Traditional major industry is in decline in Australia, and this has produced a corresponding decrease in many emissions to air. For example, in the 5 years to 2014–15, the National Pollutant Inventory recorded decreases in total industry emissions of sulfur dioxide, carbon monoxide and ammonia of 10–15 per cent. On the other hand, in the same period, total PM10 emissions increased by 75 per cent and PM2.5 by 9 per cent, all because of the increase in mining activity. Mining is not located in or near major metropolitan areas, but is sometimes close to, or encroaches on, rural towns and residences, where it can be a significant pressure on air quality. Pressure also arises from the processing and transport of the mine output to port. An additional pressure is blast fume from mine blasting, which is a yellow–orange colour because of the high concentrations of nitrogen dioxide, and can be blown beyond the mine fence line. Blast fume is easily identifiable by its colour, pungent odour and taste, and it can irritate the eyes and throat. Box ATM9 describes research into emissions from coal-seam gas extraction activities.
Expansion of the urban fringe into farmland brings suburbs closer to farming industry, and the dust, odour and noise of intensive farming can be a pressure on air quality for the incoming residents. More generally, dust and odour are the main causes of air quality complaints to environmental authorities.