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Signs and Symptoms Suggestive of Carbon Monoxide Poisoning and Corresponding Carboxyhemoglobin Saturation 22,26
Source publication
The temazcal is a wood-fired steam bath used in the rural highlands of Guatemala for bathing and healing. We measured carbon monoxide (CO) among 288 participants in 72 temazcales. Participants were drawn from communities who participated in the RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects) chimney stove interventi...
Contexts in source publication
Context 1
... CO exposures among women cooking with solid fuels in poorly venti- lated homes are sometimes high enough to result in COHb between 2.5% and 16%, with upper limits com- parable to upper limits seen in heavy smokers. 15,16 Signs and Symptoms of Carbon Monoxide Toxicity Table 1 outlines potential signs and symptoms of CO toxicity with the corresponding estimated range of COHb levels. Most of these findings are drawn from clinical case reports of acute CO poisoning where exposure concentration and duration, prior to the determination of COHb, is typically unknown. ...
Citations
... Cooking-related biomass smoke exposure is the major source of HAP in this rural Guatemalan population where the RESPIRE and CRECER studies were conducted, followed by temazcal (wood-fueled sauna bath) use (Lam et al., 2011;Thompson et al., 2011). The locally produced biomass chimney stoves provided in the study improved fuel combustion and vented biomass smoke outdoors, thus reducing household concentrations . ...
... Comparison of reductions in particulate matter and urinary metabolite concentrations among cookstove intervention studies Intervention, country: comparison concentrations. This was not unexpected; sauna baths used in this region have been shown to greatly increase CO levels, another by-product of incomplete combustion of wood fuel [35,42]. This bathing practice, which creates a super-saturated, high-heat environment, cannot be measured using typical monitoring methods, such as gravimetric or personal PM 2.5 monitors, because in our past experience, filters became humid and monitors failed under these conditions. ...
Household air pollution from solid fuels is a leading risk factor for morbidity and mortality worldwide. Pregnant women’s exposure to polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs), two components of solid-fuel smoke, is associated with adverse birth outcomes. Even with improved solid-fuel stoves, exposure to PAHs and VOCs remains high. Therefore, cleaner cooking fuels need to be prioritized.
We aimed to quantify exposure reduction to PAHs and VOCs among pregnant women in rural Guatemala with a liquefied petroleum gas (LPG) stove intervention.
Urine from pregnant women (N = 50) was collected twice: at <20 weeks gestation, when women cooked exclusively with wood, and 6–8 weeks after receiving an LPG stove. Metabolites of four PAHs and eight VOCs were analyzed. Concurrent with urine collection, personal 48-h PM2.5 exposure was measured.
Women cooking exclusively with wood were exposed to high levels of particulate matter (PM2.5), which was reduced by 57% with the LPG stove. Urinary concentrations of total PAH metabolites (−37%), PMA (benzene metabolite; −49%), and CNEMA (acrylonitrile metabolite; −51%) were reduced. However, recent use of a wood-fired sauna bath led to large increases in excretion of urinary toxicant metabolites (+66–135%).
This is the first study to report PAH and VOC reductions from an LPG stove intervention introduced during pregnancy. However, other sources of air pollution minimized the gains seen from using an LPG stove. Thus, all sources of air pollution must be addressed in concert to reduce exposures to levels that protect health.
... There was no proportional increase in predicted exhaled CO in peak hours over non-peak hours when examined against the respective differences in indoor CO levels (Fig. 4). It has been reported that exhaled CO can be used to predict blood COHb% (Jarvis et al., 1986;Kao and Nanagas, 2005;Thompson et al., 2011) as the two share a strong relationship. We have fitted predicted exhaled CO levels with modelled COHb% values derived from 2-min TWA indoor CO concentrations and found an excellent agreement, the 3-degree polynomial fit being slightly better than linear (Supplementary Fig. 2a and b). ...
The study describes human exposure to indoor CO generated by coal cookstoves in roadside food-vending shanties in Kolkata mega city in India.
... Ten (20%) used an open fire and 40 (80%) used a plancha stove without a chimney or in a deteriorated condition as their principal stove. Additional sources of smoke were as follows: 36 (72%) used a wood-fired steam bath (a temascal, or chuj) for bathing [53], 33 (66%) burned garbage near the home, 23 (46%) cooked animal food outdoors over an open fire and 7 (14%) were exposed to second-hand smoke (median of 1 cigarette/week smoked at home). ...
Background:
Three billion people use solid cooking fuels, and 4 million people die from household air pollution annually. Shifting households to clean fuels, like liquefied petroleum gas (LPG), may protect health only if stoves are consistently used. Few studies have used an implementation science framework to systematically assess "de-implementation" of traditional stoves, and none have done so with pregnant women who are more likely to adopt new behaviors. We evaluated an introduced LPG stove coupled with a phased behavioral intervention to encourage exclusive gas stove use among pregnant women in rural Guatemala.
Methods:
We enrolled 50 women at < 20 weeks gestation in this prospective cohort study. All women received a free 3-burner LPG stove and ten tank refills. We conducted formative research using COM-B Model and Theoretical Domains Framework (TDF). This included thematic analysis of focus group findings and classes delivered to 25 pregnant women (Phase 1). In Phase 2, we complemented classes with a home-based tailored behavioral intervention with a different group of 25 pregnant women. We mapped 35 TDF constructs onto survey questions. To evaluate stove use, we placed temperature sensors on wood and gas stoves and estimated fraction of stove use three times during pregnancy and twice during the first month after infant birth.
Results:
Class attendance rates were above 92%. We discussed feasible ways to reduce HAP exposure, proper stove use, maintenance and safety. We addressed food preferences, ease of cooking and time savings through cooking demonstrations. In Phase 2, the COM-B framework revealed that other household members needed to be involved if the gas stove was to be consistently used. Social identity and empowerment were key in decisions about stove repairs and LPG tank refills. The seven intervention functions included training, education, persuasion, incentivization, modelling, enablement and environmental restructuring. Wood stove use dropped upon introduction of the gas stove from 6.4 h to 1.9 h.
Conclusions:
This is the first study using the COM-B Model to develop a behavioral intervention that promotes household-level sustained use of LPG stoves. This study lays the groundwork for a future LPG stove intervention trial coupled with a behavioral change intervention.
Trial registration:
NCT02812914, registered 3 June 2016, retrospectively registered.
... The remaining 13 women were past the 3rd month post-partum and were, therefore, not included in this sub-study. Since use of wood-fired sauna baths have been shown to greatly increase levels of CO exposure, one byproduct of incomplete combustion of wood fuel (Lam et al., 2011;Thompson et al., 2011b), we measured urinary metabolite concentrations after multiple types of smoke exposure such as cooking and sauna baths. Urine samples (n = 68) were collected three times over a 72 h period: at first morning urine (fasting), after lunch and following dinner or sauna bath use (Fig. 1B). ...
... (Thompson et al., 2011a;Boy et al., 2002;Mishra et al., 2004;). Another study (Thompson et al., 2011b) assessing the health effects of peak CO exposure from use of temazcal (steam baths) reported symptoms suggestive of CO poisoning. Measured concentrations were very high (mean 67.5 ppm; median 52 ppm) but overlapping with the range we observed during traditional stove use. ...
Cooking with biomass fuel is an important source of household air pollution (HAP) in developing countries, and a leading risk factor for ill-health. Although various designs of "improved cookstoves" (ICS) have been promoted as HAP interventions in these settings, few of them have undergone in-field evaluation, partly due to the challenge of conducting field measurements in remote settings. In this study we assessed the change in carbon monoxide (CO) exposure following the replacement of the traditional three-stone stove with a popular ICS in 49 homes in Western Kenya. We also assessed the suitability of using kitchen CO as a proxy for kitchen PM2.5. Reduction in 48h mean kitchen CO was 3.1ppm (95% CI: -8.1, 1.8) and in personal CO was 0.9ppm (95% CI: -4.3, 2.6) following stove replacements. Overall, 48-h kitchen and personal CO exposures were lower after stove replacement (28% and 12%, respectively) but with wide confidence intervals that also suggested possible increases in exposure. There were statistically significant reductions in peak kitchen and personal CO concentrations represented by the 8-h 95th percentile: reductions of 26.1ppm (95% CI: -44.6, -7.6) and 8.0ppm (95% CI: -12.2, -3.8), respectively. This is equivalent to 53% reduction in kitchen CO and 39% reduction in personal CO. We found good correlation between kitchen CO and PM2.5 concentrations overall (r=0.73, n=33 over averaging periods approximating 1day), which varied by time of day and exposure setting. These variations limit the applicability of CO as a proxy measure for PM2.5 concentrations. A combination of interventions, including better designed stoves, improved ventilation and cleaner fuels, may be needed to reduce HAP to levels that are likely to improve health.
... Additionally, personal exposure monitoring does not account for dramatic exposures these women experience while using the temazcal, with average CO exposures that are 10 times higher than the 15-min World Health Organization guideline for indoor air quality; additional research into the impact of this unique exposure on lung health is warranted. 22,23 For these reasons, the overall impact of the stove on participants' cumulative lifetime exposure during these two studies was likely small. Finally, because the exposure-response relationship between particulate matter and lung function may be nonlinear (with smaller eff ects at higher exposure levels), more substantial reductions in exposure may be necessary to impact lung function. ...
Chronic Obstructive Pulmonary Disease (COPD) is the third most frequent cause of death globally with much of this burden attributable to household biomass smoke exposure in developing countries. As biomass smoke exposure is also associated with cardiovascular disease, lower respiratory infection, lung cancer, and cataracts, it presents an important target for public health intervention.
Lung function in Guatemalan women exposed to woodsmoke from open fires was measured throughout the RESPIRE stove intervention trial, and continued during the CRECER cohort study. In RESPIRE, early stove households received a chimney woodstove at the beginning of the 18-month trial while delayed stove households received a stove at trial completion. Personal exposure to woodsmoke was assessed with exhaled breath carbon monoxide and personal CO tubes. Change in lung function between intervention groups and as a function of woodsmoke exposure was assessed using random effects models.
Of 306 women participating in both studies, acceptable spirometry was collected in 129 early stove and 136 delayed stove households (n=265), with 5.6 years mean follow-up. Despite reduced woodsmoke exposures in early stove households, there were no significant differences in any of the measured spirometric variables during the study period; FEV1, FVC, FEV1/FVC ratio, and annual change, after adjustment for confounding.
In these young Guatemalan women, there was no association between lung function and early randomization to a chimney stove or personal woodsmoke exposure. Future stove intervention trials should incorporate cleaner stoves, longer follow-up, or potentially susceptible groups to identify meaningful differences in lung function.
... Cooking is more than simply heating food. ''Successful cookery requires a thousand things done well'', says Michael Symons in his History of Cooks and Cooking (Symons 2004). Cooking involves combining different techniques or tasks to make a meal, like heating, boiling, simmering, steaming, baking, grilling, frying, or smoking among others. ...
The implementation of clean fuel and stove programs that achieve sustained use and tangible health, environmental, and social benefits to the target populations remains a key challenge. Realization of these benefits has proven elusive because even when the promoted fuels-stoves are used in the long term they are often combined (i.e., "stacked") with the traditional ones to fulfill all household needs originally met with open fires. This paper reviews the rationale for stacking in terms of the roles of end uses, cooking tasks, livelihood strategies, and the main patterns of use resulting from them. It uses evidence from case studies in different countries and from a 1-year-long field study conducted in 100 homes in three villages of Central Mexico; outlining key implications for household fuel savings, energy use, and health. We argue for the implementation of portfolios of clean fuels, devices and improved practices tailored to local needs to broaden the use niches that stove programs can cover and to reduce residual open fire use. This allows to integrate stacking into diagnosis tools, program monitoring, evaluation schemes, and implementation strategies and establish critical actions that researchers and project planners can consider when faced with actual or potential fuel-device stacking.
... A particular form of the traditional temazcal (i.e. wood-fired steam baths) used by Native American groups are routinely used by indigenous populations in Central America, including an estimated 1-2 million indigenous Mayan people in the western highlands of Guatemala (26). The temazcales used by these populations are typically small (~5.5 m 3 ), minimally ventilated rooms (<0.5 air changes per hour) that are heated by burning a wood fire inside the structure to warm volcanic rocks (26) (Figure 1). ...
... Users enter the temazcal once the fire has reduced to smoke-emitting embers, which are traditionally left inside the structure during use. A recent survey of 97 households in the western highlands of Guatemala showed that >90% of respondents use the temazcal once or twice per week, and 4% use it as frequently as three times per week, typically for hygienic or ceremonial purposes (26). Only 4% of surveyed individuals indicated that they use the temazcal less than twice per month. ...
... A second study of the same population found that the average CO concentration in the temazcal during use was 661 ± 62 ppm, with a range from <7 ppm to >1980 ppm (27). Average exhaled (alveolar) CO levels in adults following temazcal was 61 ppm, and ranged from 3 to 230 ppm (26). These environmental and biological concentrations are high enough to pose a risk of acute effects from CO poisoning. ...
In Central America, the traditional temazcales or wood-fired steam baths, commonly used by many Native American populations,
are often heated by wood fires with little ventilation, and this use results in high wood smoke exposure. Urinary mutagenicity
has been previously employed as a non-invasive biomarker of human exposure to combustion emissions. This study examined the
urinary mutagenicity in 19 indigenous Mayan families from the highlands of Guatemala who regularly use temazcales (N = 32), as well as control (unexposed) individuals from the same population (N = 9). Urine samples collected before and after temazcal exposure were enzymatically deconjugated and extracted using solid-phase
extraction. The creatinine-adjusted mutagenic potency of urine extracts was assessed using the plate-incorporation version
of the Salmonella mutagenicity assay with strain YG1041 in the presence of exogenous metabolic activation. The post-exposure mutagenic potency
of urine extracts were, on average, 1.7-fold higher than pre-exposure samples (P < 0.005) and also significantly more mutagenic than the control samples (P < 0.05). Exhaled carbon monoxide (CO) was ~10 times higher following temazcal use (P < 0.0001), and both CO level and time spent in temazcal were positively associated with urinary mutagenic potency (i.e. P < 0.0001 and P = 0.01, respectively). Thus, the wood smoke exposure associated with temazcal use contributes to increased excretion of conjugated
mutagenic metabolites. Moreover, urinary mutagenic potency is correlated with other metrics of exposure (i.e. exhaled CO,
duration of exposure). Since urinary mutagenicity is a biomarker associated with genetic damage, temazcal use may therefore
be expected to contribute to an increased risk of DNA damage and mutation, effects associated with the initiation of cancer.
... [4] Aside from being exposed to woodsmoke while cooking (two to three times a day), these women are also exposed to very high amounts of smoke during weekly bathing in a wood-fired sauna (temazcal). [50] Thus, the benefit of smoke reduction from using the chimney stove may be offset by the continued, although intermittent, use of the temazcal and this may explain why the distributions of exposure for the two groups overlap. Better metrics are necessary to more accurately characterize chronic woodsmoke exposure in future studies. ...
More than two-fifths of the world's population uses solid fuels, mostly biomass, for cooking. The resulting biomass smoke exposure is a major cause of chronic obstructive pulmonary disease (COPD) among women in developing countries.
To assess whether lower woodsmoke exposure from use of a stove with a chimney, compared to open fires, is associated with lower markers of airway inflammation in young women.
We carried out a cross-sectional analysis on a sub-cohort of participants enrolled in a randomized controlled trial in rural Guatemala, RESPIRE.
We recruited 45 indigenous women at the end of the 18-month trial; 19 women who had been using the chimney stove for 18-24 months and 26 women still using open fires.
We obtained spirometry and induced sputum for cell counts, gene expression of IL-8, TNF-α, MMP-9 and 12, and protein concentrations of IL-8, myeloperoxidase and fibronectin. Exhaled carbon monoxide (CO) and 48-hr personal CO tubes were measured to assess smoke exposure.
MMP-9 gene expression was significantly lower in women using chimney stoves. Higher exhaled CO concentrations were significantly associated with higher gene expression of IL-8, TNF-α, and MMP-9. Higher 48-hr personal CO concentrations were associated with higher gene expression of IL-8, TNF- α, MMP-9 and MMP-12; reaching statistical significance for MMP-9 and MMP-12.
Compared to using an open wood fire for cooking, use of a chimney stove was associated with lower gene expression of MMP-9, a potential mediator of airway remodeling. Among all participants, indoor biomass smoke exposure was associated with higher gene expression of multiple mediators of airway inflammation and remodeling; these mechanisms may explain some of the observed association between prolonged biomass smoke exposure and COPD.
