8. Air pollution

8.1 Background

Clean air is essential for sustaining all life on Earth. Good air quality is important for human health and wellbeing and is associated with better physical and mental health, longer life, and reduced healthcare costs. Clean air is also essential for biodiversityThe variety of all life and living processes in the environment. and ecosystemA biological community of interacting living and non-living things. health.

In contrast, poor air quality can endanger both human health and the environment. Exposure to air pollutants can lead to breathing problems and respiratory disease, heart disease, asthma attacks, eye and throat irritation, declines in mental and physical performance, headaches and tiredness, anxiety and depression, and babies being born underweight. Polluted air also affects plants, damages buildings and significantly lowers visibility.

Poor air quality is mostly a concern in places where there are lots of people, industry and vehicles. The main sources of air pollution are:

• Emissions (or smoke) from fires – bushfires, controlled burnsAlso known as prescribed or hazard reduction burns, controlled burns are fires that are started on purpose to reduce fuel loads and help protect homes, farms and infrastructure. They are also used to improve the health of ecosystems and for cultural reasons by Aboriginal people., wood heaters and open fireplaces in homes release carbon monoxide, nitrogen dioxide and particles into the air that are bad for our health.
• Exhaust emissions from vehicles – Cars, trucks and other vehicles that are powered by fossil fuels such as petrol and diesel release carbon monoxide, nitrogen dioxide and a variety of tiny particles. Motor vehicles that use diesel fuel generally emit more nitrogen dioxide and particles than petrol-powered vehicles.
• Emissions from industry – Factories and coal fired energy plants produce carbon monoxide, nitrogen dioxide and particles. Although these emissions are mostly generated outside the ACT, they can still affect the ACT’s air quality.
• Emissions from urban development – Development activities like land clearing and road works release dust and soil particles into the air.
• Chemical reactions – Ozone can form on warm, still, sunny days, when oxides of nitrogen (mainly from industry, vehicles and natural gas) react with carbon-containing gases (mainly from industry, vehicles and vegetation). Ozone can also form when sunlight activates chemical reactions in bushfire smoke. Ozone is a gas that can both harm and help. High in the atmosphere it helps us, as the ozone layer blocks much of the Sun’s harmful ultraviolet radiation. But ozone low in the atmosphere, and other air pollutants, can harm our health.

Pollen counts and human health

Pollen is a very fine powder produced by trees, flowers, grasses and weeds to fertilise other plants. Although pollen in not considered to be air pollution, it can affect the health of some people by triggering hay fever and asthma.

The ACT has Australia’s highest rate of hay fever, with almost one in three residents affected – and the problem is getting worse. Between 2007 and 2018, there was a 10% rise in the number of people affected.

The peak pollen season happens in spring, but there is pollen that also triggers allergic reactions in late winter and summer.

Over the past 90 years, Canberra’s urban development and associated tree planting have increased the amount of allergy causing pollen. In future, climate change is likely to affect the onset, duration and intensity of the pollen season, as well as worsening how pollen affects people.

This infographic shows the main plant species that release a large amount of pollen in the ACT. It also shows what time of year each plant releases pollen (grey coloured bars) and when they release the most pollen (blue coloured bars). The graph at the bottom of the infographic shows when pollen amounts are highest in ACT. The data reveals that whilst spring has the highest amount of pollen in the air, pollen can still be present throughout the year.

Source: The Australian National University.

More information on pollen in Canberra can be found HERE.