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Cited by 13Energy and Environment ImpactsAir Quality and Health ImpactsIndoor Air Quality and Microbial Exposure

Effect of a solar lighting intervention on fuel-based lighting use and exposure to household air pollution in rural Uganda: A randomized controlled trial

Open access
Wallach, Eli S., Lam, Nicholas L., Nuwagira, Edwin, Muyanja, Daniel, Tayebwa, Mellon, Valeri, Linda, Tsai, Alexander C., Vallarino, Jose +2 more·2022·Indoor Air
DOI 10.1111/ina.12986PMC PMC9059846
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Abstract

Solar lighting is an alternative to polluting kerosene and other fuel-based lighting devices relied upon by millions of families in resource-limited settings. Whether solar lighting provides sustained displacement of fuel-based lighting sources and reductions in personal exposure to fine particulate matter (PM2.5) and black carbon (BC) has not been examined in randomized controlled trials. Eighty adult women living in rural Uganda who utilized fuel-based (candles and kerosene lamps) and/or clean (solar, grid, and battery-powered devices) lighting were randomized in a 1:1 ratio to receive a home solar lighting system at no cost to study participants (ClinicalTrials.gov NCT03351504). Among intervention group participants, kerosene lamps were completely displaced in 92% of households using them. The intervention led to an average exposure reduction of 36.1 μg/m3 (95% CI −70.3 to −2.0) in PM2.5 and 10.8 μg/m3 (95% CI −17.6 to −4.1) in BC, corresponding to a reduction from baseline of 37% and 91%, respectively. Reductions were greatest among participants using kerosene lamps. Displacement of kerosene lamps and personal exposure reductions were sustained over 12 months of follow-up. Solar lighting presents an immediate opportunity for achieving sustained reductions in personal exposure to PM2.5 and BC and should be considered in household air pollution intervention packages.

Integrity signals

Registry

Crossref · 10.1111/ina.12986

Cites

47 of 47 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

29 of 39 cited sources checked · 11 supported · 1 flagged · accuracy not yet measured

  • Premisecitation

    Without electricity, households may use kerosene lamps, candles, and other polluting fuel-based lighting as temporary illumination.

    “In the absence of electricity, households may turn to kerosene lamps, candles, and other polluting fuel-based lighting devices as a stopgap technology for illumination17.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [17] source

      The Household Uses section says kerosene lamps are common where electricity is unavailable or unreliable, and the Lighting section describes a simple-wick lamp also called a “kerosene candle.” The paper does not establish that households use ordinary candles or that fuel-based lighting is a temporary stopgap; it describes kerosene as often the primary lighting fuel. (LLM, conf=0.84)

      Experimental — accuracy not yet measured
  • Premisecitation

    A published before-after pilot study of solar lamps in rural Kenya suggests that the PM2.5 contribution could be much larger for household members who do not cook.

    “Results from a published before-after pilot study of solar lamps conducted in rural Kenya suggest the contribution to PM2.5 could be much greater for household members that do not perform cooking tasks18.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
  • Premisecitation

    A prior observational study in rural southwest Uganda found that open wick kerosene lamp users had 1.91 times higher living room PM2.5 and 4.7 times higher BC than solar lighting users, after wealth adjustment.

    “In an observational study conducted in rural southwest Uganda, participants using open wick kerosene lamps had 1.91 times higher PM2.5 and 4.7 times higher BC concentrations in living rooms as compared to participants using solar-based lighting, even after adjusting for household wealth 19.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [19] source

      The Results report 4.72 times higher living-room black carbon levels for open-wick lamps versus solar lighting in a model adjusted for household wealth. They also report 1.91 times higher PM2.5, but only in a sensitivity analysis excluding readings of 500 μg/m³ or above; the main adjusted estimate was 2.53. The claim omits that qualification on the 1.91 figure. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
  • Premisecitation

    Open wick kerosene lamps in particular are strong indoor sources of PM2.5 that is largely black carbon.

    “Kerosene lamps, particularly open (simple) wick lamps, are potent sources of indoor fine particulate matter (PM2.5) composed of mostly black carbon (BC) 20–22.”
    Quote in the paperSubstantial claim2 of 3 sources checked
    • cites [20] source

      The Particle size concentrations section reports that a single simple wick lamp produced PM2.5 concentrations at least an order of magnitude above the WHO 24-hour guideline in the test kiosk. The Conclusion says the crudest kerosene lamps emit the most PM2.5. Our copy does not establish that this particulate matter is mostly black carbon; it estimates particle mass using an assumed soot density rather than measuring its composition. (LLM, conf=0.88)

      Experimental — accuracy not yet measured
    • cites [21] source
    • cites [22] source
  • Premisecitation

    Women in resource-limited settings face greater household air pollution exposure than men.

    “In resource-limited settings, women are exposed to higher levels of household air pollution compared to men and represent a vulnerable subgroup14”
    Quote in the paperSubstantial claim1 of 1 sources checked
  • May combine two claims. 35
  • Classified as probably not a substantial claim. 15

  • May combine two claims.

    Premisecitation

    Because kerosene lamps give dim light, people sit close to the source where pollutant concentrations are higher, which raises the intake fraction and makes lighting sources account for a larger share of total exposure than source emission rates alone would suggest.

    “The dim light produced by kerosene lamps necessitates participants to sit in close proximity the light source where pollutant concentrations are higher20, increasing the pollutant intake fraction and leading lighting sources to account for a larger fraction of total exposure than might be assumed from source emission rates alone.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [20] source

      Split into 2 atoms — 0 confirmed, 1 partially supported, 1 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    Observational research links household kerosene use to tuberculosis, unlike biomass fuel use, and also to acute lower respiratory infection.

    “observational studies showing strong associations between household kerosene use and tuberculosis but not household biomass fuel use and tuberculosis 27,28, and between household kerosene use and acute lower respiratory infection 29.”
    Quote in the paperSubstantial claim3 of 3 sources checked
    • cites [27] source
    • cites [28] source

      The Results and Conclusion report a strong association between kerosene use and TB, and little evidence of an association for biomass used for cooking. But they also report an association between biomass used for household heating and TB, so the unqualified contrast with biomass fuel use overstates the finding. The acute lower respiratory infection claim has a separate citation in the citing sentence and is not attributed to this source. (LLM, conf=0.91)

      Experimental — accuracy not yet measured
    • cites [29] source

  • May combine two claims.

    Premisecitation

    Fossil fuel-derived particles that are inhaled deposit in tissue and enter the systemic circulation readily, and they may be more toxic than biomass burning particles.

    “Inhaled fossil fuel-derived particles have been found to have high tissue deposition and penetration into the systemic circulation 23,24, and may be more toxic than particles resulting from biomass burning 17,25.”
    Quote in the paperSubstantial claim2 of 4 sources checked
    • cites [23] source
    • cites [24] source
    • cites [17] source

      The citation is attached to the comparison with biomass-burning particles, not the preceding deposition claim. In Human Exposures and Pollutant Emissions > Cooking (page unavailable), the review reports a higher emission factor for genotoxic PAHs from kerosene stoves than from wood, which lends limited support to a possible toxicity difference. But Toxicology > Combustion Products (page unavailable) says the effect of combustion source on particle toxicity has been less studied; the copy does not establish that fossil fuel-derived particles are more toxic than biomass-burning particles. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [25] source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Modern cooking solutions such as LPG stoves and electric appliances may achieve greater exposure reductions than improved biomass stoves, but scaling them beyond trials faces challenges in fuel supply reliability and affordability.

    “Modern cooking solutions such as liquid petroleum gas (LPG) stoves and electric appliances show promise for achieving greater exposure reductions41,42 compared with improved biomass stoves, but scaling these solutions beyond trial settings will present new challenges; notably those related to reliability of fuel supplies and issues around affordability 43–46.”
    Quote in the paperNot a substantial claim4 of 6 sources checked
    • cites [41] source

      The Discussion (page unavailable) says free fuel is an element of the HAPIN trial unlikely to be operationalized at scale, supporting the affordability concern. Methods > Intervention (page unavailable) describes continuous LPG delivery during the trial, but the paper does not explicitly establish that unreliable fuel supplies pose a challenge beyond trials. The earlier comparison of exposure reductions is attached to different citations in the citing sentence. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [42]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [43] source

      The Discussion sections “Cost to the household” and “Adoption and use” identify affordability as a barrier to uptake of the advanced biomass cookstove studied in Malawi. They do not address the reliability of LPG or electricity supplies, or establish affordability barriers for scaling those solutions beyond trials. The exposure-reduction comparison is attached to other citations in the citing sentence. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [44] source

      The Introduction (page unavailable) says some households cannot afford or access modern fuels, supporting affordability and access as barriers to wider uptake. It does not specifically address the reliability of LPG or electricity supplies, or scaling those solutions beyond trials. The exposure-reduction comparison is attached to different citations in the citing sentence. (LLM, conf=0.82)

      Experimental — accuracy not yet measured
    • cites [45] source

      The Conclusion (page unavailable) says that alternative clean stove models face barriers to widespread use, including low willingness to pay and the need for low production and operating costs. It does not address the reliability of LPG or electricity supplies. The comparative exposure-reduction claim is attached to other citations in the citing sentence, not this source. (LLM, conf=0.85)

      Experimental — accuracy not yet measured
    • cites [46] source

  • May combine two claims.

    Premisecitation

    Kerosene emissions consist predominantly of black carbon, which distinguishes kerosene from other common indoor particulate sources.

    “Emissions from kerosene are composed predominantly of BC, making it unique among other common particulate sources found in homes21.”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [21] source

      The Results (Emission factors; page not provided) say that most particulate matter from the tested kerosene wick lamps was black carbon and that their BC-to-total-carbon ratio was much higher than for other BC sources. The claim omits the lamp-specific condition and applies the finding to kerosene emissions generally; the paper also distinguishes wick-lamp emissions from those of kerosene cookstoves. (LLM, conf=0.85)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Studies have suggested that kerosene-based emissions are more toxic than biomass-fuel emissions.

    “While studies have suggested that kerosene-based emissions are more toxic than biomass-fuel based emissions 25–28”
    Quote in the paperNot a substantial claim3 of 4 sources checked
    • cites [25] source

      The Discussion (page not available in our copy) suggests that fossil-fuel combustion particles, especially coal-derived particles, have greater long-term cardiovascular toxicity than biomass particles. It does not identify kerosene emissions or establish a kerosene-versus-biomass comparison; the study concerns ischemic heart disease mortality in older U.S. adults. (LLM, conf=0.86)

      Experimental — accuracy not yet measured
    • cites [26] source
    • cites [27] source

      The Discussion (page unavailable) describes potentially harmful kerosene emissions, including ultrafine particles and combustion products linked to adverse respiratory effects. It does not say that kerosene-based emissions are more toxic than biomass-fuel emissions; the Results compare fuel use in relation to TB, not emission toxicity. (LLM, conf=0.78)

      Experimental — accuracy not yet measured
    • cites [28] source

      The Discussion reports higher concentrations of several VOCs from kerosene stoves than from wood-burning stoves and suggests that the fuels’ pollutant mixtures may differ in toxic effects. It does not establish that kerosene emissions are more toxic overall than biomass emissions; the Conclusion also cautions that kerosene emissions vary by device and fuel quality. Page numbers are not provided in our copy. (LLM, conf=0.84)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Other studies support that transitioning to solar lighting can bring benefits beyond pollution exposure reduction, including household savings, more income-generating activity, gender empowerment, social inclusion, and improved education from more homework time.

    “Other studies have corroborated that the potential benefits of a transition to solar lighting extend well beyond reductions in pollution exposure to include savings on household expenditures, increase in income generating activities, gender empowerment, social inclusion, and improved education due to more time spent on homework12,13.”
    Quote in the paperNot a substantial claim2 of 2 sources checked
    • cites [12] source
    • cites [13] source

      The Results (Qualitative interviews; page not provided) report lower household lighting expenditures, more time for income-generating activities, improved community relationships, and educational gains linked to children being able to do homework after sunset. The study enrolled women, but the passages do not report gender empowerment as an outcome; that part of the claim is unsupported. (LLM, conf=0.86)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Premisecitation

    A pre-post comparison in peri-urban Kenya found high uptake of pico-solar lamps and average personal PM2.5 reductions above 50% among exclusive kerosene lamp users over a three-month follow-up.

    “results from a pre-post comparison of personal PM2.5 exposure after introduction of pico-solar lamps in peri-urban Kenya showed both high uptake of the solar lamps as well as average reductions in excess of 50% to personal PM2.5 exposure among exclusive kerosene lamp users over a short three-month follow-up period 18.”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites [18] source

      The Abstract reports 90% displacement of kerosene-lamp use and reductions in average personal PM2.5 exposure of 50% for adults and 73% for pupils. But §2.1 says follow-up measurements occurred after 3–4 weeks, not three months; the Abstract describes households using mainly, not exclusively, kerosene for lighting. Pages are unavailable in our copy. (LLM, conf=0.89)

      Experimental — accuracy not yet measured

  • May combine two claims.

    Findingown data

    Among intervention participants, the percentage using any kerosene-based lighting was 68% at baseline, 32% at one week, 14% at three months, 14% at six months, and 8% at 12 months.

    “The percentage of intervention participants using any kerosene-based lighting was 68% at baseline, 32% at one week, 14% at three months, 14% at six months, and 8% at 12 months.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Both the displacement of kerosene lamps and the personal exposure reductions persisted throughout the 12-month follow-up.

    “Displacement of kerosene lamps and personal exposure reductions were sustained over 12 months of follow-up.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The conversion factor from absorption coefficient to black carbon mass is 1.0.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Nearly all participants used firewood (95%) or charcoal (3.8%) as their primary cooking fuel.

    “All but one participant reported using either firewood (95%) or charcoal (3.8%) as their main cooking fuel.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For fuel-based lighting households, these reductions corresponded to 33% and 100% decreases in PM2.5 and black carbon relative to the intervention group's baseline, respectively.

    “These reductions corresponded to a 33% and 100% reduction in PM2.5 and BC relative to the intervention group’s baseline, respectively.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Secondary kerosene lighting was widespread: 52.5% used open wick kerosene lamps and 27.5% used hurricane kerosene lamps as secondary sources.

    “Notably, use of kerosene-based lighting as a secondary lighting source was common, with 52.5% reporting secondary use of open wick kerosene lamps and 27.5% reporting secondary use of hurricane kerosene lamps.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    At baseline, 43.8% used fuel-based lighting as their primary source, and the remainder used clean sources.

    “with 43.8% reporting primary fuel-based lighting (all but two reporting use of either open wick or hurricane lamps) while the rest reported primary clean lighting sources (flashlights, solar-based, or electricity from the national grid).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Most of the decline in kerosene use happened within the first three months after the solar lighting intervention, and for most households within the first week.

    “most reduction in kerosene usage occurred sometime within the first three months following the solar lighting intervention – and for most households within the first week following the intervention.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    These exposure decreases represented 37% and 91% reductions from baseline for PM2.5 and BC, respectively.

    “corresponding to a reduction from baseline of 37% and 91%, respectively.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The conversion factor from absorption coefficient to black carbon mass is 1.0.

  • May combine two claims.

    Findingown data

    The intervention-related reductions corresponded to average decreases relative to baseline of 37% for PM2.5 and 91% for black carbon.

    “These reductions corresponded to an average reduction relative to baseline of 37% for PM2.5 and 91% for BC.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Secondary use of fuel-based lighting was widespread even among people with grid or solar lighting access, because of frequent grid outages, too few clean lighting points, or payment interruptions that terminated pay-as-you-go solar service.

    “secondary use of fuel-based lighting sources was widely prevalent even among those who had access to the electrical grid or solar lighting due to frequent grid outages, insufficient lighting points from clean lighting sources, or due to payment interruptions leading to service termination of pay-as-you-go solar lighting devices.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    The main analysis followed intention-to-treat, including every participant with at least one post-intervention follow-up measurement of living room and personal PM2.5 and BC.

    “The primary analysis used intention to treat principles; all participants with at least one follow-up measurement of living room and personal PM2.5 and BC levels after the intervention were included.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    One control participant was lost to follow-up at six months.

    “There was only one participant who was lost to follow-up (a control group participant at six months).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Separate randomization schedules were created for baseline primary lighting source strata-fuel-based versus clean-to prevent chance imbalance.

    “To avert chance imbalances by primary lighting source, we generated separate randomization schedules for subsets of study participants defined by strata of baseline primary lighting source, namely: fuel-based (hurricane or open-wick kerosene lamps, candles) vs. clean (national electrical grid, battery-powered devices, solar lamp or solar lighting system).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The regression models adjusted for baseline primary lighting source because randomization had been stratified on it.

    “Randomization was stratified by primary lighting source at baseline (fuel-based vs. clean) and therefore was adjusted for in the regression models.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductown data

    Eighty women were randomized 1:1 with a computerized random number generator.

    “We recruited a total of 80 women who were based in 8 villages and randomized them in a 1:1 allocation ratio using a computerized random number generator”
    • Also stated in: § RESULTS · plain
      “This study included 80 women from distinct households who were randomized in a 1:1 allocation ratio to the intervention vs. control (delayed-start intervention) groups”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    Because of the intervention's nature, neither participants nor field staff could be blinded.

    “Blinding of participants and field staff was not possible due to the nature of the study intervention.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    In this one-year randomized delayed-start controlled trial in rural southwestern Uganda, the indoor solar lighting intervention had high uptake, lowered kerosene-based lighting use, and reduced personal exposure to black carbon and PM2.5 over the study period.

    “In this one-year randomized, delayed-start controlled trial conducted in a rural region of southwestern Uganda, an indoor solar lighting system intervention had high uptake, reduced kerosene-based lighting use, and led to reduced personal exposure to BC and PM2.5 over the one-year study period.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    Field blanks were included to correct for possible sampling-related bias in filter weights.

    “Field blanks were used to account for potential bias in filter weight due to sampling methods.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Exposure reduction estimates from this study suggest that fuel-based lighting sources accounted for about one third of the average participant's daily PM2.5 exposure burden and three quarters of their black carbon exposure.

    “Exposure reduction estimates from this study suggest that fuel-based lighting sources accounted for approximately one third of the daily PM2.5 exposure burden among the average participant, and three quarters of their BC exposure.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductreasoning

    The final models included only baseline primary lighting source and season as covariates.

    “in final models we only adjusted for baseline primary lighting source (which was included to account for the stratified randomization design) and season (wet /dry)”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    A Ugandan study of a more expensive home solar system than the one used here estimated break-even after 3.14 years and additional benefits including near-complete elimination of fires and burns from fuel-based lighting.

    “A study performed in Uganda for a more expensive home solar system than the one used in our study estimated a break-even point after 3.14 years47 as well as additional benefits such as near-complete elimination of fires and burns attributed to fuel-based lighting.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [47] source

  • May combine two claims.

    Interpretationreasoning

    The absence of an observed intervention effect on living room PM2.5 and black carbon may be explained by decreases in living room levels from pre- to post-intervention in both groups and by changes in where participants spent time because the intervention provided four lighting points.

    “While we did not observe an impact on living room levels of PM2.5 and BC, this may be attributed to the decrease in living room PM2.5 and BC in the post-intervention period compared to the pre-intervention period for both control and intervention group participants, as well as changes in where participant spent their time as the intervention lighting system provided four lighting points.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    The solar lighting effect on personal exposure reduction was observed even though control participants also had an overall exposure decrease, probably because controls displaced some fuel-based lighting themselves.

    “The effect of solar lighting on reducing in personal exposure was observed despite an overall decrease in exposure among controls, likely resulting from the control group’s own displacement of fuel-based lighting.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable).

    Interpretationown data

    The kerosene displacement benefits seen here, together with high adoption and wide availability of solar lighting in resource-limited settings, suggest that combining stove-related and lighting services in household energy programs may be complementary.

    “The benefits of kerosene lighting displacement observed in this study, combined with high adoption rates and widescale availability of solar lighting devices in resource-limited settings, suggest that coupling thermal (stove-related) and illumination services within household energy programs may be complementary.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductreasoning

    A non-trivial share of control participants stopped using fuel-based lighting after enrollment, which would underestimate the intervention effect on air pollution exposure and indoor air quality.

    “First, a non-trivial proportion of control group participants abandoned fuel-based lighting after trial enrollment. This would lead to an underestimate of the effect of the intervention on air pollution exposure and indoor air quality.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    These trial findings extend prior work by using a randomized design to confirm that fuel-based lighting contributes to household air pollution exposure and by showing for the first time that sustained personal black carbon and PM2.5 reductions can occur without changes to cooking practices.

    “The trial findings presented here extend our prior findings, using a randomized controlled design, to confirm that fuel-based lighting contributes to household air pollution exposure, and showing for the first time that a sustained decrease in personal BC and PM2.5 exposure can be achieved, even without changes to cooking practices.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: No earlier randomized controlled trial has assessed how an indoor solar lighting system affects personal household air pollution exposure.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Device use and personal PM2.5 and black carbon exposure were measured longitudinally over one year to assess sustained impact.

    “Finally, we measured device usage and personal exposure to PM2.5 and BC longitudinally over the one year study period in order to assess sustained impact.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Kerosene-based lighting use and intervention solar lighting uptake were measured objectively with sensors instead of self-report.

    “We were able to objectively measure kerosene-based lighting usage and uptake of the intervention solar lighting system using sensors rather than relying on self-report”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Study design and conductown data

    Group assignment was balanced by age and socioeconomic status, and all but two participants were the primary cook in their household.

    “Group assignment was balanced across age and socioeconomic status, and all but two participants served as the primary cook in their household.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The transition away from fuel-based lighting among all participants reduced the calculated intervention effect on pollution exposure, but it also suggests that barriers to adopting cleaner lighting are low compared with cooking and other household energy measures.

    “While this transition away from fuel-based lighting in all study participants reduced the calculated effect size of the study intervention on pollution exposure for intervention compared to control group participants in our study, it also suggests that the barriers to adoption of cleaner lighting technology are low relative to cooking and other household energy measures.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    The trial was designed as a proof-of-concept study to determine solar lighting intervention uptake and to identify its effect size on personal pollution exposure independent of cooking interventions.

    “this was a trial designed as a “proof of concept” study to determine the uptake of a solar lighting intervention and to identify the effect size on personal pollution exposure independent of cooking interventions.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationown data

    This study further confirms that solar lighting technology is a viable and well-received alternative to fuel-based lighting in resource-limited settings.

    “Our study provides further confirmation that solar lighting technology is a viable and well received alternative to fuel-based lighting in resource-limited settings.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Because the primary unit of measure was women who were usually the primary cooks, the measured exposure benefits may not represent all household members and would likely underestimate reductions for those who do not regularly cook.

    “Finally, the primary unit of measure for this study was women who in most instances were the primary cooks for their families. As a result, exposure benefits measured here are not necessarily indicative of all household members, and in particular would underestimate the magnitude of reduction in those that do not regularly contribute to cooking duties.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    In conclusion, the clean lighting intervention was highly effective at displacing fuel-based lighting, had high uptake, and produced significant personal black carbon reductions and a trend toward PM2.5 reduction.

    “In conclusion, we found that a clean lighting intervention was highly effective in displacing fuel-based lighting, had high uptake, and led to significant reductions in personal exposure to BC and a trend towards reduction in PM2.5.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    The study population is representative of the broader rural Ugandan population, where 70% use kerosene lamps for light and 90.2% cook outdoors or have a separate dedicated kitchen.

    “Our study population is representative of the broader rural population in Uganda where 70% of participants use kerosene lamps for light and where 90.2% of participants either cook outdoors or have a separate dedicated kitchen48,49.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [48]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [49]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    Per lumen, solar lighting costs less than fuel-based lighting, so customers can eventually recover their investment in a solar home system.

    “on a per-lumen basis solar lighting is less costly than fuel-based lighting as fuel-based lighting burns efficiently, allowing customers to eventually recoup their investment in a solar home system.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    This study further confirms that when present, fuel-based lighting can be an important contributor to household air pollution exposure and may need to be addressed together with efforts to reduce cooking and other stove-related emissions.

    “Our study provides further confirmation that when present, fuel-based lighting can be an important contributor to household air pollution exposure that may need to be addressed alongside efforts to mitigate high emissions from cooking and other stove-related (thermal) service needs.”
    Quote in the paperSubstantial claim
45 of 45

  • The authors state this as an assumption.

    The conversion factor from absorption coefficient to black carbon mass is 1.0.

    “We assumed a factor of 1.0 for converting the absorption coefficient to BC mass 36,37”

  • The paper relies on this without support.

    In a pre-post study in Kenya, introducing three portable solar lamps per household displaced kerosene lamp use by over 90% over three months and reduced personal PM2.5 exposure by 50% among women and 73% among teenage pupils, despite continued solid fuel cooking.

    “In a pre-post study among Kenyan households using kerosene as a primary lighting source, introduction of three portable solar lamps per household displaced kerosene lamp use by over 90% over a three-month follow-up period and reduced personal PM2.5 exposure by 50% among women and 73% among teenage pupils, despite continued use of solid fuels for cooking.”

  • The paper relies on this without support.

    Lamp stacking is common in this context; most solar systems are too small to meet all lighting needs exclusively or are paid monthly with remote termination for missed payments.

    “Participants reporting use of solar lighting systems were also included because lamp stacking is common in this context: most solar systems are too small (have too few light sources) to meet all lighting needs on an exclusive-use basis or are paid for on a monthly basis with the company remotely terminating the function of the solar system in the event of missed payments.”

  • The paper relies on this without support.

    Prior household air pollution interventions have concentrated mainly on cooking practices and have paid much less attention to other household energy sources.

    “To date, interventions aimed at mitigating exposure to indoor air pollution occurring in households have focused predominantly on strategies to alter cooking practices, with far less focus on potential exposures from other household energy sources.”

  • The paper relies on this without support.

    No earlier randomized controlled trial has assessed how an indoor solar lighting system affects personal household air pollution exposure.

    “To our knowledge, this is the first randomized controlled trial to evaluate the effect of an indoor solar lighting system on personal exposure to household air pollution.”
5 of 5

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Two baseline kerosene-use averages are given for the intervention group

    Minor

    The intervention group's baseline use is reported as 2.38 hours per day, but later as 2.22 hours per day. The earlier passage identifies 2.22 hours as the average across kerosene users, not the intervention-group average.

  • The conclusion downplays a statistically significant PM2.5 result

    Minor

    The paper defines p < 0.05 as statistically significant and reports a PM2.5 intervention effect with p = 0.038. Its conclusion instead describes that effect as a trend toward reduction.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. Lam N, 2019, The Dirty Footprint of the Broken Grid: The Impact of Fossil Fuel Backup Generators in Developing Countries
  2. Checkley W, 2020, Effects of a cleaner energy intervention on cardiopulmonary outcomes in Peru: a randomized controlled trial, Am J Respir Crit Care Med
  3. Uganda Bureau of Statistics (UBOS), 2017, 2016 Uganda Demographic and Health Survey Key Findings
  4. Uganda Bureau of Statistics (UBOS), 2016, The National Population and Housing Census 2014 – Main Report, Kampala, Uganda

Cited by

Sorted by citations

Related

Authors
Wallach, E. S., Lam, N. L., Nuwagira, E., Muyanja, D., Tayebwa, M., Valeri, L., Tsai, A. C., Vallarino, J., Allen, J. G., & Lai, P. S.
Affiliations
  • Cal Poly Humboldt (US)
  • Mbarara University of Science and Technology (UG)
  • Columbia University (US)
  • Harvard University (US)
Corresponding author
Lai, Peggy S.
ORCID
Venue
Indoor Air
Publisher
Wiley
Published
2022-02
Volume
32
Issue
2
Pages
e12986-e12986
ISSN
  • 0905-6947 (ISSN-L)
  • 1600-0668
DOI
10.1111/ina.12986
PMC
PMC9059846
OpenAlex
W4212858676
Semantic Scholar
ff4f3178a531b5006a6cd447d5583835182f3149
Cited by
13
References
47
Citations by year
2026: 2 · 2025: 4 · 2024: 4 · 2023: 2 · 2022: 1
FWCI
0.65
Type
journal article
Language
en
Open access
Licence
Locations
  • Indoor Air (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
  • Massachusetts General Hospital
  • American Thoracic Society
  • National Institutes of Health (K23 ES023700, R01MH113494)
Topics
  • Physical Sciences › Environmental Science › Pollution › Energy and Environment Impacts
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Air Quality and Health Impacts
  • Physical Sciences › Environmental Science › Health, Toxicology and Mutagenesis › Indoor Air Quality and Microbial Exposure
Keywords
solar-powered lighting, household air pollution, kerosene lamps, PM2.5, black carbon, personal exposure, rural households, clean cooking, Uganda
MeSH terms
Adult, Air Pollutants, Air Pollution, Cooking, Environmental Exposure, Female, Humans, Lighting, Uganda, Air Pollution, Indoor, Particulate Matter

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read under definition version 3 (extract-v3) on 2026-09-28.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-09-28.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

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