Importance of clean and healthy air
What is air
We breathe the air in the earth’s lower atmosphere. Together nitrogen and oxygen are the main components make up 99%. The remaining 1% consists of small quantities of particles and other gases, such as water vapour, carbon dioxide, methane, nitrous oxide and ozone. These are all normal components of the atmosphere and, at these naturally occurring low levels, are unlikely to adversely affect people and other life forms.
However, when the concentrations of some of these components increase, they can harm us or the environment. Increasing levels of some gases are also contributing to climate change that in turn affects air quality:
- Carbon dioxide, from human activities such as burning of fossil fuels, has increased by more than 1/3 over the last 300 years.
- Methane arising from rice cultivation, domestic grazing animals, termites, landfills and mining has tripled since 1750.
- The average concentration of nitrous oxide from land use conversion, fossil fuel combustion, biomass burning and soil fertilisers increases in concentration at a rate of 0.2 to 0.3% per year.
What is air pollution
Air pollution occurs when concentrations of airborne gases and particles become high enough, and persist for long enough to cause adverse effects on people, plants, animals and property.
Most air pollution is anthropogenic (caused by humans), but can also come from natural sources such as wildfires. Common anthropogenic sources of air emissions are motor vehicles, industry, wood heaters, open burning, and dust from mining and other activities.
Adverse health effects can result from both short- and long-term exposure to air pollution. Accordingly, some pollutants have multiple standard concentrations depending on the time period of exposure.
Health impacts can include:
- premature death
- aggravation of cardiovascular and respiratory diseases
- damage to lung tissue, structure and function
- cancer
- changes in the function of the nervous system.
For many air pollutants, no threshold concentrations have been identified below which there are no effects on health. Harm can occur even at comparatively low concentrations. For example, although air quality in SA is generally good when compared with national and international standards, pollution still results in measurable health impacts and consequential economic costs.
In addition to direct health impacts, some air pollutants, such as dust and odour, can be a nuisance and diminish amenity. This may affect the wellbeing of those exposed and indirectly affect health through additional stress, lack of sleep and sense of being powerless.
Both individual pollutants and the mix of them may have effects. For example, sulfur and nitrogen compounds combine together in the atmosphere forming acidic substances which may impact on the health of humans, acidify soil and water, and also damage buildings and other structures. Nitrogen oxides contribute to ground-level ozone formation and can also be responsible for excessive growth of aquatic plants and oxygen depletion of waterbodies, reducing the water quality and health of aquatic ecosystems.
There is considerable Australian evidence indicating fine particles are the greatest risk for communities, especially those living in urban areas. Other pollutants, such as nitrogen dioxide, also remain a health concern. Airborne lead and sulfur dioxide were once an issue in urban areas, but this is no longer the case due to changes in vehicle fuels over the last 30 years. However, both remain an issue in regional cities such as Port Pirie, due to major manufacturing processes.
The amount of lead and sulfur dioxide emissions is expected to significantly reduce in the future as a result of the transformation of the Port Pirie smelter into an advanced multi-metals processing and recovery facility. The refurbished plant officially opened in January 2018.