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We characterised trace gas emissions from Australian temperate forest fires through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for temperate forest fires elsewhere (North America) and for fires in another dominant Australian ecosystem (savanna) and find significant differences in both cases. Indeed, we find that although the emission factors of some species agree within 20%, including those of hydrogen cyanide, ethene, methanol, formaldehyde and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes, ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

Southeast Asia experiences frequent fires in fuel-rich tropical peatlands, leading to extreme episodes of regional haze with high concentrations of fine particulate matter (PM 2.5 ) impacting human health. In a study published recently, the first field measurements of PM 2.5 emission factors for tropical peat fires showed larger emissions than from other fuel types. Here we report even higher PM 2.5 emission factors, measured at newly ignited peat fires in Malaysia, suggesting that current estimates of fine particulate emissions from peat fires may be underestimated by a factor of 3 or more. In addition, we use both field and laboratory measurements of burning peat to provide the first mechanistic explanation for the high variability in PM 2.5 emission factors, demonstrating that buildup of a surface ash layer causes the emissions of PM 2.5 to decrease as the peat fire progresses. This finding implies that peat fires are more hazardous (in terms of aerosol emissions) when first ignited than when still burning many days later. Varying emission factors for PM 2.5 also have implications for our ability to correctly model the climate and air quality impacts downwind of the peat fires. For modelers able to implement a time-varying emission factor, we recommend an emission factor for PM 2.5 from newly ignited tropical peat fires of 58 g of PM 2.5 per kilogram of dry fuel consumed (g/kg), reducing exponentially at a rate of 9%/day. If the age of the fire is unknown or only a single value may be used, we recommend an average value of 24 g/kg.

Savanna fires contribute approximately 40–50% of total global annual biomass burning carbon emissions. Recent comparisons of emission factors from different savanna regions have highlighted the need for a regional approach to emission factor development, and better assessment of the drivers of the temporal and spatial variation in emission factors. This paper describes the results of open-path Fourier transform infrared (OP-FTIR) spectroscopic field measurements at 21 fires occurring in the tropical savannas of the Northern~Territory, Australia, within different vegetation assemblages and at different stages of the dry season. Spectra of infrared light passing through a long (22–70 m) open-path through ground-level smoke released from these fires were collected using an infrared lamp and a field-portable FTIR system. The IR spectra were used to retrieve the mole fractions of 14 different gases present within the smoke, and these measurements used to calculate the emission ratios and emission factors of the various gases emitted by the burning. Only a handful of previous emission factor measures are available specifically for the tropical savannas of Australia and here we present the first reported emission factors for methanol, acetic acid, and formic acid for this biome. Given the relatively large sample size, it was possible to study the potential causes of the within-biome variation of the derived emission factors. We find that the emission factors vary substantially between different savanna vegetation assemblages; with a majority of this variation being mirrored by variations in the modified combustion efficiency (MCE) of different vegetation classes. We conclude that a significant majority of the variation in the emission factor for trace gases can be explained by MCE, irrespective of vegetation class, as illustrated by variations in the calculated methane emission factor for different vegetation classes using data sub-set by different combustion e

Current good practice guidelines for national greenhouse gas inventories requires that seasonal variation in emission factors from savanna fires be considered when compiling national accounts. African studies concluded that the emission factor for methane decreases during the dry season principally due to curing of the fuels. However, available data from Australian tropical savannas shows no effect of seasonality on emission factors, consistent with observations that the fine fuels appear to cure fully soon after the start of the fire season. To test whether the seasonality in greenhouse gas emission factors reported for Africa also occurs in Australia, methane and nitrous oxide emission factors were measured in early and in late dry season fires in Western Arnhem Land, a region typical of much of the northern Australia savanna zone. We found no significant seasonality in methane emission factors, but there was substantial variation in emission factors associated with inter-fire differences in vegetation and fuel. This variation could be explained almost completely by combustion efficiency. Nitrous oxide emission factors were not related to combustion efficiency but showed some variation across vegetation and fuel size class. Both methane and nitrous oxide emission factors were consistent with previous work in northern Australia and with some published values from Africa. The absence of a significant seasonal trend in emission factors indicates that savanna fire emissions in northern Australia can be managed by strategic prescribed burning.

When compared to established point-samplingmethods, Open-Path Fourier Transform Infrared (OP-FTIR)spectroscopy can provide path-integrated concentrations ofmultiple gases simultaneously, in situ and near-continuously.The trace gas pathlength amounts can be retrieved from themeasured IR spectra using a forward model coupled to anon-linear least squares fitting procedure, without requiring¿background¿ spectral measurements unaffected by the gasesof interest. However, few studies have investigated the accuracyof such retrievals for CO2, CH4 and CO, particularlyacross broad concentration ranges covering those characteristicof ambient to highly polluted air (e.g. from biomassburning or industrial plumes). Here we perform such an assessmentusing data collected by a field-portable FTIR spectrometer.The FTIR was positioned to view a fixed IR sourceplaced at the other end of an IR-transparent cell filled withthe gases of interest, whose target concentrations were variedby more than two orders of magnitude. Retrievals madeusing the model are complicated by absorption line pressurebroadening, the effects of temperature on absorption bandshape, and by convolution of the gas absorption lines and theinstrument line shape (ILS). Despite this, with careful modelparameterisation (i.e. the optimum wavenumber range, ILS,and assumed gas temperature and pressure for the retrieval),concentrations for all target gases were able to be retrievedto within 5%. Sensitivity to the aforementioned model inputswas also investigated. CO retrievals were shown to be most sensitive to the ILS (a function of the assumed instrumentfield-of-view), which is due to the narrow nature of COabsorption lines and their consequent sensitivity to convolutionwith the ILS. Conversely, CO2 retrievals were most sensitiveto assumed atmospheric parameters, particularly gastemperature. Our findings provide confidence that FTIRderivedtrace gas retrievals of CO2, CH4 and CO based onmodeling can yield results with high acc

In the last three decades, a new ‘haze season’ has emerged in Indonesian, Malaysian, and Singaporean societies to signify the recurring air pollution episode caused by the widespread burning of tropical peatlands. This study delves into the discursive framework of ‘seasonality’ surrounding the societal perception and response to haze, exploring ‘haze season’ as an adaptation context and ‘haze’ as a mitigation strategy. Deploying a three-step methodology, this paper identifies and analyses key storylines used by various political actors to attribute meaning to haze, namely (1) ‘it keeps coming back’, (2) ‘it will go away’, and (3) ‘it is normal’. Different political actors deploy these storylines for distinct purposes. The objectives of storyline deployment align mostly between governments and corporations seeking to explain, legitimise, and detract from mitigation inefficiencies and adaptation inadequacies, with civil society organisations being the sole challenges and critique of this patronage network structures, where governments and companies tolerate unsustainable agroforestry practices leading to haze. The study underscores the significance of understanding the politics involved in constructing ‘seasons of the Anthropocene’. Divergent framing of seasonality by different actors reveals the underlying mechanisms influencing environmental change mitigation and adaptation. The construction of Anthropocene seasons can be a double-edged sword, with familiarisation enhancing societal preparedness, while normalisation can lead to desensitisation and inertia towards mitigation. Untangling the divergent pathways of politicising Anthropocene seasonalities holds the key to determining whether and how societies can build a ‘liveable future’. By grasping the dynamics of the ‘haze season’ discourse, we can project effective environmental action and address the challenges posed by recurring haze episodes.

Last week New York City was shrouded in smoke from wildfires nearly 2,000 kilometres away in Quebec, Canada, bringing the attention of global media. Thomas Smith writes that while forest fires in Canada are not unusual, they have begun unusually early, likely due to an unseasonal heatwave experienced by much of northern Canada. He argues that fossil-fuel induced climate change and irresponsible land management practices are driving more extreme, larger and more destructive fires, and that we should expect a devastating fire season in Canada and more smoke episodes downwind.

The widespread burning of tropical peatlands across regions of Malaysia and Indonesia is now considered an annual event in equatorial Southeast Asia. The fires cause poor air quality (‘haze’) across the region, affecting the health of millions, but little has been written about how people in Southeast Asia make sense of this recurring phenomenon. In this paper, we investigate the emergent social construction of the ‘haze season’. Borrowing from anthropology literature, we define ‘seasons’ as a social construct that enables societies to organise their livelihoods around the expectation of recurring phenomena. The construction of ‘haze season’, in turn, reflects ongoing deliberation and contestation of the societal perception of and reaction to the causes and effects of haze. To do that, we analysed more than 35,000 news articles published in Indonesia, Malaysia and Singapore to investigate the timing of haze season reporting and key themes associated with the season. Deploying keyness analysis and structural topic modelling (STM), we find a strong distinction between the themes of articles written about the ‘haze season’ and articles that simply refer to the haze problem alone. Articles that mention ‘haze’ but not ‘haze season’ focus on the root causes of the haze crisis – peatland fires in Indonesia, oil palm plantations, deforestation – as well as geopolitical cooperation to prevent fires (e.g., through ASEAN). We found that the ‘haze season’ articles have a strong association with the effects of the haze crisis, particularly during the haze season months (June to October), suggesting that seasonality plays a role in adaptation behaviour. Outside of the haze season months, articles focus more on haze mitigation and associated political action. As a season that has emerged entirely as the result of human activity, affecting hundreds of millions of people over a spatial extent of millions of square kilometres, we argue that the ‘haze season’ is a ‘Season of the Anthr

Even though there is an increased understanding that the haze issue is anthropogenic, as the haze season becomes increasingly normalised (more severe one year and less so the other, but taken as a given), society may “forget” that haze is anthropogenic and hence avoidable. This storyline thus may also contribute to absolving governments of responsibility or pressure to act, writes Helena Varkkey, Felicia Liu, and Tom Smith

Repeat observations underpin our understanding of environmental processes, but financial constraints often limit scientists’ ability to deploy dense networks of conventional commercial instrumentation. Rapid growth in the Internet-Of-Things (IoT) and the maker movement is paving the way for low-cost electronic sensors to transform global environmental monitoring. Accessible and inexpensive sensor construction is also fostering exciting opportunities for citizen science and participatory research. Drawing on 6 years of developmental work with Arduino-based open-source hardware and software, extensive laboratory and field testing, and incor- poration of such technology into active research programmes, we outline a series of successes, failures and lessons learned in designing and deploying environmental sensors. Six case studies are presented: a water table depth probe, air and water quality sensors, multi-parameter weather stations, a time-sequencing lake sediment trap, and a sonic anemometer for monitoring sand transport. Schematics, code and purchasing guidance to reproduce our sensors are described in the paper, with detailed build instructions hosted on our King’s College London Geography Environmental Sensors Github repository and the FreeStation project website. We show in each case study that manual design and construction can produce research-grade scientific instrumentation (mean bias error for calibrated sensors –0.04 to 23%) for a fraction of the conventional cost, provided rigorous, sensor-specific calibration and field testing is conducted. In sharing our collective experiences with build-it- yourself environmental monitoring, we intend for this paper to act as a catalyst for physical geographers and the wider environmental science community to begin incorporating low-cost sensor development into their research activities. The capacity to deploy denser sensor networks should ultimately lead to superior envi- ronmental monitoring at the local to global sc

This paper presents an autoethnographic study which tracks the experience of routinely monitoring personal exposure to air pollution, using Plume Labs' “Flow” device. While conventional air quality data is provided by static monitoring stations, this paper seeks to understand how new intimate data from portable sensors can influence decision-making and induce behavioural change. This is explored in relation to self-tracking and the “Quantified Self” (QS) movement, recognising that the environment is intrinsically part of the self and the body. Through autoethnography and reflecting on experiences in London and Kuala Lumpur, this paper explores the practicalities of using Flow and its potential as a transformative tool to facilitate societal consciousness and change towards “the optimal self” with minimised exposure to air pollution. Through personal experience and interactions with others, this paper finds that individuals' willingness and ability to attempt to minimise exposure to air pollution is subject to a combination of factors within and beyond one's control. However, while self-tracking does not necessarily translate into attempts to minimise exposure, choosing to be exposed to higher levels of air pollution in certain circumstances becomes an active decision. While some maintained their scepticism of Flow's potential, and others remained apathetic towards air pollution, Flow was found to be particularly effective in cultivating curiosity and consciousness through its facilitation of conversations about air quality. Flow's provision of otherwise absent information and its potential to create a network of better-informed individuals is exciting but uncertain. This paper raises important questions about the role of the QS and such sensor devices in addressing urban air pollution and creating a sense of collective accountability to the environment, moving towards a new goal of “the optimal environment for our optimal selves.”.

This article analyses the denialist narratives of the negative environmental impact of oil palm plantations on tropical peat by the media of Indonesia, Malaysia and Singapore. Specifically, we focus on media coverage of the 2016 International Peat Congress, where scientifically misleading claims that it is sustainable to develop oil palm plantations on tropical peatlands were made. We found that media reporting of the denialist narrative is more prevalent than that of the peer-reviewed science consensus-view that plantations on tropical peat could cause excessive greenhouse gas emissions and enhance the risk of fires. Four mutually complementary narratives were used by Indonesian and Malaysian media to construe denialism, which closely resemble the four climate denialist narratives identified by Elsasser and Dunlap (2013). These denialist narratives draw heavily upon information advocated by divergent knowledge communities (Goldstein 2016) and appeal to a nationalist sentiment of ‘us’ - palm oil-producing developing countries - and ‘them’ - western developed countries producing research critical of the industry. The Malaysian press has most extensively deployed this nationalistic sentiment, whereas the Singaporean media has not actively endorsed or rejected any of the denialist narratives. Our findings suggests that media representation of the issue is a reflection of an amalgamation of economic, diplomatic and nationalistic concerns, determined by political, socio-cultural nuances specific to each country. Importantly, our article alerts to the continuation of unsustainable practices as justified by the media to the public, and that the prevalence of these denialist narratives constitute a significant obstacle in resolving pressing issues such as transboundary haze, biodiversity loss, and land-use change related greenhouse gas emissions in Southeast Asia.

Peat fires are a global-scale source of carbon emissions and a leading cause of regional air quality deterioration, especially in Southeast Asia. The ignition and spread of peat fires are strongly affected by moisture, which acts as an energy sink. However, moisture effects on peat fire emissions are poorly understood in the literature. Here we present the first experimental work to investigate transient gas and particle emissions for a wide range of peat moisture contents (MCs). We include drying, ignition, smouldering spread, and even flaming stages. Peat samples conditioned to different MCs were burnt in the laboratory where a suite of diagnostics simultaneously measured mass loss rate, temperature profiles, real-time concentration of 20 gas species, and size-fractioned particle mass. It was found that MC affects emissions, in addition to peat burning dynamics. An increase in MC below a smouldering threshold of 160% in dry basis leads to a decrease in NH 3 and greenhouse gas emissions, including CO 2 and CH 4. The burning of wet peat emits more coarse particles (between 1 and 10 µm) than dry peat, especially during the ignition stage. In contrast, flaming stage emits mostly soot particles less than 1 µm, and releases 100% more fully oxidised gas species including CO 2, NO 2 and SO 2 than smouldering. The examination of the resulting modified combustion efficiency (MCE) reveals that it fails to recongnise smouldering combustion with sufficient accuracy, especially for wet peat with MC > 120%. MCE confuses drying and flaming, and has significant variations during the ignition stage. As a result, MCE is not valid as a universal fire mode indicator used in the field. This work fills the knowledge gap between moisture and emissions, and provides a better understanding which can help mitigate peat fires.

We characterised trace gas emissions from Australian temperate forest fires through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for temperate forest fires elsewhere (North America) and for fires in another dominant Australian ecosystem (savanna) and find significant differences in both cases. Indeed, we find that although the emission factors of some species agree within 20 %, including those of hydrogen cyanide, ethene, methanol, formaldehyde and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes, ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

Southeast Asia experiences frequent fires in fuel‐rich tropical peatlands, leading to extreme episodes of regional haze with high concentrations of fine particulate matter (PM2.5) impacting human health. In a study published recently, the first field measurements of PM2.5 emission factors for tropical peat fires showed larger emissions than from other fuel types. Here we report even higher PM2.5 emissions factors, measured at newly ignited peat fires in Malaysia, suggesting current estimates of fine particulate emissions from peat fires, may be underestimated by a factor of three or more. In addition, we use both field and laboratory measurements of burning peat to provide the first mechanistic explanation for the high variability in PM2.5 emission factors, demonstrating that build‐up of a surface ash layer causes the emissions of PM2.5 to decrease as the peat fire progresses. This finding implies that peat fires are more hazardous (in terms of aerosol emissions) when first ignited than when still burning many days later. Varying emission factors for PM2.5 also has implications for our ability to correctly model the climate and air quality impacts downwind of the peat fires. For modelers able to implement a time varying emission factor, we recommend an emission factor for PM2.5 from newly ignited tropical peat fires of 58 grams of PM2.5 per kilogram of dry fuel consumed (g.kg‐1), reducing exponentially at a rate of 9% per day. If the age of the fire is unknown or only a single value may be used, we recommend an average value of 28 g.kg‐1. Plain Language Summary This paper provides evidence that peat fire emissions of fine particulates are much larger than for other fires when the peat is newly ignited but decrease rapid as the fire progresses. This is important because it means that newly ignited fires are particularly detrimental to ambient air quality in impacted regions.

Smouldering peat fires, the largest fires on Earth in terms of fuel consumption, are reported in six continents and are responsible for regional haze episodes. Haze is the large scale accumulation of smoke at low altitudes in the atmosphere. It deteriorates air quality, disrupts transportation and causes health emergencies. Research on peat emissions and haze is modest at best and many key aspects remain poorly understood. Here, we compile an up-to-date inter-study of peat fire emission factors (EFs) in the literature both from laboratory and field studies. Tropical peat fires present larger EFs for the prominent carbon gas species than boreal and temperate peat fires, possibly due to the higher fuel carbon content (56.0% vs. 44.2%). In contrast, tropical peat fires present slightly lower PM2.5 EFs for unknown reasons but probably related to combustion dynamics. An analysis of the modified combustion efficiency, a parameter widely used for determining the combustion regime of wildfires, shows it is partially misunderstood and highly sensitive to unknown field variables. This is the first review on smouldering peat emissions and haze. Our integration of the existing literature, allows for the identification of existing gaps in knowledge and is expected to accelerate progress towards mitigation strategies.

Fires in tropical peatlands account for >25% of estimated total greenhouse gas emissions from deforestation and degradation. Despite significant global and regional impacts, our understanding of specific gaseous fire emission factors (EFs) from tropical peat burning is limited to a handful of studies. Furthermore, there is substantial variability in EFs between sampled fires and/or studies. For example, methane EFs vary by 91% between studies. Here we present new fire EFs for the tropical peatland ecosystem; the first EFs measured for Malaysian peatlands, and only the second comprehensive study of EFs in this crucial environment. During August 2015 (under El Niño conditions) and July 2016, we embarked on field campaigns to measure gaseous emissions at multiple peatland fires burning on deforested land in Southeast Pahang (2015) and oil palm plantations in North Selangor (2016), Peninsula Malaysia. Gaseous emissions were measured using open-path Fourier transform infrared spectroscopy. The IR spectra were used to retrieve mole fractions of 12 different gases present within the smoke (including carbon dioxide and methane), and these measurements used to calculate EFs. Peat samples were taken at each burn site for physicochemical analysis and to explore possible relationships between specific physicochemical properties and fire EFs. Here we present the first evidence to indicate that substrate bulk density affects methane fire EFs reported here. This novel explanation of interplume, within-biome variability, should be considered by those undertaking greenhouse gas accounting and haze forecasting in this region and is of importance to peatland management, particularly with respect to artificial compaction.