Air quality special statement spring–summer 2019–20: PM2.5 particles

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

Key points

During spring–summer 2019–20, smoke raised daily PM2.5 concentrations to record levels across the NSW air quality monitoring networks. The 5 highest daily PM2.5 levels since 1994 were recorded between 15 November 2019 and 5 January 2020.

• Daily PM2.5 levels were above the benchmark on 99 days (or 54% of spring–summer days) in the standard monitoring network, mainly due to bushfire smoke in spring–summer 2019–20, compared to 4 days in spring–summer 2018–19. Bushfire emergency monitoring stations recorded 46 days above the benchmark, including 10 days not recorded by the standard monitoring network.
• The highest daily PM2.5 level reached 560 µg/m³, 22 times the benchmark, at Wagga Wagga North in the South-west Slopes on 5 January 2020 due to bushfire smoke. This record ranked the highest daily PM2.5 level since 1994.

The highest daily PM2.5 level reached 560 µg/m3, 22 times the benchmark, at Wagga Wagga North in the South-west Slopes on 5 January 2020 due to bushfire smoke. This record ranked the highest daily PM2.5 level since 1994.

More detail

Maximum daily and hourly PM2.5 concentrations recorded across the regions of the NSW Air Quality Monitoring Network are summarised below.

• Maximum daily PM2.5 levels ranged from 80 µg/m³ (three times the benchmark) in the Upper Hunter to 560 µg/m³ (22 times the benchmark) in the South-west Slopes.
• Wagga Wagga North in the South-west Slopes recorded the highest daily PM2.5 level since 1994, with 560 µg/m³ on 5 January 2020. A slow-moving low-pressure trough, with light winds turning southwest to southeast, brought thick smoke to the South-west Slopes in the afternoon. The hourly PM2.5 levels at Wagga Wagga North peaked at 1799 µg/m³ at 7pm in the evening on this day.
• The second to the fifth highest daily PM2.5 levels since 1994 also occurred in spring-summer 2019-20.
  • The bushfire air quality monitoring station at Port Macquarie on the Mid-North Coast recorded 443 µg/m³ (18 times the benchmark) on 15 November 2019.
  • The Katoomba air quality monitoring station in the Blue Mountains and Lithgow Air Watch Project recorded 436 µg/m³ (17 times the benchmark) on 26 December 2019.
  • The Goulburn air quality monitoring station in the Southern Tablelands, commissioned on 6 November 2019, recorded 516 µg/m³ (21 times the benchmark) on 1 January 2020 and 480 µg/m³ (19 times the benchmark) on 5 January 2020.
  • Before spring–summer 2019–20, the highest daily PM2.5 level was 416 µg/m³ (almost 17 times the benchmark), recorded at Wallsend in the Lower Hunter on 23 September 2009, during the Red Dawn dust event.
• Maximum daily PM2.5 levels at bushfire air quality monitoring stations ranged from 44 µg/m³ (2 times the benchmark) at Lismore in the Northern Rivers to 443 µg/m³ (18 times the benchmark) at Port Macquarie.
• Maximum hourly PM2.5 levels at standard monitoring stations ranged from 212 µg/m³ in the Newcastle Local region to 2182 µg/m³ in the Southern Tablelands.
• Maximum hourly PM2.5 levels at bushfire standard monitoring stations ranged from 149 µg/m³ at Lismore to 1280 µg/m³ at Port Macquarie.
• Maximum hourly PM2.5 levels at bushfire indicative monitoring stations ranged from 461 µg/m³ at Coffs Harbour to 2500 µg/m³ at Batemans Bay on the South Coast (Note: the Coffs Harbour bushfire monitoring station operated standard and indicative monitoring instruments during November 2019 to February 2020, as a scientifically controlled approach to bushfire air quality monitoring).

Summary statistics

Number of days with PM2.5 24-hour (daily) average concentrations above the national benchmark of 25 µg/m³, across stations in the standard monitoring network and at bushfire emergency standard monitoring stations, during spring-summer 2019–20. Stations nearer to bushfires recorded more days above the benchmark.

Number and percentage of days in spring and summer 2019–20 with PM2.5 24-hour average concentrations above the benchmark across regions in the NSW standard monitoring network and at bushfire air quality monitoring stations, during spring–summer 2019–2020. Generally, more days above the benchmark were recorded in summer than in spring.

Annual number of days above the PM2.5 daily benchmark, in 1994–2019 compared to January–February 2020

Maximum PM2.5 24-hour concentrations across the regions in the standard monitoring network and at the bushfire air quality monitoring stations during spring-summer 2019–20.

Maximum regional daily PM2.5 from 1 September 2019 to 29 February 2020 for Sydney and Illawarra regions. Generally, the highest levels were recorded from mid-November 2019 to early January 2020.

Maximum regional daily PM2.5 from 1 September 2019 to 29 February 2020 for Sydney and Illawarra regions. Generally, the highest levels were recorded from mid-November 2019 to early January 2020.

Maximum regional daily PM2.5 from 1 September 2019 to 29 February 2020 for Northern Tablelands, North-west Slopes, Central Tablelands, Southern Tablelands and South-west Slopes regions. Generally, the highest levels were recorded from mid-November to mid-January.

Maximum hourly PM2.5 levels showing times and dates recorded across NSW regions and bushfire air quality monitoring stations, during spring–summer 2019–20

PM2.5 one-hour average concentrations recorded by indicative monitors at bushfire air quality monitoring stations, 21 November 2019 to 29 February 2020. Northern regions recorded highest levels from late November to mid-December. Southern regions recorded highest levels from mid-December to late January.

Maximum rural PM2.5 one-hour average concentrations recorded by indicative monitors at long-term rural air quality monitoring stations, spring–summer 2019–20.