Plant Biomass Derived Materials E-Book

• Herausgeber: Wiley-VCH GmbH
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1171

Veröffentlichungsjahr: 2024

Beschreibung

Plant Biomass Derived Materials

Comprehensive overview of materials derived from biomass, including extraction techniques, important building blocks, and a wide range of applications

Plant Biomass Derived Materials provides insights into the different sources and kinds of biomass and covers a variety of techniques to derive important building blocks from raw resources; after foundational knowledge is covered, the text continues to discuss a comprehensive list of materials and applications, ranging from nanomaterials, polymers, enzymes, dyes, and composites, to applications in energy, biomedical, water purification, aeronautics, automotive and food applications, and more.

Written by four highly qualified authors with significant experience in both industry and academia, Plant Biomass Derived Materials includes information on:

• Biomass and its relationship to the environment, chemistry of biomass, lignin and starch, and recent trends of cashew nutshell liquid in the field
• Plant biomass mucilage, plant based colorants, revival of sustainable fungal based natural pigments, and algal-based natural pigments for textiles
• Biorefinery from plant biomass (including a case study in sugarcane straw), forest and agricultural biomass, and manufacture of monomers and precursors
• Chemical routes for the transformation of bio-monomers into polymers and manufacture of polymer composites from plant fibers

Providing foundational knowledge on the subject and a wide array of specific applications of biomass, Plant Biomass Derived Materials is an essential resource for chemists, materials scientists, and all academics and professionals in fields that intersect with biomass: an abundant renewable resource used for many diverse purposes.

Leseprobe

Plant Biomass Derived Materials

Sources, Extractions, and Applications

Edited by Seiko Jose, Sabu Thomas, Lata Samant, and Sneha Sabu Mathew

Editors

Dr. Seiko JoseICAR‐Central Sheep & WoolResearch Inst.Malpura (Tehsil)Tonk (Dist) Via‐JaipurRajasthanIndia, 304501

Prof. Dr. Sabu ThomasMahatma Gandhi UniversityPriyadarhsini Hills P.O.Kottayam, KeralaIndia, 686 560

Dr. Lata SamantGovind Ballabh Pant UniversityUdham Singh Nagar, UttarakhandPantnagarIndia, 263145

Sneha Sabu MathewMahatma Gandhi UniversityPriyadarhsini Hills P.O.Kottayam, KeralaIndia, 686 560

Cover Image: © petrmalinak/Shutterstock

All books published by WILEY‐VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.: applied for

British Library Cataloguing‐in‐Publication DataA catalogue record for this book is available from the British Library.

Bibliographic information published by the Deutsche NationalbibliothekThe Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2024 WILEY‐VCH GmbH, Boschstr. 12, 69469 Weinheim, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form – by photoprinting, microfilm, or any other means – nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Print ISBN: 978‐3‐527‐35076‐6ePDF ISBN: 978‐3‐527‐83901‐8ePub ISBN: 978‐3‐527‐83902‐5oBook ISBN: 978‐3‐527‐83903‐2

Preface

The ceaseless surge in the global population has exerted unprecedented pressure on agricultural systems, consequently resulting in a substantial boom in the generation of agricultural residues. As the population continues to grow, the demand for food, feed, and fiber increases, requiring intensified agricultural production. This intensification often involves practices such as increased cultivation, higher yields, and the use of chemical inputs, which can result in larger quantities of agricultural residues being generated. Agricultural residues encompass various organic materials left over after crop harvesting or processing. To meet the escalating food demand, modern agricultural practices tend to focus on high‐yielding varieties and mechanized farming, which in turn contributes to increased residue production. The accumulation of agricultural residues poses challenges for waste management and disposal. If not managed properly, these residues may lead to environmental problems such as air and water pollution and soil degradation. They also contribute to greenhouse gas emissions, as their decomposition can release methane, a potent greenhouse gas. However, it is essential to recognize that agricultural residues also hold significant potential and value. Instead of perceiving them solely as waste, they can be viewed as valuable resources that can be effectively utilized. To address the challenges associated with the substantial generation of agricultural residues, it is crucial to promote the efficient use, valorization, and recycling of agricultural residues.

Our book, Plant Biomass Derived Materials: Sources, Extractions, and Applications, is dedicated to exploring the remarkable potential and versatility of plant biomass as a renewable resource. In the initial chapters, readers are provided with a comprehensive overview of biomass, covering its chemistry, extraction methods, and applications. These chapters explore the extraction and synthesis of valuable compounds such as lignin, starch, bio‐resin, and plant mucilage. Moving forward, the second section focuses on colorants obtained from plants, fungi, and algae, showing their unique properties and applications. The third part of the book presents a comprehensive exploration of composites developed from polymers and lignin derived from plant residues, offering valuable knowledge in this field. It further provides an extensive examination of the advanced applications of plant biomass in bioplastics, energy production, automotive and aerospace industries, food packaging, water purification, and beyond. In the final sections, the book addresses the vital aspects of recycling plant biomass, as well as the proper handling, storage, and preservation of these valuable resources. These considerations contribute to a holistic understanding of the subject matter and equip readers with practical insights.

This book provides a comprehensive understanding of plant biomass and showcases its immense potential in diverse industries. By highlighting emerging trends and recent advancements in the field, the book offers valuable insights into the future prospects of plant biomass‐derived materials. We believe scholars, researchers, and academicians can leverage this book as a roadmap to explore new avenues of research, discover innovative applications, and contribute to the development of sustainable and eco‐friendly technologies. The book serves as a platform for interdisciplinary collaborations, stimulating discussions, and knowledge exchange among experts from different fields. It empowers readers to envision a greener future by harnessing the power of plant biomass, making it an indispensable resource for anyone seeking to contribute to the advancement of sustainable materials and technologies.

EditorsSeiko Jose, Sabu Thomas, Lata Samant, and Sneha Sabu Mathew

1Biomass – An Environmental Concern

Deepak S. Khobragade

Datta Meghe College of Pharmacy, Datta Meghe Institute of Higher Education and Research, Sawangi (M), Wardha, India

1.1 Introduction

Any biological organic matter derived from living or dead organisms can be called “biomass.” Every type of biomass is directly or indirectly obtained from the photosynthesis process [1]. Thus, biomass is a natural material with an organic matrix obtained from plants and animals [2]. It encompasses various materials, like wood, agricultural and industrial remains, and animal and human waste. Due to its range, there are substantial differences in biomass composition, whether of industrial or domestic origin [3]. With this vast heterogeneity in the usage and origin of materials, the definition of “biomass” varies. There is a wide range of biomass materials that can be broadly grouped as raw or derived. Cellulose, hemicelluloses, lignin, starch, and proteins are some of the main elements of biomass [4–7]. Various biomass sources of diverse origins, like agricultural, forestry, industrial, and other sources, are presented in Table 1.1 and depicted in Figure 1.1.

Biomass is now primarily used for feed, followed by food, and finally for the production of energy, fuels, and chemical feedstock. It accounts for 13% of global final energy consumption (other renewables contribute another 5%). The industrial organic chemical sector produces 550 million tonnes of chemicals and 275 million tonnes of nitrogen fertilizer, but the chemicals contain only 500 million tonnes of carbon. Furthermore, organic compounds used in organic chemistry contain approximately 100 million tonnes of carbon [8]. Currently, sugar, starch, and vegetable oil are the primary sources of biofuels and biochemicals [9]. Consumers interest and the need for replacement of fossil fuels with renewable energy sources are driving up demand for bio‐products. The price level of feedstocks, such as lignocellulose, sugars, starch, and oils, is another factor influencing the competitiveness of biochemical products [9]. Price comparisons of bio‐based carbon to fossil‐based carbon, as well as cost comparisons of processing bio‐based materials with the corresponding fossil‐based materials, are difficult to specify because they are dependent on raw materials and the molecular economy of the processes into the final products. The various advantages and disadvantages of biomass are depicted in Table 1.2.

Table 1.1 Sources of biomass.

Woody biomass (WB)

Nonwoody biomass (NWB)

Animal biomass (AB)

Processed waste (PW)

Processed fuels (PF)

Shrubs

Energy crops

Animal waste

Sawmill wastes

Charcoal

Trees

Cereal straws

Animal residues

Plant oil cake

Briquette and densified biomass

Bushes

Plant fibers, leaves and roots

Animal remains

Fruit waste and nutshells

Biogas

Forest floor sweepings

Grasses

Decomposed animals

Flesh

Vegetable oil

Palms

Banana

Bagasse Producer gas

Bamboo

Soft plant stems

Cereal husk

Methanol and ethanol

Forest residues

Water plants

Industrial wood, bark and logs

Industrial residues

Agricultural residues

sewage and other municipal waste

Figure 1.1 Types of biomass and examples.

Table 1.2 Advantages and limitations of biomass use.

Advantages

Limitations

Biomass is a renewable energy source

Biomass plants necessitate a large amount of space

It is available consistently and extensively

It could lead to deforestation

It is considered as carbon neutral.

It is not entirely clean

It helps to reduce our reliance on fossil fuels.

Biomass energy is inefficient compared to fossil fuels.

Is less costly than fossil fuels.

Biomass plants require a lot of space

It results in less garbage in landfills.

Huge requirement of resources like water

Biomass production generates revenue for manufacturers.

Table 1.3 Biomass classification.

Type of biomass

Content

Utility

References

Wood and woody biomass

Logs,stems and branches RootsFoliageBarkChips, pellets, and lumpsBriquettesSawdust

Fuel in itself

Heat and electricity generation

Biogas generation

Fermentation for producing chemical products like alcohol and biodiesel

Manure as by‐product

[3]

Herbaceous biomass

GrassesStrawsLeavesOther residues like fruits, shells, and husks.

Aquatic biomass

AlgaeSeaweedLakeweedKelpWater hyacinth, etc.

Animal and human waste biomass

ExcretaDead and decaying animalsSkin and bones, etc.

Miscellaneous biomass

Food wasteFood processing factory waste

Mineral oil is refined to produce fossil fuels and basic chemicals with very high carbon efficiency and low labor intensity. In contrast, biomass necessitates more processing steps, which increase the cost and labor requirements (see bioethanol production). Renewable energy sources such as solar, wind, hydro, and geothermal energy, as well as nuclear energy, are carbon‐free in the energy industry. The transportation sector accounts for one‐third of total final energy demand and 23% of global energy‐related CO2 emissions. Oil products meet approximately 96% of global transportation energy needs, with the remainder being met by electricity and biogas; thus increased use of renewables in the transportation sector is a high priority in the decarbonization of this sector.

The use of biofuels and other renewable energy sources, such as solar and wind, can help decarbonize the transportation sector [10]. The EU and the US have set limits on food‐based biofuels. Although only 2% of global land is used for biofuel feedstock production, the “fuel versus food” debate shows that biomass used for industrial purposes is a sensitive issue in society. Some feedstocks (e.g. maize, oilseeds, sugarcane, and vegetable oil) have relatively high demand: biofuels consume 20% of global sugarcane, 12% of global vegetable oil, and 10% of global coarse grain production. Because biofuel accounts for a very small proportion of overall land use changes, crop competition may be reduced (as a percentage of total final energy consumption). Renewable energy sources play a critical role in the economy’s “decarbonization,” or the process of reducing the amount of greenhouse gas (GHG) emissions produced by the combustion of fossil fuels. These sources are called biomass only if they cannot be reused for subsequent processing [11]. The classification of biomass is presented in Table 1.3.

1.2 Biomass as an Energy Source

Factors that determine the usage of fuel are (i) cost, (ii) accessibility, (iii) stove type and technical features, (iv) cooking practices, (v) cultural preferences, and (vi) awareness about the potential health impacts [12]. Biomass is available on earth in many places, like agriculture, domestic farms, forests, and oceans. The total biomass reserves on land are estimated to be around 1.8 trillion tons, with an additional 4 billion tonnes in the ocean. Biomass is an enormously significant energy source, available everywhere, and bioenergy is the energy generated from biomass. About 33 000 EJ of energy can be produced by the total biomass present in the world. It is more than 80 times the total annual energy requirement of the world. Currently, biomass provides about 14% of the basic energy requirements of the world, i.e., 56.9 million exajoule per year globally (1230 million tonnes of oil equivalent per year) [8, 9]. About 159 billion liters of biofuel are produced each year globally from various biomass sources.

Solid biomass (wood, shrubs, herbs, wood chips, wood pellets, and other biomass sources) provides the majority of household biomass supply (85%). Biomass‐based liquid biofuels contribute 8%, municipal and industrial waste contribute 5%, and biogas makes up a meager 2% of the total biomass supply. The utilization of biomass is not equal around the world. In some underdeveloped and developing countries, as much as 50% of the total energy needs are generated by wood combustion. In 2020, 1.93 billion m3 of wood was produced globally as fuel. Africa and Asia had 36% and 37% of annual wood production, respectively. With 40.5 million tonnes produced globally, wood pellets are the most sought‐after source. About 53.6 million metric tonnes of wood charcoal were produced in Africa, i.e. 65% of the total wood charcoal production globally.

In 2019, 2.59 EJ of energy was generated from municipal (56%, i.e. 1.45 EJ) and industrial waste (44%, i.e. 1.14 EJ). Globally, biomass was used to generate 655 terawatt‐hours (TWh) of electricity. Of the total bioelectricity generated, 68% was from solid biomass sources, about 17% from municipal and industrial waste, and the remaining from other sources. Asia produced 39% (255 TWh), Europe produced 35% (230 TWh), and the rest of the world produced 35% (230 TWh). About 1.17 EJ of heat was produced from biomass‐based sources in 2019. About 53% of the heat energy was produced from solid biomass sources, 25% from municipal solid waste, and the remainder from other biomass sources [10]. According to the 2018 World Biogas Association (WBA) report, biomass energy production in developed countries stands at 11% of the total energy produced [13]. In the USA, about 3% of energy demands (about 70 Mtoe yr−1) are met by biomass. In Europe, 3.5% of its energy is derived from biomass (around 40 Mtoe yr−1). European countries like Finland, Sweden, and Austria, with approximately 18%, 17%, and 13% of total energy generation from biomass, respectively, have a relatively high use of biomass energy in Europe [14]. Various methods of bioenergy generation and their concerns are presented in Table 1.4. [3, 15–17]

Table 1.4 Main conversion technologies and their corresponding products.

Process

Method

Biomass

Product

Concerns

References

Thermochemical conversion

Combustion

Agricultural residues

Woody residues

Animal wastes

Heat

Electricity

Air pollution by releasing gases such as CO

2

, CO, nitrogen oxides, and volatile organic compounds

[3]

Pyrolysis

Agricultural residues

Woody residues

Pyrolysis oil

Producer gas

Char

Pollution by synthetic gases and oils, ash, char, and heavy metals

Gasification

Agricultural residues

Woody residues

Producer gas

Liquid fuels

Char

Pollution by tars, heavy metals, halogens, and alkaline compounds

Liquefaction

Agricultural residues

Algal biomass

Fertilizer/biofuel

Syngas

Liquid fuels

Release of corrosive materials and salts

Biochemical conversion

Anaerobic digestion

Animal wastes

Sewage sludge

Liquid fuels

Biogas

Electricity

Toxic and asphyxiant spills and gases. High COD liquids

Fermentation

Agricultural residues

Sugars

Starch

Liquid fuels (bioethanol)

Release of a high amount of CO

2

Physicochemical conversion

Esterification/Transesterification

Vegetable oils

Animal fats

Waste oils

Liquid fuels

Glycerol

Air water and soil pollution with the release of toxic chemicals

1.3 The Environmental Concern of Biomass

Burning fuels, fossils, or biomass releases carbon dioxide (CO2). Apart from CO2 emissions, burning any kind of biomass also emits other pollutants and particulate matter into the air, like CO, volatile organic compounds, and oxides of nitrogen. Sometimes, biomass can emit more pollutants than fossil fuels, and many of these pollutants cannot be sequestered by plants. Pollutants from biomass consumption can create environmental and human health problems if not properly controlled. During biomass processing, waste products like heavy metals, tar, alkaline compounds, and halogens are released, which cause environmental and health hazards. Because of the release of toxic exudates, gases, dust, and ash (both fly and bottom), biomass power generation has serious environmental consequences. It can also produce fire, explosions, high noise levels, odors, and other environmental hazards [18, 19]. Biomass, particularly biomass‐based energy, is referred to as a carbon‐neutral and nonpolluting energy source. This is not true; depending on the method of use and processing, biomass poses its own environmental risks. Although advanced processing can reduce emissions and subsequent pollution compared to fossil fuels, it cannot be considered environmentally safe [20–22]. Some of the environmental and health hazards of WB are discussed below.

1.4 Air Pollution

During the processing and burning of biomass, pollutants like gases, dust, biomass ash, fly ash, and char are released into the air, adversely affecting the environment by polluting the air and subsequently human health.

1.4.1 Gaseous Emissions

Gaseous emission is the main drawback of biomass utilization when used directly for energy, i.e. burning or processing to obtain a somewhat more efficient biofuel or energy source. Biomass utilization is one of the major sources of GHGemissions. The most common gases emitted are CO2, NO2, CO, and other nitric oxides. Though CO2 is considered the main GHG responsible for global warming and other environmental problems, NO2, which is produced during biomass generation, processing, and usage, is more harmful to the cause of global warming, i.e. 298 times that of CO2. The point here is that relatively less NO2 is released by fossil fuels as compared to biomass‐based energy sources [23, 24]. It is reported that if we use NWB for processing, then relatively high levels of sulfur, chlorine, and ash are generated compared to processing WB [25]. It is well established that sulfur and chlorine have many hazardous effects on health and the environment. Sulfur as well as nitrogen are present in the majority of biomass, and their oxides (NOx and SOx) produced as by‐products of processing have a huge negative impact on the environment [26].

1.4.2 Dust

Dust is generally generated during most of the stages of biomass production, handling, and processing [27]. The handling of dry and friable solid biomass is a major source of airborne particles. When viewed in isolation, biomass appears to be a minor source of dust particles that pollute the environment. But collective dust production by total biomass production, processing, and utilization is very high. Limits for particulate emission are (i) 0.60 g kg−1 of air for rural areas or urban areas with a population of 50 000 and (ii) 0.20 g particulates kg−1 of air for urban areas with a population of 50 000 [28]. Common agricultural biomass produces approximately 8% (ranging from 6% to14%) of the world’s dust [29]. Persons dealing with biomass, in general, are exposed to and inhale >10 mg m−3 of dust, which is much higher than the limits of 1.5 mg m−3, said to be acceptable by environmental groups [30]. Inhalation of dust can cause lung damage, interstitial lung disease, COPD (chronic obstructive pulmonary disease), asthma, pneumonitis, cancer, and irritation of the skin and eyes [31]. The size range of 0.2–5 m of dust is considered the most dangerous, causing serious health problems for humans and other living organisms.

1.4.3 Biomass Ash (Bottom Ash)

Ash is the residue left after the combustion of biomass. Materials like ash pose great risks to our health and the environment. But most of the attention is paid to gaseous emissions and other pollutants. Ash content can reach up to 20% in mass for some biomasses. Deposition and uncontrolled release of ash can result in extensive pollution of water sources, air, and soil. The ash can contain toxic elements like arsenic, chromium, lead, barium, cadmium, nickel, and others. These elements have been linked to cancer, neurological disorders, and lung and heart diseases. When exposed in large quantities, they can cause serious health problems and even death. The problem with ash is that it is not classified as hazardous waste, so there are no guidelines for its safe disposal. Even though there are no standards for the leaching of chemicals from it into the environment, ashes are fouling and slagging [32].

1.4.4 Fly Ash

Apart from residue ash, biomass can generate fly ash. It is called fly ash because it is released from gases, especially during combustion. It is a fine powder consisting of noncombustible matter that remains after incomplete combustion. Fly ash comprises spherical and irregular particles with diameters less than 10 μm. The fly ash has a higher concentration of heavy metals and other harmful elemental contaminants than the bottom ash. Based on the variety and source of biomass, the composition of biomass varies. The fly ash not only contaminates the air by releasing hazardous pollutants but also gets deposited in or mixed with water bodies, making them unsafe for drinking. Compared to bottom ash, the potential for health hazards with fly ash is multiplied. [33–35]

1.4.5 Carbon Monoxide Poisoning

It has been known since long that the leading product of biomass burning is carbon monoxide (CO), a colorless and odorless gas. CO is the most common cause of gas poisoning and has very hazardous effects [36]. CO enters the bloodstream after inhalation and binds with hemoglobin to form carboxyhemoglobin (COHb). CO has a great affinity for hemoglobin, and as much as 80–90% of absorbed CO binds with hemoglobin, thus declining the oxygen‐carrying capacity of the blood and causing severe hypoxia. Compared to oxygen, hemoglobin has 200–250 times more affinity for CO than for oxygen [37, 38].

1.5 Water Use and Water Pollution

The commercial production of biomass uses a huge quantity of water. [39] Biomass cultivation needs a continuous water supply, and irrigating biomass fields for commercial purposes uses groundwater and surface water. Evan plants, which generate energy from biomass, consume a great deal of water. For example, ethanol production facilities require approximately 3–4 gallons of water per liter. Another critical point is that these processes require pure water, which is pumped from a very deep source [40]. These all have a significant impact not only on surface water but also on groundwater levels. Thus, increased biomass production can produce drought‐like conditions, affect aquatic habitats, and affect water availability for other purposes like food crops, drinking, hydropower, and fish farming.

As a by‐product of biomass processing, wastewater is produced as effluent. Various toxic pollutants like phenolic components, polycyclic aromatic hydrocarbons, benzene, toluene, ethylbenzene, and xylene are present in the released wastewater from biomass processing units. Apart from contaminating water and rendering it unsafe for domestic, agricultural, or fishery use, improper, unregulated disposal of these effluents causes other environmental problems. Biomass burning also leads to excessive fume production, which is released into the atmosphere, thus affecting the quality of not only the air but also increasing the incidence of acidic rain with a pH ranging from 3 to 6. Also, rainwater contains higher concentrations of ions like SO42−, NO3−, and NH4+ in areas where biomass burning is more prevalent [41].

1.6 Impact on Soil

The presence of hazardous pollutants or contaminants in soil is termed “soil pollution.” The presence of pollutants in high concentrations in soil poses a great risk to the ecosystem and human health. The high level of naturally occurring elements in the soil is also considered pollution. The direct use of biomass in agriculture not only increases the heavy metal concentration but also adds new heavy metals to the soil, which may lead to hazardous levels of heavy metal contamination. Because of the release of organic acids by biomass and the oxidative activation of compound heavy metals into molecular heavy metals, biomass activity activates heavy metals [42]. Soil pollution by biomass also alters the microbial content of soil and thus affects the basic nature of soil, including its nutritional values and fertility [43]. It indirectly also affects basal soil respiration (BSR) and nematode populations. These are directly or indirectly related to changes in heavy metal concentrations in soil. The ash that is formed by biomass burning, especially by the process of converting biomass into bioenergy, is generally not handled properly and gets mixed with the soil. This ash is detrimental to soil quality and nature due to its high elemental content, including hazardous heavy metals. This contaminated soil also becomes a reason for leaching contaminants into surrounding water bodies and even groundwater. The problem with soil pollution is that it also leads to the accumulation of pollutants in the plants or crops grown on polluted soil, causing health hazards to humans and animals who consume them.

Soil erosion is an indirect effect of excessive biomass consumption. Soil erosion is a condition where soil particles get detached from the surface either by wind, rain, or flowing water. One cause of soil erosion is the removal of crop residue for biofuel production. Fast‐growing crops need a lot of nutrients and are harvested in relatively less time than regular crops, thus making soil prone to erosion due to repeated planting and harvesting activity. Also, cutting wild trees for fuelwood results in the creation of bare land where soil erosion is most severe. The various health hazards of by‐products of biomass processing are depicted in Table 1.5.

Table 1.5 Hazardous effects of by‐products of biomass processing on health and environment.

Aromatic hydrocarbon

Effect on human

Effect on environment

References

Naphthalene (tertiary tar)

Hemolytic anemia,

Hemolysis

Depletion of pulmonary glutathione.

Dose‐dependent necrosis of bronchiolar epithelia.

Cause cataracts

Damages retina.

Poor air quality with increased polycyclic aromatic hydrocarbon in air and water.Toxic to animals and fish

[44

,

45]

,

Benzene (secondary/tertiary tar)

Anemia

Drowsiness

Dizziness

Headaches

Tremors and confusion

Cancer

Benzene in soil or waterContaminates groundwater leading to toxicity

[46]

Toluene (Secondary tar)

Headaches

Intoxication

Convulsions

Narcosis

Death (on chronic exposure)

Toxic to small animals, fish, and other aquatic organisms

[47

,

48]

Xylene (secondary tar)

Irritation of skin, eyes, nose, and throat

Difficulty in breathing and headache

Reduced muscle coordination Dizziness

Confusion

Bio accumulates in fishHigh acute toxicity to aquatic organisms

[49

,

50]

Ethyl benzene (secondary/tertiary tar)

Paralysis

Trouble in breathing

Liver toxicity

Death (on chronic exposure)

Water contamination with high acute toxicity to animals, birds, and aquatic life causes death

[51]

1.7 Indoor Pollution

Burning biomass fuel in an open area or on traditional stoves produces huge amounts of fumes or smoke. It also releases gases like CO2, CO, hydrocarbons, organic oxides, free radicals, chlorinated organics, and particulate matter. [52]. Some contain particulate matter, an inhalable material with a diameter of 10 μm. Acceptable MPM (mean particulate matter) levels, as per WHO guidelines, are 25–50 g m−1[53]. The average indoor PM concentration is generally above 2000 g m−1 in developing or underdeveloped countries at peak times [54, 55].

1.8 Deforestation and Land Degradation

Biomass energy consumption constitutes about 50–90% of total energy consumption in some parts of the world. Fuelwood is the primary domestic fuel and the main source of energy in these countries. In many of these countries, fuelwood is also used commercially to produce coal as an industrial energy source. Forests, agricultural or village trees, and forest residues are the main sources of fuelwood. To satisfy this huge need for biomass, these countries are dependent on their forests. Also, forest land is cleared for agriculture, animal husbandry, and cattle feeding. This takes a heavy toll on forests and woodlands. It results in the cutting of trees around villages and a decrease in forest area, leading to deforestation. Deforestation, in turn, leads to soil erosion, increased flood risks, and even desertification. Even if NWB fuels are used, they cause problems with insufficient fodder for animals, both wild and domestic. The reason is that wild animals feed on grass and shrubs, while domestic animals mainly feed on crop residues, grass, and shrubs [56].

1.9 Health Hazards

Biofuels and bioenergy, though allegedly believed to be clean and safe, are the main cause of indoor air pollution. The prolonged use of this form of energy results in respiratory infections and many other disorders that pose a serious threat to humans [57]. There are many incidences of respiratory and other diseases reported in poor and underdeveloped Asian and African countries. Some of the health hazards caused by biomass energy are discussed below.

1.10 Non‐respiratory Illness

1.10.1 In Children

1.10.1.1 Lower Birth Weight

It has been reported that the inhalation of smoke by pregnant women from biofuel burning affects the growth of the fetus. The babies of mothers who use traditional methods of biofuel burning for daily household chores have low weights when compared with babies born to mothers using cleaner fuels [58].

1.10.1.2 Nutritional Deficiency

Biomass fuel also affects the growth of babies exposed to biomass smoke. Long‐term exposure to biomass fuel smoke may lead to nutritional insufficiencies and anemia. It may even cause underdevelopment in children, thus affecting their growth [59, 60].

1.10.2 Respiratory Illness in Adults

1.10.2.1 Interstitial Lung Disease

Women from developing countries, especially those living in rural areas, suffer from severe interstitial lung disease. It has been dubbed “hut lung” because most of the women who suffer from it are poor and live in small houses where biofuels are burned indoors for cooking and other purposes [61]. Interstitial lung disease is a form of pneumoconiosis in which the lungs are damaged by prolonged exposure to smoke and particulate matter.

1.10.2.2 Chronic Obstructive Pulmonary Disease (COPD)

Biomass smoke is one of the major causes of COPD, especially in nonsmoking men and women living in rural areas of developing and underdeveloped countries. [62–64]. Exposure to biomass smoke causes COPD with clinical features that necessitate hospitalization and reduce the quality of sufferers’ lives. COPD patients have a mortality rate comparable to tobacco smokers [65, 66]. The BMF is a major contributor to the pathogenesis of COPD, which has the highest global disease burden.

1.10.2.3 Tuberculosis

Tuberculosis (TB) is still a life‐threatening disease in many countries like Asia and Africa. It is already proven that TB infection is increasing, especially in women periodically exposed to biomass fuel. Several studies have found a link between biomass smoke exposure and TB [67, 68]. BMF smoke harms the lungs and the function of alveolar macrophages [69–71]. Damaged alveolar macrophages are an easy target for Mycobacterium tuberculosis. The healthy alveolar macrophages act as an early defense mechanism against bacteria.

1.10.2.4 Lung Cancer

Biomass smoke has been identified as a “probable carcinogen” (Group 2a) by the IARC (International Agency for Research on Cancer). IARC also classified coal, a common household fuel, as carcinogenic. (Group 1) [72]. Prolonged exposure to biomass fuel smoke may develop adenocarcinoma of the lungs [73, 74]. Inhalation of biomass smoke from the burning of coal and wood is a major lung cancer‐causing factor in the nonsmoking population.

1.10.3 Non‐respiratory Illness in Adults

1.10.3.1 Cardiovascular Disease

Particulate air pollution is proven to increase the incidence of cardiovascular diseases. Particulate air pollution causes rapid increase in fibrinogen, plasma viscosity, platelet activation, and endothelin release. These changes have been found to be statistically significant in the development of cardiovascular diseases [75]. BMF smoke contains up to 20% less than 3 particulate matter. The people who inhale the BMF smoke are exposed to hazardous levels of PM, thus making them highly susceptible to cardiovascular diseases.

1.10.3.2 Cataracts

Studies have found a significant association between exposure to BMF smoke and cataracts or blindness [76, 77]