24 hour NEPM Standard)...................................................... 12-14
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Applying a Graded Report Card Approach to Australia’s Urban Air Quality
As part of the State of the Environment reporting process, a qualitative assessment was made
of ambient air quality in the eight state and territory capitals and in a small number of major
regional or industrial centres. The results of that assessment (generalised across periods of up
to 11 years ) are set out in Assessment Summaries 3.4 – 3.7 in the Atmosphere Chapter of the
2011 Report.
The assessments were based on analysis of air quality monitoring data for ozone and particles
(PM10) collected in accordance with protocols under the National Environment Protection
(Ambient Air Quality) Measure (NEPM(AAQ)). These data were transformed into an Air
Quality Index (AQI) that related directly to the health-based standards in the NEPM (AAQ).
Five qualitative AQI categories are used in public reporting of air quality.
Very
Poor
150+
Poor
100–
149
Fair
67–99
Good
34–66
Very
Good
0–33
Air quality is unhealthy
and everyone may begin
to experience health
effects. People from
sensitive groups may
experience more serious
health effects.
Air quality is unhealthy for
sensitive groups. The
general population is not
likely to be affected in this
range.
Air quality is acceptable.
However, there may be a
health concern for very
sensitive people.
Air quality is considered
good, and air pollution
poses little or no risk.
Air quality is considered
very good and air
pollution poses little or no
risk.
Source: Department of Sustainability, Environment, Water, Population and Communities,
2011: State of the Air in Australia 1999-2008
These categories were used as the framework for assessing each cities’ air quality (in terms of
ozone and particles).
(repeated from Box 3.9, Atmosphere chapter, SoE 2011)
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
The assessment approach based the characterisation of an airshed on its worst performing
monitoring station, rather than the total number of exceedences across the airshed, since this
is strongly influenced by the number of monitoring stations. Only data from monitoring
stations established in accordance with an approved NEPM monitoring plan were considered.
(In some cases, less than 10 years of NEPM monitoring data were available, and in one case –
Perth - 11 years of data were available.) Most large regional cities have only one NEPM
monitoring station, and most monitor particles but not ozone, since they lack the scale of
industry and traffic likely to give rise to ozone as a secondary pollutant. In each state the
regional cities selected for analysis of PM10 and ozone (where this was monitored) were the
worst performing in the state.
It is recognised that the 10-year goals set in the Ambient Air Quality NEPM for ozone and
particles allow for one exceedence per year for ozone and five exceedences per year for
particles. Nevertheless, given the nature of thehealth-based standards, andy exceedence may
have a potentially adverse impact and should therefore be taken into consideration, even if the
goal is met.
Ozone levels were calculated against the four-hour exposure standard rather than the onehour, as the four-hour standard is more likely to give a better indication of the impact on the
general population, rather than on sensitive individuals who are likely to be affected by acute
(i.e. shorter term) events.
Procedure For each year, monitoring data for ozone and PM10 from each of the selected
stations were converted into air quality index (AQI) values. These were used as the basis for
calculating the percentage of observations that fell into each of the five AQI-based qualitative
categories (very good, good, fair, poor, and very poor) commonly used by Australian
environment protection agencies to report air quality.
Each of these yearly percentage distributions for each pollutant at each station was then
assessed against the criteria set out in Table , to assign a general AQI score to each pollutant.
The results across the period were represented graphically to assist in identifying any trends.
It must be emphasised that the criteria set out in Table A are essentially subjective in nature.
In almost all cases, their application resulted in the most frequently occurring AWI category
being selected to generalise the year as a whole. In a small number of years, the the AQI
distribution was bimodal, with the result being borderline between the very good and good
categories.
Overall qualitative AQI scores for ozone and PM10 were then assigned to each city, based on
the most frequently occurring scores during the decade. A summary of the results is
presented in assessment summaries 3.4 and 3.5 of the Atmosphere chapter of SoE 2011.
Due to limitations of space, graphs showing the annual percentage frequency
distributions of AQI scores for each city (for ozone and for particles) could not be
included in the Report. These are set out in Figures 1 - 4 below. The generalised
qualitative assessments in Assessment Summaries 3.4 - 3.7 were based on the average
AQI percentage distributions shown in these figures.
Figures 1 and 2 show the percentage frequency distributions of the Air Quality Index
categories for each of the capital cities - Figure 1 for ozone and Figure 2 for PM10.
The graphs have been produced in accordance with the method outlined above.
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 1 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Ozone (4 hour NEPM Standard)
Adelaide - Netley - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
Poor 100-149
60%
50%
40%
30%
20%
Fair
67-99
Good
37-66
Very Good 0-33
10%
0%
Brisbane - Flinders View - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
0%
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 1 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Ozone (4 hour NEPM Standard) (cont.)
Canberra - Monash - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
70%
Very Poor 150+
60%
Poor
100-149
50%
40%
Fair
67-99
30%
Good
37-66
20%
Very Good 0-33
10%
0%
Melbourne - Melton - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
60%
Poor
100-149
50%
40%
Fair
30%
Good
67-99
37-66
20%
Very Good 0-33
10%
0%
2002
2003
2004
2005
2006
2007
2008
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 1 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Ozone (4 hour NEPM Standard) (cont.)
Perth - Rolling Green - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
Sydney - Oaklands - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 2 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard)
Adelaide - Netley - PM10
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
Poor
60%
50%
40%
30%
20%
100-149
Fair
67-99
Good
37-66
Very Good 0-33
10%
0%
Brisbane - Flinders View - PM10
Air Quality Index Categories
100%
90%
80%
70%
Very Poor 150+
60%
Poor
50%
100-149
40%
Fair
67-99
30%
Good
37-66
20%
10%
Very Good 0-33
0%
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 2 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard) (cont.)
Canberra - Monash - PM10
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
Darwin - Casuarina - PM10
Air Quality Index Categories
100%
90%
80%
70%
Very Poor 150+
60%
Poor
50%
40%
30%
20%
100-149
Fair
67-99
Good
37-66
Very Good 0-33
10%
0%
2004
2005
2006
2007
2008
Average
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 2 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard) (cont.)
Hobart - Newtown - PM10
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
60%
Poor
100-149
50%
Fair
67-99
30%
Good
37-66
20%
Very Good 0-33
40%
10%
0%
2006
2007
2008
Average
Melbourne - Mooroolbark - PM10
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 2 Capital Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard) (cont.)
Perth - South Lake - PM10
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
60%
50%
40%
30%
20%
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
10%
0%
Sydney - Bringelly - PM10
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
Fair
Good
100-149
67-99
37-66
Very Good 0-33
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 3 Cities - Air Quality Index - Percentage Frequency Distributions –
Ozone (4 hour NEPM Standard)
NSW - Kembla Grange - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
Very Poor
70%
Poor
60%
50%
40%
30%
20%
100-149
Fair
67-99
Good
37-66
Very Good
10%
150+
0-33
0%
Vic - Moe - O3 (4hr)
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
0%
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 4 Regional Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard)
NSW - Wagga Wagga - PM10
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
Poor
60%
50%
100-149
Fair
67-99
30%
Good
37-66
20%
Very Good 0-33
40%
10%
0%
Qld - West Mackay - PM10
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 4 Regional Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard) (cont.)
Port Pirie - PM10
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
Launceston - Ti Tree Bend - PM10
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
Poor
60%
50%
40%
30%
20%
100-149
Fair
67-99
Good
37-66
Very Good 0-33
10%
0%
2006
2007
2008
Average
Australia ■ State of the Environment 2011 Supplementary information
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Assessing the condition of ambient air
Figure 4 Regional Cities - Air Quality Index - Percentage Frequency Distributions –
Particles (PM10 24 hour NEPM Standard) (cont.)
Victoria - Geelong South - PM10
Air Quality Index Categories
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Very Poor 150+
Poor
100-149
Fair
67-99
Good
37-66
Very Good 0-33
WA - Bunbury - PM10
Air Quality Index Categories
100%
90%
80%
Very Poor 150+
70%
60%
Poor
50%
Fair
40%
30%
20%
10%
Good
100-149
67-99
37-66
Very Good 0-33
0%
Australia ■ State of the Environment 2011 Supplementary information
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