Indicator assessment
CONDITION
TREND
DATA QUALITY
The extreme air pollution from the 2019–20 bushfires is excluded for this indicator.
PM2.5 is the most serious air quality issue for the ACT. Exceedances of the daily air pollution standards occur in most years in the Tuggeranong Valley, mainly due to smoke from wood heaters. Periods of elevated PM2.5 levels are likely to have health implications for sensitive community members. The other air pollutants monitored in the ACT are compliant with air quality standards, except for ozone which recorded one exceedance in 2019.
CONDITION
Environmental condition is healthy across the ACT, OR pressure likely to have negligible impact on environmental condition/human health.
Environmental condition is neither positive or negative and may be variable across the ACT, OR pressure likely to have limited impact on environmental condition/human health.
Environmental condition is under significant stress, OR pressure likely to have significant impact on environmental condition/ human health.
Data is insufficient to make an assessment of status and trends.
TREND
DATA QUALITY
Adequate high-quality evidence and high level of consensus.
Limited evidence or limited consensus.
Evidence and consensus too low to make an assessment.
Assessments of status, trends and data quality are not appropriate for the indicator.
Introduction
For information on this indicator see Background: Air quality.
Ambient air quality standards are set by the National Environment Protection Council through the National Environment Protection (Ambient Air Quality) Measure (AAQ NEPM). Compliance with the AAQ NEPM standards is used to determine whether the ACT is achieving the national environment protection standards for ambient air quality.
Air quality impacts of the 2019–20 bushfire season
Although smoke from bushfires is excluded from the ACT’s air quality compliance assessments, it is important to acknowledge the consequences of the 2019–20 bushfire season.
The 2019–20 bushfires in NSW and the ACT severely impacted Canberra’s air quality. The worst air quality occurred in December 2019 to early January 2020 with smoke from nearby NSW fires moving across the ACT (Figure 1). Over the 91 days of summer, air pollution monitoring at the Monash Station in Tuggeranong showed that there were periods on 56 days where the pollution levels exceeded the national standards for health, including 42 days with air pollution above the hazardous to health rating. For many days, the air quality in Canberra was the worst of any major city in the world and the worst in Canberra since air quality monitoring began in the early 1980s. On 1 January, PM2.5 pollution levels were at around 25 times the threshold to be considered hazardous.
Figure 1: Air Quality Index ratings from the Monash station in Tuggeranong over the 2019–20 summer period.
Data sourced from: ACT Health Directorate.
For more information on the air quality impacts of the 2019–20 bushfire season see 4. Bushfires in the ACT and Protecting Canberra’s Air Quality.
PM2.5
Particulate matter less than 2.5 micrometres in size (PM2.5) is the most serious air quality issue for the ACT with levels that are likely to have health implications for sensitive individuals. This is mainly due to the regular occurrences of elevated PM2.5 levels from wood heater smoke, as well as from fires (bushfire and controlled burns) and dust storms.
Between 2015 and 2022, the annual maximum PM2.5 levels recorded at the Monash Station exceeded the National Environment Protection (Ambient Air Quality) Measure (AAQ NEPM) standard of 25 μg/m3 for all years except 2022 (Figure 2). The annual maximum PM2.5 levels recorded at the Florey Station also exceeded the AAQ NEPM standard for all years except 2015, 2017, and 2022 (Figure 3). Annual maximum PM2.5 levels are generally higher at the Monash Station because of the topography of the Tuggeranong Valley which reduces the dispersal of air pollutants.
Figure 2: Daily maximum PM2.5 levels, Monash Station, 2015–2022.
Data sourced from: ACT Health Directorate.
Figure 3: Daily maximum PM2.5 levels, Florey Station, 2015–2022.
Data sourced from: ACT Health Directorate
The impacts of the 2019–20 bushfire season are evident at the Monash Station with extremely high maximum PM2.5 levels of 308 μg/m3 in 2019 and 1,147 μg/m3 in 2020, and at the Florey Station with 320 μg/m3 in 2019 and 983 μg/m3 in 2020.
Monitoring results show no long-term trends in PM2.5 levels. High levels and annual variations are likely due to the occurrence of calm autumn and winter days which increase the accumulation of urban pollution from wood heaters.
PM2.5 exceedances
There were a total of 67 exceedances of the daily National Environment Protection (Ambient Air Quality) Measure (AAQ NEPM) standard for PM2.5 at the Monash and Florey Stations from 2015 to 2022, with 36 of these occurring over the reporting period (2019 to 2022). Wood heaters were responsible for 48 (72%) of all daily exceedances, 11 (16%) were caused by controlled burns, and eight (12%) caused by dust storms (Figure 4). Smoke from the 2019–20 bushfire season resulted in 23 daily exceedances in 2019 and 25 in 2020. It is important to note that events such as dust storms, controlled burns and bushfires, which cannot be controlled through normal air quality management programs, are not included in the assessment of AAQ NEPM standard compliance.
Figure 4: Number of PM2.5 exceedances by cause, Monash and Florey Stations, 2015–2022.
Data sourced from: ACT Health Directorate.
Note: Does not include exceedances caused by bushfire smoke.
With the lower target for PM2.5 in 2025 (from 25 to 20 μg/m3 for one day average concentrations), the number of daily standard exceedances will increase in the future unless there are reductions in Canberra’s PM2.5 pollution, particularly from wood heaters.
For the Monash Station, there were 51 exceedances of the daily AAQ NEPM standard for PM2.5 from 2015 to 2022, with exceedances occurring in every year except for 2022 (Figure 5). These results show that as well as generally having higher annual maximum PM2.5 levels, daily AAQ NEPM standard exceedances are far more likely in the Tuggeranong Valley.
Figure 5: Number of PM2.5 exceedances by cause, Monash Station, 2015–2022.
Data sourced from: ACT Health Directorate.
Note: Does not include exceedances caused by bushfire smoke.
Wood heater smoke was responsible for 40 (nearly 80%) of the daily exceedances, controlled burns for seven and dust storms for four days. Consequently, daily PM2.5 levels at the Monash Station were not compliant with the AAQ NEPM standard for 40 days between 2015 and 2022, or for 17 days over the 2019 to 2022 reporting period.
The highest annual number of annual exceedances was 13 in 2020, with 12 of these from wood heater smoke. The high number of exceedances in 2020 may have been associated with COVID-19 restrictions and the uptake of working from home arrangements. This would likely have increased wood heater use due to people spending more time at home during the 2020 autumn and winter period. If PM2.5 exceedances were higher in 2020 because of increased wood heater use during COVID-19 restrictions, this suggests that any growth in the ACT’s wood heater use is detrimental to air quality.
Given the severe air quality impacts over the 2019—20 summer from bushfire smoke, the additional poor air quality in the cooler months of 2020 is of concern for the health and wellbeing of a Canberra community so recently exposed to extended periods of hazardous air pollution.
There are far fewer exceedances of the daily AAQ NEPM standard for PM2.5 at the Florey Station, with 16 occurring from 2015 to 2022 (Figure 6). Wood heater smoke was responsible for eight (50%) of the exceedances, and controlled burns and dust storms each responsible for four days each. This means that daily PM2.5 levels at the Florey Station were not compliant with the AAQ NEPM standard for eight days between 2015 and 2022, with seven of these occurring over the 2019 to 2022 reporting period. Exceedances caused by wood heater smoke also only occurred in three of the years from 2015 to 2022. The highest number of exceedances was six in 2020, all of these from wood heater smoke. As with the Monash Station, these exceedances in the cooler months followed the severe air quality impacts of the 2019–20 bushfire season.
Figure 6: Number of PM2.5 exceedances by cause, Florey Station, 2015–2022.
Data sourced from: ACT Health Directorate.
Note: Does not include exceedances caused by bushfire smoke.
The 2020 Monash and Florey stations’ exceedances of the daily AAQ NEPM standard for PM2.5, combined with air pollution from bushfire smoke, make 2020 one of the worst years on record for Canberra’s air quality.
With the exception of the 2019–20 bushfire years, results for annual average PM2.5 levels for the Monash Station and the Florey Station are compliant with the AAQ NEPM standard of 8 μg/m3 from 2015 to 2022 (Figure 7). However, for non-bushfire years, the annual average levels are closer to exceeding the annual standard than for other monitored pollutants.
Figure 7: Annual average PM2.5 levels: Monash and Florey stations, 2015–2022.
Data sourced from: ACT Health Directorate.
The suggested lower target for annual PM2.5 in 2025 (from 8 to 7 μg/m3) will increase the number of annual standard exceedances in the future unless there are reductions in Canberra’s PM2.5 pollution, particularly from wood heaters. For example, Monash Station would have failed the 2025 target from 2015 to 2017, and Florey Station from 2015 to 2018.
Impact of wood heaters on air quality
The replacement of wood heaters with energy efficient electric heating is critical to improving air quality in the ACT. This is particularly the case for the Tuggeranong Valley where wood heaters have been responsible for nearly 80% of the daily PM2.5 exceedances from 2015 to 2022. Seasonal averages for the Monash station clearly show the impact of wood heaters on PM2.5 levels (Figure 8). During the late autumn and winter months, PM2.5 levels are elevated in response to peak wood heater usage.
Figure 8: Monthly average of daily maximum PM2.5 levels, Monash Station, 2016 to 2022.
Data sourced from: ACT Health Directorate.
Note: The high PM2.5 levels caused by bushfire smoke in December 2019 and January 2020 have been excluded from this analysis.
Increased PM2.5 levels in response to wood heater usage is especially evident over 24-hour monitoring periods for days that exceed the daily AAQ NEPM standard (Figure 9). PM2.5 levels increase significantly in the evenings as wood heaters are used, peaking at night, before decreasing until 6am. There is then a smaller increase in PM2.5 levels as wood heaters are again used to warm residences in the morning, before dropping to lower levels throughout the daylight hours. The increased PM2.5 levels are above the AAQ NEPM standard for much of the evening and morning resulting in average daily PM2.5 levels above 25 μg/m3.
Figure 9: Hourly PM2.5 levels over a 24-hour period for five days that exceeded the daily AAQ NEPM standard at the Monash Station.
Data sourced from: ACT Health Directorate
Note: Exceedances are only recorded when the average PM2.5 levels for the entire day are above 25 μg/m3.
The time of increased PM2.5 levels means that the community experiences high PM2.5 levels during many outdoor activities such commuting to and from work, commuting to school in the morning, evening sports training, and evening activities such as exercising and dog walking after work. High PM2.5 levels can also enter residences through the movement of external air into homes.
PM2.5 levels can also be high on days which do not exceed the daily AAQ NEPM standard. Figure 10 shows the PM2.5 levels for five days which did not exceed the daily AAQ NEPM standard. These days show a similar pattern in high PM2.5 levels in response to wood heater use, although the average over the 24-hour period did not exceed 25 μg/m3. Despite this, PM2.5 levels were still high enough to degrade air quality and impact on community health.
Figure 10: Hourly PM2.5 levels over a 24-hour period for five days that did not exceed the daily AAQ NEPM standard at the Monash Station.
Data sourced from: ACT Health Directorate.
Note: Exceedances are only recorded when the average PM2.5 levels for the entire day are above 25 μg/m3.
It is clear that periods of elevated PM2.5 levels are likely to have health implications for sensitive community members, even when levels do not exceed the daily AAQ NEPM standard.
More information on the impacts of wood heaters on the Canberra community can be found in the Commissioner for Sustainability and the Environment’s investigation into wood heater policy in the ACT.
Other air pollutants
Particulate matter less than 10 micrometres in size (PM10)
From 2015 to 2022 there were many exceedances of the PM10 standards due to bushfires and dust storms. Although these are not included in the assessment of AAQ NEPM standard compliance, they remain significant in terms of air quality and community health. The total exceedances (Monash and Florey Stations combined) of the PM10 standards from 2015 to 2022 include:
- one exceedance in 2015 due to dust storms
- seven exceedances in 2018 due to dust storms
- 29 exceedances in 2019, 21 due to bushfires and eight from dust storms, and
- 27 exceedances in 2020, 24 due to bushfires and three from dust storms.
However, results show compliance against the daily PM10 standard for all stations from 2015 to 2022 when exceptional events (bushfires and dust storms) are removed.
There were exceedances of the annual AAQ NEPM standards for PM10 in 2019 and 2020, but these were again the result of the 2019–20 bushfires. It should be noted that whilst these years did not meet the ACT Government’s lower annual standard of 20 μg/m3, they did meet the NEPM standard of 25 μg/m3.
There are also no long-term trends in PM10 levels, with events such as dust storms, controlled burns and bushfires responsible for increased levels. The 2019-20 bushfires led to extremely high PM10 levels, reaching 1,076 μg/m3 on 5 January 2020.
Ozone
Ozone levels in the ACT were greatly increased by the 2019–20 bushfires. In December 2019, ozone levels were above the AAQ NEPM standards for two days, and for four days in January and February 2020. Ozone levels were also above the AAQ NEPM standards for one day in January 2019 due to hotter weather increasing the conversion of vehicle emissions to ozone.
There were no other exceedances of the AAQ NEPM standards for ozone from 2015 to 2022. Overall, results show no long-term trends in ozone levels, with annual variations in maximum concentrations likely due to hotter temperatures and smoke from hazard reduction burns and bushfires in the region.
Carbon monoxide (CO)
Carbon monoxide levels were greatly increased by the 2019–20 bushfires. There was one exceedance of the AAQ NEPM standard on 31 December 2019 which was the first exceedance of the carbon monoxide standard since the commencement of air quality monitoring in the ACT.[2] The carbon monoxide standard was also exceeded on two days in January 2020, including a new maximum CO record of 22 ppm on 1 January.
There were no other exceedances of AAQ NEPM standards for CO from 2015 to 2022. There was also little difference in CO levels between the stations. Overall, CO levels appear to be slightly declining, likely due to improvements in vehicle emissions which are the main source of CO pollution in the ACT.
Nitrogen dioxide (NO2)
Bushfire smoke in 2020 caused two exceedances of the AAQ NEPM standards for NO2, the first time since the commencement of air quality monitoring in the ACT.[3]
There were no other exceedances of AAQ NEPM standards for NO2 from 2015 to 2022. There was also little difference in NO2 levels between the Monash and Florey monitoring stations. Overall, results show that NO2 levels appear to be stable, with some slight annual variations in maximum concentrations.
NEPM compliance
Compliance with the AAQ NEPM ensures that the ACT is achieving the national environment protection standard for the assessment of air quality. The ACT must report annually on compliance with the AAQ NEPM to the National Environment Protection Council. Up to and including 2022–23, the ACT’s air quality monitoring and reporting activities were found to comply with the NEPM.
With regard to air quality levels in the ACT, compliance was only met for PM2.5 at Monash Station in 2022, with all other years since 2015 recording exceedances of the standard. For the Florey Station, the PM2.5 standard was exceeded in 2016, 2020 and 2021. Particle pollution is acknowledged as the major pollutant of concern in the ACT, in particular emissions from wood heaters.
Compliance for other monitored air pollutants has generally been met in the ACT, with exceedances cause by exceptional events such as bushfire, planned burns and dust storms.
Data gaps
Although the ACT’s air quality monitoring network fully meets the requirements set out under the AAQ NEPM, a comprehensive assessment of air quality across the ACT requires more extensive monitoring coverage. This would improve the assessment of localised air pollution for urban areas that are not situated near the current monitoring stations. For example, differences in local air pollution levels are clearly demonstrated in the number of particulate matter (PM2.5) exceedances recorded at the Monash Station compared to the Florey Station.
← Previous