Humankind faces the most prolonged and worst exposure to pollution within the four walls of its homes - indoors - where biomass combustion spells a quiet doom for millions. Surprisingly, most research has chosen to ignore this problem in favour of the more visible outdoor sources of pollution
Within the enemy
HEAVEN is where home istheysay. Factshowevertell adifferent tale. Of coursetheystop short of categoricallydeclaring that the humblehomestead is a veritablehell-holebut results of the limitedresearches into the problem ofindoor air pollution do giveample cause for concern. They allpoint to one single truth:biomass fuels (woodcropresiduesand animal dung)burnt indoorsfor daily cooking and spaceheating in millions ofhouseholds across the developingworldare slowly turning these'heavens' into smog-filledquagmiresand death-traps for theoblivious teeming humanity thatoccupies them.
Such fuels are used by more than three-quarters of Indian households and nearly half the world's population relies on theni,writes Kirk R Smithprofessor of environmental healthsciences at the University ofCaliforniaBerkeleyusand anacknowledged expert on thesubject of indoor air pollutioninThe National Medical Journalof India (Vol 9No 3). While collating exact statistical data onthe pollution generated indoorsby these fuels has turned out tobe a difficult and unmanageable exerciserough estimateshold these pollutants responsible for almost 60 per cent ofthe total worldwide exposure toparticulates. But the worldwith its usual myopic penchantfortraining its guns on lesserevilsdirects 99 per cent ofits airpollution research and controlefforts onto outdoor pollutionwhich accounts for less than twoper cent of particulate exposure in the cities of thedeveloped world.
Health effects of the pollutedair indoorsnaturallygohand-in-hand with exposure.Biomass fuels combine withopen chulhas (stoves) andinadequate ventilation to playhavocwith the lives of two majorvulnerable groups - children andwomen. Acute respiratoryinfection (ARZ)one of the threemajor causes of infant mortalityin India - the other two being diarrhoea and malnutrition - is a result of exposure tofine particulate matter both outdoors and indoors. Amongadult womenchronic lung ailments and cor pulmonale (heartdisease secondary to chronic lung disease) are the commonkillerswhile adverse outcomes of pregnancy and eye disordersconstitute other significant irritants.
Concentrations of particulates found indoors - according to available studies - often exceed the levels found outdoors even in the cities of coal-burning northern Chinawhichqualify as some of the dirtiest in the world. Considering thefact that the maximum number of human person-hours arespent indoors in the cities and villages of developing nations(according to Smiththe total human time spent in urban outdoor environments anywhere in the world makes up only about eight per cent of the total)exposure to and the resultant negative impact on health from particulates do constitutea notable threat. The World Bank's classification - in 1991 -of indoor air pollution in developing nations as one of the fourmost critical global environmental problems can be seen as arecognitionthough belatedof this threat.
It has been found that compared to modem cooking fuelslike kerosene and liquid petroleum gas (LPG)biofuels generate10times more respirable particulates per meal owing totheir low thermal and heat-transfer efficiencies. Biofuel combustion is responsible for the emission of pollutants such assulphur dioxidenitrogen dioxidecarbon monoxidetotalsuspended particles (TSP) and poly-aromatic hydrocarbons.What makes biofuel smoke particularly deadly is its composition which is similar to tobacco smoke.
A recent study of the effects of exposure to indoor air pollution from the use of cooking fuels on women in an urbanslum in Pondicherry (The National Medical Journal of IndiaVol 9No 3) has concluded that women who were exposed tobiofuel smoke suffered more from "respiratory illnesses anddecreased pulmonary functions" compared to those exposedto kerosene or LPG smoke. Two earlier studies- one conducted in Chandigarh and theother in Nepal - had also come to a similarconclusion: in both cases women usingbiofuels suffered more from chronic bronchitis than those using LPG.
Experts have identified six major categories of ill-health which can be attributed to exposures indoors:
• Acute respiratory infections in young chidren
• Adverse pregnancy outcomes (low birth-weightstillbirth or neonatal death) forwomen exposed during pregnancy
• Lung cancer
• Chronic lung ailments (bronchitis or asthma) and associated heart maladies
• Diseases of the eyes
• Increase in the severity of coronary artery disease
Kirk R Smith estimates that seven million children fallprey every year to diarrhoea and / or ARI (in the form of pneumonia); by itselfARi is responsible for 4.3 million deaths outof this seven. This is 30 per cent more than the numbers thatsuccumb to diarrhoea. Alsomore episodes of illness areattributed to ARi than to any other disease category.
The first published study of Am in children (1982)basedon the examination of Zulu 'infants in a South African hospitalhad found that children living in homes with woodstoves wereabout five times as likely to develop severe ARi as those without. In another study (published in 1991) in The Gambia inAfricainfant girls carrie4 on their mothers' backs duringcooking were found to be six times as vulnerable to ARi as opposed to those who were not. One study that had targetedschool-going children in Malaysia found little evidence of theinvolvement of woodstoves in their ill-health; insteadanincreased prevalence of symptoms associated with environ-mental tobacco smoke and the use of mosquito coils wasdetected.
With regard to adverse pregnancy outcomescarbonmonoxide emitted in the course of biomass combustion isperceived to be one of the major culprits. Considerableamounts of this undesirable gas has been detected in thebloodstreams of women cooking with biomass in India andGuatemala. Besidesstudies conducted in western India associate a 50 per cent increase in stillbirths to exposures sufferedby the region's pregnant women.
Another health impact of indoor pollution is chronicobstructive lung diseaseor COLDwhich has been found toaffect non-smoking women cooking on biomass stoves morethan those who have used these stoves sparingly. In Nepalalmost 15 per cent of non-smoking women are plagued bychronic bronchitis.
Research has pinpointed many chemicals such as thepotent poly-aromatic hydrocarbons in biomass smokewhichare known to cause cancer in test animals in laboratories.Their presence in mixtures which are responsible for cancer inhumans has also been established. A '70s study conducted inKenya had led researchers to assume the possible associationof nasopharyngeal cancer to biomass smokebut later studiesfailed to confirm the finding.
Lung canceron its partis a relatively minor problem inmost developing countries. HoweverChinawhere coal is awidely-used medium in the kitchenshas the dubious distinction of having one of the highest numbers of ruralwomen suffering from this fatal disease. The soot-emittingcoal stoves in China's urban centres haveby virtue of theirenormous potential to snuff out the lives of those who usethembeen the focus of most research on urban indoor pollution.
Recent researchsays environmental health scientistJamuna Ramakrishnahas brought into focus a scenario thatgives more cause for concern: even relatively low pollutantconcentrationswhich had previously been believed to havebeen safecould be responsible for adverse impacts on health.
It has been observed that industrialisation and development isusually accompanied by a tendency on the part of the peopleto shift from the use of low-density biomass fuels to that ofhigher quality fuels. The pattern - referred to as the 'energyladder'- couldin the case of Indiamean a progression fromdung to agro-residueswoodkerosenegas and electricityinthat order.
Practicallyhoweverthe situation is more complicated.Factors suck as scarcity (availability of wood and kerosene isoften irregular)steep costs and erratic and unreliable supply(as in the case of electricity or gas) actually forcesconsiderablesections of populations in developing nations down the ladder. The poor are the worst hit: the choice is usually betweenspending a large fraction of their incomes on fuels and usinganimal dung and agricultural residues.
Since emissions of debilitating pollutants are more whendungresidues or wood is burned (lower down the ladder)this phenomenon of the forced downward shift could be oneof the principal factors affecting the increase or persistence ofindoor air pollution in countries like India. The phenomenonalso explains the reason why the least developed nations bearthe brunt of indoor pollution.
Despite the wide-ranging and enormous implications of theproblem on humanity as a wholestudies in the fieldhamstrung bysevere resource constraints and alack of priorityhave mainly reliedon inadequate and small samplesizes and simplified exposuredeterminations.
Expert opinionas a consequenceis still in a haze over theexact fraction of ill-health occuring due to indoor air pollution.'The presence of numerous other'multiple risk factors like povertyand malnutritionfor instancewhich govern health effectsmakeit difficult to put forth a clearcause- and- effect relationshipbetween exposure and healthimpact.
Howeverthe concept of totalexposure assessment has broughtwith it a measure of change in perception. "From a conviction thatthe major concern was ambient air pollution and that the highest exposures occur in urbanareas of industrialised countrieswe have moved to a realisation that since people spend the majority of their time indoorssources of air pollution within homes and offices may be theprimary contributors to human exposuresand thus to healthimpactsexplains Jamuna Ramakrishna.
The domestic cooking stove having been identified as the principal culprit, studies have concentrated on improving stove design and upgrading fuels; the study conducted in the Pondicherry slum, referred to earlier in this analysis, recommends the use of smokeless chulhas or cleaner fuels Re biogas. The earliest improved stoves introduced in India in the '50s had been designed to reduce smoke levels in kitchens.
A more holistic view, however, is the need of the hour, feels Ramakrishna. It is imperative that the kitchen environment be considered as a complete workplace, with all its concurrent hazards kept in mind while dealing with ways and means to de-pollute its atmosphere. Besides, studies also must consider such diverse factors as diet compositions, cooking behaviour, types of fuels and stoves, building materials used and the relation between indoor and outdoor air pollution.
Jamuna Ramakrishna, in an exhaustive paper presented at the Preparatory Meeting on Indoor Air Pollution held in Kenya in 1995, divides ongoing research on indoor air pollution into five categories:
• Measurement of indoor air pollution exposures and relating these to health impact
• Improving stove designs
• Improving fuels
• Attempts to understand the relationship between indoor and outdoor air pollution, in terms of the economics of air pollution control
• Alternative approaches to tackling the problem
Of particular interest in the first category of research are two studies undertaken by the New Delhi-based Tata Energy Research Institute (TERI) - one in the villages of the Garhwal Himalaya and the other in the slums of Delhi. The Garhwal study, according to TERI's Sumeet Saksena, differed from other similar studies in its efforts at comparing exposures suffered by women and children to that endured by the menfolk of the region, in the process estimating the amount of time women actually spent near cookstoves. The study found that in remote areas, 80-100 per cent of daily exposure of women and children was contributed by indoor environments, and that adult women experienced the highest concentrations of TSP - 1, 100-2,000 @tg / m3 - followed by children (540- 1,000 mg / m3 ).
The TERI's Delhi study targeted infants living in the capital's squalid slums, and aimed at establishing the extent of interaction between indoor and outdoor pollutions; slums, which demonstrate a tendency to proliferate near sources of pollution like industries, offered the ideal field for studying both the types of pollution in relation to each other and to the health of the children who were exposed to them. In Delhi, pollutants from the slow combustion of various combustible materials by domestic and commercial sources account for eight per cent of the total pollution.
The study discovered that the childrens' exposure to respirable suspended particulates due to cooking was higher in the slum houses which used wood. Besides substantiating the oft-repeated findings about health impacts, the study threw light on certain interesting aspects. For instance, it found that awareness of the risks entailed by indoor air pollution was at an abysmal nadir so amongst mothers and thatambient airpollution levels may not be an adequateproxy for indoor air pollution". The Wstudy suggested two intervention efforts:a maternal educational and awarenesscampaign and introduction of improvedventilation systems.
Under the national programme onimproved cookstoves (NPIC) - supervised by the ministry of non-conventional energy sources - an estimated30.6million households (25 per cent of householdsthat require less polluting stoves) will be providedwith improved cookstoves by March 1997. The IndianBureau of Standardson its parthas prepared standardsand procedures for testing thermal and combustionefficiency and emission of TSP with regard to these stoves.
But experts are sceptical about the scope and efficacyof the NPIC. Sumeet Saksena finds the target-oriented approach of the programme especially galling.The officials concerned with the distribution of the stoves carry out their task with the sole aim of meeting the targets set before them, and no cross-checking or follow-up measures are initiated,says Saksena. He alsopoints out that although the programme has its regionalcentreslittle effort has been made to suit the typesof the cookstoves to the particular regions which they aremeant for.
The NPIC hasto its credittried to improve matters inresponse to the criticism. Over the yearsit has reduced theamount of subsidy offered to the users of its stoves (to instill asense of ownership in them) and has tried to design stoveswith specific diets and cooking practices in mind.
In the case of improved fuels and alternativestheir easyavailability is an important consideration. Research onimproved fuels has focussed on the use of safer alternativeslike solar powerbiogas and iawdustamong others. Howeverin the absence of a convenient and cheap way of storing solarenergysolar cookers have failed to make any considerablemark. The immense potential of biogas remainslikewisetobe fully exploited. In factmost research in the area of fuelupgradation has preferred tokeep the concerns of commercialutility and profitability in mindrather than keeping those ofindoor air pollution.
Efforts in intervention haveall said and donebeen markedby a glaring limitation: a lack of involvement of thepeople who are directly or indirectly affected by the menaceof indoor air pollutionparticularly women. The point ofconcern here is the status of women in developingnations. jamuna Ramakrishna points out: "In many waystheproblem of indoor pollution as it exists today is an outwardsign of the low value placed on the time and labour ofwomen.
An integrated approachkeeping in mind all therelevant considerationshas to be taken to tackle this all-pervasive problem. Community based and non-governmentalorganisations have done commendable work in this respect;the official machinery could pool in its bit to buttress theseefforts by prioritising fuel availibility and pricing andpaying attention to the necessity of propagating wellventilatedlow-cost housing.
With inputs from Piya Kochhar and Deepan Joshi
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