Health effects related to exposure to air pollution such as ozone (O3) have been documented. The World Health Organization has recommended the use of the Sum of O3 Means Over 35 ppb (SOMO35) to perform Health Impact Assessments (HIA) for long-term exposure to O3. We estimated the avoidable mortality associated with long-term exposure to tropospheric O3 in 14 cities in Mexico using information for 2015. The economic valuation of avoidable deaths related to SOMO35 exposure was performed using the willingness to pay (WTP) and human capital (HC) approaches. We estimated that 627 deaths (95% uncertainty interval (UI): 227–1051) from respiratory diseases associated with the exposure to O3 would have been avoided in people over 30 years in the study area, which confirms the public health impacts of ambient air pollution. The avoidable deaths account for almost 1400 million USD under the WTP approach, whilst the HC method yielded a lost productivity estimate of 29.7 million USD due to premature deaths. Our findings represent the first evidence of the health impacts of O3 exposure in Mexico, using SOMO35 metrics.
Background:
Reusing wastewater for irrigation is a longstanding practice that enhances crop yields and improves climate resilience. Without treatment, however, wastewater contains harmful pathogens and chemicals. Reuse of untreated wastewater has been shown to be harmful to the health of nearby communities, but the routes of exposure are unknown and do not appear to be occupational. Some routes occur throughout entire communities, such as food contamination. Other routes may be spatially dependent, such as spread by domestic animals or through aerosolization.
Objectives:
To examine whether those wastewater exposure routes with a spatial dependency affect health, we estimated the risks of diarrheal disease in children under age 5 associated with living near wastewater canals, while adjusting for potential individual- and household-level confounders.
Methods:
We conducted three surveys over 1 y in the Mezquital Valley, Mexico, to measure diarrhea in children. The distance between each participating household and a wastewater canal was measured using GPS coordinates. The association between proximity and diarrhea was estimated with a multilevel logistic regression model accounting for spatial autocorrelation.
Results:
A total of 564 households completed one to three surveys, resulting in 1,856 survey observations of 646 children. Children living
from a canal had 45% lower odds of diarrhea than those living within
of a canal, and children living
away had 70% lower odds of diarrhea [
vs.
adjusted odds ratio
, 95% credible interval (CI): 0.33, 0.91;
vs.
adjusted
, 95% CI: 0.11, 0.82].
Discussion:
The estimated decline in diarrheal prevalence with household distance from a canal persisted after controlling for occupational exposure. Identifying the specific routes of exposure that drive this relationship will help identify which interventions, such as upstream treatment, can reduce health risks for entire communities where wastewater exposure occurs.
https://doi.org/10.1289/EHP6443
Wastewater for irrigation in low- and middle-income countries can recharge aquifers and potentially contaminate supply sources. The infiltration rate has increased 13-fold in Mexico's Mezquital Valley, the largest agricultural area wastewater-irrigated worldwide, thus we assume that wastewater had contaminated supply sources. Fecal indicator bacteria (FIB) counts were enumerated in household water of two wastewater-irrigated areas, Tula and Tlahuelilpan, and a groundwater irrigated area, Tecozautla. During 2016–2017, household water, wastewater, and groundwater were sampled, analyzing fecal coliforms, fecal enterococci, and Escherichia coli, following membrane filtration procedures, and confirming the presence of E. coli by polymerase chain reaction. Nearly 50% of household water contained fecal contamination of up to 4.62 × 104 CFU/100 mL. Significant differences between FIB counts in household water from Tula and Tecozautla were observed by Kruskal–Wallis and Dunnett tests. Household water samples from Tula contained highest FIB counts. Wastewater from Tula and Tlahuelilpan contained counts of six orders-of-magnitude of FIB. Counts were high when residual chlorine was <0.2 mg L−1 and underwater storage. This research serves as a baseline to observe improvement with a newly installed wastewater treatment plant. Safe irrigation wastewater reuse should be performed under strict surveillance, considering human safety a priority.
Objetivo. Analizar la evidencia sobre la relación entre la contaminación del aire y un riesgo mayor de morbimortalidad por Covid-19. Material y métodos. Se utilizó una adaptación de la metodología de revisiones rápidas de Cochrane. La búsqueda se realizó en PubMed y MedRxiv y se limitó hasta el 28 y 26 de abril, respectivamente. Los títulos y resúmenes fueron revisados por cinco investigadores que, a su vez, revisaron los textos completos de la selección final. Resultados. Se encontraron 450 manuscritos, 15 cumplieron los criterios de inclusión. La evidencia encontrada reporta que la incidencia y el riesgo de morbilidad y mortalidad por Covid-19 se incrementan con la exposición crónica y aguda a la contaminación del aire, particularmente a material particulado (PM2.5, PM10) y dióxido de nitrógeno. Conclusiones. Se requieren más estudios especialmente en ciudades latinoamericanas. Es necesario fortalecer las recomendaciones en las ciudades con mayores niveles de contaminantes y reducir sus emisiones.
The aim of this pilot study was to evaluate the link between housing and children´s respiratory symptoms, through the construction of an index (HSHI) based on the definition of healthy-sustainable housing criteria, in a semi-urban community from Morelos, Mexico. A general and household questionnaire, and respiratory symptoms diary were applied in 60 households to gather information about schoolchildren, respiratory health, housing and lifestyle characteristics. HSHI was constructed using principal component analysis. The association between HSHI and the presence and duration of respiratory symptoms was assessed using logistic and Poisson regression models. HSHI had five components, which accounted for 63% of variance, and were classified into poor and sufficient quality. It was observed that schoolchildren who inhabit a sufficient-quality house, showed a reduction in nose irritation duration and in the allergic symptoms probability regarding component 1 (ventilation, lighting and cloth washing) and presented three times less duration of common cold by component 2 (construction material, painted walls inside the house and type of bathroom) compared to poor-quality house inhabitants. Our results suggest that living in a sufficient-quality house, as described by the HSHI, reduced the prevalence of wheezing episodes and the probability of ear pain, providing evidence about the positive association of a healthy-sustainable housing on the respiratory health of schoolchildren.
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