Two Decades of Air Pollution Health Risk Assessment: Insights From the Use of WHO's AirQ and AirQ+ Tools.

Objectives: We evaluated studies that used the World Health Organization's (WHO) AirQ and AirQ+ tools for air pollution (AP) health risk assessment (HRA) and provided best practice suggestions for future assessments. Methods: We performed a comprehensive review of studies using WHO's AirQ and AirQ+ tools, searching several databases for relevant articles, reports, and theses from inception to Dec 31, 2022. Results: We identified 286 studies that met our criteria. The studies were conducted in 69 countries, with most (57%) in Iran, followed by Italy and India (∼8% each). We found that many studies inadequately report air pollution exposure data, its quality, and validity. The decisions concerning the analysed population size, health outcomes of interest, baseline incidence, concentration-response functions, relative risk values, and counterfactual values are often not justified, sufficiently. Many studies lack an uncertainty assessment. Conclusion: Our review found a number of common shortcomings in the published assessments. We suggest better practices and urge future studies to focus on the quality of input data, its reporting, and associated uncertainties.

WHO air quality database: relevance, history and future developments.

Air pollution is the second most important risk factor for noncommunicable diseases, but air quality monitoring is lacking in many low- and middle-income countries. The World Health Organization (WHO) recently released its 2022 updated air quality database status report. This report contains data from about 6743 human settlements, a sixfold increase from 1102 settlements in its first publication in 2011, which shows that air pollution is increasingly recognized as a health priority at global and national levels. However, progress varies across the world. More than 90% of the settlements in the database are in high- and middle-income countries and areas mainly in China, Europe, India and North America. The database is crucial for increasing awareness of air pollution, and for calculating global exposures and the corresponding burden of disease attributable to air pollution. This article describes the progress made and challenges in collecting air quality data. The database uses official data sources which can be difficult to access and assess, because air quality monitoring is done by different government bodies or uses varying monitoring methods. These air quality data can be used by the health sector to engage in discussions on monitoring air quality to protect public health, and facilitate multisectoral engagement of United Nations agencies to support countries to conform with the 2021 WHO air quality guidelines. Although air pollution levels in most countries are higher than those recommended in the guidelines, any action policy-makers take to reduce air pollution will help reduce the burden of air pollution on health.

Bien que la pollution de l'air représente le deuxième facteur de risque le plus important pour les maladies non transmissibles, de nombreux pays à revenu faible et intermédiaire ne mènent aucun contrôle de la qualité de l'air. L'Organisation mondiale de la Santé (OMS) a récemment publié l'édition 2022 du rapport de situation relatif à sa base de données sur la qualité de l'air. Ce rapport renferme des informations sur près de 6743 établissements humains, un chiffre six fois supérieur aux 1102 établissements humains figurant dans la première publication de 2011, ce qui montre que la pollution de l'air est davantage reconnue comme une priorité en matière de santé, tant à l'échelle nationale qu'internationale. Pourtant, les avancées ne sont pas les mêmes partout dans le monde. Plus de 90% des établissements mentionnés dans la base de données se trouvent dans des pays à revenu faible et intermédiaire, ainsi que dans des régions principalement situées en Chine, en Europe, en Inde et en Amérique du Nord. Cette base de données est essentielle pour mieux sensibiliser à la pollution de l'air, mais aussi pour calculer l'exposition mondiale et l'impact des maladies qui lui sont attribuables. Le présent article décrit les progrès réalisés et les défis qui subsistent dans la collecte d'informations liées à la qualité de l'air. La base de données utilise des sources officielles, qui peuvent être difficiles d'accès et compliquées à évaluer car le contrôle de la qualité de l'air est effectué par plusieurs organismes gouvernementaux ou emploie des méthodes différentes. Les informations ainsi récoltées peuvent être exploitées par le secteur de la santé pour entamer des discussions sur le contrôle de la qualité de l'air. Objectif: préserver la santé publique et favoriser la mobilisation multisectorielle d'agences des Nations Unies pour aider les pays à se conformer aux lignes directrices de l'OMS relatives à la qualité de l'air, qui datent de 2021. Même si, dans la plupart des pays, les niveaux de pollution de l'air dépassent les recommandations formulées dans ces lignes directrices, toute action entreprise par les responsables politiques pour les faire baisser contribuera à réduire l'impact qu'exerce cette pollution sur la santé.

La contaminación del aire es el segundo factor de riesgo más importante de las enfermedades no transmisibles, pero en muchos países de ingresos bajos y medios no se vigila la calidad del aire. La Organización Mundial de la Salud (OMS) publicó hace poco su informe actualizado de 2022 sobre el estado de la base de datos de calidad del aire. Este informe contiene datos de unos 6743 asentamientos humanos, es decir, seis veces más que los 1102 asentamientos de su primera publicación en 2011, lo que demuestra que la contaminación del aire se reconoce cada vez más como una prioridad sanitaria a nivel mundial y nacional. Sin embargo, los progresos varían en todo el mundo. Más del 90% de los asentamientos de la base de datos se encuentran en países y regiones de ingresos altos y medios, principalmente en China, Europa, India y Norteamérica. La base de datos es esencial para aumentar la concienciación sobre la contaminación del aire y para calcular las exposiciones globales y la correspondiente carga de morbilidad atribuible a la contaminación del aire. Este artículo describe los progresos realizados y los desafíos que plantea la recopilación de datos sobre la calidad del aire. La base de datos utiliza fuentes de datos oficiales a las que puede resultar difícil acceder y evaluar porque el control de la calidad del aire lo realizan diferentes organismos gubernamentales o utilizan métodos de control que varían. El sector sanitario puede utilizar estos datos sobre la calidad del aire para participar en debates sobre la vigilancia de la calidad del aire con el fin de proteger la salud pública y facilitar el compromiso multisectorial de los organismos de las Naciones Unidas para ayudar a los países a cumplir las directrices de la OMS 2021 sobre la calidad del aire. Aunque los niveles de contaminación del aire en la mayoría de los países son superiores a los recomendados en las directrices, cualquier medida que adopten los responsables de formular políticas para reducir la contaminación del aire contribuirá a reducir la carga de la contaminación del aire sobre la salud.

Ambient Air Quality Standards and Policies in Eastern Mediterranean Countries: A Review.

Objectives: National ambient air quality standards (NAAQS) are critical tools for controlling air pollution and protecting public health. We designed this study to 1) gather the NAAQS for six classical air pollutants: PM2.5, PM10, O3, NO2, SO2, and CO in the Eastern Mediterranean Region (EMR) countries, 2) compare those with the updated World Health Organizations Air Quality Guidelines (WHO AQGs 2021), 3) estimate the potential health benefits of achieving annual PM2.5 NAAQS and WHO AQGs per country, and 4) gather the information on air quality policies and action plans in the EMR countries. Methods: To gather information on the NAAQS, we searched several bibliographic databases, hand-searched the relevant papers and reports, and analysed unpublished data on NAAQS in the EMR countries reported from these countries to the WHO/Regional office of the Eastern Mediterranean/Climate Change, Health and Environment Unit (WHO/EMR/CHE). To estimate the potential health benefits of reaching the NAAQS and AQG levels for PM2.5, we used the average of ambient PM2.5 exposures in the 22 EMR countries in 2019 from the Global Burden of Disease (GBD) dataset and AirQ+ software. Results: Almost all of the EMR countries have national ambient air quality standards for the critical air pollutants except Djibouti, Somalia, and Yemen. However, the current standards for PM2.5 are up to 10 times higher than the current health-based WHO AQGs. The standards for other considered pollutants exceed AQGs as well. We estimated that the reduction of annual mean PM2.5 exposure level to the AQG level (5 µg m-3) would be associated with a decrease of all natural-cause mortality in adults (age 30+) by 16.9%-42.1% in various EMR countries. All countries would even benefit from the achievement of the Interim Target-2 (25 µg m-3) for annual mean PM2.5: it would reduce all-cause mortality by 3%-37.5%. Less than half of the countries in the Region reported having policies relevant to air quality management, in particular addressing pollution related to sand and desert storms (SDS) such as enhancing the implementation of sustainable land management practices, taking measures to prevent and control the main factors of SDS, and developing early warning systems as tools to combat SDS. Few countries conduct studies on the health effects of air pollution or on a contribution of SDS to pollution levels. Information from air quality monitoring is available for 13 out of the 22 EMR countries. Conclusion: Improvement of air quality management, including international collaboration and prioritization of SDS, supported by an update (or establishment) of NAAQSs and enhanced air quality monitoring are essential elements for reduction of air pollution and its health effects in the EMR.

Laser cladding of bioactive glass coating on pure titanium substrate with highly refined grain structure.

Free from toxic elements biomaterial potentially applicable for load bearing biomedical implants was obtained for the first time by laser cladding of S520 bioactive glass onto ultrafine-grained commercially pure titanium. The cladding process affected the refined structure of the substrate inducing martensitic transformation near its surface. The α' acicular martensite gradually passes into relatively large grains with increasing distance from the substrate surface, which subsequently are transformed into smaller grains of about 2 µm in diameter. Both the melted zone, where the martensite crystalline structure was found, and the HAZ are characterised by relatively lower hardness in comparison with that of the substrate core indicating increased ductility. Such a combination of zones with different properties may have a synergistic effect and is beneficial for the obtained biomaterial. A characteristic region in the form of about 3 µm width band was formed in the melted zone at about 10 µm below the titanium surface. The results of EDS analysis indicate that several glass elements moved into the region while the titanium content in the same area was decreased. High bioactivity of the coated S520 glass was revealed by in vitro testing with SBF solution and almost complete reduction of P concentration occurred after 14 days.

Long-term trends and health impact of PM2.5 and O3 in Tehran, Iran, 2006-2015.

The main objectives of this study were (1) investigation of the temporal variations of ambient fine particulate matter (PM2.5) and ground level ozone (O3) concentrations in Tehran megacity, the capital and most populous city in Iran, over a 10-year period from 2006 to 2015, and (2) estimation of their long-term health effects including all-cause and cause-specific mortality. For the first goal, the data of PM2.5 and O3 concentrations, measured at 21 regulatory monitoring network stations in Tehran, were obtained and the temporal trends were investigated. The health impact assessment of PM2.5 and O3 was performed using the World Health Organization (WHO) AirQ+ software updated in 2016 by WHO European Centre for Environment and Health. Local baseline incidences in Tehran level were used to better reveal the health effects associated with PM2.5 and O3. Our study showed that over 2006-2015, annual mean concentrations of PM2.5 and O3 varied from 24.7 to 38.8 µg m-3 and 35.4 to 76.0 µg m-3, respectively, and were significantly declining in the recent 6 years (2010-2015) for PM2.5 and 8 years (2008-2015) for O3. However, Tehran citizens were exposed to concentrations of annual PM2.5 exceeding the WHO air quality guideline (WHO AQG) (10 µg m-3), U.S. EPA and Iranian standard levels (12 µg m-3) during entire study period. We estimated that long-term exposure to ambient PM2.5 contributed to between 24.5% and 36.2% of mortality from cerebrovascular disease (stroke), 19.8% and 24.1% from ischemic heart disease (IHD), 13.6% and 19.2% from lung cancer (LC), 10.7% and 15.3% from chronic obstructive pulmonary disease (COPD), 15.0% and 25.2% from acute lower respiratory infection (ALRI), and 7.6% and 11.3% from all-cause annual mortality in the time period. We further estimated that deaths from IHD accounted for most of mortality attributable to long-term exposure to PM2.5. The years of life lost (YLL) attributable to PM2.5 was estimated to vary from 67,970 to 106,706 during the study period. In addition, long-term exposure to O3 was estimated to be responsible for 0.9% to 2.3% of mortality from respiratory diseases. Overall, long-term exposure to ambient PM2.5 and O3 contributed substantially to mortality in Tehran megacity. Air pollution is a modifiable risk factor. Appropriate sustainable control policies are recommended to protect public health.

3D analysis of thermal and stress evolution during laser cladding of bioactive glass coatings.

Thermal and strain-stress transient fields during laser cladding of bioactive glass coatings on the Ti6Al4V alloy basement were numerically calculated and analysed. Conditions leading to micro-cracking susceptibility of the coating have been investigated using the finite element based modelling supported by experimental results of microscopic investigation of the sample coatings. Consecutive temperature and stress peaks are developed within the cladded material as a result of the laser beam moving along the complex trajectory, which can lead to micro-cracking. The preheated to 500°C base plate allowed for decrease of the laser power and lowering of the cooling speed between the consecutive temperature peaks contributing in such way to achievement of lower cracking susceptibility. The cooling rate during cladding of the second and the third layer was lower than during cladding of the first one, in such way, contributing towards improvement of cracking resistance of the subsequent layers due to progressive accumulation of heat over the process.

"What We Breathe Impacts Our Health: Improving Understanding of the Link between Air Pollution and Health".

Air pollution contributes to the premature deaths of millions of people each year around the world, and air quality problems are growing in many developing nations. While past policy efforts have succeeded in reducing particulate matter and trace gases in North America and Europe, adverse health effects are found at even these lower levels of air pollution. Future policy actions will benefit from improved understanding of the interactions and health effects of different chemical species and source categories. Achieving this new understanding requires air pollution scientists and engineers to work increasingly closely with health scientists. In particular, research is needed to better understand the chemical and physical properties of complex air pollutant mixtures, and to use new observations provided by satellites, advanced in situ measurement techniques, and distributed micro monitoring networks, coupled with models, to better characterize air pollution exposure for epidemiological and toxicological research, and to better quantify the effects of specific source sectors and mitigation strategies.

Survey of Ambient Air Pollution Health Risk Assessment Tools.

Designing air quality policies that improve public health can benefit from information about air pollution health risks and impacts, which include respiratory and cardiovascular diseases and premature death. Several computer-based tools help automate air pollution health impact assessments and are being used for a variety of contexts. Expanding information gathered for a May 2014 World Health Organization expert meeting, we survey 12 multinational air pollution health impact assessment tools, categorize them according to key technical and operational characteristics, and identify limitations and challenges. Key characteristics include spatial resolution, pollutants and health effect outcomes evaluated, and method for characterizing population exposure, as well as tool format, accessibility, complexity, and degree of peer review and application in policy contexts. While many of the tools use common data sources for concentration-response associations, population, and baseline mortality rates, they vary in the exposure information source, format, and degree of technical complexity. We find that there is an important tradeoff between technical refinement and accessibility for a broad range of applications. Analysts should apply tools that provide the appropriate geographic scope, resolution, and maximum degree of technical rigor for the intended assessment, within resources constraints. A systematic intercomparison of the tools' inputs, assumptions, calculations, and results would be helpful to determine the appropriateness of each for different types of assessment. Future work would benefit from accounting for multiple uncertainty sources and integrating ambient air pollution health impact assessment tools with those addressing other related health risks (e.g., smoking, indoor pollution, climate change, vehicle accidents, physical activity).

Quantifying the health impacts of ambient air pollutants: recommendations of a WHO/Europe project.

OBJECTIVE: Quantitative estimates of air pollution health impacts have become an increasingly critical input to policy decisions. The WHO project "Health risks of air pollution in Europe--HRAPIE" was implemented to provide the evidence-based concentration-response functions for quantifying air pollution health impacts to support the 2013 revision of the air quality policy for the European Union (EU). METHODS: A group of experts convened by WHO Regional Office for Europe reviewed the accumulated primary research evidence together with some commissioned reviews and recommended concentration-response functions for air pollutant-health outcome pairs for which there was sufficient evidence for a causal association. RESULTS: The concentration-response functions link several indicators of mortality and morbidity with short- and long-term exposure to particulate matter, ozone and nitrogen dioxide. The project also provides guidance on the use of these functions and associated baseline health information in the cost-benefit analysis. CONCLUSIONS: The project results provide the scientific basis for formulating policy actions to improve air quality and thereby reduce the burden of disease associated with air pollution in Europe.

Biomonitoring-based environmental public health indicators.

This chapter discusses the use ofbiomonitoring-based indicators of exposure to environmental pollutants in environmental health information systems. Matrices for biomonitoring, organization and standardization of surveillance programs, the use of intake and body burden data, and the interpretation of surveillance data are discussed. The concept of environmental public health indicators is demonstrated using the "Persistent organic pollutants in human milk" indicator implemented in the Environment and Health Information System (ENHIS) of the WHO Regional Office for Europe. This indicator is based on the data from the WHO-coordinated surveillance of persistent organic pollutants in human milk as well as data from selected national studies. The WHO survey data demonstrate a steady decline in breast milk concentrations of dioxins across Europe. The data from biomonitoring surveys in Sweden also show a steady decline of breast milk concentrations of most persistent organic pollutants since 1970s with the exception of polybrominated diphenyl ethers (PBDEs) which increased rapidly until the late 1990s and then started to decline after the implementation of policy measures aiming at reducing exposures. The application of human biomonitoring data in support of environmental public health policy actions requires carefully designed standardized and sustainable surveillance, comprehensive interpretation of the data, and an effective communication strategy based on credible information presented in the form of indicator factsheets.

Exposure assessment for estimation of the global burden of disease attributable to outdoor air pollution.

Ambient air pollution is associated with numerous adverse health impacts. Previous assessments of global attributable disease burden have been limited to urban areas or by coarse spatial resolution of concentration estimates. Recent developments in remote sensing, global chemical-transport models, and improvements in coverage of surface measurements facilitate virtually complete spatially resolved global air pollutant concentration estimates. We combined these data to generate global estimates of long-term average ambient concentrations of fine particles (PM(2.5)) and ozone at 0.1° × 0.1° spatial resolution for 1990 and 2005. In 2005, 89% of the world's population lived in areas where the World Health Organization Air Quality Guideline of 10 µg/m(3) PM(2.5) (annual average) was exceeded. Globally, 32% of the population lived in areas exceeding the WHO Level 1 Interim Target of 35 µg/m(3), driven by high proportions in East (76%) and South (26%) Asia. The highest seasonal ozone levels were found in North and Latin America, Europe, South and East Asia, and parts of Africa. Between 1990 and 2005 a 6% increase in global population-weighted PM(2.5) and a 1% decrease in global population-weighted ozone concentrations was apparent, highlighted by increased concentrations in East, South, and Southeast Asia and decreases in North America and Europe. Combined with spatially resolved population distributions, these estimates expand the evaluation of the global health burden associated with outdoor air pollution.