Women exposure to household air pollution after an improved cookstove program in rural San Luis Potosi, Mexico

Socioeconomic and Environmental Aspects of Traditional Firewood for Cooking on the Example of Rural and Peri-Urban Mexican Households

Firewood is a solid biofuel that is widely used for cooking in Mexico’s residential sector. This study seeks to identify relevant factors in firewood consumption patterns, and their implications for climate change, gender, and health, and for energy poverty in Mexico, by climate region and socioeconomic level. For this purpose, a statistical analysis was conducted of recently published official information. We estimate that a total of 31.3 million Mexicans—26% of the total population—use firewood, and we have identified three main types of users: (i) exclusive firewood users (30%); (ii) mixed firewood users using firewood as their primary fuel (18%) and (iii) mixed firewood users using firewood as their secondary fuel source (52%). Total consumption of firewood was estimated at 116.6 PJ, while estimated greenhouse gas emissions were 8.1 million tCO2e. Out of all the households studied, 53% were in the tropical climate region; 59% were categorized as being in the “low” socioeconomic level; and 75% were in population centers comprising fewer than 2500 inhabitants. Some 68% of households do not pay for the acquisition of firewood, and for those households that do pay for the resource, estimated transactions total USD 286.9 million. Expenditures on firewood for energy represent up to 10% of household income. Finally, it was estimated that 15.7 million direct users of firewood are women who use the resource in three-stone fires, in which they expose themselves to health risks in doing so. In conclusion, main universal findings, the study’s limitations, and future research are presented.

Pregnant Women's Exposure to Household Air Pollution in Rural Bangladesh: A Feasibility Study for Poriborton: The CHANge Trial

The use of liquefied petroleum gas (LPG) for cooking is a strategy to reduce household air pollution (HAP) exposure and improve health. We conducted this feasibility study to evaluate personal exposure measurement methods to representatively assess reductions in HAP exposure. We enrolled 30 pregnant women to wear a MicroPEM for 24 h to assess their HAP exposure when cooking with a traditional stove (baseline) and with an LPG stove (intervention). The women wore the MicroPEM an average of 77% and 69% of the time during the baseline and intervention phases, respectively. Mean gravimetric PM_2.5 mass and black carbon concentrations were comparable during baseline and intervention. Temporal analysis of the MicroPEM nephelometer data identified high PM_2.5 concentrations in the afternoon, late evening, and overnight during the intervention phase. Likely seasonal sources present during the intervention phase were emissions from brick kiln and rice parboiling facilities, and evening kerosene lamp and mosquito coil use. Mean background adjusted PM_2.5 concentrations during cooking were lower during intervention at 71 μg/m³, versus 105 μg/m³ during baseline. Representative real-time personal PM_2.5 concentration measurements supplemented with ambient PM_2.5 measures and surveys will be a valuable tool to disentangle external sources of PM_2.5, other indoor HAP sources, and fuel-sparing behaviors when assessing the HAP reduction due to intervention with LPG stoves.

Prenatal PM2.5 exposure in the second and third trimesters predicts neurocognitive performance at age 9-10 years: A cohort study of Mexico City children

INTRODUCTION

Prenatal exposure to fine particulate matter air pollution (PM2.5) is an important, under-studied risk factor for neurodevelopmental dysfunction. We describe the relationships between prenatal PM2.5 exposure and vigilance and inhibitory control, executive functions related to multiple health outcomes in Mexico City children.

METHODS

We studied 320 children enrolled in Programming Research in Obesity, GRowth, Environment and Social Stressors, a longitudinal birth cohort study in Mexico City. We used a spatio-temporal model to estimate daily prenatal PM2.5 exposure at each participant's residential address. At age 9-10 years, children performed three Go/No-Go tasks, which measure vigilance and inhibitory control ability. We used Latent class analysis (LCA) to classify performance into subgroups that reflected neurocognitive performance and applied multivariate regression and distributed lag regression modeling (DLM) to test overall and time-dependent associations between prenatal PM2.5 exposure and Go/No-Go performance.

RESULTS

LCA detected two Go/No-Go phenotypes: high performers (Class 1) and low performers (Class 2). Predicting odds of Class 1 vs Class 2 membership based on prenatal PM2.5 exposure timing, logistic regression modeling showed that average prenatal PM2.5 exposure in the second and third trimesters correlated with increased odds of membership in low-performance Class 2 (OR = 1.59 (1.16, 2.17), p = 0.004). Additionally, DLM analysis identified a critical window consisting of gestational days 103-268 (second and third trimesters) in which prenatal PM2.5 exposure predicted poorer Go/No-Go performance.

DISCUSSION

Increased prenatal PM2.5 exposure predicted decreased vigilance and inhibitory control at age 9-10 years. These findings highlight the second and third trimesters of gestation as critical windows of PM2.5 exposure for the development of vigilance and inhibitory control in preadolescent children. Because childhood development of vigilance and inhibitory control informs behavior, academic performance, and self-regulation into adulthood, these results may help to describe the relationship of prenatal PM2.5 exposure to long-term health and psychosocial outcomes. The integrative methodology of this study also contributes to a shift towards more holistic analysis.

Organophosphate Esters in Indoor Environment and Metabolites in Human Urine Collected from a Shanghai University

In China, organophosphate esters (OPEs) are widely used in indoor environments. However, there is little information regarding the internal and external exposure of university students to OPEs. Therefore, in this study, nine OPEs and eight OPE metabolites (mOPEs) were measured in indoor dust and atmospheric PM2.5 samples from a university campus in Shanghai, as well as in urine samples collected from the university students. The total concentration of OPEs in the indoor dust in female dormitories (1420 ng/g) was approximately twice that in male dormitories (645 ng/g). In terms of indoor PM2.5, the highest OPE concentration was found in meeting rooms (105 ng/m3, on average), followed by chemical laboratories (51.2 ng/m3), dormitories (44.9 ng/m3), and offices (34.9 ng/m3). The total concentrations of the eight mOPEs ranged from 279 pg/mL to 14,000 pg/mL, with a geometric mean value of 1590 pg/mL. The estimated daily intake values based on the indoor dust and PM2.5 OPE samples (external exposure) were 1-2 orders of magnitude lower than that deduced from the concentration of urinary mOPEs (internal exposure), indicating that dermal contact, dust ingestion, and inhalation do not contribute significantly to OPE exposure in the general population. Moreover, additional exposure routes lead to the accumulation of OPEs in the human body.

Exposure to polycyclic aromatic hydrocarbon mixtures and early kidney damage in Mexican indigenous population

The traditions and habits of indigenous communities in México include the use of wood and biomass burning to cook their food, which generates large amounts of smoke and therefore pollution inside the households. This smoke is composed of a complex mixture of polycyclic aromatic hydrocarbons (PAHs) which at high levels of exposure cause carcinogenic, genotoxic effects and some chronic pulmonary and cardiovascular diseases; however, few studies relate kidney health with exposure to PAHs. Thus, the aim of this study was the evaluation of 10 hydroxylated metabolites of PAHs (OH-PAHs), and their correlation with biomarkers of early kidney damage renal (cystatin-C (Cys-C)), osteopontin (OPN), retinol-binding protein-4 (RPB-4), and neutrophil gelatinase-associated lipocalin (NGAL) in the indigenous population of the Huasteca Potosina in Mexico. The results demonstrate the presence of the OH-PAHs and kidney damage biomarkers in 100% of the study population. The OH-PAHs were shown in the following order of frequency, 1-OH-PYR > 4-OH-PHE > 2-OH-NAP > 1-OH-NAP > 9-OH-FLU > 3-OH-FLU > 2-OH-FLU > 3-OH-PHE and with the following percentages of detection 97.6, 87.8, 78, 73.2, 68.3, 31.7, 14.6, and 12.2%, respectively. NGAL and RBP-4 were present in above 85% of the population, with mean concentrations of 78.5 ± 143.9 and 139.4 ± 131.7 ng/g creatinine, respectively, OPN (64%) with a mean concentration of 642.6 ± 723.3 ng/g g creatinine, and Cys-C with a mean concentration of 33.72 ± 44.96 ng/g creatinine. Correlations were found between 1-OH-NAP, 2-OH-NAP, 9-OH-FLU, and 4-OH-PHE and the four biomarkers of early kidney damage. 3-OH-FLU with OPN and 1-OH-PYR correlated significantly with NGAL, OPN, and RPB-4.

Analysis of urinary metabolites of polycyclic aromatic hydrocarbons in precarious workers of highly exposed occupational scenarios in Mexico

Exposure to polycyclic aromatic hydrocarbons (PAHs) is a risk factor for human health. Workers are a vulnerable group due to their high exposure and therefore require special attention to mitigation measurements; however, some groups of workers are especially vulnerable, precarious workers. The objective of this research was to evaluate mixtures of hydroxylated PAHs (OH-PAHs) in precarious workers in Mexico. The following activities were evaluated: (i) brickmakers (TER), stonemasons (ESC), indigenous workers (TOC) and mercury miners (CAM). Ten OH-PAHS were analyzed: 1-hydroxynaphtalene and 2-hydroxynaphtalene; 2-,3- and 9-hydroxyfluorene; 1-,2-,3- and 4-hydroxyphenanthrene; and 1-hydroxypyrene in urine by GC-MS, chemical fingerprints of the sites were established by multivariate analysis. One hundred forty-nine precarious workers participated in the study. The populations presented total OH-PAHs concentrations of 9.20 (6.65-97.57), 14.8 (9.32-18.85), 15.7 (6.92-195.0), and 101.2 (8.02-134.4) μg/L for CAM, ESC, TER, and TOC, respectively (median (IQR)). The results of the multivariate analysis indicate that the indigenous population presented a different fingerprint compared to the three scenarios. The chemical fingerprints among the brickmakers and mercury mining population were similar. The results of the concentrations were similar and in some metabolites higher than workers in occupations classified as carcinogenic by the IARC; therefore, the control of exposure in these occupations acquires great importance and surveillance through biological monitoring of OH-PAHs should be applied to better estimate exposure in these working populations.

Effectiveness of Gas and Chimney Biomass Stoves for Reducing Household Air Pollution Pregnancy Exposure in Guatemala: Sociodemographic Effect Modifiers

Household air pollution (HAP) due to solid fuel use during pregnancy is associated with adverse birth outcomes. The real-life effectiveness of clean cooking interventions has been disappointing overall yet variable, but the sociodemographic determinants are not well described. We measured personal 24-h PM_2.5 (particulate matter <2.5 µm in aerodynamic diameter) thrice in pregnant women (n = 218) gravimetrically with Teflon filter, impactor, and personal pump setups. To estimate the effectiveness of owning chimney and liquefied petroleum gas (LPG) stoves (i.e., proportion of PM_2.5 exposure that would be prevented) and to predict subject-specific typical exposures, we used linear mixed-effects models with log (PM_2.5) as dependent variable and random intercept for subject. Median (IQR) personal PM_2.5 in µg/m³ was 148 (90-249) for open fire, 78 (51-125) for chimney stove, and 55 (34-79) for LPG stoves. Adjusted effectiveness of LPG stoves was greater in women with ≥6 years of education (49% (95% CI: 34, 60)) versus <6 years (26% (95% CI: 5, 42)). In contrast, chimney stove adjusted effectiveness was greater in women with <6 years of education (50% (95% CI: 38, 60)), rural residence (46% (95% CI: 34, 55)) and lowest SES (socio-economic status) quartile (59% (95% CI: 45, 70)) than ≥6 years education (16% (95% CI: 22, 43)), urban (23% (95% CI: -164, 42)) and highest SES quartile (-44% (95% CI: -183, 27)), respectively. A minority of LPG stove owners (12%) and no chimney owner had typical exposure below World Health Organization Air Quality guidelines (35 μg/m³). Although having a cleaner stove alone typically does not lower exposure enough to protect health, understanding sociodemographic determinants of effectiveness may lead to better targeting, implementation, and adoption of interventions.

Critical review of social, environmental and health risk factors in the Mexican indigenous population and their capacity to respond to the COVID-19

The objective of this study was to conduct a critical analysis of the social, environmental and health risk factors in the Mexican indigenous population in the context of the COVID-19 disease pandemic, and to propose strategies to mitigate the impacts on these communities. Regarding social factors, we identified the return of indigenous people to their communities, poor access to water, language barriers, and limited access to the Internet, as factors that will not allow them to take the minimum preventive measures against the disease. Additionally, environmental risk factors associated with pollutants from biomass burning were identified. In health, the lack of coverage in these areas and comorbidities such as diabetes mellitus, hypertension, respiratory tract infections, and chronic pulmonary diseases were identified. Some existing government programmes were identified that could be supported to address these social, environmental and health gaps. We believe that the best way to address these issues is to strengthen the health system with a community-based approach. Health is the best element of cohesion for inserting development and progress proposals in indigenous communities, given the vulnerability to which they are exposed in the face of the COVID-19 pandemic. In this review, all information is provided (as possible) on risk factors and potential solutions in indigenous communities in the hope of providing solutions to this pandemic and providing a reference for future studies.

Assessment of kidney health and exposure to mixture pollutants in the Mexican indigenous population

The indigenous population is one of the most vulnerable to suffer from contaminated environments. One of the target organs to suffer early deterioration from exposure to toxins is the kidney. The objective of this article was to evaluate biomarkers of exposure to organic and inorganic toxins and biomarkers of early kidney damage in urine from an indigenous Tenek population in Mexico. The biomarkers of exposure were Li, Be, Al, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Mo, Sn, Ba, and Pb evaluated by ICP-MS and hippuric acid for toluene exposure evaluated by UV-coupled with liquid chromatography; the biomarkers of kidney damage were cystatin C (Cys-C), osteopontin (OPN), retinol-binding protein-4 (RPB-4), and neutrophil gelatinase-associated lipocalin (NGAL). Thirty-one urine samples were obtained from indigenous people; 16, 42, 45.1, and 45.2% of the population exceeded the reference values for Pb, Zn, As, and hippuric acid respectively. Our results demonstrate significant correlations between the metals tested and the proteins associated with renal damage; Cys-C, OPN, and RPB4 showed a significant correlation with Li, B, and Mo, as well as hippuric acid in the case of Cys-C and Zn in OPN and RPB-4; NGAL did not present significant correlations with any of the pollutants of the study. This pilot study contributes to the evidence of great inequity in health associated to environmental pollution matters faced by indigenous people and addresses the need of initiatives for mitigation under the perspective that health is a fundamental human right.