atmosphere Review A Clean Air Plan for Sydney: An Overview of the Special Issue on Air Quality in New South Wales Clare Paton-Walsh 1,2,* , Peter Rayner 3 , Jack Simmons 1,2 , Sonya L. Fiddes 3,4,5, Robyn Schofield 3 , Howard Bridgman 6, Stephanie Beaupark 1,2, Richard Broome 7, Scott D. Chambers 1,8 , Lisa Tzu-Chi Chang 9, Martin Cope 5, Christine T. Cowie 10,11,12 , Maximilien Desservettaz 1, Doreena Dominick 1,2, Kathryn Emmerson 5 , Hugh Forehead 13 , Ian E. Galbally 1,5 , Alan Griffiths 1,8 , Élise-Andrée Guérette 1,5, Alison Haynes 2,14, Jane Heyworth 12,15, Bin Jalaludin 12,16, Ruby Kan 9, Melita Keywood 5 , Khalia Monk 9 , Geoffrey G. Morgan 12,17, Hiep Nguyen Duc 9 , Frances Phillips 1,2 , Robert Popek 18 , Yvonne Scorgie 9, Jeremy D. Silver 3 , Steve Utembe 3,19, Imogen Wadlow 1,3, Stephen R. Wilson 1,2 and Yang Zhang 20 1 Centre for Atmospheric Chemistry, University of Wollongong, Wollongong, NSW 2522, Australia; [email protected] (J.S.); [email protected] (S.B.); [email protected] (S.D.C.); [email protected] (M.D.); [email protected] (D.D.); [email protected] (I.E.G.); [email protected] (A.G.); [email protected] (É.-A.G.); [email protected] (F.P.); [email protected] (I.W.); [email protected] (S.R.W.) 2 School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia; [email protected] 3 School of Earth Sciences, University of Melbourne, Melbourne, VIC 3010, Australia; [email protected] (P.R.); sonya.fi[email protected] (S.L.F.); robyn.schofi[email protected] (R.S.); [email protected] (J.D.S.); [email protected] (S.U.) 4 Climate and Energy College, University of Melbourne, Melbourne, VIC 3010, Australia 5 Climate Science Centre, CSIRO Oceans and Atmosphere, Aspendale, VIC 3195, Australia; [email protected] (M.C.); [email protected] (K.E.); [email protected] (M.K.) 6 School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia; [email protected] 7 Environmental Health Branch, Health Protection NSW, Sydney, NSW 2050, Australia; [email protected] 8 Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia 9 New South Wales Department of Planning, Industry and Environment, Lidcombe, Sydney, NSW 2141, Australia; [email protected] (L.T.-C.C.); [email protected] (R.K.); [email protected] (K.M.); [email protected] (H.N.D.); [email protected] (Y.S.) 10 South West Sydney Clinical School, University of New South Wales & Ingham Institute of Medical Research, Liverpool, NSW 2170, Australia; [email protected] 11 Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW 2037, Australia 12 Centre for Air Pollution, Energy and Health Research, Glebe, Sydney, NSW 2037, Australia; [email protected] (J.H.); [email protected] (B.J.); geoff[email protected] (G.G.M.) 13 SMART Infrastructure Facility, University of Wollongong, Wollongong, NSW 2522, Australia; [email protected] 14 Centre for Sustainable Ecosystem Solutions, University of Wollongong, Wollongong, NSW 2522, Australia 15 School of Population and Global Health, University of Western Australia, Curtin, WA 6907, Australia 16 Ingham Institute for Applied Medical Research, University of New South Wales, Liverpool, NSW 2170, Australia 17 School of Public Health, Faculty Medicine and Health, University of Sydney, Sydney, NSW 2006, Australia 18 Department of Basic Research in Horticulture, Institute of Horticultural Sciences, Faculty of Horticulture and Biotechnology, Warsaw University of Life Sciences—SGGW, 02-787 Warsaw, Poland; [email protected] Atmosphere 2019, 10, 774; doi:10.3390/atmos10120774 www.mdpi.com/journal/atmosphere Atmosphere 2019, 10, 774 2 of 37 19 Environment Protection Authority, Victoria, Melbourne, VIC 3001, Australia 20 Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA; [email protected] * Correspondence: [email protected] Received: 26 October 2019; Accepted: 18 November 2019; Published: 4 December 2019 Abstract: This paper presents a summary of the key findings of the special issue of Atmosphere on Air Quality in New South Wales and discusses the implications of the work for policy makers and individuals. This special edition presents new air quality research in Australia undertaken by (or in association with) the Clean Air and Urban Landscapes hub, which is funded by the National Environmental Science Program on behalf of the Australian Government’s Department of the Environment and Energy. Air pollution in Australian cities is generally low, with typical concentrations of key pollutants at much lower levels than experienced in comparable cities in many other parts of the world. Australian cities do experience occasional exceedances in ozone and PM2.5 (above air pollution guidelines), as well as extreme pollution events, often as a result of bushfires, dust storms, or heatwaves. Even in the absence of extreme events, natural emissions play a significant role in influencing the Australian urban environment, due to the remoteness from large regional anthropogenic emission sources. By studying air quality in Australia, we can gain a greater understanding of the underlying atmospheric chemistry and health risks in less polluted atmospheric environments, and the health benefits of continued reduction in air pollution. These conditions may be representative of future air quality scenarios for parts of the Northern Hemisphere, as legislation and cleaner technologies reduce anthropogenic air pollution in European, American, and Asian cities. However, in many instances, current legislation regarding emissions in Australia is significantly more lax than in other developed countries, making Australia vulnerable to worsening air pollution in association with future population growth. The need to avoid complacency is highlighted by recent epidemiological research, reporting associations between air pollution and adverse health outcomes even at air pollutant concentrations that are lower than Australia’s national air quality standards. Improving air quality is expected to improve health outcomes at any pollution level, with specific benefits projected for reductions in long-term exposure to average PM2.5 concentrations. Keywords: air quality; New South Wales; traffic; smoke; urban greening 1. Introduction 1.1. Objectives of This Review Paper The special issue of Atmosphere on Air Quality in New South Wales, Australia, brings together papers that describe the outcomes of research undertaken by the Clean Air and Urban Landscapes (CAUL) hub and its collaborators, including a number of measurement campaigns, and a series of papers describing the results of the first major comparison of air quality models in Australia. In this overview paper, we aim to: 1. review the existing literature relevant for understanding air quality in New South Wales; 2. summarise the key findings of research included in this special issue of Atmosphere (with an emphasis on the implications for policy makers); and 3. finally, we outline a number of policy options that we believe should be prioritised, along with supporting evidence from this research and the wider scientific literature. Atmosphere 2019, 10, 774 3 of 37 1.2. Air Quality in Sydney Air pollution has recently been identified as the largest environmental risk factor to human health worldwide, with fine particulate matter the greatest contributor to impacts from poor air quality [1]. Sydney, in the state of New South Wales (NSW), is a city located on the south-eastern coast of Australia (33◦520 S, 151◦120 E). It has a population of 5.1 million people (as of June 2017) [2] and experiences a temperate climate with warm summers and no defined dry season [3]. Sydney has a similar latitude and continental position to the South American cities of Montevideo, Uruguay and Buenos Aires, Argentina and the South African city of Cape Town. Much of the urban area of the city of Sydney lies within a basin with elevated topography bounding the basin to the north, west, and south, with the Tasman Sea located at the eastern extent of the basin. The temperate coastal basin geography of Sydney means it is influenced by both synoptic and meso-scale meteorological phenomena [4]. In particular, cold air drainage into the basin during the cooler part of the year and afternoon sea breezes in the warmer months are frequent, persistent meso-scale processes that impact the city’s air quality [5,6]. The New South Wales Department of Planning, Industry and Environment (DPIE) operates an extensive network of air quality monitoring stations across the Sydney region, monitoring six different measures of ‘criteria air pollutants’, which are used as indicators of air quality in NSW. These are ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), sulfur dioxide (SO2), visibility, and fine particles (including those with aerodynamic diameters below 10 microns and 2.5 microns known as PM10 and PM2.5, respectively). Measurements of each pollutant are normalised to the standard specified in the National Environment Pollution Measure for Ambient Air Quality (NEPM) [7]. This normalised information is published as the ‘Air Quality Index’ (AQI) for each pollutant. The air quality index for a monitoring station is determined by the highest criteria pollutant AQI. Similarly, the AQI for each region is determined by the highest station AQI [8]. Despite the relatively low air pollutant concentrations in Sydney in relation to comparable international cities, significant health impacts occur in the city [9]. Exposure (even at low concentrations) to pollutants, such as CO, nitrogen oxides (NOX), and fine particulate matter (PM), has been found to increase hospital admissions for five outcomes of cardiovascular disease in elderly people in Sydney [10].