impact of improved cookstoves on indoor air quality in the...

Impact of improved cookstoves on indoor airquality in the Bundelkhand region in India

Chaya ChengappaDevelopment Alternatives, 23 Sree Rama Mandir Road, Basavanagudi, Bangalore 560004, India

E-mail: [email protected]

Rufus EdwardsDepartment of Epidemiology, School of Medicine, University of California, Irvine, CA 92697-3957, USA

Rajesh BajpaiDevelopment Alternatives, 1087 Civil Lines, Jhansi 284001, India

Kyra Naumoff Shields and Kirk R. SmithSchool of Public Health, University of California, Berkeley, CA 94720-7360, USA

Despite the reach of India’s National Program on Improved Chulhas, little quantitative monitoringand evaluation of improved stove projects in India has previously been undertaken by non-govern-mental organizations. Development Alternatives (DA) recently distributed 980 improved chimneycookstoves (Sukhad stoves) in the Bundelkhand region of India. In a subset of these households(n = 60), DA undertook a comprehensive assessment of the impact of the improved Sukhad stoveon indoor air quality. Measurements of carbon monoxide (CO) and fine particulate matter (PM2.5)were conducted for a 48-hour period in 60 rural kitchens in Bundelkhand before and after instal-lation of the Sukhad stove. One year after the installation of the of the Sukhad, 48-hour averageCO concentrations were reduced, on average, by 70 % (p < 0.001) in the homes of regular usersof the improved stove. Similarly, 48-hr average PM2.5 concentrations were reduced, on average, by44 % (p < 0.01). Given these reductions, continued promotion of the Sukhad stove would be war-ranted, while simultaneously improving stove design. Similar to other Household Energy and Health(HEH) projects, there were many homes that transitioned to use of the improved stove, while main-taining a traditional stove in the home, which highlights the need for follow-up in stove trainingafter installation of the improved stove. Although challenging, the monitoring and evaluation pro-vided important information about actual use of the stove in communities, and was important inunderstanding the adoption process for these rural families.

1. IntroductionEstablished in 1983, Development Alternatives (DA) is anon-profit organization devoted to fostering large-scale ef-forts to attain sustainable livelihoods for the poor of India.DA’s experiences working in the household energy sectorspan two decades and emanate from a fundamental con-cern over the low performance, inefficiency and pollutionassociated with domestic cooking, lighting and space-heating devices commonly used in India. Since 1999, DAhas worked with approximately 25,000 households in 200villages in the Bundelkhand region, a poverty-strickenarea of about 400 km2 in central India. A large segmentof the rural households in Bundelkhand report poor healthof mothers and infants due to problems created by indoorair pollution (IAP), as well as other conditions such aspoor water and sanitation and poor nutrition.

In this region, the main source of IAP comes from theuse of semi-processed and unprocessed biomass fuelsused in traditional, poorly-designed, inefficient stoves that

households depend on for their everyday cooking andheating needs. Even in the limited number of middle-in-come and high-income households in this region, inade-quate supplies of clean fuel options such as liquifiedpetroleum gas (LPG) and electricity result in relativelycommon usage of inefficient cookstoves. Wood andcowdung cakes are the primary fuel sources, and keroseneis used for lighting. Because women and children spendlarge amounts of time in the kitchen, this sub-populationis disproportionately affected. Indoor air quality (IAQ)may be worsened depending on the hours the stove is lit,the kitchen size and household ventilation. The problemis further aggravated as most of the poor live in a singleroom, which serves as a kitchen as well as living andbedroom area.

In India, a large-scale government sponsored programcalled the National Programme on Improved Chulhas(chulha is Hindi for cookstove) (NPIC) was launched in1983 to conserve forests, reduce the time required of rural

Energy for Sustainable Development • Volume XI No. 2 • June 2007

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women to collect fuel and, as a secondary objective, re-duce IAP. Although impressive achievements (viz., 34million improved cookstoves (ICSs) installed by 2001-2002) were claimed, field studies showed that benefits interms of fuel saved and/or improvement in IAQ wereminimal or non-existent [Gusain, 1990; Mahapatra, 2003].The heavily subsidized and target-oriented program en-couraged promotion of many sub-standard designs thatwere frequently discarded or malfunctioning within oneyear of their installation or distribution. Due to the sub-sidy, there was no incentive for the installer, manufactureror the supplier to maintain the quality of the product afterinstallation or render after-sales service. In addition, dueto the lack of systematic monitoring and evaluation, therewas little or no timely feedback from the field about theperformance of the stoves or their acceptability in actualuse.

Previous ICS programs including those under the NPICin the Bundelkhand region have not been quantitativelyevaluated. On the basis of the analyses of the NPIC ingeneral and DA’s own knowledge about the area, however,any initial achievements that might have been attainedwere not sustained once the incentives under the NPICwere withdrawn.

As part of the Household Energy and Health (HEH)Project, we used quantitative methods, designed accordingto standard protocols, to undertake a comprehensive as-sessment of the impact of an improved stove – the Sukhadstove – in the Bundelkhand region. The project was de-signed to monitor IAQ in the kitchen area, measure stoveperformance using two standardized tests, and to assessany changes in the health of women and children due tothe installation of the improved stove. We report here find-ings of the IAQ monitoring and evaluation conducted ina subset of the 980 households (n = 60) where the Sukhadstove was promoted to quantitatively evaluate the changesin IAQ due to its installation. Results from stove perform-ance testing are discussed in an accompanying paper[Bailis et al., 2007] in this issue and results from our re-search on the social impacts of health of women and chil-dren will be published elsewhere.1.1. Characteristics of fuel use in households in theBundelkhand regionFuel used in both traditional and improved cookstoves isprimarily wood and cowdung cakes. As availability offirewood has diminished over the years, households haveturned to using a locally available weed, a species of Ipo-moea, in combination with other available firewood fortheir primary fuel. Generally resource-poor families usemore Ipomoea sp. and/or other weedy biomass due to lackof access to better quality fuel. Burning Ipomoea sp. pro-duces a particularly intense and foul-smelling smoke thatis anecdotally reported to be associated with skin and eyeirritation, cough, and headache, although we know of nosystematic studies of its effects. Ipomoea sp. and otherlocally available wood (including twigs and branches) arecollected from nearby fields and surrounding areas everytwo to five days or every 30 days depending on availablestorage space and economic status (those who can afford

to do so buy firewood in large quantities). Women spendapproximately six to ten hours per week gathering fire-wood and/or preparing cowdung cakes [TSB, 2003]. Mostfamilies own animals and use their own cattle for makingcowdung cakes. Families that do not own cattle collectdung from nearby fields. In either case, however, dungavailability is not sufficient, and most families purchasedung cakes at regular intervals of one to two days. Wastebiomass, such as crop residues, is also used for fuel when-ever it is available. In addition, kerosene is used to startthe fire and, in a few cases, to provide fuel for kerosenestoves. LPG is used among a few high-income families.Expenditure for fuel ranges from Rs. (rupees) 50 (US$1.10) to Rs. 250 (US$ 5.50) per month.

Cooking is invariably done by women. All cookstovesare generally used for one to four hours per day for prepa-ration of two meals for an average family of five to eightmembers [TSB, 2003]. On the basis of baseline surveys,neither family size nor cookstove size has a discerniblecorrelation with the time spent cooking or with the hoursof cookstove use per day. Instead, hours of cookstove useper day depend primarily on the condition of fuel; forexample, both wood and cowdung cakes take longer toignite during the monsoon and winter seasons when thefuel is generally wetter.1.2. Description of traditional stove in theBundelkhand regionIn the Bundelkhand region, the traditional cookstove(TCS), or chulha, is a single-pot U-shaped stove made ofmud and clay. In households, it can take on either a port-able or fixed form (Figure 1) [TSB, 2003]. Both stovetypes are manufactured by local potters. Fixed stoves areinstalled, typically by the woman of the house, in eachhousehold using a mud and straw mixture. In contrast, theportable stoves can be easily moved, depending on pre-ferred cooking conditions. Both the fixed and portablestoves are cleaned after cooking and plastered with a coatof mud slurry. The size of the traditional cookstove isapproximately the same in most of the households. Mosthouseholds have two chulhas and typically keep one in-doors and one outdoors. The households cook outdoorsduring the summer (4 months), and, in some cases, duringthe winter as well. Cooking normally occurs indoors dur-ing the monsoon and winter seasons (8 months). If re-quired, both the indoor and outdoor cookstoves are usedsimultaneously.1.3. Description of improved stove in the BundelkhandregionThe ICS evaluated here is known as the Sukhad stove(Figure 1). This stove is generally suitable for a familywith six to eight members who use flat or spherical bot-tom vessels 19-30 cm in diameter for food preparation.Cooks like the stove because strong heat is provided underboth the first and second pot-hole. The Sukhad stove isdesigned so that the second pot-hole is raised by approxi-mately 6 cm above the level of the first pot-hole with theaim of avoiding interference between pot rims when cook-ing with two large pots. Each Sukhad stove typically sellsfor approximately 350 rupees (US$ 8) and is available for


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purchase in most public marketplaces.The Sukhad stove is manufactured locally by artisans.

It is a single structure made of reinforced concrete, andis a twin-pot stove with a chimney. The body of this stoveis constructed using a fabricated steel mold into whichconcrete, made in part from locally available clay mate-rials, is poured. The same mold can be used to manufac-ture six stoves per day. A separate mold is used tospin-cast the chimney pipe from asbestos cement. Thestove’s cowl is made of cement mortar. A cast-iron gratewas sold with the Sukhad stove for an additional Rs. 22(US$ 0.50); its usage was strongly promoted during theinstallation demonstration in each household.1.4. Description of Sukhad stove disseminationprogram in the Bundelkhand regionAs part of DA’s “Energy Services for Village Households

and Livelihood Enterprises” project, 980 Sukhad stoveswere distributed to households in the Bundelkhand regionfrom January 2003 to January 2005 (a total of 1430 ICSswere distributed as part of the program; 450 were of othertypes). DA’s strategy for disseminating the stoves usedtwo approaches (Figure 2). The “community awarenessand mobilization” component consisted of (1) buildingstove awareness and demand through social marketing;(2) stove demonstrations in local markets and at villagefairs; and (3) stove promotion through local self-helpgroups, DA’s Social Action Group (SAG), elected mem-bers of panchayats, or village councils, and other com-munity-based organizations. For example, self-helpgroups are informal groups that are used for collectiveaction. These groups usually promote savings amongmembers and use their pooled savings to meet their con-sumption, production and investment credit requirements.The SAG is a branch of DA. This group designs innova-tive strategies and integrated approaches to manage natu-ral resources and strengthen local institutions. It offersplanning and management, capacity-building, field imple-mentation, monitoring and evaluation and policy adviceservices. One of the SAG’s focal areas is enhancing live-lihood options for economically and socially disadvan-taged sections of society. The “market and enterprisedevelopment” efforts were designed to (1) develop will-ingness to pay in highly underdeveloped markets; (2) in-crease stove credibility though use by individuals called“early adopters”; (3) create a marketing push through theuse of micro-entrepreneurs; and (4) engage in brand de-velopment for the stove. Following these efforts, the Suk-had stoves were sold to each household at market price,and household members were permitted to purchase thestove in one lump-sum or using an installment paymentplan.

DA estimates that 8.6 million homes out of the 10.84million in 52 districts in Uttar Pradesh and MadhyaPradesh states meet affordability criteria to purchase oneor another cookstove, on the basis of demographic data.On the basis of relationship among product, benefits andavailable solutions, and DA’s manufacturing and dissemi-nation capacity, 1 million of these homes have been tar-geted by DA for initial stove dissemination efforts.

2. Data and methods2.1. Study site descriptionThe Bundelkhand region, located in central India, com-prises 13 districts in the states of Madhya Pradesh andUttar Pradesh (Figure 3). This region is semi-arid andpartly rocky with an average annual rainfall of 780 mmconcentrated predominantly in the months of July and Au-gust. The run-off rate is high, however, resulting in dryconditions most of the year. The daytime temperatures canreach a high of 48º C during the summer months and alow of 2º C in the winter. Due to the cold winters, stovesare also used to satisfy household heating needs.

80 % of families live in villages, with 20 % in thetowns of Tikamgarh and Datia. 89 % of these householdsare poor. Household income ranges from Rs. 900 (US $20,

Figure 1. Cookstoves used in the Bundelkhand region. Both a fixed tradi-tional cookstove, or chulha, and a portable chulha are shown in the pho-tograph above. An improved Sukhad stove that DA is promoting with atwo-pot design and chimney is shown in the photograph below. Optionalaccesssories that improve combustion efficiency, e.g., pottery liners andcast-iron grates, are sold separately.


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subsistence level of occasional wage-earners) to Rs. 3600per month (US $80). The households selected for ourstudy were located in clusters around Radhapur, Niwari,and Thona in the Bundelkhand region. Villages in theThona cluster were: Ramgarh, Pura, Kacchipura, Rajapur,and Neemkhere. Villages in the Niwari cluster were: Ku-warpura, Bhelsa, Mounpura and Makara. Villages in theRadhapur cluster were: Ghatwaha, Rajpura, Bhojpura, andJhijora. Across these villages, households used a combi-nation of cowdung cakes made at home and wood – col-lected from the agricultural fields or forests – for fuel.The relatively small increases in fuel use in the winter(as MJ consumed per capita per day) are presented in[Bailis et al., 2007] in this issue. This study did not assessthe nuances of changing ratios of cowdung cakes to woodacross seasons, though, as expected, the fuels were wetterduring the monsoon season.2.2. Study designFrom July 2004 to September 2005, monitoring was car-ried out in 60 households using a “paired, before and af-ter” study design without controls in order to quantifychanges in IAQ in the kitchens of rural households inBundelkhand [Smith et al., 2007, in this issue]. The sam-ple size was calculated assuming a coefficient of variationof 0.7 and a desire to detect at least a 30 % change inIAQ after the installation of the Sukhad stove. On theseassumptions, the necessary sample size was 43 house-holds. To account for anticipated household drop-outs,however, we enrolled 60 households.

The first round of monitoring occurred from July toAugust 2004; initially, all households relied on the TCS

for the majority of their cooking and heating needs (n =60). One month after the installation of the Sukhad stove,a second round of monitoring occurred during the mon-soon season (n = 60; August to September 2004). Thethird monitoring phase was conducted during the winterseason (n = 60; October 2004 to February 2005). Thefourth and final phase was conducted approximately 12months after the installation of the Sukhad stove duringthe summer/pre-monsoon season (n = 25; July to August2005). The comparisons presented in this paper focus onhomes that relied primarily on the improved stove fortheir cooking and heating needs (regular users), and forwhich both before and after measurements passed dataquality objectives. The evaluation study was designed andimplemented with technical assistance from the Universityof California.2.3. Household selectionAs with many rural areas where housing is not stand-ardized, a wide range of different stove and kitchen con-figurations were encountered in the Bundelkhand region.Specifically, households in the Bundelkhand region havethree general types of kitchens – indoor, semi-indoor (with3 walls), and outdoor (open-air kitchen with a makeshiftthatched roof for summer). Our intent, therefore, was tomeasure the most common configurations in the area, asmeasuring the impact of Sukhad stoves in all housing con-figurations would have required a prohibitively large sam-ple size. Thus, our inclusion criteria required thatparticipants had to use the same type of TCS, purchasethe Sukhad stove, rely on the same primary fuel, andhave similar household characteristics. An extensive

Figure 2. Schematic of DA’s Sukhad stove dissemination program in the Bundelkhand region. Community awareness and mobilization: the TARANirman Kendra is essentially a laboratory at DA. The focus of this group is to promote alternatives to traditional methods with environmental, economicalor health benefits, and ensure the transfer of these technologies from “lab to land”. Enterprise development: the marketing associate is a local personactive in the dissemination of improved cookstoves. The associate sells stoves and provides after-sales service for a commission.


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pre-monitoring survey of households that purchased theimproved Sukhad cookstove was conducted using a ques-tionnaire based on specific criteria – including kitchenlocation, kitchen size and family size – to select studyhouseholds. A total of 60 households with indoor kitchensand similar kitchen and family sizes were randomly se-lected from around Radhapur, Niwari, and Thona in theBundelkhand region for inclusion in the study; these com-munities were selected for their proximity to each otherand because enough households in these villages pur-chased the Sukhad stove. Each household provided oralconsent before enrolling in the study. During the sum-mer/pre-monsoon season the sample size was reduced to25 households because study participants preferred tocook outdoors. They could easily move the TCS outside,while the fixed Sukhad remained indoors.2.4. Indoor air pollution monitoringIAQ was assessed by continuously measuring concentra-tions of PM2.5 and CO for 48 hours in household kitchenlocations in the same houses before and after the instal-lation of the Sukhad stove in three phases (during differ-ent seasons) starting from June 2004. PM2.5 measurementswere made using the UCB monitor (University of Cali-fornia Berkeley, Berkeley, CA, USA) developed to moni-tor PM2.5 in rural biomass-burning kitchens [Litton et al.,2004; Edwards et al., 2006; Chowdhury et al., 2007].Carbon monoxide was monitored using the Hobo COmonitor (Onset Computer Corporation, Pocasset, MA,

USA). CO and PM2.5 measurements were conducted ac-cording to standard protocols [Smith et al., 2007, in thisissue]. Both instruments contain dataloggers, which storethe minute-by-minute data over the entire measurementperiod in their memories. These data are then downloadedinto a personal computer after monitoring.

During the first visit to the household, the field staffadministered a standard verbal consent form as requiredby the University of California Human Subjects Commit-tee. The field team also placed a nail on the wall to hangthe IAQ instruments according to standardized criteria –1 m away from the combustion zone and 1.45 cm highon the side of the stove away from open doors or win-dows. Upon returning to monitor CO and PM2.5 after theinstallation of the ICS, the field team placed the instru-ments on the same nail unless the location of the newICS was different from the location of the TCS. DA’s IAQfield team, which performed all IAQ monitoring in com-munities, consisted of coordinators, data entry clerks andfield staff. All members of the team underwent a two-week training course on standard IAQ monitoring proto-cols before field work and attended a data analysisworkshop after field work completion; all training wasconducted by collaborators from the University of Cali-fornia. Data analysis used SPSS version 9 (SPSS Inc),Stata version 9 (StataCorp, LP) and Microsoft Excel.2.5. Household post-monitoring questionnairesOver the course of the study, each household was visited

Figure 3. Location of the Bundelkhand region in India


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eight to ten times by the field team. All questionnaireswere administered in the local language (Hindi). Standardpost-monitoring questionnaires – which had been devel-oped, piloted and revised before the study started – wereroutinely administered after the completion of the 48-hourmonitoring period. This questionnaire collected informa-tion on fuel use, stove use, cooking habits, the number ofpeople cooked for and other information that describedhousehold activities during the 48-hour monitoring period.Administering this questionnaire required approximately30 minutes.

3. ResultsThe 61 kitchens in which IAQ was monitored were lo-cated in 13 different villages in three separate areas in theBundelkhand region. We present here comparisons ofchanges in IAQ levels as a result of installation of theSukhad stove, only in households that reported using theimproved stove in indoor kitchens as their primary cook-ing stove for cooking and heating needs (regular users)[1].Overall, 61 % of the households in this study reportedregular use of the improved stove.

Figure 4 represents typical CO and PM2.5 concentra-tions measured throughout the 48-hour sample period inthe same household, before and after the installation ofthe Sukhad improved stove. The CO and PM2.5 peaks oc-cur together, as would be expected since both pollutantsare produced during combustion. Due to the continuousnature of the data collected, both the time of actual cook-ing events and the peak exposure concentrations are re-corded in the data. The correlation between 48-hr CO andPM2.5 measurements in households using the traditionalstove at baseline is shown in Figure 5 (n = 36, adjustedr2 = 0.74)[2].

Table 1 shows the CO and PM2.5 measurements fromall villages during the monsoon, winter and summer sea-son. After one year (summer season), the 48-hr meanPM2.5 concentration was significantly reduced, on aver-age, by 44 % (p < 0.01)[3]; the 48-hr mean CO concen-tration was also significantly reduced, on average, by70 % (p < 0.001). Similarly, one to two months after Suk-had installation (monsoon season), the 48-hr mean PM2.5concentration was significantly reduced, on average, by36 % (p < 0.02); the 48-hr mean CO concentration wasalso significantly reduced, on average, by 32 % (p < 0.01).Six months after the Sukhad installation (winter season),however, our team experienced technical challenges. Dueto poor data quality, the winter PM2.5 monitoring resultshave been excluded from our analysis. Regarding CO, thedifference in mean concentration between the traditionalchulha and the Sukhad stove in the winter was not sig-nificant (Figure 6).

Figure 7a depicts the absolute difference in 48-hourmean PM2.5 concentration between the Sukhad stove andthe traditional stove in all households with valid pairedmeasurements during the monsoon season (N = 30). Al-though the mean PM2.5 concentration was reduced in 63 %of the households, the Sukhad stove increased the 48-hourPM2.5 concentration as compared to the traditional stove

in 37 % of the households. Although not directly assessed,this could be the result of either differences in amount ofcooking and cooking tasks between monitoring periods inthese homes, or lack of familiarity with correct function-ing of the stove, e.g., lighting the fire with no pot on thestove so the smoke is directly emitted into the kitchenrather than through the chimney. Figure 7b shows the ab-solute difference in 48-hour mean CO concentration be-tween the Sukhad stove and the traditional stove in allhouseholds with valid paired measurements during themonsoon season (N = 37). Similar to the case of the PM2.5measurements, the Sukhad stove increased the 48-hourCO concentration in 49 % of the households as comparedto the TCS, presumably again for the reasons stated above.During the summer season, the Sukhad stove, as comparedto the traditional stove, decreased 48-hour PM2.5 concen-trations in 40 % of the households (N = 15) and decreased48-hour CO concentrations in 67 % of the households(N = 15).

4. DiscussionOverall, the Sukhad stove was well accepted by the users[TSB, 2003]. Users felt that, if properly used, the secondpot chamber helped cook the meals and heat water fasterthan the traditional stove. Users mentioned other benefitsof the Sukhad stove, including less eye irritation due tosmoke, cleaner kitchens, fuel savings, easier to light, lessmaintenance, and safer (does not burn hands as much asthe traditional stove). In a follow-up survey after the con-clusion of our study, approximately 92 % (900/980) ofthe households with installed Sukhad stoves reported us-ing it as their primary stove. In the households monitoredfor IAQ, however, the fraction not using the improvedstove as their primary stove for cooking and heating needswas larger (39 %), electing to keep a traditional stove forcooking tasks. Thus, similar to situations in China inwhich unvented stoves were maintained in the samekitchen, benefits of the improved stove are often largelynegated [Edwards et al., 2007]. There are a number ofreasons for continued use of the traditional stove in somehomes. (1) a transition from the traditional stove to theimproved stove would be expected from social theoriesof technology dissemination [Rogers, 1995], with rapidadopter groups adopting the new stove entirely, some par-tially, and some more reluctantly. (2) Unlike modern gasstoves, for example, power output on improved stoves isnot easily adjustable. Thus, improved stoves may notserve all cooking needs, and a traditional stove is fre-quently retained for high-power tasks such as heatingwater. (3) As explained in Section 4.1 below, the stovedesign was not ideal for cooking rotis, a local flatbreadin the area and one of the staples of the regional diet.

For households that used the stove as the primary stovefor cooking and heating needs, reductions in average 48-hour kitchen CO concentrations were observed during allmonitoring periods, including 1-2 months, 6 months and1 year after installation of the improved stove. Similarly,PM2.5 reductions were observed during all monitoring pe-riods, except for the 6-month winter monitoring period


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Figure 4. Graphs representing typical 48-hour concentrations of CO (below), as measured by the HOBO CO monitor, and PM2.5 (above), as measuredby the UCB particle monitor, in the same study household before and after the installation of the Sukhad stove. The measurements on the Sukhadstove were taken during the monsoon season.


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Figure 5. Correlation between 48-hr CO and PM2.5 measurements in households that relied primarily on the traditional chulha for their cooking andheating requirements during baseline (N = 36, adjusted r2 = 0.74). The outlying point was excluded from the correlation analysis.

Table 1. Paired before-and-after comparisons of 48-hour CO and PM2.5 means in households that relied primarily on theSukhad stove for their cooking and heating needs

a. Monsoon: 1-2 months after installation of improved stove

Before After p-value(Wilcoxon

signed rank test)

MeanpercentchangeN Mean SD Maximum Mean SD Maximum

PM2.5 (mg/m3) 30 0.52 0.75 4.14 0.33 0.39 2.09 < 0.02 36

CO (ppm) 37 7.88 6.73 29.9 5.38 3.89 18.9 < 0.01 32

b. Winter: 6 months after installation of improved stove


signed rank test)


PM2.5 (mg/m3) NA[1] NA NA NA NA NA NA NA NA

CO (ppm) 36 7.90 6.8 29.9 5.5 4.7 17.6 < 0.16 30

c. Summer: sub-sample (N = 15) 1 year after installation of improved stove


signed rank test)


PM2.5 (mg/m3) 15 0.65 1.01 4.14 0.36 0.47 1.93 < 0.01 44

CO (ppm) 15 8.67 7.8 29.9 2.68 2.8 8.4 < 0.001 69


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Figure 6. (Top) boxplot of 48-hour mean CO concentration in households using the traditional and Sukhad stoves (monsoon, winter and summerseasons); (bottom) boxplot of 48-hour mean PM2.5 concentration in households using the traditional and Sukhad stove (monsoon and summer seasons).In a boxplot, the line in the box represents the median concentration, while the lower bound of the box represents the 25th percentile and the upperbound represents the 75th percentile.


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Figure 7. Absolute difference, in each household, between the Sukhad and the traditional chulha 48-hour mean CO (7a, top) and PM2.5 (7b, bottom)concentrations. Each bar represents one household. Negative values represent households where the Sukhad stove reduced the 48-hour mean concen-tration; positive values represent households where the Sukhad stove increased the 48-hour mean concentration.


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for which data quality was not sufficient to make the com-parisons. Reductions of PM2.5 during the other seasons,however, indicated that the Sukhad stove resulted in ap-proximately 40 % reduction in 48-hour average kitchenconcentrations. The Sukhad stove also resulted in approxi-mately 30 % reduction in 48-hour average CO kitchenconcentrations. Although during the summer the reportedreductions were greater (69 %), the sample size was muchsmaller; the average concentration of CO was 50 % lowerthan that observed during the other two seasons. Possiblythe reduced use of cowdung during the summer resultedin decreased CO concentrations, given that the overallcombustion in the stove would be improved. A morelikely explanation, however, is that the decreased samplesize in the summer reduced some of the variability; thesummer sample size was smaller as this monitoringphase was primarily designed as a sub-sample to vali-date reductions.

During the winter period, due to the high indoor con-centrations, particulate deposition on the inner surfaces ofthe particle monitors built up due to the initially inade-quate cleaning protocols. The deposited particulate matterand associated effects of humidity resulted in an elevatedand noisy electronic background due to scattering of thelight source, and resulted in mass estimates that were notreliable. To avoid such scenarios, we recommend institut-ing and adhering to strict data quality assurance and qual-ity control practices when examining data frommonitoring instruments at the end of each day. By per-forming daily data quality control, households that requirerepeat monitoring due to instrument failure can be iden-tified and re-monitored.

The reductions presented in this paper were for homesthat reported they were regular users of the Sukhad stove.Similar to most other ICS programs, participants in somevillages elected to retain a traditional stove or other cook-ing stoves (kerosene or charcoal) even after installationof the Sukhad stove. Of the surveyed households, 60 %used only the Sukhad stove (used for cooking two meals)while 40 % used both the Sukhad (used for cooking onemeal only) and their TCS for cooking. Because the inten-tion of this monitoring exercise was to assess the potentialbenefits of the Sukhad stove, households that did not in-stall the Sukhad stove or that did not regularly use theSukhad stove were excluded from the analysis. On thebasis of these reductions, continued promotion of Sukhadstoves is warranted. Increased efforts should be under-taken after installation of the ICS, however, to access andincrease the effective adoption rates. In addition, the re-sultant PM2.5 and CO concentrations after installation ofthis stove were still high, and in some cases increased,indicating that considerable additional improvementscould be made through stove design and follow-up ofstove function in the homes. Our monitoring and evalu-ation efforts provide a strong rationale to continue Sukhadstove development to achieve more significant reductions.

An additional 50 % in the number of study homes wereenrolled in our study beyond those required to see sig-nificant differences, in order to account for participants

who did not purchase Sukhad stoves or who were notregular users of the stove. In our experience, the numberof “extra” households necessary to enroll in the study de-pends on the number of times the field team visits thehousehold. More visits create a greater feeling of coop-eration with the household, and frequently result in im-provements in data quality and fewer householddrop-outs. For example, our field team visited the housemidway through the 48-hour monitoring period to checkon monitor function and Sukhad stove usage and to an-swer questions. These conversations with the householdmembers provided invaluable feedback in perceptions ofthe stove and its suitability for local cooking tasks.

Questionnaire data collected during our study includedinformation on the number of meals cooked and fuelquantity and use. In future studies, however, it would bemore useful to stove dissemination groups to collect in-formation that helps determine why the household pur-chased the ICS; how many used it regularly; and why theTCS was still required by some households. Informationshould also be collected about space-heating and lightingrequirements and how long the cook spent in the kitchenwhile the stove was lit. This information would providea more nuanced perspective on the acceptance and utilityof the stove, and help stove designers to develop stovesthat meet local needs.4.1. Monitoring and evaluation effortsThe two key benefits of our monitoring and evaluationexercise were obtaining qualitative data on stove designand use, and quantitative data about before and after IAQconcentrations. Firstly, our results facilitated the designof more efficient and lower-emission stoves. As the pro-ject progressed, DA made several modifications to theSukhad stove on the basis of feedback provided by users.The size of the fire-box mouth was increased to accom-modate larger fuel pieces and to allow for the cooking ofrotis. The Sukhad manufacturing process was alsochanged. The cement body was reinforced with a metalmesh to both increase its strength and decrease the like-lihood of cracks developing in the stove body. The thick-ness of the metal grate was also increased to extend itsuseful life. Subsequent stove models progressively be-came lighter in weight by both reducing the amount ofcement used in the body of the stove and by improvingthe stove design. Additionally, lighter-weight pottery andceramic liners were designed to both improve stove ther-mal performance and to facilitate transportation of thestoves. On the basis of these improvements, DA createdan improved twin-pot model stove known as “PotteryLiner II stove”. This stove is not fully cast in concrete;instead it is made from fired clay components that aremuch easier to transport to the target villages. At the vil-lages, stoves are installed in situ with the clay componentsand a mud body.

Due to these improvements, we expect that only ap-proximately 200 Sukhad stoves will be sold in 2007 com-pared to over 3000 of the Pottery Liner II stoves.Although the rapid change in stove models presents somechallenges to government and funding agencies that might


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wish for a single value quantifying the relative reductions(of, e.g., IAP) as a result of the improved stove, the im-provement of stove models represents a positive and morevaluable outcome of the monitoring and evaluation ap-proach. For example, given the continual improvement ofstove model throughout the course of the project, the stovebecame structurally more robust, more thermally efficientand better suited to local cooking practices.

The second benefit of our monitoring and evaluationefforts was the documentation of IAQ improvements dueto primary use of the Sukhad stove. In areas where littlepublic information is available on the relative advantagesof improved stoves, this evidence can be used in promo-tional materials for stoves.

Our first monitoring and evaluation project proved tobe both a challenging and an enriching experience. Theresources and personnel requirements to conduct suchstudies, however, should not be underestimated. Althoughtesting stove performance in households is conceptuallysimple, in practice it is complicated by changing patternsof stove usage and willingness to participate during thelong time-frame for before-and-after assessments, each ofwhich tends to increase the number of homes that are re-quired for monitoring. Further, although installing, main-taining and analyzing data from the IAQ monitors workedwell, careful training of the field team is required as datadownloading and analysis requires careful and diligentwork to maintain the number of households with completeinformation. In addition since multiple home visits are re-quired for a variety of reasons including building relation-ships with participants, absences at the household, guestsat the household, festivals, and so forth, realistic assess-ments should be made for personnel and transportationrequirements. Finally, every effort must be focused onregular data entry to facilitate data analysis as the largeamount of data can quickly become overwhelming.

Although challenging, the information obtained in themonitoring and evaluation study was valuable not only indocumenting the IAQ improvement as a result of regularuse of the Sukhad stove, but also in providing informationabout the participant perceptions of the stove and actualusage within different communities. All of this informa-tion was of great benefit to DA.

Given the time and resource commitments involved inconducting this number of home visits over a one-yearperiod and DA’s technical capacity in indoor air monitor-ing, DA will likely hire local project consultants for thenext improved stove monitoring and evaluation project to

facilitate timely project completion. One consultant wouldmanage the field work and the second would be a spe-cialist in IAQ working in the health sector to performstatistical analysis and interpretation of IAQ data. Despitethe large amount of effort required for a successful pro-ject, the value of the monitoring and evaluation is clearin the feedback on stove performance, and DA plans tocontinue conducting both laboratory tests and field trialsof new improved stoves in order to promote the improve-ment of IAQ in all Indian households.

Acknowledgements

Our thanks go first to the participating families for their patience and cooperation duringthis study. We would also like to thank the leadership of S. Patara and the field team atDevelopment Alternatives, Jhansi, for conducting the household monitoring in different sea-sons over the years. We would like to thank the Shell Foundation for providing the resourcesto conduct this study.

Notes

1. The winter during the monitoring period (October 2004 to February 2005) was quitesevere, and stoves were used for both household cooking and heating needs.

2. r2 is a statistical measure of the degree to which two measurements are correlated. Inthis case, it indicates that 74 % of the change in the PM2.5 level was predicted by thechange in CO.

3. p refers to the probability that the measured difference occurred just by chance, i.e.,does not represent a true difference. By convention, if the p-value of a comparison isless than 0.05 (5 %), the difference is termed “significant”.

References

Bailis, R., Berrueta, V., Chengappa, C., Dutta, K., Edwards, R., Masera, O., Still, D., andSmith, K.R., 2007. “Performance testing for monitoring improved biomass stove interven-tions: experiences of the Household Energy and Health Project”, Energy for SustainableDevelopment, XI(2) (this issue), pp. 57-70.

Chowdhury, Z., Edwards, R., Johnson, M., Naumoff Shields, K., Allen, T., Canuz, E., andSmith, K.R., 2007. “An inexpensive light-scattering particle monitor: field validation”, Journalof Environmental Monitoring, submitted.

Edwards, R., Smith, K., Liu, Y., Yin, Z., He, G., and Sinton, J., 2007. “Household CO andPM levels measured as part of a review of China’s national improved stove program”, IndoorAir, accepted, in press.

Edwards, R., Smith, K.R., Kirby, B., Allen, T., Litton, C.D., and Hering, S., 2006. “An inex-pensive dual-chamber particle monitor: laboratory characterization”, Journal of the Air andWaste Management Association, 56, pp. 789-799.

Gusain, P., 1990. Renewable Energy in India, Vikas Publishing House, New Delhi.

Litton, C.D., Smith, K.R., Edwards, R., and Allen, T., 2004. “Combined optical and ionizationmeasurement techniques for inexpensive characterization of micrometer and submicrometeraerosols”, Aerosol Science and Technology, 38, pp. 1054-1062.

Mahapatra, R., 2003. “Up in smoke”, Down to Earth, Vol. 11, No. 17, pp. 25-28.

Rogers, E.M., 1995. Diffusion of Innovations, Free Press, New York.

Smith, K.R., Dutta, K., Chengappa, C., Gusain, P.P.S., Masera, O., Berrueta, V., Edwards,R., Bailis, R., and Naumoff Shields, K., 2007. “Monitoring and evaluation of improvedbiomass cookstove programs for indoor air quality and stove performance: conclusions fromthe Household Energy and Health Project”, Energy for Sustainable Development, XI(2) (thisissue), pp. 5-18.

TSB (Technology Systems Branch at Development Alternatives), 2003. Baseline Study onEnergy Use Patterns and Demand, Technology Systems Branch at Development Alterna-tives.

CorrigendumIn Volume XI, No. 2 of Energy for Sustainable Development, in the article “Energy-poverty alleviation inPakistan through use of indigenous energy resources”, Section 6 on Page 60 starts with the sentence“The overall energy use in Pakistan is around 2.25 EJ (terajoule, 1018 J) per annum, and it is estimated thatit will grow to over 2.9 EJ by 2008 [GOP, 2005a].”The word “terajoule” in the parenthesis should be substituted with “exajoule”.The error is deeply regretted. — Editorial Team


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