Background: Air

Air quality

Air quality is one of the most tangible indicators of the state of our local environment, and has significant impacts on human health and wellbeing. Clean air is associated with better physical and mental health, longer life and significant financial savings from reduced health-care expenses and work absences. Clean air is also essential for biodiversity and ecosystem health. Conversely, when air pollutants reach high enough concentrations, they can endanger both human health and the environment.

The main sources of air pollution in Canberra are wood heaters, motor vehicles (especially diesel exhaust), wind-blown dust, bushfires, planned burning activities and industry. Everyday choices, such as driving cars and burning wood for domestic heating, can have a significant impact on air quality.

Air quality is primarily of concern in areas with high concentrations of population, transport and industrial activities. Such areas can experience localised air quality problems which have the potential to cause adverse health impacts. Cardiovascular and respiratory complaints are some of the most common and widespread effects, with acute cases resulting in increased doctor and hospital visits, and even death in extreme cases. Many people, such as those with chronic respiratory conditions, are at greater risk of experiencing adverse health events when exposed to poor quality air.

Air quality has also been shown to affect people’s levels of happiness and mental wellbeing. Research from around the world has shown higher levels of a range of air pollutants to be associated with lower levels of life satisfaction. There is also evidence that air pollution can lower people’s cognitive function and contribute to depression and anxiety.

For more, see Life in the Haze.

Higher temperatures and reduced rainfall associated with climate change is likely to increase the impact of smoke and dust on air quality (see Climate change). Planned burning to reduce the severity of bushfires is also likely to increase smoke impacts. In addition, higher temperatures are likely to increase ozone formation.

Pollen concentrations are also a challenge in the ACT, which was reported to have the highest rate of allergic rhinitis in Australia (29% of the population) in 2017–18.^[1] For more information see Health impacts of pollen and spores.

Amenity

In the context of air, amenity refers to environmental nuisance such as the occurrence of noise, smoke, dust, light and pollution incidents. These can interfere with daily activities and quality of life by impacting on health and wellbeing, the quiet enjoyment of households (for example, the ability to sleep, study, relax and use outdoor space) and use of public recreational areas. Impacts on amenity can have significant health consequences such as respiratory illnesses, sleep deprivation, as well as economic consequences such as the ability to work.

Background to indicators

Indicator A1: Compliance with air quality standards

Measuring air quality in the ACT

The ACT’s air quality monitoring network has only two National Environment Protection (Ambient Air Quality) Measure (AAQ NEPM) compliant monitoring stations at Monash and Florey. The Monash station is situated in the Tuggeranong Valley, the Florey station in Belconnen (Figure 1). A third station at Civic does not satisfy AAQ NEPM compliance requirements and is not reported here. The Florey station was established in February 2014 to comply with AAQ NEPM monitoring requirements for the ACT’s growing population.

The National Environment Protection Council (NEPC) sets ambient air quality reporting standards and goals through the AAQ NEPM. This AAQ NEPM prescribes targets for pollutants in ambient air, as well as the methods that should be used to monitor the pollutants. The ACT EPA reports annually against the AAQ NEPM standards and goals. Compliance with the AAQ NEPM standards ensures that the ACT is achieving the national environment protection standards for ambient air quality and that monitoring of AAQ NEPM pollutants is being undertaken appropriately.

The pollutants included in the AAQ NEPM are:

• carbon monoxide (CO)
• lead
• nitrogen dioxide (NO₂)
• ozone
• sulfur dioxide
• particulate matter less than 10 micrometres in size (PM₁₀)
• particulate matter less than 2.5 micrometres in size (PM_2.5).

The ACT monitors the levels of CO, NO₂, ozone, PM₁₀ and PM_2.5 in ambient air. The ACT does not monitor sulfur dioxide due to the lack of heavy industry in the region, and lead levels have not been monitored since the phase-out of leaded petrol in 2002.

To comply with the AAQ NEPM, the ACT Government must demonstrate that air quality meets the specified standards (Table 1). For PM₁₀, the ACT Government has set a lower annual standard of 20 μg/m3, as opposed to the NEPM standard of 25 μg/m3. There is also an additional lower target for particles as PM_2.5 to be achieved by 2025 – from 25 to 20 μg/m³ for one day average concentrations, and from 8 to 7 μg/m³ for the annual average concentrations. Poor air quality arising from fire (both unplanned and controlled burns), or pollution events such as dust storms, are excluded from AAQ NEPM compliance assessments.

More information on air quality monitoring and annual results can be found in the ACT Air Quality Reports.^[2]

Table 1: National Environment Protection (Ambient Air Quality) Measure standards and goals

Pollutant	Averaging period	Maximum concentration
Carbon monoxide	8 hours	9.0 ppm
Nitrogen dioxide	1 hour 1 year	0.08 ppm 0.015 ppm
Photochemical oxidants (as ozone)	8 hours	0.065 ppm
Particles as PM10	1 day 1 year	50 μg/m3 25 μg/m3
Particles as PM2.5	1 day 1 year	25 μg/m3 8 μg/m3
2025 target for particles as PM2.5	1 day 1 year	20 μg/m3 7 μg/m3

Notes: μg/m3 = micrograms per cubic metre; PM_2.5 = particulate matter less than 2.5 micrometres; PM₁₀ = particulate matter less than 10 micrometres; ppm = parts per million. The PM_2.5 standard came into effect in February 2016. Before this date, the PM_2.5 standard was advisory only.

Interpreting the data

The concentration of air pollutants depends on several factors, including the rate of emissions, the weather and the topography of the area. For example, wood smoke levels are more pronounced in winter in the Tuggeranong Valley than in other areas of the ACT largely because of the topography of the area. These factors need to be taken into account when interpreting monitoring results.

Particulate matter

Smoke from domestic wood heaters, controlled burns and bushfires, are the most significant sources of particulate matter in the ACT. Particle pollution is also produced by industry and motor vehicle emissions. Particle pollution can also result from anthropogenic sources (smoke from wood heaters and controlled burning, motor vehicles – particularly diesel, and industry) and natural sources (dust storms, bushfires and pollen). Particle pollution is usually the community’s main indicator of air quality, as it is often evident as a haze which reduces visibility. Climate change is likely to increase the occurrence of particle pollution with conditions leading to dust storms and more prevalent fires.

Particle pollution is the most significant air quality problem in the ACT with high levels associated with respiratory and cardiovascular illness. Current research suggests that there is no level of PM at which health impacts do not occur. The specific effect of a particle on health depends on its size, composition and concentration. Particles are associated with increased respiratory symptoms, aggravation of asthma, increased mortality and hospital admissions for heart and lung diseases.

The most common measures of particles are PM₁₀ (particulate matter that is 10 micrometres or less in diameter) and PM_2.5 (particulate matter that is 2.5 micrometres or less in diameter). In comparison, a human hair is about 100 micrometres in diameter. Particles smaller than 2.5 micrometres are considered to have more significant health impacts due to their deeper penetration into the lungs.

Ozone

Ozone is not directly emitted into the air; it is formed when volatile organic compounds (from industry, vehicles and vegetation) and oxides of nitrogen (from industry, vehicles and natural gas use) react in sunlight. These reactions only produce significant amounts of ozone on warm sunny days with light or recirculating winds. Ozone can also form downwind of bushfires when the chemicals in smoke react in the presence of sunlight. In the future, the higher temperatures predicted as a result of climate change are likely to lead to a greater potential for ozone formation.

Human exposure to high concentrations of ozone can result in decreased lung function, increases in asthma attacks, and increases in hospital admissions for people with heart and lung conditions. Higher levels of ozone can also affect vegetation growth and ecosystems.

Carbon monoxide (CO)

Carbon monoxide (CO) is mainly produced from vehicle engine exhaust. High levels of CO can affect human health, especially for children, the elderly and those with asthma. Very high levels of CO may cause health problems for birds and animals. CO also plays a role in climate change. Although CO is a weak greenhouse gas, it can affect the concentrations of other stronger greenhouse gases, including carbon dioxide and methane.

Nitrogen dioxide (NO₂)

Nitrogen dioxide (NO₂) is mainly produced from vehicle engine exhaust. NO₂ is also produced by the burning of fuels such as natural gas and diesel. NO₂ is harmful to human health, especially for children, the elderly and those with asthma. Low levels of NO₂ can irritate the eyes, nose, throat and lungs of humans and animals. Very high levels of NO₂ can affect the environment by killing plants and roots, and damaging the leaves of agricultural crops. Very high levels of NO₂ can also cause an increase in rain acidity, which can harm ecosystems.

Indicator A2: Health impacts of air pollution

Polluted air causes a range of short and long-term negative health outcomes. The common air pollutants present in the ACT – particles, nitrogen dioxide, carbon monoxide and ozone – are all associated with a range of harmful effects on human and environmental health.

The impacts of air pollution on human health is dependent on a range of factors including exposure level and the age and background health status of individuals. Many people, such as those with chronic respiratory conditions, are at greater risk of experiencing adverse health events when exposed to poor-quality air. Cardiovascular and respiratory complaints are some of the most common effects, with acute cases resulting in increased doctor and hospital visits, and even death in extreme cases. 

The AAQ NEPM standards are designed to adequately protect human health and wellbeing. However, there is a large body of evidence that demonstrates that air pollution, even at concentrations below the current air quality standards, is associated with adverse health effects.^[3] The strongest evidence relates to premature mortality and effects on the respiratory and cardiovascular system. Particulate matter is estimated to be the individual pollutant responsible for the largest burden of disease from outdoor pollution. 

In recognition of the evidence on health impacts, national standards are moving towards the position that there is no safe concentration for sensitive people, especially for particles (PM₁₀, PM_2.5). In 2013, the International Agency for Research on Cancer classified outdoor air pollution and particulate matter as carcinogenic to humans.

Any reduction in air pollution will result in health benefits, even where pollutant concentrations are within the air quality standards.

Indicator A3: Emissions of major air pollutants

Knowledge on the sources of air pollutants is important for the management of air pollution. The sources and amounts of pollutants emitted into the atmosphere are influenced by many factors including population, economic activity, prosperity, mobility and personal behaviour.

Due to the low level of industrial activity in the ACT, air quality is largely determined by activities and conditions in our urban areas. For instance, the number of cars being driven and the use of wood heaters in Canberra’s suburbs are major factors influencing air quality.

The sources and volumes of emissions of air pollutants in the ACT is reported in the National Pollutant Inventory (NPI). Whilst point source emissions are reported annually, data on the sources and emissions of diffuse source air pollution dates from a single 1999 study. It is important to note that diffuse sources of air pollutants, especially from transport and wood heaters, are the most significant contributors to air pollution in the ACT. Consequently, in the absence of current data it is not possible to assess changes in air pollution emissions.

Indicator A4: Amenity

Impacts on amenity such as increased noise, smoke, odour, dust and other pollution can affect health and wellbeing. Noise is the second most common form of pollution experienced by the community, after air pollution, and is increasing with growth in population, urbanisation and traffic. The Environment Protection Authority is responsible for investigating noise, odour, smoke, dust, light and other pollution complaints, and for enforcing compliance with guidelines in the ACT. As the number of complaints increase, so does the burden on compliance and enforcement resources.

Noise can significantly impact on quality of life, community health and can reduce economic performance. Noise can cause disturbance to sleep, interfere with reading and relaxing, and can be a barrier to spending time outdoors. Health impacts from chronic or acute noise include sleep deprivation, contribution to heart disease, impaired learning, hypertension, raised blood pressure, and stress.

Identification of impacts on amenity come from community complaints received by the ACT government. The number of complaints are dependent on a range of factors such as the sensitivity of community members to particular issues, and the number of complaints made about each individual event. Consequently it is difficult to assess trends in amenity. Despite this, complaints data does provide information on everyday environment impacts concerning the ACT community.