BURNING BIOMASS FUEL & LUNG DISEASES
Dr. M. Sabir
Delhi chokes on smoke from neighboring states
A study by IIT Kanpur listed stubble burning as the third
Highest contributor to Delhi’s winter air-pollution, after
construction dust and vehicular fumes. DELHI Updated: Oct 24,
2016 14:26 IST, Soumya Pillai and Vishal Rambani ,Hindustan Times
Every year with the start of winter season air pollution caused by stubble (crops residue) burning becomes a hot topic. Stubble (crops residue) is a ‘biomass fuel’ also used in some rural homes of India for cooking and heating purposes.
Air pollution occurs when gases, dust particles, fumes (or smoke) or odor are introduced into the atmosphere (indoor as well as outdoor) in a way that makes it harmful to humans, animals and plant. It occurs when the environment is contaminated by any chemical, physical or biological agents that modify the natural characteristics of the atmosphere. Things that pollute the air are called pollutants.
Nature tries to provide a clean & pollution free environment. It is mostly the human activities for progress and lust to get more & more creates ground for pollution.
Human activities in the home and related to economic and industrial development, growth in population, climatic changes and natural calamities contribute to increasing level of environmental pollution, especially in under developed & developing countries.
Most people spent approximately half of their time in home, household quality of environment is equally important as the the environment outside home. The term ‘indoor air pollution’ refer to the air pollution in home – ‘household air pollution’ (HAP) and at work place or school.
Large numbers of indoor air pollutants are responsible for HAP, but indoor burning of fuel – especially solid fuel (biomass & coal) plays major role in producing HAP.
Indoor fuels used all over the globe include solid, liquid and gas fuels. Solid fuels include biomass and coal. Biomass fuel (BMF) refers to any living or recently living plant and/or animal-based material such as wood, twigs, dried animal dung (e.g., cow dung), charcoal (a product of incomplete burning of wood), grass, or agricultural crop residues (e.g., corn husk, straw, and bagasse – biomass remaining after processing sugar-cane). Coal (different from charcoal) is a naturally occurring fossil fuel includes ‘smoky’ coal (bituminous coal) and ‘smokeless’ coal (anthracite coal). Liquid fuel includes kerosene and liquefied petroleum gas (LPG). Gas fuels include methane and natural gas. LPG and natural gas, in addition to electricity, are widely viewed as clean fuels.
In India biomass fuel smoke exposure is because of:
– Cooking in home.
– Cooking animal food.
– Large scale cooking for social & religious gatherings
– Commercial cooking- food, production of Gurh & Bura from sugarcane & Mawa from milk in some parts of rural areas.
– Indoor heating during extreme winter especially in northern India.
– Burning agricultural waste to prepare their field for next crop.
– Commercial uses for heating in small indutries
– Burning garbage in colonies of urban areas
Biomass fuel in household cooking
World Health Organization reports that half of the world’s population, specially living in under developed & developing countries uses biomass fuel as the primary source of household energy mostly for cooking & internal heating purposes.
In our country biomass fuel is mostly used for cocking purpose but in extremes of winter especially in Northern India it is also used for indoor heating.
As reported by WHO (2012) and International Institute of Population Sciences (IIPS), it is estimated that three-quarters of Indian households use biomass fuel as the primary means for household cooking, mostly in rural area (90%) and that too (90%) on an open fire.
In the rural areas of our country firewood (62%) is most common type of biomass fuel used followed by dung cakes (14%), and agricultural crop residues, straw, shrubs, grass etc(13%) are used to fire different type of chullahs (stove).
Although majority of urban household of India uses cleaner fuels mostly LPG but still significant number of households uses firewood (22%) and kerosene (8%). Factors such as affordability, education, and availability, constraints on cooking space and social customs, play a significant role in the choice of fuel in urban areas, whereas in rural India availability, social customs and lack of awareness plays important role in deciding cooking fuel
Housing pattern affects HAP (specially caused by biomass fuel) qualitatively as well as quantitatively depending upon the type of house, location of house, type of kichen & its location.
Most houses in low and middle income countries where solid fuel is commonly used are poorly ventilated, usually with ought chimney in homes. In many of these houses during winter ventilation is deliberately minimized to conserve energy, leading to substantially increase in exposure to pollutants.
Socioeconomic status is a major predictor of exposure to house hold air pollution (HAP) in most cultures. The less expensive fuel options such as biomass fuels in any context are generally less efficient fuels, produce more smoke, and are used by people belonging to lower socioeconomic status living in poorly designed homes mostly in crowded localities.
The Household behavior (behavior of the individuals living in the house) for cooking, lighting, and heating varies by culture, gender, age, and socioeconomic status. In most cultures, women plays important role in the home, so are maximum sufferer to biomass fuels smoke exposure. Infants and young children living in home with the women have relatively more exposure to HAP as compared to older children and man. Men in most cultures have greater exposure to occupational, industrial, agricultural and tobacco smoke, as compared to HAP.
Air Pollutants from Burning Biomass fuel
On an average, an individual breaths about 10,000 liters of air, per day from his surrounding environment, indoor (home, work place) as well as outdoor. This Inhaled air contains vital life saving component e.g. oxygen as well numerous pollutants causing potential lung damage (sometimes life threatening).
Gases and particulate matter released from burning of fuels ( mostly biomass fuel) used for cooking, heating & lightening and tobacco products are major contributors to indoor air pollution in under developed and developing countries. In more developed countries, gases and chemicals related to air conditioning, furnishing, interior decoration, exposure to formaldehyde and cigarette smoke, especially in newer sealed buildings contribute to increased levels of indoor air pollution.
Burning biomass fuels emits toxic fumes into the air. Major content of these fumes are:
- Suspended particles – Particulate matteris the sum of all solid and liquid particles suspended in air, many of which are hazardous. This complex mixture contains for instance dust, pollen, soot, smoke, and liquid droplets. These particles come in much different size and vary in composition and origin. Particles are either directly emitted into the air by sources such as combustion processes ((biomass fuel etc) and windblown dust, or formed in the atmosphere by transformation of emitted gases such as sulpher di oxide.
Particulate forms of air pollutants can be categorized according to particle size (aerodynamic diameter) e.g. Large (PM10) less than 10 mm, Fine ( PM2.5) less than 2.5 mm, and Ultrafine particles less than 0.1 mm or 100 nm. The determination of the concentration of suspended particles in a particular setting offers the best indicator of health risk.
- Carbon monoxide (CO)- Significant amount of carbon monoxide is released during household cooking using dung (38 g/meal), crop residues (17 g/meal), wood (5g/meal), and kerosene (2g/meal), respectively. The short-term health effects of CO exposure include dizziness, headaches, nausea, and feeling weak. Long-term exposure to carbon monoxide can cause serious heart & lung diseases. Excessive exposure can cause death.
- Vapor forms of Organic pollutants – Polyorganic and polyaromatic hydrocarbons – Polyaromatic hydrocarbons (PAH) include a large class of compounds released during the incomplete combustion of organic matter. Many of these chemicals are capable of producing cancer. A study by the National Institute of Occupational Health showed that the indoor levels of PAH (total) in air during use of dung, wood, coal, kerosene, and LPG were 3.56, 2.01, 0.55, 0.23, and 0.13 μg/m3, respectively .
- Formaldehyde – The mean levels of formaldehyde emitted from cattle dung (670 μg/m3), wood (652 μg/m3), coal (109 μg/ m3), kerosene (112 μg/m3), and LPG (68 μg/m3) have been calculated. Formaldehyde is recognized as an acute irritant to lung tissue and long-term exposure to it can cause a reduction in vital capacity capacity of lungs and chronic bronchitis and in few cases lung cancer & leukemia.
The toxic fumes released from a biomass stove contain organic chemicals that are known mutagens (early process for cancer production) immune system (defense system of body) suppressants, severe irritants to lungs producing inflammation and adversely affect cleaning process in air tubes of lungs (harm to cells containing brush like cilia in airways). A number of other chemicals released have been demonstrated to be human carcinogens ( cancer producing agents). Several toxic inorganic chemicals are known to cause asphyxiation (lack of oxygen) stillbirth, infant death, heart disease, and severe acute and chronic lung disease.
Burning agricultural waste – Burning of agricultural biomass residue, or Crop Residue Burning has been identified as a major health hazard. In addition to causing exposure to extremely high levels of Particulate Matter to people living in the immediate vicinity, it is also a major regional source of pollution. In the month of October kharif harvesting season begins, is the worst time especially mid of October for the pollution through crop residue burning.
Large scale burning of agriculture waste especially paddy straw affects people living in near vicinity as well in distant areas also. As per estimates, Punjab produces approximately 19-20 million tones of paddy straw and about 20 million tons of wheat straw. About 85-90 per cent of this paddy straw is burnt in the field. Wheat straw is also being burnt during the Rabi harvesting season. In Haryana, the problem of paddy straw burning also exists, although the scale (estimated at 2 million tons) is smaller than in Punjab, but it significantly add to air pollution in Delhi & surrounding areas in addition to the pollution caused by automobile & construction projects.
Burning garbage in colonies of urban areas- Globally, millions of tons of municipal solid waste are generated every day. Waste poses a threat to public health and the environment if it is not stored, collected, and disposed of properly. The perception about waste as an unwanted material of no value has dominated attitudes towards disposal. Garbage contains mostly biomass fuel in addition to disposables, polythene, clothes, paper, food wastage etc. The toxic substances in air contaminated by Burning garbage include carbon dioxide, nitrous oxide and methane. These substances are related to causation of various lung diseases and other adverse health effects as contaminants are absorbed from lungs into other parts of the body.