Australia generally has good air quality, but some events and industries can impact our air Australia generally experiences good air quality. However, air quality can be reduced by specific events (which release pollutants for a short period) or specific industries (which affect the local area). Since the 2016 state of the environment report, various events have had significant short-term impacts on Australia’s air quality, especially the bushfires of the 2019–20 summer. Air quality is intrinsically linked to our comfort and wellbeing, and there may be no ‘safe’ level of air pollution The ambient air quality standards of the National Environmental Protection Measures (NEPMs) are set for the protection of human health (e.g. to prevent respiratory and cardiovascular diseases), but there is evidence that, for some pollutants, there is no ‘safe’ level, and health effects are observed even at low exposures. In April 2021, NEPM limits were reduced for ozone, nitrogen dioxide and sulfur dioxide. Reducing the NEPM limits alone will not improve air quality, without a targeted program of reducing pollution sources and minimising exposure of the Australian population. Fine particulate matter (PM2.5) is one of the pollutants of most concern in terms of human health. Although all cities have maintained a ‘very good’ assessment for PM2.5 since 2016, peak reported levels of PM2.5 in each year remain above the air quality NEPM standard in all capital cities in Australia. PM2.5 levels are stable in Darwin, Hobart and Melbourne, but increasing elsewhere. Air quality NEPM standards for PM2.5 are set to decrease in 2025, making compliance even harder. Understanding the main sources of these smaller particles, including how they can form in the atmosphere from precursor pollutants, is key to their regulation. Our air quality depends on what we are putting into the air Peak ozone levels are increasing across Australia, in both capital cities and regional centres. Although the assessment grades in most cities are classed as ‘good’ and lie below the NEPM standards, the increasing trend suggests that it will be harder to maintain this ‘good’ assessment in future. Industrial emissions are generally well controlled, and there have been recent improvements in the emissions of hazardous substances such as lead and mercury. However, industrial emissions at Port Pirie (South Australia) and Mount Isa (Queensland) continue to be a concern for local residents. A major upgrade to smelting operations at Port Pirie that promises to reduce sulfur dioxide emissions has been delayed. The 5-year trend in the assessment of coarse particulate matter (PM10) is improving in Hobart, Melbourne and Perth. PM10 levels in Canberra and Darwin are stable compared with the previous 5 years, and in Adelaide, Brisbane and Sydney the PM10 levels are increasing. Dust can be a significant air pollutant for remote and regional areas. Levels of dust and dust storms are higher in regions with low soil moisture and sparse vegetation coverage, and dust may become an increasing problem with climate change. Wood heater smoke in winter continues to cause localised air pollution problems in built-up areas. Encouraging residents away from wood heating has been difficult; a buy-back scheme in Tasmania was successful but not implemented in other states. The Clean Air Plan for Sydney made a recommendation to ban wood heaters in urban areas. Urban smoke is also generated by prescribed burns at other times of year, but cumulatively the impacts of wood heater smoke over the winter months in Sydney are greater than the impacts of smoke generated from a few prescribed burning events. This is also likely to be true for the southern states and territories. Better information can reduce the impact of poor air quality Pollutants of concern are only assessed by states and territories at 211 fixed air quality monitoring stations across Australia. Sensitive populations living in other areas cannot rely on this information to protect their health. New networks of low-cost sensors are helping to fill in the gaps between fixed-location monitoring stations. Our communities need real-time local information during periods of poor air quality. The summer 2019–20 bushfires showed that the daily reports of 24-hour average PM10 and PM2.5 measurements were not satisfactory. The bushfires changed the way people wanted to access air quality data, find out what their exposure was and discover when the worst of the smoke had passed. The Bushfire Royal Commission recommended that air quality measurements are reported hourly, and that jurisdictions standardise how their air pollution health alert messaging is conveyed to the public.