Fresh bell peppers consumed in cities: Unveiling the environmental impact of urban and rural food supply systems.

Agriculture and its supply chain pose significant environmental threats. This study employs Life Cycle Assessment (LCA) to explore the environmental impact of fresh bell pepper production and distribution, comparing Urban and Peri-Urban Agriculture (UPA) with Rural Long-Distance Food Supply Systems (RLDFS). Four UPA scenarios (hydroponics, soil-based greenhouse, open-field conventional, and organic) and two RLDFS scenarios (soil-based greenhouse and open-field conventional) are evaluated using SimaPro, incorporating inputs from UPA practitioners and rural farmers. Results reveal an energy demand range of 0.011 to 5.5 kWh/kg eq., with urban greenhouses exhibiting the lowest consumption and hydroponics the highest due to lighting, ventilation, and irrigation. Hydroponics exhibits a global warming potential of 7.24 kg of CO2 eq·kg-1, with energy demand contributing over 95 %, surpassing other scenarios by 7-25 times, necessitating reduction for sustainability. RLDFS's environmental impact is dominated by transportation (over 70 %), meanwhile other UPA systems are influenced by irrigation, infrastructure, and fertilizers. Despite challenges, UPA-hydroponics proves to be 1.7 to 4.3 times more land-use-efficient than other scenarios, emphasizing its potential. The study highlights the need to address electricity usage in UPA-hydroponics for carbon footprint reduction. Despite challenges, hydroponics could contribute to sustainable food security, and RLDFS does not significantly lag in environmental performance compared to UPA other than Ozone layer depletion criteria attributed to fossil fuel usage in transportation. These insights offer valuable guidance for urban development and policy formulation, promoting sustainable agricultural practices and supporting policies for agronomic and supply chain sustainability.

Evaluation of ganglion cell-inner plexiform layer thickness in the diagnosis of pre-perimetric glaucoma and comparison to retinal nerve fiber layers.

PURPOSE: Evaluation of ganglion cell-inner plexiform layer thickness in the diagnosis of pre-perimetric glaucoma (PPG) and comparison to retinal nerve fiber layers. METHODS: This study was a prospective hospital-based study. A total of 30 PPG and control patients were studied for retinal nerve fiber layer thickness (RNFL) and ganglion cell-inner plexiform layer complex (GC-IPL) by spectral-domain optical coherence tomography. PPG was defined as eyes with a normal visual field and one or more localized RNFL defects that were associated with a typical glaucomatous disc appearance. Diagnostic abilities of GC-IPL, optic nerve head (ONH), and RNFL parameters were computed using area under receiver-operating curve (AUROC), sensitivity, and specificity. RESULTS: GC-IPL parameters showed significant changes in PPG cases as compared to normal subjects in each region ( P value < 0.001). RNFL parameters also differed significantly from normal subjects in all quadrants ( P value 0.003 to < 0.001). Within GC-IPL parameters, the superotemporal region had the maximum area under the curve (AUC), followed by inferior, superior, and inferotemporal regions. Within RNFL parameters, the inferior quadrant had the maximum AUC, followed by superior and nasal quadrants. the GC-IPL parameters in PPG showed that the AUC of the GC-IPL parameters was much higher than those of the ONH and RNFL values. CONCLUSION: Although both the parameters RNFL and GC-IPL showed significant changes in PPG patients compared to healthy subjects, a higher AUC of GC-IPL points toward the higher sensitivity of GC-IPL than RNFL for detecting glaucoma in early stages.

Impact of learning effect on reliability factors and global indices in visual field testing by standard automated perimetry in normal healthy subjects and primary open-angle glaucoma patients to obtain an accurate baseline perimetry chart.

Purpose: To record and evaluate the reliability parameters (fixation loss (FL) %, false positive (FP) %) and global indices (mean sensitivity (MS), mean deviation (MD), pattern standard deviation in dB) in three visual field test sessions within two weeks to assess the learning effect in normal healthy subjects and POAG patients and comparison of learning effect gender wise and age wise in primary open-angle glaucoma (POAG) patients. Methods: This study was a prospective observational study. An oculus visual field testing was done and analyzed in 30 eyes of POAG patients and 30 eyes of normal healthy subjects in three visits. Results: There were 16 (53.3%) males and 14 (46.6%) females in the POAG group and 16 (53.33%) males and 14 (46.66%) females in the normal healthy subject group. A significant difference in data change between each visit in FL, FP, MD, MS was found though the difference was more pronounced in the second visit than in the third visit. The pattern standard deviation does not change significantly in subsequent visits in both groups. Gender wise and age wise no significant difference was found in the POAG group. Conclusion: Significant improvement in reliability parameters and global indices with each subsequent visit in both the POAG group and normal patients signifies the importance of learning effect on these parameters and the need to perform at least three tests to get the baseline perimetry chart, especially in POAG patients, while in normal subjects, second perimetric result can be accepted. It was also concluded that the learning effect is not influenced by age and gender.

Strong methane point sources contribute a disproportionate fraction of total emissions across multiple basins in the United States.

Understanding, prioritizing, and mitigating methane (CH4) emissions requires quantifying CH4 budgets from facility scales to regional scales with the ability to differentiate between source sectors. We deployed a tiered observing system for multiple basins in the United States (San Joaquin Valley, Uinta, Denver-Julesburg, Permian, Marcellus). We quantify strong point source emissions (>10 kg CH4 h-1) using airborne imaging spectrometers, attribute them to sectors, and assess their intermittency with multiple revisits. We compare these point source emissions to total basin CH4 fluxes derived from inversion of Sentinel-5p satellite CH4 observations. Across basins, point sources make up on average 40% of the regional flux. We sampled some basins several times across multiple months and years and find a distinct bimodal structure to emission timescales: the total point source budget is split nearly in half by short-lasting and long-lasting emission events. With the increasing airborne and satellite observing capabilities planned for the near future, tiered observing systems will more fully quantify and attribute CH4 emissions from facility to regional scales, which is needed to effectively and efficiently reduce methane emissions.

Diverse biosphere influence on carbon and heat in mixed urban Mediterranean landscape revealed by high resolution thermal and optical remote sensing.

A fundamental challenge in verifying urban CO2 emissions reductions is estimating the biological influence that can confound emission source attribution across heterogeneous and diverse landscapes. Recent work using atmospheric radiocarbon revealed a substantial seasonal influence of the managed urban biosphere on regional carbon budgets in the Los Angeles megacity, but lacked spatially explicit attribution of the diverse biological influences needed for flux quantification and decision making. New high-resolution maps of land cover (0.6 m) and irrigation (30 m) derived from optical and thermal sensors can simultaneously resolve landscape influences related to vegetation type (tree, grass, shrub), land use, and fragmentation needed to accurately quantify biological influences on CO2 exchange in complex urban environments. We integrate these maps with the Urban Vegetation Photosynthesis and Respiration Model (UrbanVPRM) to quantify spatial and seasonal variability in gross primary production (GPP) across urban and non-urban regions of Southern California Air Basin (SoCAB). Results show that land use and landscape fragmentation have a significant influence on urban GPP and canopy temperature within the water-limited Mediterranean SoCAB climate. Irrigated vegetation accounts for 31% of urban GPP, driven by turfgrass, and is more productive (1.7 vs 0.9 µmol m-2 s-1) and cooler (2.2 ± 0.5 K) than non-irrigated vegetation during hot dry summer months. Fragmented landscapes, representing mostly vegetated urban greenspaces, account for 50% of urban GPP. Cooling from irrigation alleviates strong warming along greenspace edges within 100 m of impervious surfaces, and increases GPP by a factor of two, compared to non-irrigated edges. Finally, we note that non-irrigated shrubs are typically more productive than non-irrigated trees and grass, and equally productive as irrigated vegetation. These results imply a potential water savings benefit of urban shrubs, but more work is needed to understand carbon vs water usage tradeoffs of managed vs unmanaged vegetation.

The Impact of COVID-19 on CO2 Emissions in the Los Angeles and Washington DC/Baltimore Metropolitan Areas.

Responses to COVID-19 have resulted in unintended reductions of city-scale carbon dioxide (CO2) emissions. Here, we detect and estimate decreases in CO2 emissions in Los Angeles and Washington DC/Baltimore during March and April 2020. We present three lines of evidence using methods that have increasing model dependency, including an inverse model to estimate relative emissions changes in 2020 compared to 2018 and 2019. The March decrease (25%) in Washington DC/Baltimore is largely supported by a drop in natural gas consumption associated with a warm spring whereas the decrease in April (33%) correlates with changes in gasoline fuel sales. In contrast, only a fraction of the March (17%) and April (34%) reduction in Los Angeles is explained by traffic declines. Methods and measurements used herein highlight the advantages of atmospheric CO2 observations for providing timely insights into rapidly changing emissions patterns that can empower cities to course-correct CO2 reduction activities efficiently.

Biochar amendment reduced the risk associated with metal uptake and improved metabolite content in medicinal herbs.

Contaminations of heavy metals such as lead (Pb) and cadmium (Cd) in medicinal plants (MPs) not only restrict their safe consumption due to health hazards but also lower their productivity. Biochar amendments in the soil are supposed to immobilize the toxic metals, improve the soil quality and agricultural productivity. However, the impact of biochar on growth attributes, metal accumulation, pharmacologically active compounds of MPs, and health risk is less explored. An experiment was performed on three medicinal plants (Bacopa monnieri (L.), Andrographis paniculata (Burmf.) Nees, and Withaniasomnifera (L.)) grown in a greenhouse in soil co-contaminated with Pb and Cd (at two concentrations) without and with biochar amendments (2 and 4% application rates). The fractionation of Pb and Cd, plant growth parameters, stress enzymes, photosynthetic capacity, pharmacologically active compounds, nutrient content, uptake and translocation of metals, antioxidant activities, and metabolite content were examined in the three MPs. The accumulation of Pb and Cd varied from 3.25-228 mg kg1 and 1.29-20.2 mg kg-1 , respectively, in the three MPs, while it was reduced to 0.08-18 mg kg-1 and 0.03-6.05 mg kg-1 upon biochar treatments. Plants grown in Pb and Cd co-contaminated soil had reduced plant biomass (5-50% depending on the species) compared to control and a deleterious effect on photosynthetic attributes and protein content. However, biochar amendments significantly improved plant biomass (21-175%), as well as photosynthesis attributes, chlorophyll, and protein contents. Biochar amendments in Pb and Cd co-contaminated soil significantly reduced the health hazard quotient (HQ) estimated for the consumption of these medicinal herbs grown on metal-rich soil. An enhancement in secondary metabolite content and antioxidant properties was also observed upon biochar treatments. These multiple beneficial effects of biochar supplementation in Pb and Cd co-contaminated soil suggested that a biochar amendment is a sustainable approach for the safe cultivation of MPs. This article is protected by copyright. All rights reserved.

Arsenic-induced differential expression of oxidative stress and secondary metabolite content in two genotypes of Andrographis paniculata.

The present study explores the differential responses of two genotypes (APwC: wild collection and APMS: mass selection line) of A. paniculata against the three application rates of arsenic (42, 126, and 200 mg kg-1). The oxidative enzymes, As accumulation in different tissues, plant growth, and content of pharmacologically important ent-labdane-related diterpenes (ent-LRDs) of the two genotypes were evaluated in the study. Results demonstrated that As uptake significantly reduced plant biomass in APwC and APMS by 5-41.5% and 9-33% in a dose-response manner, respectively. The APMS exhibited lower bioconcentration and translocation factors, higher As tolerance index, and higher content of ent-LRDs as compared to APWC. As treatment induced a decrease in the sum of four metabolite content of APMS (1.43 times) and an increase in that of APWC (1.12 times) as compared to control. Likewise, variance in the production of 5,7,2',3'-tetramethoxyflavanone, and stress enzymes was also observed between APwC and APMS. The increase in the expression of ApCPS2 suggested its involvement in channeling of metabolic flux towards the biosynthesis of ent-LRDs under As stress.

Large and seasonally varying biospheric CO2 fluxes in the Los Angeles megacity revealed by atmospheric radiocarbon.

Measurements of Δ14C and CO2 can cleanly separate biogenic and fossil contributions to CO2 enhancements above background. Our measurements of these tracers in air around Los Angeles in 2015 reveal high values of fossil CO2 and a significant and seasonally varying contribution of CO2 from the urban biosphere. The biogenic CO2 is composed of sources such as biofuel combustion and human metabolism and an urban biospheric component likely originating from urban vegetation, including turf and trees. The urban biospheric component is a source in winter and a sink in summer, with an estimated amplitude of 4.3 parts per million (ppm), equivalent to 33% of the observed annual mean fossil fuel contribution of 13 ppm. While the timing of the net carbon sink is out of phase with wintertime rainfall and the sink seasonality of Southern California Mediterranean ecosystems (which show maximum uptake in spring), it is in phase with the seasonal cycle of urban water usage, suggesting that irrigated urban vegetation drives the biospheric signal we observe. Although 2015 was very dry, the biospheric seasonality we observe is similar to the 2006-2015 mean derived from an independent Δ14C record in the Los Angeles area, indicating that 2015 biospheric exchange was not highly anomalous. The presence of a large and seasonally varying biospheric signal even in the relatively dry climate of Los Angeles implies that atmospheric estimates of fossil fuel-CO2 emissions in other, potentially wetter, urban areas will be biased in the absence of reliable methods to separate fossil and biogenic CO2.

California's methane super-emitters.

Methane is a powerful greenhouse gas and is targeted for emissions mitigation by the US state of California and other jurisdictions worldwide1,2. Unique opportunities for mitigation are presented by point-source emitters-surface features or infrastructure components that are typically less than 10 metres in diameter and emit plumes of highly concentrated methane3. However, data on point-source emissions are sparse and typically lack sufficient spatial and temporal resolution to guide their mitigation and to accurately assess their magnitude4. Here we survey more than 272,000 infrastructure elements in California using an airborne imaging spectrometer that can rapidly map methane plumes5-7. We conduct five campaigns over several months from 2016 to 2018, spanning the oil and gas, manure-management and waste-management sectors, resulting in the detection, geolocation and quantification of emissions from 564 strong methane point sources. Our remote sensing approach enables the rapid and repeated assessment of large areas at high spatial resolution for a poorly characterized population of methane emitters that often appear intermittently and stochastically. We estimate net methane point-source emissions in California to be 0.618 teragrams per year (95 per cent confidence interval 0.523-0.725), equivalent to 34-46 per cent of the state's methane inventory8 for 2016. Methane 'super-emitter' activity occurs in every sector surveyed, with 10 per cent of point sources contributing roughly 60 per cent of point-source emissions-consistent with a study of the US Four Corners region that had a different sectoral mix9. The largest methane emitters in California are a subset of landfills, which exhibit persistent anomalous activity. Methane point-source emissions in California are dominated by landfills (41 per cent), followed by dairies (26 per cent) and the oil and gas sector (26 per cent). Our data have enabled the identification of the 0.2 per cent of California's infrastructure that is responsible for these emissions. Sharing these data with collaborating infrastructure operators has led to the mitigation of anomalous methane-emission activity10.

A Multiplatform Inversion Estimation of Statewide and Regional Methane Emissions in California during 2014-2016.

California methane (CH4) emissions are quantified for three years from two tower networks and one aircraft campaign. We used backward trajectory simulations and a mesoscale Bayesian inverse model, initialized by three inventories, to achieve the emission quantification. Results show total statewide CH4 emissions of 2.05 ± 0.26 (at 95% confidence) Tg/yr, which is 1.14 to 1.47 times greater than the anthropogenic emission estimates by California Air Resource Board (CARB). Some of differences could be biogenic emissions, superemitter point sources, and other episodic emissions which may not be completely included in the CARB inventory. San Joaquin Valley (SJV) has the largest CH4 emissions (0.94 ± 0.18 Tg/yr), followed by the South Coast Air Basin, the Sacramento Valley, and the San Francisco Bay Area at 0.39 ± 0.18, 0.21 ± 0.04, and 0.16 ± 0.05 Tg/yr, respectively. The dairy and oil/gas production sources in the SJV contribute 0.44 ± 0.36 and 0.22 ± 0.23 Tg CH4/yr, respectively. This study has important policy implications for regulatory programs, as it provides a thorough multiyear evaluation of the emissions inventory using independent atmospheric measurements and investigates the utility of a complementary multiplatform approach in understanding the spatial and temporal patterns of CH4 emissions in the state and identifies opportunities for the expansion and applications of the monitoring network.

Enhanced North American carbon uptake associated with El Niño.

Long-term atmospheric CO2 mole fraction and δ13CO2 observations over North America document persistent responses to the El Niño-Southern Oscillation. We estimate these responses corresponded to 0.61 (0.45 to 0.79) PgC year-1 more North American carbon uptake during El Niño than during La Niña between 2007 and 2015, partially offsetting increases of net tropical biosphere-to-atmosphere carbon flux around El Niño. Anomalies in derived North American net ecosystem exchange (NEE) display strong but opposite correlations with surface air temperature between seasons, while their correlation with water availability was more constant throughout the year, such that water availability is the dominant control on annual NEE variability over North America. These results suggest that increased water availability and favorable temperature conditions (warmer spring and cooler summer) caused enhanced carbon uptake over North America near and during El Niño.

Biochar-mediated sequestration of Pb and Cd leads to enhanced productivity in Mentha arvensis.

Immobilization of cadmium (Cd) and lead (Pb) along with the alleviation of their phytotoxicity in Mentha arvensis by biochar was examined in this investigation. A greenhouse experiment was executed to evaluate the effect of biochar (BC) amended Cd and Pb spiked soil on their immobilization and uptake, plant growth, photosynthetic attributes (total chlorophyll, photosynthetic rate, transpiration rate, and stomatal activity) and oxidative enzymes (guaiacol peroxidase: POD; catalase: CAT and superoxide dismutase: SOD). In the present study, the photosynthetic attributes showed that BC significantly improved the total chlorophyll, photosynthetic, transpiration rates, and stomatal activity in the plants. The incorporation of BC in soil increase the Pb and Cd tolerance in M. arvensis vis-à-vis improved the biomass yield and nutrient intake. In addition, biochar has also reduced the POD, CAT, and SOD in the plant as well as improved the soil pH and enzymatic activities. Overall, BC immobilized the Cd and Pb in soil by providing the binding site to the metals and reduced the phytotoxicity in M. arvensis. However, large-scale field trials of BC are required for safe cultivation of M. arvensis which is known for its phytopharmaceuticals importance.

Carbon dioxide and methane measurements from the Los Angeles Megacity Carbon Project - Part 1: calibration, urban enhancements, and uncertainty estimates.

We report continuous surface observations of carbon dioxide (CO2) and methane (CH4) from the Los Angeles (LA) Megacity Carbon Project during 2015. We devised a calibration strategy, methods for selection of background air masses, calculation of urban enhancements, and a detailed algorithm for estimating uncertainties in urban-scale CO2 and CH4 measurements. These methods are essential for understanding carbon fluxes from the LA megacity and other complex urban environments globally. We estimate background mole fractions entering LA using observations from four "extra-urban" sites including two "marine" sites located south of LA in La Jolla (LJO) and offshore on San Clemente Island (SCI), one "continental" site located in Victorville (VIC), in the high desert northeast of LA, and one "continental/mid-troposphere" site located on Mount Wilson (MWO) in the San Gabriel Mountains. We find that a local marine background can be established to within ~1 ppm CO2 and ~10 ppb CH4 using these local measurement sites. Overall, atmospheric carbon dioxide and methane levels are highly variable across Los Angeles. "Urban" and "suburban" sites show moderate to large CO2 and CH4 enhancements relative to a marine background estimate. The USC (University of Southern California) site near downtown LA exhibits median hourly enhancements of ~20 ppm CO2 and ~150 ppb CH4 during 2015 as well as ~15 ppm CO2 and ~80 ppb CH4 during mid-afternoon hours (12:00-16:00 LT, local time), which is the typical period of focus for flux inversions. The estimated measurement uncertainty is typically better than 0.1 ppm CO2 and 1 ppb CH4 based on the repeated standard gas measurements from the LA sites during the last 2 years, similar to Andrews et al. (2014). The largest component of the measurement uncertainty is due to the single-point calibration method; however, the uncertainty in the background mole fraction is much larger than the measurement uncertainty. The background uncertainty for the marine background estimate is ~10 and ~15 % of the median mid-afternoon enhancement near downtown LA for CO2 and CH4, respectively. Overall, analytical and background uncertainties are small relative to the local CO2 and CH4 enhancements; however, our results suggest that reducing the uncertainty to less than 5 % of the median mid-afternoon enhancement will require detailed assessment of the impact of meteorology on background conditions.

Regional atmospheric CO2 inversion reveals seasonal and geographic differences in Amazon net biome exchange.

Understanding tropical rainforest carbon exchange and its response to heat and drought is critical for quantifying the effects of climate change on tropical ecosystems, including global climate-carbon feedbacks. Of particular importance for the global carbon budget is net biome exchange of CO2 with the atmosphere (NBE), which represents nonfire carbon fluxes into and out of biomass and soils. Subannual and sub-Basin Amazon NBE estimates have relied heavily on process-based biosphere models, despite lack of model agreement with plot-scale observations. We present a new analysis of airborne measurements that reveals monthly, regional-scale (~1-8 × 10(6)  km(2) ) NBE variations. We develop a regional atmospheric CO2 inversion that provides the first analysis of geographic and temporal variability in Amazon biosphere-atmosphere carbon exchange and that is minimally influenced by biosphere model-based first guesses of seasonal and annual mean fluxes. We find little evidence for a clear seasonal cycle in Amazon NBE but do find NBE sensitivity to aberrations from long-term mean climate. In particular, we observe increased NBE (more carbon emitted to the atmosphere) associated with heat and drought in 2010, and correlations between wet season NBE and precipitation (negative correlation) and temperature (positive correlation). In the eastern Amazon, pulses of increased NBE persisted through 2011, suggesting legacy effects of 2010 heat and drought. We also identify regional differences in postdrought NBE that appear related to long-term water availability. We examine satellite proxies and find evidence for higher gross primary productivity (GPP) during a pulse of increased carbon uptake in 2011, and lower GPP during a period of increased NBE in the 2010 dry season drought, but links between GPP and NBE changes are not conclusive. These results provide novel evidence of NBE sensitivity to short-term temperature and moisture extremes in the Amazon, where monthly and sub-Basin estimates have not been previously available.

Impact of biochar amendment on enzymatic resilience properties of mine spoils.

Soil enzymes are crucial for soil nutrient cycling function. Understanding of the factors that control their response to major disturbances such as dumping of environmentally toxic acidic waste remains limited. We evaluated the effect of dumping of overburden (OB) and their amendments using biochar, on the resistance and resilience of soil enzyme activities involved in phosphorus, nitrogen, sulphur and carbon cycling (acid & alkaline phosphatase, urease, arylsulphatase, dehydrogenase, phenol oxidases, cellulase and ß-glucosidase). For investigation the soils treated with OB and with the mixture of OB and biochar were used for the cultivation of bacopa were used. We assessed 0 day, 45 day and 90 days activities of the target soil enzymes, available phosphorus, nitrogen, sulphur, soil organic carbon and microbial identification. The resilience and resistance index of all the treatments were calculated. We found that phyto-remediated OB-contaminated soil has its own resilience power. However, biochar addition enhanced the enzyme resistance and resilience of OB contaminated soil. In silico study indicates that biochar-Fe complex play a significant role in enzymatic activities. Overall, the results indicate a significant influence of phytoremediation and biochar addition on soil enzymatic activity that is extremely resistant to OB. This study provides insight on how biochar addition modulates soil biochemical and microbiological response to OB affected soils.

Detecting fossil fuel emissions patterns from subcontinental regions using North American in situ CO2 measurements.

The ability to monitor fossil fuel carbon dioxide (FFCO2) emissions from subcontinental regions using atmospheric CO2 observations remains an important but unrealized goal. Here we explore a necessary but not sufficient component of this goal, namely, the basic question of the detectability of FFCO2 emissions from subcontinental regions. Detectability is evaluated by examining the degree to which FFCO2 emissions patterns from specific regions are needed to explain the variability observed in high-frequency atmospheric CO2 observations. Analyses using a CO2 monitoring network of 35 continuous measurement towers over North America show that FFCO2 emissions are difficult to detect during nonwinter months. We find that the compounding effects of the seasonality of atmospheric transport patterns and the biospheric CO2 flux signal dramatically hamper the detectability of FFCO2 emissions. Results from several synthetic data case studies highlight the need for advancements in data coverage and transport model accuracy if the goal of atmospheric measurement-based FFCO2 emissions detection and estimation is to be achieved beyond urban scales. KEY POINTS: Poor detectability of fossil fuel CO2 emissions from subcontinental regionsDetectability assessed via attribution of emissions patterns in atmospheric dataLoss in detectability due to transport modeling errors and biospheric signal.

Comparative study of thermal properties of bio-coal from aromatic spent with low rank sub-bituminous coals.

In present investigation, biocoal samples were prepared from aromatic plant waste of two perennial grasses, i.e. Cymbopogon flexuosus (lemongrass) and Vetiveria zizanioides (khus) after oil extraction, root of Rosa damascene (rose), bark of Eucalyptus citriodora. These biocoals were characterized by proximate, ultimate, metal, thermogravimetric analysis (TGA), Fourier Transform Infra Red (FTIR) spectroscopy and ash analyses. Activation energies, initial temperature of devolatilization, maximum rate of weight loss (Rmax), fouling, slagging and alkali index were determined on the basis of TGA and ash analysis. These biocoals have good calorific values. There is possibility of slagging and fouling in combustion system but it is not severe. Owing to their similar fuel properties as high sulphur sub-bituminous coal, they can be good candidates for co-firing. Blending of these biocoals with high sulphur coals will serve dual purpose as (i) alternate fuel, and (ii) reduction in SO2 emission.