Open-field Burning Research Articles

LCA analysis on the management of typical lignocellulosic agricultural wastes: Case studies and comparison in Greece and China

Significant quantities of lignocellulosic agricultural residues are produced worldwide, and their management is quite problematic. In Greece and in general in the Mediterranean, large quantities of prunings are produced, especially from olive trees. The common practice of managing these residues is by burning them in the fields. On the other hand, in China, but also globally, huge amounts of residues are produced from cotton cultivation and efforts are being made to avoid the residues' usual burning in the fields. Beyond the development and refinement of energy and material utilization technologies for this waste, as well as the necessary economic analyses, very important for the scientific community is the study of the environmental impacts concerning the conventional management practices versus alternative ones that involve the wastes’ utilization.In this work and through the analysis of case studies in Greece and China for the management of the aforementioned typical lignocellulosic agricultural residues, comparative life cycle assessments of open-field burning practices versus energy production practices through gasification or pyrolysis are attempted. The results proved to be interesting and both cases agree with each other qualitatively despite the use of different tools and the application in different countries and agricultural residues. The comparative results highlight the need for immediate adoption of sustainable practices against the highly damaging conventional ones.

Enhancing carbon reduction and sustainable agriculture in Thailand: An assessment of rice straw utilization strategies

This research explores strategies for carbon reduction through the utilization of rice straw waste in Thailand, focusing on three project approaches: (1) converting rice straw into biomass fuel pellets for power plants, (2) transforming rice straw into biochar using high-tech systems and blending it with fertilizers, and (3) using conventional systems for biochar production. The study assesses the greenhouse gas (GHG) reduction potential of these approaches compared to traditional open-field burning of rice straw. The results indicate that Project 2, which involves high-tech biochar production, exhibits the highest potential for GHG reduction and carbon sequestration, with a potential to reduce emissions by approximately 12.19–13.05 MTCO2e/year. This approach also has potential for generating valuable carbon credits due to biochar’s long-term carbon sequestration and soil enhancement benefits. In contrast, Project 1 yields a reduction of about 4.06–4.35 MTCO2e/year, while Project 3 results in negative emission reduction. The study recommends prioritizing and incentivizing biochar production projects, upgrading low-tech systems, balancing the use of biomass fuel pellets, leveraging carbon credits for funding, and enhancing public awareness.

Variation in oxidative potential of fine particulate matter and its association with chemical constituents at a regional site in India

Fine particulate matter (PM2.5) constituents are greatly affected by site-specific emission sources and are one of the main reasons for oxidative stress that leads to cardiovascular ailments. This study investigated the temporal, seasonal, and episodic variations in the oxidative potential (OP) of PM2.5 and its association with chemical components. Additionally, we have also examined the effect of filter substrates on OP. Dithiothreitol (DTT) and ascorbic acid (AA) acellular assays were used to estimate the formation of reactive oxygen species (ROS) in PM2.5 samples collected over a year from a regional site in India. PM2.5 morphology and functional groups were also analyzed. Results showed that OPDTTv was at the highest in winter (2.56 ± 0.84 nmol min−1 m−3) and at the lowest during monsoon (0.79 ± 0.65 nmol min−1 m−3). OPAAv exhibited the highest activity in post-monsoon (0.09 ± 0.04 nmol min−1 m−3) and least in summer (0.05 ± 0.04 nmol min−1 m−3). Biomass burning (BB) and open-field burning of crop residue during the rabi and kharif harvesting seasons were associated with significantly elevated PM2.5 toxicity, which is indicative of the contribution of combustion-derived particles. OPDTTv and OPAAv levels from BB in post-monsoon were 21 % and 67 % higher than the levels observed during BB in summer. Flaky irregular agglomerates and porous structures were observed during the BB period. Fourier-transformed infrared spectroscopy revealed that traffic-emitted organic hydrocarbons CH functional group was dominant across the season. Further, chemical species such as organics (OC and EC fractions) and ions (SO42−, NH4+, Cl−, NO3−) were found to be significantly associated with OP. Among the three filter substrates, the Teflon showed higher OP variability for both assays. This study emphasizes the impact of regional toxic aerosols across seasons and during episodic events. It contributes to our understanding of the toxicity of ambient PM2.5, which is crucial for developing targeted air-quality management strategies.

A P-graph Approach for Planning Sustainable Rice Straw Management Networks

The Philippines produces up to 15.2 Mt of rice straw waste annually. Unmanaged rice straw waste disposal can lead to pollution from open field burning. On the other hand, rice straw agricultural waste can be used sustainably to produce valuable products such as mushrooms, fodder, pellets, or bioenergy, in a rice straw management system. Such systems can be optimized using Process Integration tools so that the raw materials are used efficiently at the maximum profit and with a minimal carbon footprint. The P-graph framework is an efficient Process Integration tool that solves Process Network Synthesis problems. A P-graph finds the optimal and suboptimal solutions for further analysis, which is useful in decision-making. This work developed a P-graph model for a rice straw management network considering the straw collection and storage steps and the production of both bioenergy and non-bioenergy products. The model can generate optimal and sub-optimal solutions (based on profit) and can simulate raw material disruption scenarios. The model is demonstrated through a case study on three rice straw fields with a maximum total rice straw yield of 96.84 t/yr. The case study considered the operating and raw material costs but did not consider the fixed and investment costs in the calculation of the profit. The results show that mushroom production using rice straw as substrate is the optimal solution with a potential profit of US$ 14 659.60/yr, followed by pellet production with a potential profit of US$ 12 627.90/yr. Disruption scenarios at reduced diesel, manual labor, and rice straw show that mushroom production is still the optimum solution, showing the robustness of the solution. This basic model shows that P-graphs can be applied to rice straw management networks to aid with decision-making for sustainability. Caution must be exercised as the results are context- and location- specific.

Development and performance evaluation of paddy straw based insulating block composite for low temperature storage application

The study focuses on the conversion of crop residues into thermal insulation materials, to gain better utility with value addition. Such applications will divert the paddy straw to useful purposes, leading to reduction in the open field burning of paddy straw in various developing countries. The process was optimized for manufacturing of insulating block composite and evaluating the mechanical and thermal performance of the same. Properties like compressive strength, internal bonding strength, density, porosity, and thermal conductivity were studied for the block. The optimum physical and mechanical properties were observed as moisture content 8–10 %, a block density 450–500 kg/m3, porosity 70 % with particle size of 8–15 mm. The mixture ratio of block was optimized as paddy straw 574.9 g, clay 840 g, and seed lac 260 g with thermal conductivity, compressive strength, bonding strength, and porosity as 0.08 W/m K, 1.19 MPa, 0.028 MPa, and 70.7 %, respectively, using Response Surface Methodology. An eco-friendly, economical and sustainable technological value addition for paddy straw was obtained and used for insulation purposes in cold storages as well as drying chambers. Paddy straw insulating block can also be utilized in combination with conventional insulation materials.

Mitigating agricultural residue burning: challenges and solutions across land classes in Punjab, India

Abstract India faces significant air quality challenges, contributing to local health and global climate concerns. Despite a national ban on agricultural residue burning and various incentive schemes, farmers in northern India continue to face difficulties in curbing open-field burning. Using data from 1021 farming households in rural Punjab in India, we examine the patterns and drivers of the adoption of no-burn agriculture, particularly for farmers who mulch instead of burning crop residue. We find a growing trend in no-burn farming practices among farmers between 2015 and 2017, with the highest adoption rates among large farmers compared to medium and small farmers. Our findings suggest that access to equipment and learning opportunities may increase the likelihood of farmers using straw as mulch instead of burning it. Specifically, social learning appears to increase the likelihood of farmers embracing no-burn practices relative to learning from extension agencies. Furthermore, the form of learning depends on farm size. While large and medium farmers exhibit a variety of learning strategies, small farmers primarily self-learn. These results underscore the importance of a multiprong policy that provides sufficient access to equipment and a combination of learning platforms that enabling farmers from different land classes to adopt no-burn technologies.

Advancing Energy Recovery from Sugarcane Leaf via Two-Stage Anaerobic Digestion for Hydrogen and Methane Production: Impacts on Greenhouse Gas Mitigation and Sustainable Energy Production

This study aims to enhance energy recovery from sugarcane leaf (SCL) through two-stage anaerobic digestion (TSAD) for hydrogen and methane production. The influence of hydraulic retention time (HRT) on this process was investigated. Optimal conditions established through batch experiments (5% total solids (TS) (w/v) and rice straw compost inoculum) were applied in semi-continuous stirred tank reactors (CSTR-H2 and CSTR-CH4). Remarkably, the highest production rates were achieved with HRTs of 5 days for CSTR-H2 (60.1 mL-H2/L·d) and 25 days for CSTR-CH4 (238.6 mL-CH4/L·d). Microbiological analysis by 16s rRNA sequencing identified Bacillus as predominant in CSTR-H2 followed by Lactobacillus and Clostridium. Utilizing SCL for TSAD could reduce greenhouse gas (GHG) emissions by 2.88 Mt-CO2 eq/year, compared to open-field burning, and mitigate emissions from fossil-fuel-based power plants by 228 kt-CO2 eq/year. This research underscores the potential of TSAD for efficient energy recovery and significant GHG emission reductions.

Opportunities for mitigating net system greenhouse gas emissions in Southeast Asian rice production: A systematic review

Southeast Asia (SEA) is a key producer and exporter of rice, accounting for around 28% of rice produced globally. To effectively mitigate greenhouse gas (GHG) emissions in SEA rice systems, field methane (CH4) and nitrous oxide (N2O) emissions have been intensively studied. However, an integrated assessment of system-level GHG emissions which includes other carbon (C) balance components, such as soil organic carbon (SOC) or energy use, that can positively or negatively influence the net capacity for climate change mitigation is lacking. We conducted a systematic review of published research in SEA rice systems to synthesize findings across four main components of net system emissions: (1) field GHG emissions, (2) energy inputs, (3) residue utilization beyond the field, and (4) SOC change. The objectives were to highlight effective mitigation opportunities and explore cross-component effects to identify tradeoffs and key knowledge gaps. Field GHG emissions were the largest contributor to net system emissions in agreement with existing scientific consensus, with results showing that practices such as floodwater drainage and residue removal are sound options for CH4 mitigation. On the other hand, increasing SOC potentially provides a large GHG mitigation opportunity, with long-term continuous rice cropping and practices such as residue incorporation and biochar application promoting SOC increase. A reduction in energy inputs was mainly achieved by optimizing agrochemical use, especially N fertilizers. For residue utilization beyond the field, GHG emission mitigation mainly came from preventing open field burning through residue removal. Removed residue can subsequently be used for producing energy that offsets GHG emissions associated with conventional fuel sources (e.g. fossil fuel-based electricity generation) or substituting material used in other production systems. Integrating all four components of net system emissions into one analysis underscores the following two main takeaways. First, the components of field GHG emissions and SOC change are the biggest opportunities for reducing net system emissions and need to be considered for effective climate change mitigation. Second, the reduction of C inputs through residue removal and increased soil aeration through multiple drainage will lower CH4 emissions but may also potentially decrease SOC stocks over time. Hence, we argue that future research needs to consider cross-component effects to optimize net system emissions, specifically the “stacking” of best management practices for mitigation related to field GHG emissions or SOC change in long-term experiments.

Shiitake spent mushroom substrate as a sustainable feedstock for developing highly efficient nitrogen-doped biochars for treatment of dye-contaminated water

Edible white-rot mushrooms are organisms that are cultivated at an industrial scale using wood-based substrates. The mushroom industry has an estimated annual production of 34 Mt of edible mushrooms, and approximately 70 wt% of the substrate is left as waste known as spent mushroom substrate (SMS). The huge volumes of SMS generated by mushroom farms hinder proper recycling, meaning that combustion or open-field burning are common disposal practices. This paper shows a concept that could help reduce the environmental impact of the mushroom industry. SMS from the cultivation of shiitake mushroom was used as a carbon precursor for the production of nitrogen-doped activated biochar that was used to remove reactive orange-16 (RO-16) azo dye from water, as well as contaminants from two synthetic effluents and real sewage water. Melamine was used as a nitrogen dopant and phosphoric acid as an activating agent. Samples without the addition of melamine were used for comparison. The doping/impregnation process was carried out in one-step, followed by pyrolysis at 700 and 900 °C for 1 h. BET, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used for the characterization of the biochars. The specific surface area of the doped samples was slightly lower, i.e., 1011 m2/g (SMS-700 °C), 810 m2/g (SMS-700 °C + N), 1095 m2/g (SMS-900 °C), and 943 m2/g (SMS-900 °C + N). Raman spectroscopic analysis showed that the N-doped biochars had more defective carbon structures than the non-doped ones. XPS analysis showed that doping with melamine led to the formation of N-functionalities on the surface of the biochar particles. The kinetics of adsorption were well represented by the Avrami model. The adsorption isotherms were well-fitted by the Liu model. The maximum adsorption capacities (qmax) of RO-16 were much higher for the N-doped biochars, i.e., 120 mg/g (SMS-700 °C), 216 mg/g (SMS-700 °C + N), 168 mg/g (SMS-900 °C), and 393 mg/g (SMS-900 °C + N). N-doped biochar samples were more effective for the removal of contaminants from synthetic effluents and sewage water. N-doped biochar produced at 900 °C showed good recyclability. This work concludes that SMS is a valuable waste that could be used for the production of activated carbon and that N-doping helped to improve the adsorption performance to a great extent.

Residue removal and nitrogen cycling in burn and non‐burn Kentucky bluegrass seed production systems

AbstractKentucky bluegrass (Poa pratensis L.) postharvest residue in northern Idaho has historically been burned to maintain stand life and profitability. Alternatives to open field burning are necessary to reduce adverse impacts of burning on air quality and several have been proposed. However, limited information is available on the impact of residue management on residue removal and nitrogen cycling. In this study, the impact of residue management on residue nutrient dynamics and nitrogen availability was evaluated within replicated full load burn (FLB), bale then burn (BB), bale then mow then harrow (BMH), and system (SYST) (BMH year 1, BB year 2, and FLB year 3) plots in Kootenai County, ID from 2002 to 2006. Standing and non‐standing residues were measured immediately following grass seed harvest and periodically thereafter in each plot. Averaged across years, non‐standing residue (thatch) removal ranged from −13% in BMH to 61% in FLB, and removal of standing biomass ranged from 6% in BMH to 92% in FLB. The combined removal of both non‐standing and standing residue was 18% with BMH, 57% with SYST, 69% with BB, and 75% with FLB. Plant N uptake ranged from 53 kg N ha−1 in FLB in 2006 to 131 in SYST (BMH) in 2003 and nitrogen use efficiency, calculated using partial factor productivity formula, ranged from 0.6 to 5.8 kg bluegrass seed per kg N fertilizer. Mean NO3−–N concentrations from lysimeters 10‐cm deep were 14 mg NO3−–N L−1 in FLB, 12 mg NO3−–N L−1 in BB, and 6 mg NO3−–N L−1 in BMH treatments for years 2003–2006. Greater concentrations of NO3−–N in burn treatments were available for plant uptake or leaching compared to the BMH treatment. The data indicate that the efficacy of any residue management system will vary from year to year and impact seed production in the following year. Nitrogen availability varied across residue management systems, suggesting N fertilizer product, rate, and timing to optimize N use efficiency may also need to vary.

Trends of source apportioned PM2.5 in Tianjin over 2013–2019: Impacts of Clean Air Actions

A long-term (2013–2019) PM2.5 speciation dataset measured in Tianjin, the largest industrial city in northern China, was analyzed with dispersion normalized positive matrix factorization (DN-PMF). The trends of source apportioned PM2.5 were used to assess the effectiveness of source-specific control policies and measures in support of the two China's Clean Air Actions implemented nationwide in 2013–2017 and 2018–2020, respectively. Eight sources were resolved from the DN-PMF analysis: coal combustion (CC), biomass burning (BB), vehicular emissions, dust, steelmaking and galvanizing emissions, a mixed sulfate-rich factor and secondary nitrate. After adjustment for meteorological fluctuations, a substantial improvement in PM2.5 air quality was observed in Tianjin with decreases in PM2.5 at an annual rate of 6.6%/y. PM2.5 from CC decreased by 4.1%/y. The reductions in SO2 concentration, PM2.5 contributed by CC, and sulfate demonstrated the improved control of CC-related emissions and fuel quality. Policies aimed at eliminating winter-heating pollution have had substantial success as shown by reduced heating-related SO2, CC, and sulfate from 2013 to 2019. The two industrial source types showed sharp drops after the 2013 mandated controls went into effect to phaseout outdated iron/steel production and enforce tighter emission standards for these industries. BB reduced significantly by 2016 and remained low due to the no open field burning policy. Vehicular emissions and road/soil dust declined over the Action's first phase followed by positive upward trends, showing that further emission controls are needed. Nitrate concentrations remained constant although NOX emissions dropped significantly. The lack of a decrease in nitrate may result from increased ammonia emissions from enhanced vehicular NOX controls. The port and shipping emissions were evident implying their impacts on coastal air quality. These results affirm the effectiveness of the Clean Air Actions in reducing primary anthropogenic emissions. However, further emission reductions are needed to meet global health-based air quality standards.

A sustainable approach for soil amendment; available plant nutrients in rice straws

The main aim of this study is to estimate the potential of mitigating the soil degradation by the utilization of rice straws, In every crop huge quantity of crop residue is generated along with the food grains. Only small part of the crop residue is used as cattle feed and other applications, significant quantity of these crop residues are either left unutilized or disposed by means of open field burning by the farmers, because other disposal options are not economically viable for the farmers. Consequences of open field burning of crop residues in India are, contribution of particulate matter in the atmosphere, emission of CO2, CO, NH3, NOx, SOx, and smog. On burning of crop residue heat produced is also accounted for the damage of microbes and other nutrients also present on the top layer of the soil, loss of organic carbon; it adversely affects soil fertility and productivity. It has a great economic potential as it contains high carbon content and significant amount of other essential plant nutrients which are required for plant growth. Sun dried rice straw samples were collected and analysed for primary nutrients (C, H, S, N, P2O5 and K2O) required for plant growth. Moisture content was 11.70%, Elemental analysis of paddy straw on dry basis was found C = 36.04%, H = 5.25%, S = 0.28% & N = 0.69% P2O5 = 0.43% and K2O = 0.64% in the kharif season 2021. These elements were quantified by using different advanced analytical techniques.

Feasibility of 10 MW Biomass-Fired Power Plant Used Rice Straw in Cambodia

This study investigates the feasibility of rice straw for energy production in Cambodia. The potential areas for a 10 MW biomass-fired power plant installation are estimated based on rice straw availability displayed in a graphic information system (GIS). The discounted cash flow (DCF) method on the profitability index (PI) was executed by Mathlab software, which was used to determine the period of the power plant profitability. The reduction of CO and CO2 emissions from the proposed rice straw biomass-fired power plant with 10 MW capacity was calculated and compared with the coal-fired power plant and open field burning. Prey Veng, Takeo, and Battambang are potential provinces that have an estimated rice straw source of 804,796 t/annum, 720,040 t/annum, and 603,273 t/annum, respectively. Within a 20-year project, the biomass-fired power plant can reach profitability between six and ten years with the operation of the rice-straw price of 20 USD/t to 40 USD/t. The total energy produced by these potential areas is 1251 GWh/annum, with a CO2 emission avoidance of 1.06 million t/annum compared to the coal-fired power plant operation. Simultaneously, the emission savings of the biomass-fired power plant compared to open-field burning are 0.61 million t/annum of CO2 and 0.02 million t/annum of CO in the study site. The findings are prospectively essential for further designing of a small-scale biomass-fired power plant in Cambodia.

Characterisation, function and emission free pyrolysis of agricultural residue

Huge quantity of agricultural residues is disposed by open field burning (OFB) in India. It gives to an adverse condition in the atmosphere. To prevent it, a pyrolyser, is used in this study. Dry leaves, paddy straw and corn straw are burnt separately in OFB and in pyrolyser. The biomass decomposition thermally at 450°C is standardised in the pyrolyser. The carbon dioxide, carbon monoxide, nitrogen oxide, sulphur dioxide and particulate matter are considerably reduced at pyorlyser burning. Thirty percent of agricultural residue is converted into biochar which can be used to retain nutrients in the soil and carbon sequestration.

Comparison of GHG emissions from open field burning and anaerobic digestion of rice straw

ABSTRACT Rice straw (RS) has been burned in open fields in many countries, which is a growing environmental concern. Anaerobic digestion (AD) of RS is one of the sustainable alternatives to open burning of RS for converting the biomass into methane, carbon dioxide, and digestate for use as agricultural manure. The present study evaluates the RS generation, use patterns, and greenhouse gas emissions from open field burning and the AD of RS. Results indicate the AD of RS offers greater environmental benefits than that by RS open field burning. As a result of the open burning of RS in India emitted 592032.52 kg of CO2 equivalents/kg per year, whereas AD of RS contributes 122.86 kg of CO2 equivalents/kg per year. If RS were burned in an open field, its Global Warming Potential would be 493,873 times greater than that of AD. By minimizing GHG emissions and creating sustainable energy from waste, sustainable development, and circular economies are achieved.

Opportunities beyond CO2 for climate mitigation

Opportunities beyond CO2 for climate mitigation

Rapid decomposition of rice straw by application of a novel microbial consortium and study its microbial community dynamics.

Rice straw decomposition is an attractive solution to open-field burning but the traditional method has slow kinetics and takes 60-90days to obtain mature compost. In this study, we propose to boost up the decomposition process by addition of a novel microbial consortium rich in lignocellulolytic microbes. C: N ratio of the compost reached 11.69% and degradation efficiency of cellulose and hemicellulose was found to be 64 and 87% respectively within 25days. Lignocellulolytic activity of the microbial consortium was confirmed by plate and activity assay. These parameters clearly indicated that a mature compost was obtained in 25days. The 16S rRNA gene amplicon sequencing and functional analysis of predicted genes indicated amino acid and carbohydrate metabolism as the major metabolic pathway during composting. The tertiary level of functional analysis revealed the major metabolic pathways in the bacterial communities as pentose phosphate pathway, glycolysis and tricarboxylic acid cycle.

Feasibility study of prescribed burning for crop residues based on urban air quality assessment.

Open field burning of crop residue has been intentionally prohibited due to the undesired air pollution in urban regions. To better balance the urban environment and agricultural activity, this paper conducted a feasibility study of prescribed burning for crop residues based on air quality assessment in urban regions. Firstly, emission inventories were established using the top-down approach based on designed sub-regional fire as prescribed burning. Subsequently, the air qualities in urban regions were simulated by the coupled Weather Research and Forecasting Model-Community Multi-scale Air Quality Model (WRF-CMAQ) covering different sensitivity experiments. Finally, PM2.5 is selected as the main indicator of air quality, and the feasibility was assessed by controlling the factors influencing the diffusion of pollutants from prescribed burning, including burning ratio, meteorological factors (wind speed and direction), distance from burning area and burning duration. It is revealed that prescribed burning would achieve highly efficient disposal of crop residues under the premise of ensuring the air quality in urban regions by controlling the factors. Results in the study can be further exploited for designing burning scheme for crop residue, which is expected to promote a sustainable development of agriculture and urban environment.

1H NMR structural signatures of source and atmospheric organic aerosols in India.

Organic aerosols (OA) play significant roles in several atmospheric processes and adversely impact human health. This study examines the key structural units present in water- and methanol-soluble organic carbon (WSOC, MSOC) fraction of OA from emission sources (traffic and biomass cooking) and an urban background location in India. Proton nuclear magnetic resonance (1H NMR) spectroscopy was employed to assess the distribution of non-exchangeable proton structural groups of the OAs. Organic carbon, elemental carbon, black carbon, and water-soluble organic carbon (WSOC) analyses were also conducted. The 1H NMR analysis corroborated that the WSOC and MSOC fractions hold similar 1H structural groups; however, they differ in their relative distribution and absolute concentrations across the ambient locations and source emissions. The relative contribution of the proton structural groups to OA was in the order C-H>H-C-C=> H-C-O>Ar-H. The aliphatic concentration was lower in the morning tunnel entry aerosols when compared to other tunnel aerosols, whereas the unsaturated structures (H-C-C=) were present in all the tunnel aerosols within a range of 47.2-62.3μmol/m3. The aromatic groups were the maximum in the firewood aerosols, about 1.4 and 3.7 times higher than the crop residue and the mixed fuel aerosols, respectively. The total functional groups, i.e., the sum of all the observed groups, significantly correlated with C-H (r=0.96) and WSOC (r=0.7), suggesting the higher contribution of aliphatic groups in the WSOC fraction. WSOC examined in this study fits well in the established 1H NMR source identification fingerprints of urban aerosols. However, biomass cooking aerosols do not fit the established biomass burning organic aerosols (BBOAs) boundaries, exhibiting a smaller relative contribution of carbon-oxygen double bonds and a less oxidised character than open-field burning. Our results provide essential insights into the nature of urban atmospheric, near-traffic and biomass cooking OAs in India.

Carbonaceous gas and aerosol emissions from biomass burning in China from 2012 to 2021

Open biomass burning (OBB) has significant impacts on air pollution, human health, and climate change. In recent years, the issue of OBB has been the subject of increasing research. However, the emissions of carbonaceous gases and aerosols (CGA) from OBB have received less attention, and the spatiotemporal characteristics and emissions of CGA remain poorly understood. In this study, an optimized Fire Radiative Power (FRP) algorithm was used to estimate the emissions of CGA from OBB in China. Then the spatiotemporal characteristics of CGA emissions from OBB across China from 2012 to 2021 were assessed. The results show that the annual average emissions of CGA in China from 2012 to 2021 were 239.74 Mt. The spatial distribution of CGA from OBB in China is concentrated in the Northeast, North, Southwest, and East regions. Across the study period, the trend of total national emissions was first increasing then decreasing, with a maximum in 2014, and a minimum in 2018. Emissions of CGA between 2012 and 2021 were dominated by the combustion of residues in agricultural land, which accounted for 50–65% of total CGA emissions. Crop residues open field burning and burning ban were also the main reason for the sharp increase of CGA in 2014 and dramatically reduced to a minimum in 2018. The study provides new insights into OBB and carbon neutrality. The results provide valuable information for stakeholders, allowing for the implementation of effective regional policies to reduce emissions of CGA in China.