Statistical data set
Figure 2: Mean hours when NO2 pollution was moderate or higher for roadside sites, 1997 to 2025
Updated 30 June 2026
| Site type | Year | Number of sites | Daily Air Quality Index | Mean number of hours per site |
|---|---|---|---|---|
| Urban Traffic | 1997 | 7 | mod_4 | 14.857142857142858 |
| Urban Traffic | 1998 | 15 | mod_4 | 13.4 |
| Urban Traffic | 1999 | 17 | mod_4 | 9.588235294117647 |
| Urban Traffic | 2000 | 19 | mod_4 | 7.842105263157895 |
| Urban Traffic | 2001 | 21 | mod_4 | 5.142857142857143 |
| Urban Traffic | 2002 | 21 | mod_4 | 2 |
| Urban Traffic | 2003 | 20 | mod_4 | 25.4 |
| Urban Traffic | 2004 | 22 | mod_4 | 24.954545454545453 |
| Urban Traffic | 2005 | 22 | mod_4 | 38.04545454545455 |
| Urban Traffic | 2006 | 21 | mod_4 | 34.76190476190476 |
| Urban Traffic | 2007 | 18 | mod_4 | 34.388888888888886 |
| Urban Traffic | 2008 | 24 | mod_4 | 38.208333333333336 |
| Urban Traffic | 2009 | 27 | mod_4 | 20.962962962962962 |
| Urban Traffic | 2010 | 30 | mod_4 | 25.7 |
| Urban Traffic | 2011 | 31 | mod_4 | 12.612903225806452 |
| Urban Traffic | 2012 | 29 | mod_4 | 9.10344827586207 |
| Urban Traffic | 2013 | 32 | mod_4 | 4.65625 |
| Urban Traffic | 2014 | 28 | mod_4 | 3.9285714285714284 |
| Urban Traffic | 2015 | 38 | mod_4 | 4.868421052631579 |
| Urban Traffic | 2016 | 50 | mod_4 | 5.22 |
| Urban Traffic | 2017 | 61 | mod_4 | 2.7868852459016393 |
| Urban Traffic | 2018 | 63 | mod_4 | 1.4444444444444444 |
| Urban Traffic | 2019 | 66 | mod_4 | 0.7727272727272727 |
| Urban Traffic | 2020 | 65 | mod_4 | 0.13846153846153847 |
| Urban Traffic | 2021 | 62 | mod_4 | 0.08064516129032258 |
| Urban Traffic | 2022 | 65 | mod_4 | 0.046153846153846156 |
| Urban Traffic | 2023 | 61 | mod_4 | 0.01639344262295082 |
| Urban Traffic | 2024 | 64 | mod_4 | 0.0625 |
| Urban Traffic | 2025 | 60 | mod_4 | 0 |
| Urban Traffic | 1997 | 7 | mod_5 | 2.5714285714285716 |
| Urban Traffic | 1998 | 15 | mod_5 | 0.6666666666666666 |
| Urban Traffic | 1999 | 17 | mod_5 | 0.47058823529411764 |
| Urban Traffic | 2000 | 19 | mod_5 | 0.2631578947368421 |
| Urban Traffic | 2001 | 21 | mod_5 | 1.0476190476190477 |
| Urban Traffic | 2002 | 21 | mod_5 | 0.8095238095238095 |
| Urban Traffic | 2003 | 20 | mod_5 | 2.55 |
| Urban Traffic | 2004 | 22 | mod_5 | 1.4090909090909092 |
| Urban Traffic | 2005 | 22 | mod_5 | 5.090909090909091 |
| Urban Traffic | 2006 | 21 | mod_5 | 3.0476190476190474 |
| Urban Traffic | 2007 | 18 | mod_5 | 3.5555555555555554 |
| Urban Traffic | 2008 | 24 | mod_5 | 3.7916666666666665 |
| Urban Traffic | 2009 | 27 | mod_5 | 0.48148148148148145 |
| Urban Traffic | 2010 | 30 | mod_5 | 1.7666666666666666 |
| Urban Traffic | 2011 | 31 | mod_5 | 0.3870967741935484 |
| Urban Traffic | 2012 | 29 | mod_5 | 0.10344827586206896 |
| Urban Traffic | 2013 | 32 | mod_5 | 0.21875 |
| Urban Traffic | 2014 | 28 | mod_5 | 0.14285714285714285 |
| Urban Traffic | 2015 | 38 | mod_5 | 0.2894736842105263 |
| Urban Traffic | 2016 | 50 | mod_5 | 0.52 |
| Urban Traffic | 2017 | 61 | mod_5 | 0.47540983606557374 |
| Urban Traffic | 2018 | 63 | mod_5 | 0.047619047619047616 |
| Urban Traffic | 2019 | 66 | mod_5 | 0 |
| Urban Traffic | 2020 | 65 | mod_5 | 0.03076923076923077 |
| Urban Traffic | 2021 | 62 | mod_5 | 0 |
| Urban Traffic | 2022 | 65 | mod_5 | 0 |
| Urban Traffic | 2023 | 61 | mod_5 | 0 |
| Urban Traffic | 2024 | 64 | mod_5 | 0.046875 |
| Urban Traffic | 2025 | 60 | mod_5 | 0 |
| Urban Traffic | 1997 | 7 | mod_6 | 0.5714285714285714 |
| Urban Traffic | 1998 | 15 | mod_6 | 0.06666666666666667 |
| Urban Traffic | 1999 | 17 | mod_6 | 0.058823529411764705 |
| Urban Traffic | 2000 | 19 | mod_6 | 0.10526315789473684 |
| Urban Traffic | 2001 | 21 | mod_6 | 0.23809523809523808 |
| Urban Traffic | 2002 | 21 | mod_6 | 0.047619047619047616 |
| Urban Traffic | 2003 | 20 | mod_6 | 0.15 |
| Urban Traffic | 2004 | 22 | mod_6 | 0.13636363636363635 |
| Urban Traffic | 2005 | 22 | mod_6 | 0.36363636363636365 |
| Urban Traffic | 2006 | 21 | mod_6 | 0.14285714285714285 |
| Urban Traffic | 2007 | 18 | mod_6 | 0.2777777777777778 |
| Urban Traffic | 2008 | 24 | mod_6 | 0.4583333333333333 |
| Urban Traffic | 2009 | 27 | mod_6 | 0.037037037037037035 |
| Urban Traffic | 2010 | 30 | mod_6 | 0.2 |
| Urban Traffic | 2011 | 31 | mod_6 | 0.03225806451612903 |
| Urban Traffic | 2012 | 29 | mod_6 | 0 |
| Urban Traffic | 2013 | 32 | mod_6 | 0.09375 |
| Urban Traffic | 2014 | 28 | mod_6 | 0 |
| Urban Traffic | 2015 | 38 | mod_6 | 0.02631578947368421 |
| Urban Traffic | 2016 | 50 | mod_6 | 0.08 |
| Urban Traffic | 2017 | 61 | mod_6 | 0.06557377049180328 |
| Urban Traffic | 2018 | 63 | mod_6 | 0.015873015873015872 |
| Urban Traffic | 2019 | 66 | mod_6 | 0 |
| Urban Traffic | 2020 | 65 | mod_6 | 0 |
| Urban Traffic | 2021 | 62 | mod_6 | 0 |
| Urban Traffic | 2022 | 65 | mod_6 | 0 |
| Urban Traffic | 2023 | 61 | mod_6 | 0 |
| Urban Traffic | 2024 | 64 | mod_6 | 0.015625 |
| Urban Traffic | 2025 | 60 | mod_6 | 0 |
| Urban Traffic | 1997 | 7 | high_7 | 0.14285714285714285 |
| Urban Traffic | 1998 | 15 | high_7 | 0 |
| Urban Traffic | 1999 | 17 | high_7 | 0 |
| Urban Traffic | 2000 | 19 | high_7 | 0 |
| Urban Traffic | 2001 | 21 | high_7 | 0.047619047619047616 |
| Urban Traffic | 2002 | 21 | high_7 | 0 |
| Urban Traffic | 2003 | 20 | high_7 | 0.05 |
| Urban Traffic | 2004 | 22 | high_7 | 0.045454545454545456 |
| Urban Traffic | 2005 | 22 | high_7 | 0.045454545454545456 |
| Urban Traffic | 2006 | 21 | high_7 | 0.047619047619047616 |
| Urban Traffic | 2007 | 18 | high_7 | 0 |
| Urban Traffic | 2008 | 24 | high_7 | 0 |
| Urban Traffic | 2009 | 27 | high_7 | 0 |
| Urban Traffic | 2010 | 30 | high_7 | 0 |
| Urban Traffic | 2011 | 31 | high_7 | 0 |
| Urban Traffic | 2012 | 29 | high_7 | 0 |
| Urban Traffic | 2013 | 32 | high_7 | 0 |
| Urban Traffic | 2014 | 28 | high_7 | 0.03571428571428571 |
| Urban Traffic | 2015 | 38 | high_7 | 0 |
| Urban Traffic | 2016 | 50 | high_7 | 0 |
| Urban Traffic | 2017 | 61 | high_7 | 0 |
| Urban Traffic | 2018 | 63 | high_7 | 0 |
| Urban Traffic | 2019 | 66 | high_7 | 0 |
| Urban Traffic | 2020 | 65 | high_7 | 0 |
| Urban Traffic | 2021 | 62 | high_7 | 0 |
| Urban Traffic | 2022 | 65 | high_7 | 0 |
| Urban Traffic | 2023 | 61 | high_7 | 0 |
| Urban Traffic | 2024 | 64 | high_7 | 0 |
| Urban Traffic | 2025 | 60 | high_7 | 0 |
| Urban Traffic | 1997 | 7 | high_8 | 0 |
| Urban Traffic | 1998 | 15 | high_8 | 0 |
| Urban Traffic | 1999 | 17 | high_8 | 0 |
| Urban Traffic | 2000 | 19 | high_8 | 0 |
| Urban Traffic | 2001 | 21 | high_8 | 0 |
| Urban Traffic | 2002 | 21 | high_8 | 0 |
| Urban Traffic | 2003 | 20 | high_8 | 0.05 |
| Urban Traffic | 2004 | 22 | high_8 | 0 |
| Urban Traffic | 2005 | 22 | high_8 | 0.045454545454545456 |
| Urban Traffic | 2006 | 21 | high_8 | 0 |
| Urban Traffic | 2007 | 18 | high_8 | 0 |
| Urban Traffic | 2008 | 24 | high_8 | 0 |
| Urban Traffic | 2009 | 27 | high_8 | 0 |
| Urban Traffic | 2010 | 30 | high_8 | 0 |
| Urban Traffic | 2011 | 31 | high_8 | 0 |
| Urban Traffic | 2012 | 29 | high_8 | 0 |
| Urban Traffic | 2013 | 32 | high_8 | 0 |
| Urban Traffic | 2014 | 28 | high_8 | 0 |
| Urban Traffic | 2015 | 38 | high_8 | 0 |
| Urban Traffic | 2016 | 50 | high_8 | 0 |
| Urban Traffic | 2017 | 61 | high_8 | 0 |
| Urban Traffic | 2018 | 63 | high_8 | 0 |
| Urban Traffic | 2019 | 66 | high_8 | 0 |
| Urban Traffic | 2020 | 65 | high_8 | 0 |
| Urban Traffic | 2021 | 62 | high_8 | 0 |
| Urban Traffic | 2022 | 65 | high_8 | 0 |
| Urban Traffic | 2023 | 61 | high_8 | 0 |
| Urban Traffic | 2024 | 64 | high_8 | 0 |
| Urban Traffic | 2025 | 60 | high_8 | 0 |
| Urban Traffic | 1997 | 7 | high_9 | 0 |
| Urban Traffic | 1998 | 15 | high_9 | 0 |
| Urban Traffic | 1999 | 17 | high_9 | 0 |
| Urban Traffic | 2000 | 19 | high_9 | 0 |
| Urban Traffic | 2001 | 21 | high_9 | 0 |
| Urban Traffic | 2002 | 21 | high_9 | 0 |
| Urban Traffic | 2003 | 20 | high_9 | 0 |
| Urban Traffic | 2004 | 22 | high_9 | 0 |
| Urban Traffic | 2005 | 22 | high_9 | 0 |
| Urban Traffic | 2006 | 21 | high_9 | 0 |
| Urban Traffic | 2007 | 18 | high_9 | 0 |
| Urban Traffic | 2008 | 24 | high_9 | 0 |
| Urban Traffic | 2009 | 27 | high_9 | 0 |
| Urban Traffic | 2010 | 30 | high_9 | 0 |
| Urban Traffic | 2011 | 31 | high_9 | 0 |
| Urban Traffic | 2012 | 29 | high_9 | 0 |
| Urban Traffic | 2013 | 32 | high_9 | 0 |
| Urban Traffic | 2014 | 28 | high_9 | 0 |
| Urban Traffic | 2015 | 38 | high_9 | 0 |
| Urban Traffic | 2016 | 50 | high_9 | 0 |
| Urban Traffic | 2017 | 61 | high_9 | 0 |
| Urban Traffic | 2018 | 63 | high_9 | 0 |
| Urban Traffic | 2019 | 66 | high_9 | 0 |
| Urban Traffic | 2020 | 65 | high_9 | 0 |
| Urban Traffic | 2021 | 62 | high_9 | 0 |
| Urban Traffic | 2022 | 65 | high_9 | 0 |
| Urban Traffic | 2023 | 61 | high_9 | 0 |
| Urban Traffic | 2024 | 64 | high_9 | 0 |
| Urban Traffic | 2025 | 60 | high_9 | 0 |
| Urban Traffic | 1997 | 7 | vhigh_10 | 0 |
| Urban Traffic | 1998 | 15 | vhigh_10 | 0 |
| Urban Traffic | 1999 | 17 | vhigh_10 | 0 |
| Urban Traffic | 2000 | 19 | vhigh_10 | 0 |
| Urban Traffic | 2001 | 21 | vhigh_10 | 0 |
| Urban Traffic | 2002 | 21 | vhigh_10 | 0 |
| Urban Traffic | 2003 | 20 | vhigh_10 | 0 |
| Urban Traffic | 2004 | 22 | vhigh_10 | 0 |
| Urban Traffic | 2005 | 22 | vhigh_10 | 0 |
| Urban Traffic | 2006 | 21 | vhigh_10 | 0 |
| Urban Traffic | 2007 | 18 | vhigh_10 | 0 |
| Urban Traffic | 2008 | 24 | vhigh_10 | 0 |
| Urban Traffic | 2009 | 27 | vhigh_10 | 0 |
| Urban Traffic | 2010 | 30 | vhigh_10 | 0 |
| Urban Traffic | 2011 | 31 | vhigh_10 | 0 |
| Urban Traffic | 2012 | 29 | vhigh_10 | 0 |
| Urban Traffic | 2013 | 32 | vhigh_10 | 0 |
| Urban Traffic | 2014 | 28 | vhigh_10 | 0 |
| Urban Traffic | 2015 | 38 | vhigh_10 | 0 |
| Urban Traffic | 2016 | 50 | vhigh_10 | 0 |
| Urban Traffic | 2017 | 61 | vhigh_10 | 0 |
| Urban Traffic | 2018 | 63 | vhigh_10 | 0 |
| Urban Traffic | 2019 | 66 | vhigh_10 | 0 |
| Urban Traffic | 2020 | 65 | vhigh_10 | 0 |
| Urban Traffic | 2021 | 62 | vhigh_10 | 0 |
| Urban Traffic | 2022 | 65 | vhigh_10 | 0 |
| Urban Traffic | 2023 | 61 | vhigh_10 | 0 |
| Urban Traffic | 2024 | 64 | vhigh_10 | 0 |
| Urban Traffic | 2025 | 60 | vhigh_10 | 0 |