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A lifecycle assessment to estimate greenhouse gas emissions in Australia from the paper cycle is summarised. The greenhouse gas emissions from paper in Australia in 1999/2000 were estimated to be 12.1 million tonnes (Mt) of CO2 equivalent. Nearly half of this amount consisted of CH4 emissions from landfilled waste paper. Various waste management options were modelled to investigate the greenhouse impact of a tonne of paper over its whole lifecycle. Options that keep paper out of landfills significantly reduce greenhouse emissions, waste-to-energy recovery being most effective. Recycling is also beneficial, and is of particular interest from a management perspective because it can be controlled by the pulp and paper industry. These findings can be extended to other wood-based and organic wastes. [Copyright &y& Elsevier]

In Australia, tropospheric ozone measurements in rural locations are scarce with measurements mostly made in cities. This limits the ability to estimate background ozone levels that inform policy development. The few studies that have assessed rural ozone in Australia have been associated with short campaign monitoring or specific, short-term research programs. Recognising this deficit of information, the New South Wales Government has established long-term ozone monitoring at two rural locations. This paper presents results from the first three years of monitoring at Gunnedah. We assess seasonal, diurnal and sectoral patterns of ozone. Several events are analysed, including high ozone associated with the 2019/20 Australian Bushfire Emergency and an extreme heatwave event. We find that ozone levels at Gunnedah exceed the screening standards set by Australia's National Environmental Protection (Ambient Air Quality) Measure, emphasising the need for additional ozone monitoring in rural and regional Australia. Our early results indicate that in NSW, background ozone mixing ratios for airmasses of continental origin is likely in the range of 36–39 ppb, higher than the 14–30 ppb associated with air masses of marine origin and greater than the 30 ppb background mixing ratio used for monitoring design and standard setting in Australia. Maximum 8-hourly ozone in non-bushfire impacted events is as high as 64 ppb, demonstrating the challenges that rural/regional communities may face in always meeting the new Australian 8-h ozone standard of 65 ppb. These results add to our understanding of rural background ozone within Australia and in the southern hemisphere. • New measurements of tropospheric ozone in rural Australia. • Use of k-means clustering to estimate background ozone. • Background ozone in Australia may be higher than previously thought. • Anthropogenic component of ozone may be over-estimated when setting Australian air quality standards. • Challenges in meeting new ozone standards and WHO guidelines in rural Australia. [ABSTRACT FROM AUTHOR]

More timely and accurate air quality forecasting could contribute to better public health protection and air pollution prevention. Particulates are a significant indicator for measuring the degree of air pollution. This paper reports on research to model an early warning tool for coarse particulates when assessing the impact of the 12 satellite-derived and ground-based meteorological pollutants out of 30 pollutants considered using hourly Australian data from January 2018–December 2020. A one-dimensional convolutional neural network (CNN) was integrated with a one-directional fully gated recurrent unit (GRU) to forecast consecutive hours' air quality. The CNN model acts as a spatial feature extractor, whereas the new generation GRU makes it computationally efficient. The resultant hybrid ' CNN-GRU' is then comprehensively benchmarked outperforming an ensemble of six other deep learning models. The proposed model's efficacy is indicated at the four most air polluted Australian postcodes in the testing phase. A detailed error analysis with visual and statistical metrics for air quality forecasting ascertains the proposed model's countermeasure to reduce harm and loss. The practical tool is immensely beneficial and can be widely deployed to the regions of public health concern where air pollution is a significant hazard. [Display omitted] • A novel early warning hybrid PM10 forecasting framework designed for Australia. • 30 satellite and ground-based meteorological pollutants were considered with 7 modeling approaches. • CNN integrated with GRU outperformed the other models. • Early warning AI model show potential in the health, environment sector, and decision-making. [ABSTRACT FROM AUTHOR]

Lead is a persistent pollutant and the subject of many environmental studies, yet, in Australia, the extent of atmospheric lead emissions from the use of leaded petrol is unquantified. This paper details the first comprehensive account of leaded petrol sales and its lead concentrations over the 70 years of use in Australia. The resulting atmospheric lead emissions are calculated to provide the most complete understanding of the volume of lead released to the Australian continent from the consumption of leaded petrol. Atmospheric emissions of lead to the entire Australian continent from leaded petrol are calculated to total 240,510 tonnes over seven decades of use, peaking at 7869 tonnes in 1974. Total emissions for individual states and territories range from 1745 to 67,893 tonnes, with New South Wales responsible for the largest emissions. The effect of regulations on allowable concentrations of tetraethyl-lead additives are observed in the reduction of lead emissions in New South Wales and Victoria. The consequences to human health and the environment of leaded petrol consumption in Australia's populous cities are examined against historical air quality data and blood lead levels. [ABSTRACT FROM AUTHOR]

Abstract: The United Nations Environment Programme (UNEP) has begun a process of developing a legally binding instrument to manage emissions of mercury from anthropogenic sources. The UNEP Governing Council has concluded that there is sufficient evidence of significant global adverse impacts from mercury to warrant further international action; and that national, regional and global actions should be initiated as soon as possible to identify populations at risk and to reduce human generated releases. This paper describes the development of, and presents results from, a comprehensive, spatially and temporally resolved inventory of atmospheric mercury emissions from the Australian landmass. Results indicate that the best estimate of total anthropogenic emissions of mercury to the atmosphere in 2006 was 15 ± 5 tonnes. Three industrial sectors contribute substantially to Australian anthropogenic emissions: gold smelting (∼50%, essentially from a single site/operation), coal combustion in power plants (∼15%) and alumina production from bauxite (∼12%). A diverse range of other sectors contribute smaller proportions of the emitted mercury, but industrial emissions account for around 90% of total anthropogenic mercury emissions. The other sectors include other industrial sources (mining, smelting, and cement production) and the use of products containing mercury. It is difficult to determine historical trends in mercury emissions given the large uncertainties in the data. Estimates for natural and re-emitted emissions from soil, water, vegetation and fires are made using meteorological models, satellite observations of land cover and soil and vegetation type, fuel loading, fire scars and emission factors which account for the effects of temperature, insolation and other environmental variables. These natural and re-emitted sources comfortably exceed the anthropogenic emissions, and comprise 4–12 tonnes per year from vegetation, 70–210 tonnes per year from soils, and 21–63 tonnes per year from fires. [Copyright &y& Elsevier]

Abstract: The idea of ground-based evapotranspiration (ET) is of the most interesting for land–atmosphere interactions, such as water-saving irrigation, the performance of irrigation systems, crop water deficit, drought mitigation strategies and accurate initialization of climate prediction models especially in arid and semiarid catchments where water shortage is a critical problem. The recent year''s drought in Australia and concerns about climate change has prominent the need to manage water resources more sustainably especially in the Murrumbidgee catchment which utilizes bulk water for food security and production. This paper discusses the application of a Surface Energy Balance System (SEBS) model based on Landsat-5 TM data and field observations has been used and tested for deriving ET over Coleambally Irrigation Area (CIA), located in the southwest of NSW, Australia. 16 Landsat-5 TM scenes were selected covering the time period of 2009, 2010 and 2011 for estimating the actual ET in CIA. To do the validation the used methodology, the ground-measured ET was compared to the Landsat-5 TM retrieved actual ET results for CIA. The derived ET value over CIA is much closer to the field measurement. From the remote sensing results and observations, the root mean square error (RMSE) is 0.74 and the mean APD is 7.5%. The derived satellite remote sensing values belong to reasonable range. [Copyright &y& Elsevier]

Abstract: Recent acknowledgement of the sensitivity of air quality to changes in climate has initiated a closer examination of the relationships between meteorology and air quality. This paper presents the estimated response of daily air pollutant concentrations in Melbourne, Australia to local-scale meteorology. The meteorological-pollutant relationships have been assessed after controlling for long-term trends, seasonality, weekly emissions, spatial variation, and temporal persistence using the framework of generalized additive models (GAMs). Overall, results found that the aggregate impact of meteorological variables in the models explained 26.3% of the variance in O3, 21.1% in PM10, and 26.7% in NO2. This indicates that meteorology – at the local-scale, is a relatively strong driver of air quality in Melbourne. Analysis of partial residuals plots found that changes in temperature, particularly when above 35 °C, resulted in the strongest positive response for O3 (150%), PM10 (150%) and NO2 (120%). Other variables (boundary layer height, winds, water vapor pressure, radiation, precipitation, and mean sea-level pressure) displayed some importance for one or more of the pollutants, but their impact in the models was less pronounced. In sum, we provide results that form a solid foundation for understanding the importance of local-scale meteorology as a driver of regional air pollution. Additionally, these results can be used to provide a window into how changes in climate may affect air quality. [Copyright &y& Elsevier]

The Australian coal mining industry, as with other industries is coming under greater constraints with respect to their environmental impacts. Emissions of acid gases such as NO x and SO x to the atmosphere have been regulated for many years because of their adverse health effects. Although NO x from blasting in open-cut coal mining may represent only a very small proportion of mining operations, total NO x emissions, the rapid release and high concentration associated with such activities may pose a health risk. This paper presents the results of a new approach to measure these gas emissions by scanning the resulting plume from an open-cut mine blast with a miniaturised ultraviolet spectrometer. The work presented here was undertaken in the Hunter Valley, New South Wales, Australia during 2006. Overall this technique was found to be simpler, safer and more successful than other approaches that in the past have proved to be ineffective in monitoring these short lived plumes. The average emission flux of NO x from the blasts studied was about 0.9ktt−1 of explosive. Numerical modelling indicated that NO x concentrations resulting from the blast would be indistinguishable from background levels at distances greater than about 5km from the source. [Copyright &y& Elsevier]

This two-part series investigates the emission and transport of biomass burning aerosol (or particulate matter) across the Top End of the Northern Territory of Australia. In Part I, Meyer et al. [2008. Biomass burning emissions over northern Australia constrained by aerosol measurements: I—Modelling the distribution of hourly emissions. Atmospheric Environment, in press, doi:10.1016/j.atmosenv.2007.10.089.] used a fuel load distribution coupled with a satellite-derived imagery of fire scars and hotspots and the diurnal variation of a fire danger index to estimate hourly emission rates of particulate matter with an aerodynamic diameter of 2.5μm or less (PM2.5) for the dry season April–November 2004 at a spatial resolution of 1km×1km. In the present paper, these emission rates are used in TAPM, a three-dimensional meteorological and air pollution model, and the modelled PM2.5 concentrations and aerosol optical depths are compared with satellite and ground-based measurements. This exercise also seeks to fine-tune and validate the emission calculation methodology, a process through which it is found that cases with hotspots without any corresponding fire scars (e.g. in mountainous terrain), which were initially ignored, need to be included to improve the accuracy of model predictions. Overall, the model is able to describe the measurements satisfactorily, considering the issues associated with the model resolution, emission uncertainty, and modelled meteorology. The model hindcasts numerous exceedences of the advisory maximum PM2.5 exposure limit across the study region, with large areas in excess of 30 exceedences during the study period. Estimated mean top of atmosphere direct radiative forcing due to aerosol shows a seasonal mean of −1.8Wm−2 with a region of strong enhancement over the western portion of the Top End. [Copyright &y& Elsevier]

Current ambient air quality standards are mass-based and restricted to PM2.5 and PM10 fractions. The major contribution to both PM2.5 and PM10 fractions is from particles belonging to the coarse mode and generated by mechanical processes. These standards are thus unable to effectively control particle concentrations from combustion sources, such as motor vehicles and power plants, which tend to emit very small particles that are almost entirely respirable and in the submicron range, and dominate the nucleation and accumulation modes, which contribute much less to particle mass concentration. The aim of this work was to examine whether PM1 and PM10 would be a more effective combination of mass standards than PM2.5 (dominant in the nucleation and accumulation modes) and PM10 (dominant in the coarse mode) in controlling combustion-related ambient particles, as well as those originating from mechanical processes. First, a large body of data on particle size distributions in a range of environments in South East Queensland, Australia, was analysed, with an aim of identifying the relation between modality in the distributions and sources of particles belonging to different modes. The analyses included a matrix of the following elements: particle volume and number distributions, type of environment and locations of the modes in the range of PM1, PM2.5 and PM10 fractions. Second, with the same aim, 600 published modal location values relating to number, surface area, volume and mass size distributions for a range of environments worldwide were analysed. The analysis identified a clear and distinct separation between the location of the modes for a substantial number of environments worldwide and particle metrics, which suggests that modality in particle size distributions may be a parameter that has potential to be used in the development of PM1 air quality guidelines and standards. Based on these analyses, implications for choosing different mass standards for airborne particulate matter are discussed in the paper. [Copyright &y& Elsevier]

This paper quantifies the expected pre-combustion and combustion emissions of greenhouse gases from Australian heavy vehicles using alternative fuels. We use the term exbodied emissions for these full fuel-cycle emissions. The fuels examined are low sulfur diesel (LSD), ultra-low sulfur diesel (ULS), compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG), ethanol (from lignocellulose), biodiesel and waste oil. Biodiesel and ethanol have the lowest exbodied greenhouse gas emissions (in grams greenhouse gases per kilometre travelled). Biodiesel reduces exbodied greenhouse gas emissions from 41% to 51% whereas ethanol reduces emissions by 49–55%. In fact, both emit larger quantities of CO2 than conventional fuels, but as most of the CO2 is from renewable carbon stocks that fraction is not counted towards the greenhouse gas emissions from the fuel. The gaseous fuels (LPG, CNG) come next with emissions that range from 88% to 92% of diesel. The emissions of greenhouse gases from diesel are reduced if waste oil is used as a diesel extender, but the processing energy required to generate LSD and ULS in Australia increase their greenhouse gas emissions compared to diesel fuel. The extra energy required liquefy and cool LNG means that it has the highest exbodied greenhouse gas emissions of the fuels that were considered. [Copyright &y& Elsevier]