Print

South East Queensland air quality trends

We have measured air quality in South East Queensland since 1978.

Our monitoring program provides us with information to identify long-term trends in air quality by comparing measurements with the goals defined in the National Environment Protection (Ambient Air Quality) Measure (Air NEPM) and the Environmental Protection (Air) Policy (Air EPP).

Airborne particles—visibility reducing particles

Show data

Number of days per year visibility was below the specified distance due to airborne fine particles
Year Days <10km Days <20km (EPP(Air) objective)
1978 6 64
1979 15 92
1980 9 51
1981 7 45
1982 8 56
1983 2 18
1984 13 60
1985 3 46
1986 6 17
1987 3 12
1988 3 26
1989 5 11
1990 0 11
1991 4 30
1992 1 9
1993 6 43
1994 9 32
1995 11 36
1996 8 35
1997 8 24
1998 1 8
1999 0 2
2000 10 33
2001 3 12
2002 0 5
2003 2 9
2004 4 13
2005 2 5
2006 2 4
2007 3 9
2008 0 2
2009 4 12
2010 0 4
2011 0 4
2012 7 14
2013 2 8
2014 3 10
2015 1 4
2016 1 6
2017 1 7
2018 3 7
2019 5 21
2020 0 7

A build-up of fine particles in the air can reduce how far we can see. The Environmental Protection (Air) Policy 2019 (Air EPP) provides a visual amenity objective of 20km. This means it should be possible on a fine day to see an object 20km away.

Reductions in visibility are largely attributable to visibility-reducing particles produced by burning activities such as motor vehicle and industry emissions, bushfires and hazard-reduction burning; fine particles resulting from photochemical smog formation; and windblown dust.

Since monitoring began in 1978, there has been an overall downward trend in the number of days with reduced visibility in South East Queensland.

The closing of Brisbane’s metropolitan power stations in 1986 and the banning of backyard burning in Brisbane in 1987 were major influences in reducing the levels of visibility reducing particles.

Reduced visibility is often associated with dry conditions and bushfires or hazard-reduction burning. Better management of smoke from hazard-reduction burns (carried out to reduce the risk of severe bushfires) has further reduced the number of low visibility days. In the last two decades, years with a higher number of low visibility days have been associated with dry conditions and widespread bushfires.

Airborne particles—PM10

Show data

Number of days per year the 24-hour average PM10 concentration exceeded the specified level
Year Days >50µg/m^3  (Air NEPM standard)
1986 15
1987 19
1988 14
1989 12
1990 11
1991 10
1992 4
1993 8
1994 22
1995 11
1996 7
1997 1
1998 2
1999 4
2000 16
2001 6
2002 18
2003 4
2004 9
2005 13
2006 4
2007 11
2008 10
2009 19
2010 3
2011 6
2012 6
2013 2
2014 9
2015 6
2016 0
2017 2
2018 9
2019 30
2020 6

PM10 refers to airborne particles less than 10 micrometres in diameter.

These particles are capable of penetrating humans’ lower airways, causing possible health effects.

PM10 particles are generated by a wide range of natural processes and human activities, including:

  • wind-blown dust
  • industrial processes
  • motor vehicle emissions
  • fires.

Climatic conditions exert the greatest influence on year-to-year variations in PM10 levels, with the number of exceedances of the PM10 24-hour standard of 50µg/m3 declining in wetter years (e.g. 2010, 2013 and 2016) and increasing in drier years (e.g. 1994, 2000, 2002, 2009 and 2019) due to higher windblown dust levels and rises in the number of vegetation fires and area burnt.

Peaks in annual PM10 exceedances are associated with years when major dust storms occurred (1994, 2002, 2009 and 2019). Higher predicted temperatures and lower predicted rainfall as a result of climate change are likely to increase the occurrence of particle pollution with conditions leading to more prevalent dust storms and bushfires.

Airborne particles—PM2.5

Show data

Number of days per year the 24-hour average PM2.5 concentration exceeded the specified level
Year Days >25µg/m^3 (Air NEPM standard)
1995 2
1996 3
1997 1
1998 1
1999 0
2000 9
2001 4
2002 5
2003 3
2004 7
2005 1
2006 1
2007 0
2008 0
2009 11
2010 3
2011 4
2012 1
2013 0
2014 1
2015 1
2016 1
2017 1
2018 8
2019 27
2020 3

PM2.5 refers to airborne particles less than 2.5 micrometres in diameter.

These particles are capable of penetrating humans’ lower airways, possibly causing health effects.

PM2.5 particles originate mainly from combustion processes such as:

  • motor vehicle emissions
  • industrial processes
  • solid fuel heaters
  • fires.

Climatic conditions exert the greatest influence on year-to-year variations in PM2.5 levels, with an increased number of exceedances of the PM2.5 24-hour standard of 25µg/m3 largely associated with years with heightened bushfire activity (2000, 2004, 2009, 2018 and 2019).

Higher predicted temperatures and lower predicted rainfall as a result of climate change are likely to increase the occurrence of particle pollution with conditions leading to more prevalent dust storms and bushfires.

Nitrogen dioxide

Show data

Number of days per year the 1-hour average nitrogen dioxide concentration exceeded the specified level
Year Days >0.080ppm (Air NEPM standard) Days >0.040ppm
1978 19 135
1979 3 72
1980 5 135
1981 4 86
1982 4 121
1983 11 99
1984 0 98
1985 3 103
1986 4 98
1987 4 123
1988 7 107
1989 0 91
1990 3 106
1991 9 127
1992 13 84
1993 6 90
1994 2 85
1995 0 73
1996 0 52
1997 0 43
1998 0 49
1999 1 16
2000 0 34
2001 0 42
2002 0 65
2003 0 34
2004 0 37
2005 0 20
2006 0 12
2007 0 33
2008 0 25
2009 0 41
2010 0 39
2011 0 55
2012 1 46
2013 0 51
2014 0 48
2015 0 77
2016 0 35
2017 0 41
2018 0 45
2019 0 41
2020 0 17

Nitrogen dioxide is the product of high-temperature combustion processes such as motor vehicle engines and industries such as coal-fired power stations.

In recent years nitrogen dioxide levels have not exceeded the 1-hour standard for the protection of human health.

Progressive tightening of exhaust emission limits for new motor vehicles has reduced nitrogen dioxide levels in the air and is currently keeping pace with increasing vehicle use. However, with an increase in urban growth and motor vehicle use, the number of days with elevated nitrogen dioxide levels could become more frequent.

Photochemical smog as ozone

Show data

Number of days per year the 8-hour average ozone concentration exceeded the specified level
Year Days >0.065ppm (Air NEPM standard) Days >0.050ppm
1978 0 3
1979 3 24
1980 4 21
1981 2 8
1982 4 22
1983 2 17
1984 0 6
1985 2 8
1986 0 10
1987 12 18
1988 3 15
1989 1 1
1990 0 2
1991 1 4
1992 0 3
1993 1 4
1994 3 17
1995 4 34
1996 6 41
1997 3 29
1998 2 24
1999 2 18
2000 3 19
2001 1 15
2002 5 38
2003 2 11
2004 2 29
2005 1 23
2006 1 13
2007 1 14
2008 0 16
2009 0 20
2010 0 6
2011 2 11
2012 1 12
2013 0 11
2014 0 19
2015 0 19
2016 0 9
2017 0 17
2018 1 12
2019 5 36
2020 0 16

Photochemical smog is formed by reactions involving nitrogen oxides, volatile organic compounds and sunlight. A major component of this smog is ozone.

Exceedances of the 8-hour ozone standard occur occasionally, usually when favourable weather conditions and extra emissions of photochemical smog-forming pollutants from bushfires or hazard-reduction burning coincide.

An expanded ozone monitoring network has been in place in South East Queensland since 1994. The increase in network coverage has contributed to the increase in the number of days exceeding the specified levels seen from this time.

No discernible trend in ozone levels has been identified to date. However, with an increase in urban growth and motor vehicle use, the number of days with elevated photochemical smog levels could become more frequent.

Carbon monoxide

Show data

Number of days per year the 8-hour average carbon monoxide concentration exceeded the specified level
Year Days >9ppm (Air NEPM standard) Days >2ppm
1978 62 312
1979 160 362
1980 131 366
1981 142 346
1982 86 309
1983 7 249
1984 9 240
1985 6 220
1986 0 318
1987 2 300
1988 0 211
1989 0 284
1990 0 285
1991 0 268
1992 0 228
1993 0 154
1994 0 208
1995 0 192
1996 1 318
1997 0 333
1998 0 162
1999 0 168
2000 0 78
2001 0 111
2002 0 84
2003 0 82
2004 0 66
2005 0 37
2006 0 37
2007 0 4
2008 0 15
2009 0 8
2010 0 2
2011 0 0
2012 0 0
2013 0 0
2014 0 0
2015 0 0
2016 0 0
2017 0 0
2018 0 0
2019 0 0
2020 0 0

Carbon monoxide is formed through incomplete combustion of fuels containing carbon.

In South East Queensland, motor vehicles are the largest producer of carbon monoxide.

Progressive tightening of exhaust emission limits for new motor vehicles, in particular the fitting of catalytic converters, have significantly reduced carbon monoxide emissions and levels in the air have steadily declined over the past three decades.

Sulfur dioxide

Show data

Number of days per year the 1-hour average sulfur dioxide concentration exceeded the specified level
Year Days >0.100ppm (Air NEPM standard) Days >0.050ppm
1978 0 4
1979 9 41
1980 1 1
1981 0 0
1982 0 2
1983 0 1
1984 0 0
1985 0 2
1986 0 0
1987 0 0
1988 0 0
1989 0 16
1990 0 2
1991 0 3
1992 0 1
1993 0 1
1994 0 0
1995 0 1
1996 0 0
1997 0 0
1998 0 2
1999 0 2
2000 0 2
2001 0 3
2002 0 2
2003 0 1
2004 1 4
2005 0 12
2006 0 0
2007 0 0
2008 0 1
2009 0 4
2010 0 0
2011 0 1
2012 0 7
2013 1 4
2014 0 8
2015 1 8
2016 0 11
2017 1 7
2018 0 3
2019 0 2
2020 0 1

Sulfur dioxide is formed in combustion processes burning fossil fuels containing sulfur.

Levels in South East Queensland are generally low due to the small number of sulfur dioxide emission sources in the region.

Increased levels since 2012 are a result of the processing crude oil with a higher sulfur content at the oil refinery at the mouth of the Brisbane River.