Biomass burning (BB) is a significant air pollution source, with global, regional and local impacts on air quality, public health and climate. Worldwide an extensive range of studies has been ...conducted on almost all the aspects of BB, including its specific types, on quantification of emissions and on assessing its various impacts. China is one of the countries where the significance of BB has been recognized, and a lot of research efforts devoted to investigate it, however, so far no systematic reviews were conducted to synthesize the information which has been emerging. Therefore the aim of this work was to comprehensively review most of the studies published on this topic in China, including literature concerning field measurements, laboratory studies and the impacts of BB indoors and outdoors in China. In addition, this review provides insights into the role of wildfire and anthropogenic BB on air quality and health globally. Further, we attempted to provide a basis for formulation of policies and regulations by policy makers in China.
Open field biomass burning causes severe air pollution, public health risk and potential climate impact. a) Photo taken in Changzhou rural area on June 10, 2015; b) Photo taken in Hebei rural area on October 23, 2013; c) A traditional indoor burner in rural area in China; d) Tar ball emitted from biomass burning. Display omitted
•This review discusses wildfire and anthropogenic emission from biomass burning in China.•Field observations and laboratory studies on public health and climate impacts of biomass burning•Atmospheric process of biomass burning plumes and their transport•Proposed research priorities and insights about biomass burning in China
Pollen identification and enumeration is subject to human errors, and hence, it is crucial to evaluate the proficiency of pollen counters. Many networks still depend on manual pollen monitoring, and ...those adopting automation use manual counting data as a reference. A quality control exercise was undertaken across the AusPollen Aerobiology Collaboration Network to compare data analysis methods, gauge factors associated with accuracy, and improvements in counting proficiency. Counters were instructed to count grass and other pollen of the same two slides. Reported pollen concentrations were compared to an approximation of the true concentration values applying the published benchmark approach and alternative approach using bootstrapping technique. Participants were asked about their experience, training and usual practice via an online questionnaire. The majority (92% of 72) of reported values fell within acceptable ranges of variation from approximated true values. Outcomes were similar regardless of analysis approach, but bootstrapping did not require detection of outliers, and worked well with a small sample size with non-normal distribution. Counter reported pollen data were significantly shifted towards better outcomes compared to an initial exercise, and five of eight counters who were tested two times improved. Counting performance seemed not to be associated with amount of training received but was significantly related to counter experience. For future quality control exercises, particularly for small and skewed datasets, confidence limits of true pollen concentrations may be analysed by bootstrapping. Implementation of quality control exercises with harmonised analysis would enhance delivery of reliable pollen information to community, clinicians and government agencies for forecasting and environmental health management.
The coronavirus disease of 2019 (COVID‐19) pandemic has impacted educational systems worldwide during 2020, including primary and secondary schooling. To enable students of a local secondary school ...in Brisbane, Queensland, to continue with their practical agricultural science learning and facilitate online learning, a “Grass Gazers” citizen science scoping project was designed and rapidly implemented as a collaboration between the school and a multidisciplinary university research group focused on pollen allergy. Here, we reflect on the process of developing and implementing this project from the perspective of the school and the university. A learning package including modules on pollen identification, tracking grass species, measuring field greenness, using a citizen science data entry platform, forensic palynology, as well as video guides, risk assessment and feedback forms were generated. Junior agriculture science students participated in the learning via online lessons and independent data collection in their own local neighborhood and/or school grounds situated within urban environments. The university research group and school coordinator, operating in their own distributed work environments, had to develop, source, adopt, and/or adapt material rapidly to meet the unique requirements of the project. The experience allowed two‐way knowledge exchange between the secondary and tertiary education sectors. Participating students were introduced to real‐world research and were able to engage in outdoor learning during a time when online, indoor, desk‐based learning dominated their studies. The unique context of restrictions imposed by the social isolation policies, as well as government Public Health and Department of Education directives, allowed the team to respond by adapting teaching and research activity to develop and trial learning modules and citizen science tools. The project provided a focus to motivate and connect teachers, academic staff, and school students during a difficult circumstance. Extension of this citizen project for the purposes of research and secondary school learning has the potential to offer ongoing benefits for grassland ecology data acquisition and student exposure to real‐world science.
The coronavirus disease of 2019 (COVID‐19) pandemic has impacted educational systems worldwide, in particular primary and secondary schooling. To enable students of the local secondary school in Brisbane, Queensland, to continue with their practical agricultural science learning and facilitate online learning, a small‐scale citizen science project was designed and rapidly implemented as a collaboration between the school and a multidisciplinary university research group focused on pollen allergy. This study reflects on the process of developing and implementing this project from the perspective of the school and the university, the challenges and benefits incurred by both parties as well as the potential future implementations of this project for school learning and grassland ecology data acquisition.
Pollen monitoring in Australia has rapidly expanded, particularly in response to needs identified following the world’s most devastating thunderstorm asthma epidemic in Melbourne, 2016. Pollen ...identification and quantification are integral processes of establishing a standardised pollen monitoring network. A pilot study was designed to assess proficiency in these processes of counters who contribute to daily pollen information at established pollen monitoring sites of the AusPollen Aerobiology Collaboration Network. Counters were instructed to count grass and other pollen along four longitudinal transects of two reference slides at lens magnification of 400×. Participants were asked about their experience, training and usual practice in pollen counting via an online questionnaire. Of the 44 counters invited, 15 consented to participate. Reported pollen concentration values were compared to an approximation of the assigned true concentration values. Overall, 86% of reported values were within acceptable ranges of variation from assigned values. Apparent courting proficiency could have been affected by study limitations including slide quality and high/low pollen concentrations. Although counting performance did not appear to be related to experience and amount of training received, the majority of participants were not highly experienced or trained and the number of participants was small. It was not possible in this pilot study to make conclusions regarding relationships between training or experience and counter proficiency. Evaluation of counter proficiency is an important step in providing more accurate pollen concentrations, which are integral to local daily pollen forecasts for optimum day-to-day management of pollen-related conditions.
Grass pollen is the major outdoor trigger of allergic respiratory diseases. Climate change is influencing pollen seasonality in Northern Hemisphere temperate regions, but many aspects of the effects ...on grass pollen remain unclear. Carbon dioxide and temperature rises could increase the distribution of subtropical grasses, however, medium term shifts in grass pollen in subtropical climates have not yet been analysed. This study investigates changes in grass pollen aerobiology in a subtropical city of Brisbane, Australia, between the two available monitoring periods, 1994-1999 and 2016-2020. Potential drivers of pollen change were examined including weather and satellite-derived vegetation indicators. The magnitude of the seasonal pollen index for grass showed almost a three-fold increase for 2016-2020 over 1994-1999. The number and proportion of high and extreme grass pollen days in the recent period increased compared to earlier monitoring. Statistically significant changes were also identified for distributions of CO
, satellite-derived seasonal vegetation health indices, and daily maximum temperatures, but not for minimum temperatures, daily rainfall, or seasonal fraction of green groundcover. Quarterly grass pollen levels were correlated with corresponding vegetation health indices, and with green groundcover fraction, suggesting that seasonal-scale plant health was higher in the latter period. The magnitude of grass pollen exposure in the subtropical region of Brisbane has increased markedly in the recent past, posing an increased environmental health threat. This study suggests the need for continuous pollen monitoring to track and respond to the possible effects of climate change on grass pollen loads.
There is a lack of knowledge of how biomass burning aerosols in the tropics age, including those in the fire-prone Northern Territory in Australia. This paper reports chemical characterization of ...fresh and aged aerosols monitored during the 1-month-long SAFIRED (Savannah Fires in the Early Dry Season) field study, with an emphasis on the chemical signature and aging of organic aerosols. The campaign took place in June 2014 during the early dry season when the surface measurement site, the Australian Tropical Atmospheric Research Station (ATARS), located in the Northern Territory, was heavily influenced by thousands of wild and prescribed bushfires. ATARS was equipped with a wide suite of instrumentation for gaseous and aerosol characterization. A compact time-of-flight aerosol mass spectrometer was deployed to monitor aerosol chemical composition. Approximately 90 % of submicron non-refractory mass was composed of organic material. Ozone enhancement in biomass burning plumes indicated increased air mass photochemistry. The diversity in biomass burning emissions was illustrated through variability in chemical signature (e.g. wide range in f44, from 0.06 to 0.18) for five intense fire events. The background particulate loading was characterized using positive matrix factorization (PMF). A PMF-resolved BBOA (biomass burning organic aerosol) factor comprised 24 % of the submicron non-refractory organic aerosol mass, confirming the significance of fire sources. A dominant PMF factor, OOA (oxygenated organic aerosol), made up 47 % of the sampled aerosol, illustrating the importance of aerosol aging in the Northern Territory. Biogenic isoprene-derived organic aerosol factor was the third significant fraction of the background aerosol (28 %).
Grasses populate most biogeographical zones, and their diversity influences allergic sensitisation to pollen. Previously, the contribution of different Poaceae subfamilies to airborne pollen has ...mostly been inferred from historical herbarium records. We recently applied environmental (e)DNA metabarcoding at one subtropical site revealing that successive airborne grass pollen peaks were derived from repeated flowering of Chloridoid and Panicoid grasses over a season. This study aimed to compare spatiotemporal patterns in grass pollen exposure across seasons and climate zones.
Airborne pollen concentrations across two austral pollen seasons spanning 2017–2019 at subtropical (Mutdapilly and Rocklea, Queensland) and temperate (Macquarie Park and Richmond, New South Wales) sites, were determined with a routine volumetric impaction sampler and counting by light microscopy. Poaceae rbcL metabarcode sequences amplified from daily pollen samples collected once per week were assigned to subfamily and genus using a ribosomal classifier and compared with Atlas of Living Australia sighting records.
eDNA analysis revealed distinct dominance patterns of grass pollen at various sites: Panicoid grasses prevailed in both subtropical Mutdapilly and temperate Macquarie Park, whilst Chloridoid grasses dominated the subtropical Rocklea site. Overall, subtropical sites showed significantly higher proportion of pollen from Chloridoid grasses than temperate sites, whereas the temperate sites showed a significantly higher proportion of pollen from Pooideae grasses than subtropical sites. Timing of airborne Pooid (spring), Panicoid and Chloridoid (late spring to autumn), and Arundinoid (autumn) pollen were significantly related to number of days from mid-winter. Proportions of eDNA for subfamilies correlated with distributions grass sighting records between climate zones.
eDNA analysis enabled finer taxonomic discernment of Poaceae pollen records across seasons and climate zones with implications for understanding adaptation of grasslands to climate change, and the complexity of pollen exposure for patients with allergic respiratory diseases.
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•eDNA analysis revealed peaks of airborne pollen from different grasses across a season.•Subtropical sites showed higher pollen eDNA reads from Chloridoid grasses than temperate zones.•Panicoid grasses were common in Australian subtropical and temperate sites.•Temperate sites showed higher pollen eDNA reads from Pooid grasses than subtropical zones.•Grass pollen eDNA compositions matched distributions of plant sighting records.
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•PCA is used to study the relationship between engine different parameters.•Multiple fuel blends are investigated using diesel, coconut biodiesel and triacetin.•Increases in the rate ...of pressure rise leads to increased primary particle diameter.•Soot particles reactivity increases with fuel oxygen content.•There is a strong correlation between AE signal and engine performance parameters.
Rising concerns over environmental and health issues of internal combustion engines, along with growing energy demands, have motivated investigation into alternative fuels derived from biomasses, such as biodiesel. Investigating engine and exhaust emission behaviour of such alternative fuels is vital in order to assess suitability for further utilisation. Since many parameters are relevant, an effective multivariate analysis tool is required to identify the underlying factors that affect the engine performance and exhaust emissions. This study utilises principal component analysis (PCA) to present a comprehensive correlation of various engine performance and emission parameters in a compression ignition engine using diesel, biodiesel and triacetin. The results show that structure-borne acoustic emission is strongly correlated with engine parameters. Brake specific NOx, primary particle diameter and fringe length increases by increasing the rate of pressure rise. Longer ignition delay and higher engine speeds can increase the nucleation particle emissions. Higher air-fuel equivalence ratio can increase the oxidative potential of the soot by increasing fringe distance and tortuosity. The availability of oxygen in the cylinder, from the intake air or fuel, can increase soot aggregate compactness. Fuel oxygen content reduces particle mass and particle number in the accumulation mode; however, they increase the proportion of oxygenated organic species. PCA results for particle chemical and physical characteristics show that soot particles reactivity increases with fuel oxygen content.
Allergic rhinitis affects half a billion people globally, including a fifth of the Australian population. As the foremost outdoor allergen source, ambient grass pollen exposure is likely to be ...altered by climate change. The AusPollen Partnership aimed to standardize pollen monitoring and examine broad-scale biogeographical and meteorological factors influencing interannual variation in seasonality of grass pollen aerobiology in Australia.
Daily airborne grass and other pollen concentrations in four eastern Australian cities separated by over 1700 km, were simultaneously monitored using Hirst-style samplers following the Australian Interim Pollen and Spore Monitoring Standard and Protocols over four seasons from 2016 to 2020. The grass seasonal pollen integral was determined. Gridded rainfall, temperature, and satellite-derived grassland sources up to 100 km from the monitoring site were analysed.
The complexity of grass pollen seasons was related to latitude with multiple major summer-autumn peaks in Brisbane, major spring and minor summer peaks in Sydney and Canberra, and single major spring peaks occurring in Melbourne. The subtropical site of Brisbane showed a higher proportion of grass out of total pollen than more temperate sites. The magnitude of the grass seasonal pollen integral was correlated with pasture greenness, rainfall and number of days over 30 °C, preceding and within the season, up to 100 km radii from monitoring sites.
Interannual fluctuations in Australian grass pollen season magnitude are strongly influenced by regional biogeography and both pre- and in-season weather. This first continental scale, Southern Hemisphere standardized aerobiology dataset forms the basis to track shifts in pollen seasonality, biodiversity and impacts on allergic respiratory diseases.
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•Few Southern Hemisphere sites monitor pollen limiting aerobiology knowledge. .•AusPollen partners (2016–2020) generated pollen records at four sites across climate zones.•Seasonal grass pollen loads varied with rainfall, temperature, and grassland greenness.•Outcomes underpin pollen forecasting and tracking of health and climate change impacts.
Savanna fires contribute significantly to global aerosol loading and hence to the Earth's radiative budget. Modeling of the climatic impact of these aerosols is made difficult due to a lack of ...knowledge of their size distribution. Australia is the third largest source of global carbon emissions from biomass burning, with emissions dominated by tropical savanna fires. Despite this, only a few previous studies have reported emission factors of trace gases from this important ecosystem and there are no previous published emission factors for the aerosol properties reported here for Australian savanna fires. In June 2014, the SAFIRED campaign (Savanna Fires in the Early Dry season) took place in the Northern Territory of Australia, with the purpose of investigating emissions and aging of aerosols from Australian savanna fires. This paper presents observed enhancement ratios and inferred emission factors of trace gases (CO2, CO, CH4, N2O, and gaseous elemental mercury), particles over different size modes (Aitken and accumulation), and speciated aerosols components (organics, sulfate, nitrate, ammonium, and chloride). Nine smoke events were identified from the data using large enhancements in CO and/or aerosol data to indicate biomass burning event. The results reported in this paper include the first emission factors for Aitken and accumulation mode aerosols from savanna fires, providing useful size information to enable better modeling of the climatic impact of this important source of global aerosols.
Key Points
First emission factors for Aitken and accumulation mode particles from savanna fires
First emission factors for speciated aerosols from Australian savanna fires
First emission factors for gaseous elemental mercury from Australian savanna fires
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