World Health Organization Interim Target Research Articles

‘This smoke will finish us’: impacts of cooking with polluting fuels on air quality, health and education in three schools in Nairobi, Kenya

Links between cooking with polluting fuels (e.g. wood and charcoal), air pollution and health in domestic settings are well-established. However, few studies have been conducted in schools that rely on such fuels for catering. This study is the first investigation of air pollution, cooking, and health in schools in Nairobi, Kenya. We carried out an in-depth mixed-methods study in three schools (two primary schools and a college) in an informal settlement using wood and/or charcoal for catering. In each school, repeated 24-hour air pollution measurements (fine particulate matter (PM2.5) and carbon monoxide (CO)) were collected to assess concentrations in the main kitchen and a nearby classroom, in addition to personal exposure for the main cook. Surveys with catering staff collected data on perspectives on air pollution and health symptoms. Focus groups were conducted with catering staff, teachers and senior management to understand perceived impacts on health and the school environment. 24 hour levels of PM2.5 were found to surpass world health organization interim target level 1 (IT-1) (35 μg m−3) in all schools—with levels three times higher (107.6 μg m−3) in classrooms, ten times higher (316.2 μg m−3) in kitchens and nearly six times higher (200.9 μg m−3) among cooks. Peak levels of pollution were closely linked to times of stove use, as concentrations doubled in classrooms and tripled in kitchens during cooking. Catering staff reported being concerned about their health, and reported experiencing wheezing, chest pains, eye irritation and headaches and attempted to avoid the smoke to reduce exposure. Disturbance to classes from cooking smoke was reported by teachers, with students reporting coughing and sneezing from exposure. Support is needed to enable clean cooking transitions in schools to create a healthy and safe learning environment.

A spatial approach to assessing PM2.5 exposure level of a brickmaking community in South Africa

ABSTRACT Globally, particulate matter with an aerodynamic diameter of 2.5 µm or less poses a significant threat to human health. The first step in quantifying human health impacts caused by exposure to PM2.5 pollution is exposure assessment. Population-weighted exposure level (PWEL) estimation is one of the methods that provides a more precise exposure assessment since it incorporates the spatiotemporal distribution of population with the pollution concentration estimate. In this study, PM2.5 exposure levels in the local communities around brickmaking industries were investigated, using the population census data of the study area and 1-year data from nine PM2.5 monitoring stations installed in and around the brickmaking industries. The observed PM2.5 data was spatially interpolated using inverse distance weight (IDW). Data on PM2.5 levels across the study area were classified based on the World Health Organization interim target (IT) guidelines and the South African National ambient air quality standard (NAAQS). An annual PM2.5 population weighted exposure level of 27.6 µg/m3 was estimated for the study area. However, seasonal exposure levels of 28.9, 37.6, 26.5, and 20.7 µg/m3 were estimated for the autumn, winter, spring, and summer seasons, respectively. This implies that local communities around the brick kiln in the Vhembe District are exposed to high levels of PM2.5, especially in winter. The PM2.5 levels in the brickmaking industries as well as its other sources in the Vhembe District, therefore, need to be lowered. Findings from population exposure level to pollutants can provide valuable data for formulating policies and recommendations on exposure reduction and public health protection. Implications: PM2.5 concentration in any given environment has high spatial and temporal variability due to the presence of diffused sources in the environment. Using ambient air concentrations to directly estimate population exposure without taking into consideration the disproportionate spatial and temporal distribution of the pollutant and the population may not yield accurate results on human exposure levels. It is, therefore, important to assess the aggregated PM2.5 exposure of a populace within a given area. This study therefore examines the PM2.5 population-weighted-exposure level of the host communities of the brickmaking industry in Vhembe District, South Africa.

Reconsidering gas as clean energy: Switching to electricity for household cooking to reduce NO2-attributed disease burden

Nitrogen dioxide (NO2) is a prevalent air pollutant in urban areas, originating from outdoor sources, household gas consumption, and secondhand smoke. The limited evaluation of the disease burden attributable to NO2, encompassing different health effects and contributions from various sources, impedes our understanding from a public health perspective. Based on modeled NO2 exposure concentrations, their exposure–response relationships with lung cancer, chronic obstructive pulmonary disease, and diabetes mellitus, and baseline disability-adjusted life years (DALYs), we estimated that 1,675 (655–2,624) thousand DALYs were attributable to NO2 in urban China in 2019 [138 (54–216) billion Chinese yuan (CNY) economic losses]. The transition from gas to electricity for household cooking was estimated to reduce the attributable economic losses by 35%. This reduction falls within the range of reductions achieved when outdoor air meets the World Health Organization interim target 3 and air quality guidelines for annual NO2, highlighting the significance of raising awareness of gas as a polluting household energy for cooking. These findings align with global sustainable development initiatives, providing a sustainable solution to promote public health while potentially mitigating climate change.

Can the UK meet the World Health Organization PM2.5 interim target of 10 μg m−3 by 2030?

The recent United Kingdom (UK) Environment Act consultation had the intention of setting two targets for PM2.5 (particles with an aerodynamic diameter less than 2.5 μm), one related to meeting an annual average concentration and the second to reducing population exposure. As part of the consultation, predictions of PM2.5 concentrations in 2030 were made by combining European Union (EU) and UK government’s emissions forecasts, with the Climate Change Committee’s (CCC) Net Zero vehicle forecasts, and in London with the addition of local policies based on the London Environment Strategy (LES). Predictions in 2018 showed 6.4% of the UK’s area and 82.6% of London’s area had PM2.5 concentrations above the World Health Organization (WHO) interim target of 10 μg m−3, but by 2030, over 99% of the UK’s area was predicted to be below it. However, kerbside concentrations in London and other major cities were still at risk of exceeding 10 μg m−3. With local action on PM2.5 in London, population weighted concentrations showed full compliance with the WHO interim target of 10 μg m−3 in 2030. However, predicting future PM2.5 concentrations and interpreting the results will always be difficult and uncertain for many reasons, such as imperfect models and the difficulty in estimating future emissions. To help understand the sensitivity of the model’s PM2.5 predictions in 2030, current uncertainty was quantified using PM2.5 measurements and showed large areas in the UK that were still at risk of exceeding the WHO interim target despite the model predictions being below 10 μg m−3. Our results do however point to the benefits that policy at EU, UK and city level can have on achieving the WHO interim target of 10 μg m−3. These results were submitted to the UK Environment Act consultation. Nevertheless, the issues addressed here could be applicable to other European cities.

Associations of peak season ozone with blood pressure among older adults without hypertension in a high exposure country: evidence from the Chinese Longitudinal Healthy Longevity Survey from 2005 to 2018

BACKGROUND AND AIM: Evidence based on long-term prospective cohort studies is lacking to investigate the association between ambient ozone (O3) and blood pressure among older adults. We aim to evaluate the associations of peak season O3 with change of blood pressure in a long-term cohort study among older adults without hypertension. METHODS: We included 5940 older adults aged ≥65 years and with repeated measurements of blood pressure from 2005 to 2018 in 23 provinces of China, estimated monthly O3 exposures at 0.05 ° ×0.05 ° resolution were matched to each participant. Peak season O3 exposure was measured as the average from April to September. Outcomes include blood pressure measurements of SBP, DBP, PP and MAP. Linear mixed models were performed to evaluate the associations between O3 exposures and blood pressure. Natural splines were applied to explore the potential non-linear concentration-response associations. RESULTS: In this study, peak-season O3 ranges from 72.6 to 151.7 μg/m3 in China. In fully adjusted model, per 10 μg/m3 increase in peak season O3 was associated with increases of 2.46 mmHg (95% confidence interval [CI]: 1.85-3.06) in SBP, 2.46 mmHg (95%CI: 1.94-2.99) in PP and 0.74 mmHg (95%CI: 0.38-1.11) in MAP, but non-significant decrease in DBP. Female, ethnic minorities, and older adults who were not in marriage, underweight, with medium or low income levels were susceptible to O3 exposure. Non-linear curves indicated that the effect of O3 exposure on SBP, PP and MAP were monotone increasing, with faster increase in risk magnitude before WHO interim target 1 at 100 μg/m3, but slow down thereafter. CONCLUSIONS: The study added evidence to support the World Health Organization interim targets for peak-season O3, however, lower interim targets should be set to maintain healthy blood pressure among populations in countries with high O3 concentrations. KEYWORDS:Ozone; blood pressure; older adult; cohort study

Emission Sector Impacts on Air Quality and Public Health in China From 2010 to 2020.

Anthropogenic emissions and ambient fine particulate matter (PM2.5) concentrations have declined in recent years across China. However, PM2.5 exposure remains high, ozone (O3) exposure is increasing, and the public health impacts are substantial. We used emulators to explore how emission changes (averaged per sector over all species) have contributed to changes in air quality and public health in China over 2010–2020. We show that PM2.5 exposure peaked in 2012 at 52.8 μg m−3, with contributions of 31% from industry and 22% from residential emissions. In 2020, PM2.5 exposure declined by 36% to 33.5 μg m−3, where the contributions from industry and residential sources reduced to 15% and 17%, respectively. The PM2.5 disease burden decreased by only 9% over 2012 where the contributions from industry and residential sources reduced to 15% and 17%, respectively 2020, partly due to an aging population with greater susceptibility to air pollution. Most of the reduction in PM2.5 exposure and associated public health benefits occurred due to reductions in industrial (58%) and residential (29%) emissions. Reducing national PM2.5 exposure below the World Health Organization Interim Target 2 (25 μg m−3) would require a further 80% reduction in residential and industrial emissions, highlighting the challenges that remain to improve air quality in China.

High temporal and spatial resolution PM2.5 dataset acquisition and pollution assessment based on FY-4A TOAR data and deep forest model in China

Due to urbanization and industrialization, PM2.5 (particulate matter with a diameter less than 2.5 μm) pollution has become a serious environmental problem. The low spatial resolution and insufficient coverage of PM2.5 observation stations affect research on pollution causes and human health risks. With the launch of FY-4A, new generation of Chinese geostationary weather satellites, it is possible to obtain PM2.5 with high temporal and spatial resolution covering all China. In this study, FY-4A top-of-the-atmosphere reflectance data, meteorological factors, and geographic information were input into the deep forest (DF) model to obtain the hourly PM2.5 in China. The samples based 10-fold cross validation of DF with an hourly R2 of 0.83–0.88, and the root mean square error is 8.81–14.7 μg/m3, while the R2 of the 10-fold cross validation result based on sites was 0.77. The monthly (R2 = 0.98) and seasonal (R2 = 0.99) estimated results showed high consistency with the observations. Feature importance showed that the contribution of estimated features to the model varies with regions and seasons. Estimation results indicated the substantial spatiotemporal differences in PM2.5, and pollution was the highest between 09:00–10:00 and then gradually decreased. Regions with highest pollution of PM2.5 in China were mainly distributed in the Tarim Basin and Central China. The pollution assessment results in China indicated that: 1) In more than 80% of the winter days PM2.5 was higher than the World Health Organization interim target 3 (37.5 μg/m3); 2) The bimodal distribution of PM2.5 indicated that there are obvious differences in pollution between cities and suburbs; 3) In autumn and winter, the regions where population-weighted PM2.5 was higher than IT-3 were mainly in Beijing-Tianjin-Hebei, Central China, Guanzhong Plain, Sichuan Basin, and Yangtze River Delta. Our results showed that FY-4A has advantages of high resolution and coverage and thus shows great potential for estimating pollutants.

Emission mitigation pathways to achieve PM2.5 interim target III of the world health organization in the Pearl River Delta in 2035

By participating in the construction of China's Guangdong-Hong Kong-Macao Greater Bay Area (GBA) and as the core zone of the GBA, the region (PRD) aims to have the ambient air quality basically reaching the level of the world-class bay areas by 2035. In this study, we developed three scenario strategies (Moderate Scenario (SM), Intensified Scenario (SI) and Radical Scenario (SR)) for the PRD in 2035 taking the average annual PM2.5 concentrations in the PRD reaching the world health organization interim target 3 (WHO-III, 15 μg/m3) as the constraint standard. Under each scenario, we formulated the structural adjustment and end-of-pipe control measures to predict the development of industry, transportation and energy in the PRD in 2035. The results show that the total emissions of SO2, NOx, PM (Particulate Matters) and NMVOCs (Non-methane Volatile Organic Compounds) were 152, 511, 205 and 382kt in the SM scenario, respectively, and were 114, 436, 177 and 325kt in the SI scenario, respectively, while they are 77, 344, 143 and 269kt in the SR scenario, respectively. We also consider the emission reduction of pollutants outside the PRD. In this study, the SM, SI and SR scenarios were combined with different national scenario inventories (DPEC) in 2035 and the WRF-CMAQ model was used to simulate these scenarios. The simulation results show that annual average concentrations of PM2.5 in the PRD under the SM-DPEC1, SI-DPEC2 and SR-DPEC3 scenarios were expected to reach 15.1, 14.6 and 14.8 μg/m3, respectively, which just meet the WHO-III standard. In the process of achieving WHO-III target in the future, the government and policy makers can match the most suitable scenario in the study by referring to the actual decline of air pollutant emissions in the main contributing regions outside the PRD under each scenario, so as to obtain the best feasible control strategy in the PRD.

Disability Adjusted Life Years (DALYs) in Terms of Years of Life Lost (YLL) Due to Premature Adult Mortalities and Postneonatal Infant Mortalities Attributed to PM2.5 and PM10 Exposures in Kuwait.

Ambient air pollution in terms of fine and coarse particulate matter (PM2.5 and PM10) has been shown to increase adult and infant mortalities. Most studies have estimated the risk of mortalities through attributable proportions and number of excess cases with no reference to the time lost due to premature mortalities. Disability adjusted life years (DALYs) are necessary to measure the health impact of Ambient particulate matter (PM) over time. In this study, we used life-tables for three years (2014–2016) to estimate the years of life lost (YLL), a main component of DALYs, for adult mortalities (age 30+ years) and postneonatal infant mortalities (age 28+ days–1 year) associated with PM2.5 exposure and PM10 exposure, respectively. The annual average of PM2.5 and PM10 concentrations were recorded as 87.9 μg/m3 and 167.5 μg/m3, which are 8 times greater than the World Health Organization (WHO) air quality guidelines of 10 μg/m3 and 20 μg/m3, respectively. Results indicated a total of 252.18 (95% CI: 170.69–322.92) YLL for all ages with an increase of 27,474.61 (95% CI: 18,483.02–35,370.58) YLL over 10 years. The expected life remaining (ELR) calculations showed that 30- and 65-year-old persons would gain 2.34 years and 1.93 years, respectively if the current PM2.5 exposure levels were reduced to the WHO interim targets (IT-1 = 35 μg/m3). Newborns and 1-year old children may live 79.81 and 78.94 years, respectively with an increase in average life expectancy of 2.65 years if the WHO PM10 interim targets were met (IT-1 = 70 μg/m3). Sensitivity analyses for YLL were carried out for the years 2015, 2025, and 2045 and showed that the years of life would increase significantly for age groups between 30 and 85. Life expectancy, especially for the elderly (≥60 years), would increase at higher rates if PM2.5 levels were reduced further. This study can be helpful for the assessment of poor air quality represented by PM2.5 and PM10 exposures in causing premature adult mortalities and postneonatal infant mortalities in developing countries with high ambient air pollution. Information in this article adds insights to the sustainable development goals (SDG 3.9.1 and 11.6.2) related to the reduction of mortality rates attributed to ambient air levels of coarse and fine particulate matter.

Modeling the potential health benefits of lower household air pollution after a hypothetical liquified petroleum gas (LPG) cookstove intervention

Introduction: Improved biomass and advanced fuel cookstoves can lower household air pollution (HAP), but levels of fine particulate matter (PM2.5) often remain above the World Health Organization (WHO) recommended interim target of 35μg/m3.Methods: Based on existing literature, we first estimate a range of likely levels of personal PM2.5 before and after a liquefied petroleum gas (LPG) intervention. Using simulations reflecting uncertainty in both the exposure estimates and exposure-response coefficients, we estimate corresponding expected health benefits for systolic blood pressure (SBP) in adults, birthweight, and pneumonia incidence among children <2years old. We also estimate potential avoided premature mortality among those exposed.Results: Our best estimate is that an LPG stove intervention would decrease personal PM2.5 exposure from approximately 270μg/m3 to approximately 70μg/m3, due to likely continued use of traditional open-fire stoves. We estimate that this decrease would lead to a 5.5mmHg lower SBP among women over age 50, a 338g higher birthweight, and a 37% lower incidence of severe childhood pneumonia. We estimate that decreased SBP, if sustained, would result in a 5%–10% decrease in mortality for women over age 50. We estimate that higher birthweight would reduce infant mortality by 4 to 11 deaths per 1000 births; for comparison, the current global infant mortality rate is 32/1000 live births. Reduced exposure is estimated to prevent approximately 29 cases of severe pneumonia per year per 1000 children under 2, avoiding approximately 2–3 deaths/1000 per year. However, there are large uncertainties around all these estimates due to uncertainty in both exposure estimates and in exposure-response coefficients; all health effect estimates include the null value of no benefit.Conclusions: An LPG stove intervention, while not likely to lower exposure to the WHO interim target level, is still likely to offer important health benefits.

Health burden attributable to ambient PM2.5 in China

In China, over 1.3 billion people have high health risks associated with exposure to ambient fine particulate matter (PM2.5) that exceeds the World Health Organization (WHO) Air Quality Guidelines (AQG). The PM2.5 mass concentrations from 1382 national air quality monitoring stations in 367 cities, between January 2014 and December 2016, were analyzed to estimate the health burden attributable to ambient PM2.5 across China. The integrated exposure-response model was applied to estimate the relative risks of disease-specific mortality. Disease-specific mortality baselines in province-level administrative units were adjusted by the national mortality baseline to better reveal the spatial inequality of the health burden associated with PM2.5. Our study suggested that PM2.5 in 2015 contributed as much as 40.3% to total stroke deaths, 33.1% to acute lower respiratory infection (ALRI, <5yr) deaths, 26.8% to ischemic heart disease (IHD) deaths, 23.9% to lung cancer (LC) deaths, 18.7% to chronic obstructive pulmonary disease (COPD) deaths, 30.2% to total deaths combining IHD, stroke, COPD, and LC, 15.5% to all cause deaths. The population weighted average (PWA) attributable mortality rates (10−5 y−1) were 112.0 in current year analysis, and 124.3 in 10-year time lag analysis. The Mortality attributable to PM2.5 in 10-year time lag analysis (1.7 million) was 12% higher than the current year analysis (1.5 million). Our study also estimated site-specific annual PM2.5 concentrations in scenarios of achieving WHO interim targets (ITs) and AQG. The mortality benefits will be 24.0%, 44.8%, 70.8%, and 85.2% of the total current mortalities (1.5 million) when the PWA PM2.5 concentrations in China meets the WHO IT-1, IT-2, IT-3, and AQG, respectively. We expect air quality modeling and cost-benefits analysis of emission reduction scenarios and corresponding health benefits in meeting the site-specific annual PM2.5 concentrations (WHO IT-1, IT-2, IT-3, and AQG) this study raised.

Assessment of Population Exposure to Coarse and Fine Particulate Matter in the Urban Areas of Chennai, India.

Research outcomes from the epidemiological studies have found that the course (PM10) and the fine particulate matter (PM2.5) are mainly responsible for various respiratory health effects for humans. The population-weighted exposure assessment is used as a vital decision-making tool to analyze the vulnerable areas where the population is exposed to critical concentrations of pollutants. Systemic sampling was carried out at strategic locations of Chennai to estimate the various concentration levels of particulate pollution during November 2013–January 2014. The concentration of the pollutants was classified based on the World Health Organization interim target (IT) guidelines. Using geospatial information systems the pollution and the high-resolution population data were interpolated to study the extent of the pollutants at the urban scale. The results show that approximately 28% of the population resides in vulnerable locations where the coarse particulate matter exceeds the prescribed standards. Alarmingly, the results of the analysis of fine particulates show that about 94% of the inhabitants live in critical areas where the concentration of the fine particulates exceeds the IT guidelines. Results based on human exposure analysis show the vulnerability is more towards the zones which are surrounded by prominent sources of pollution.

Assessment of the Health Impacts and Economic Burden Arising from Proposed New Air Quality Objectives in a High Pollution Environment

We conducted a health impact assessment of the government's proposed new air quality objectives (AQO) in Hong Kong, a high pollution environment. We based this on the World Health Organization (WHO) 2005 Air Quality Guidelines (AQG) and used a lognormal probability density function to model possible changes in annual mean pollutant levels resulting from the new AQO. All of the proposed short-term AQO were based on WHO interim targets (IT) or AQG, but allowed additional exceedances of these single limit values. Compliance with these short-term AQO may reduce (18-30%) the current annual mean concentrations but the distribution proportions exceeding the annual or annualized AQG remain high (83-100%). For SO2, the proposed 24-hr AQO of 125 μg m -3 , with 3 days exceedances, cannot ensure reduction of the current annual mean but may legally permit an increase of the pollutant concentration distribution. If the proposed legal limits of AQO are fully exploited by polluters, we estimated the annual number of avoidable deaths at 1860, and avoidable health care events at 5.2 million doctor visits and 92745 hospital bed-days with a total annual community cost of US$2.6 billion. The proposed AQO may only reduce the current air pollution health impacts by 17% but could achieve 41% reduction if additional exceedances were not permitted. An epidemiologic approach should be adopted to assess external costs arising from modifications of WHOAQG and support accountability in air quality management. This analysis of the WHOAQG in a high pollution setting demonstrates problems arising from the absence of annual limits for some pollutants and the discordance between the short-term and annual AQG, suggesting that revisions based on a lognormal probability model should be considered.