Days with hazardous air quality levels
In 2019, AQI levels reached the hazardous category (with an AQI greater than 200) on a total of 115 days, compared with 59 days in 2018 (Note: The AQI includes measurements for visibility. The count in both years includes the new monitoring station at Armidale and the Upper Hunter stations at Muswellbrook, Singleton and Aberdeen; and excludes Stockton, Carrington and Mayfield. For more information, see Hunter Valley.)
During 2019, there were:
- 67 hazardous days when bushfire smoke affected particle levels at sites in one or more regions. These occurred in the warmer months, with the majority during the bushfire emergency period from October 2019.
- 36 hazardous days when dust storms affected particle levels at sites in one or more regions. These occurred in January to March and August to December (DustWatch publications).
- 16 hazardous days when smoke from hazard reduction burns affected particles, predominantly in Sydney, but also one day in the Central Coast. These occurred from April to August (outside of the bushfire danger period).
- 18 hazardous days when smoke from domestic wood heaters affected particle levels, predominantly in Armidale, but also in Orange. These were observed during the cooler months from May to September, typically overnight under calm cold conditions.
Note that on any day, hazardous levels at a site may have been affected by a combination of different sources (for example bushfire smoke and dust) and the sources may have varied between regions.
In Sydney, there were 53 hazardous particle days. Most of these days (37 days, 70%) occurred from 30 October to 31 December. These were predominantly affected by smoke from the extensive bushfires burning throughout New South Wales during the bushfire emergency period. A further 15 days (28%) were due to smoke from hazard reduction burns from April to August. These fires were reported by the NSW Rural Fire Service.
Hazardous days for each region
Sydney
- 53 hazardous days in total:
- 33 days due to bushfires: October (1), November (9) and December (23)
- 15 days due to hazard reduction burns: April (5), May (6), June (3), August (1)
- 4 days due to a combination of smoke from bushfires and dust storms: October (1), November (2) and December (1)
- 1 day due to a local fire adjacent to the St Marys monitoring station: June.
Illawarra
- 17 hazardous days in total:
- 12 days due to smoke from bushfires: October (1), November (2) and December (9)
- 2 days due to a combination of smoke from bushfires and dust storms: November
- 1 day due to a dust storm: February
- 1 day due to hazard reduction burns: June
- 1 day due to a localised unidentified source at Kembla Grange: June.
Central Coast
- 18 hazardous days in total:
- 14 days due to bushfires: October (1), November (6) and December (7).
- 3 days due to a combination of smoke from bushfires and dust storms: October (1) and November (2)
- 1 day due to hazard reduction burns: May.
Lower Hunter
- 26 hazardous days in total:
- 20 days due to bushfires: January (2), September (1), October (2), November (7) and December (8)
- 6 days due to a combination of smoke from bushfires and dust storms: October (1), November (2) and December (3)
Upper Hunter
- 16 hazardous days in total:
- 9 days due to bushfires: October (2), November (1) and December (6)
- 5 days due to a combination of smoke from bushfires and dust: November (4) and December (1).
- 2 days due to dust storms: October (1) and December (1)
North West Slopes
- 29 hazardous days in total:
- 16 days due to bushfires: January (1), October (2), November (4) and December (9)
- 10 days due to dust storms: February (1), August (1), September (1), October (3), November (3) and December (1)
- 3 days due to a combination of smoke from bushfires and dust storms: November.
Northern Tablelands
- 54 hazardous days in total:
- 30 days due to bushfires: September (4), October (3), November (10) and December (13)
- 16 days due to smoke from domestic wood heaters: May (1), June (7), July (5), August (2), September (1)
- 5 days due to dust storms: August (1), September (1), November (2) and December (1)
- 3 days due to a combination of smoke from bushfires and dust storms: November.
Central Tablelands
- 34 hazardous days in total:
- 23 days due to bushfires: November (3) and December (20)
- 5 days due to a combination of smoke from bushfires and dust storms: October (1) and November (4)
- 4 days due to dust storms: September (1), October (1), November (1) and December (1)
- 2 days most likely due to smoke from domestic wood heaters: June (1) and July (1).
South West Slopes
- 20 hazardous days in total:
- 8 days due to dust storms: January (1), February (2), March (1), September (1), October (1) and November (2)
- 7 days due to bushfires: December
- 5 days due to a combination of smoke from bushfires and dust storms: November (1) and December (4).