Oxides of nitrogen What does the National Pollutant Inventory do? Pollution in Australia comes from many different sources. Some is a result of industrial activity but there are also sources of pollution that are not industrial, like cars, woodheaters and even lawn mowers. The National Pollutant Inventory (NPI) is tracking pollution right across Australia by collecting data on about 93 different toxic substances emitted into the environment. The NPI can show you the source and location of these emissions. The substances that are studied and reported on were chosen because of the problems they can potentially cause for our health and the health of the environment. Oxides of nitrogen (or NOx) are some of the substances that the NPI tracks across Australia. Here are some fascinating facts about oxides of nitrogen and some hints on how you can help minimise their harmful effects on our health and on the environment. Oxides of nitrogen are a mixture of gases that are made up of nitrogen and oxygen gases. They include nitrogen dioxide, nitric oxide, nitrogen oxide, nitrogen monoxide and nitrous oxide (or laughing gas), just for starters! Where do oxides of nitrogen come from? What about industry? Generation of electricity is the largest source of emissions of oxides of nitrogen in Australia. Other industrial sources are mining, oil and gas extraction, different kinds of metal manufacturing and petroleum manufacturing.

What about the natural environment? Oxides of nitrogen are found in air, soil and water. Natural events such as lightning and bushfi res can also produce oxides of nitrogen.

What about transport? Oxides of nitrogen may be present in the exhaust emitted into the atmosphere by cars, aeroplanes, trains and boats. Even lawnmowers can emit oxides of nitrogen into the atmosphere!

What about in the products we buy? Common products containing oxides of nitrogen include nitrate fertilisers. Oxides of nitrogen are used to make explosives and ammunition but these are not commonly available products! Cigarette smoke and other fuel burning activities, such as wood–burning heaters in the home, can be sources of oxides of nitrogen. Do you have a heater that burns wood at your place? Lots of homes in Australia still have this type of heating. What are some of the other sources? Some agricultural and forestry activities (including ‘controlled burns’ and land clearing) increase the rate of the natural processes that produce oxides of nitrogen. What effect do oxides of nitrogen have on the environment? Oxides of nitrogen can have harmful effects on our environment and on us. The roots and leaves of agricultural crops can be damaged if there are high levels of oxides of nitrogen in the air, water or soil, and the plants may not even survive. This leads to farmers having a poorer harvest. Nitrogen dioxide also contributes to smog. High levels of oxides of nitrogen can produce acid rain which affects groundwater and soil and in turn, damages our environment and everything in it. The good news - so far, is that we have not had any acid rain in Australia. Let’s hope it stays that way! How might people be exposed to oxides of nitrogen? People can be exposed to oxides of nitrogen in the following ways: • breathing in polluted air. • smoking cigarettes and breathing in other people’s cigarette smoke. • living near coal-burning power plants or near freeways and busy roads. • living in households with wood fi res, kerosene heaters or gas stoves. • working in a job in which oxides of nitrogen are produced or used, such as in a factory that uses welding materials or explosives. Who is taking action? There are all sorts of things that we can do at home, school, and in our local community to help minimise the harmful effects of pollution on our environment. Why not investigate ways in which you can take action every day to reduce the problems that polluting substances can cause people, animals and the environment? Visit: www.npi.gov.au/about/reduce.html Where can I fi nd out more about NPI substances? For more information about oxides of nitrogen see Australia’s oxides of nitrogen emission report on the main NPI web site. You will also fi nd detailed information about the remaining 92 substances that the NPI tracks across Australia in the fact sheets on the main NPI web site.