Ambient air quality and exposure assessment study of the Gulf Cooperation Council countries: A critical review

Carbon based sensors for air quality monitoring networks; middle east perspective

IoT-based Sensors networks play a pivotal role in improving air quality monitoring in the Middle East. They provide real-time data, enabling precise tracking of pollution trends, informed decision-making, and increased public awareness. Air quality and dust pollution in the Middle East region may leads to various health issues, particularly among vulnerable populations. IoT-based Sensors networks help mitigate health risks by offering timely and accurate air quality data. Air pollution affects not only human health but also the region's ecosystems and contributes to climate change. The economic implications of deteriorated air quality include healthcare costs and decreased productivity, underscore the need for effective monitoring and mitigation. IoT-based data can guide policymakers to align with Sustainable Development Goals (SDGs) related to health, clean water, and climate action. The conventional monitor based standard air quality instruments provide limited spatial coverage so there is strong need to continue research integrated with low-cost sensor technologies to make air quality monitoring more accessible, even in resource-constrained regions. IoT-based Sensors networks monitoring helps in understanding these environmental impacts. Among these IoT-based Sensors networks, sensors are of vital importance. With the evolution of sensors technologies, different types of sensors materials are available. Among this carbon based sensors are widely used for air quality monitoring. Carbon nanomaterial-based sensors (CNS) and carbon nanotubes (CNTs) as adsorbents exhibit unique capabilities in the measurement of air pollutants. These sensors are used to detect gaseous pollutants that includes oxides of nitrogen and Sulphur, and ozone, and volatile organic compounds (VOCs). This study provides comprehensive review of integration of carbon nanomaterials based sensors in IoT based network for better air quality monitoring and exploring the potential of machine learning and artificial intelligence for advanced data analysis, pollution source identification, integration of satellite and ground-based networks and future forecasting to design effective mitigation strategies. By prioritizing these recommendations, the Middle East and other regions, can further leverage IoT-based systems to improve air quality monitoring, safeguard public health, protect the environment, and contribute to sustainable development in the region.

Research on the Spatial Correlation of China's Haze Pollution and the Government's Cooperative Governance Competitive Strategy

A government's choice of environmental strategy plays an important role in the coordinated governance of regional air pollution. Based on changes in China's environmental policies and on changes in environmental indicators over the years, this paper selects regional haze data from the years 2005, 2009, 2013, and 2017; uses social network analysis to describe the structural characteristics of a spatial correlation network in China; measures the level of coordination using a population gravity model; and further analyzes the influence of the overall structural characteristics of spatial networks on the level of coordination. The results show that the spatial association of regional haze presents a typical "central edge" network structure. The Beijing-Tianjin-Hebei region and the Yangtze River Delta region are the largest emitters in China. The coordination level of haze control in China showed a fluctuating upward trend, but the overall level of coordination is relatively low, and there is still great room for improvement. Based on the above characteristics, using the provincial panel data from 2005-2017, a two-zone spatial Durbin model was built to empirically test the impact of changes to the environmental performance assessment system on local coordinated haze-control decisions and their stage characteristics. The overall sample results show that there was a "race to the bottom" among Chinese provinces during the study period. When the haze control intensity in neighboring areas was relaxed, the regional governments also tended to relax their own environmental regulation intensity. The time-based analysis results further show that with the improvement of the environmental performance assessment system, the strategy selection of coordinated governmental haze-management presents the possibility of a "race to the top".

Age-sex differences in the global burden of lower respiratory infections and risk factors, 1990-2019: results from the Global Burden of Disease Study 2019

BACKGROUND

The global burden of lower respiratory infections (LRIs) and corresponding risk factors in children older than 5 years and adults has not been studied as comprehensively as it has been in children younger than 5 years. We assessed the burden and trends of LRIs and risk factors across all age groups by sex, for 204 countries and territories.

METHODS

In this analysis of data for the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we used clinician-diagnosed pneumonia or bronchiolitis as our case definition for LRIs. We included International Classification of Diseases 9th edition codes 079.6, 466-469, 470.0, 480-482.8, 483.0-483.9, 484.1-484.2, 484.6-484.7, and 487-489 and International Classification of Diseases 10th edition codes A48.1, A70, B97.4-B97.6, J09-J15.8, J16-J16.9, J20-J21.9, J91.0, P23.0-P23.4, and U04-U04.9. We used the Cause of Death Ensemble modelling strategy to analyse 23 109 site-years of vital registration data, 825 site-years of sample vital registration data, 1766 site-years of verbal autopsy data, and 681 site-years of mortality surveillance data. We used DisMod-MR 2.1, a Bayesian meta-regression tool, to analyse age-sex-specific incidence and prevalence data identified via systematic reviews of the literature, population-based survey data, and claims and inpatient data. Additionally, we estimated age-sex-specific LRI mortality that is attributable to the independent effects of 14 risk factors.

FINDINGS

Globally, in 2019, we estimated that there were 257 million (95% uncertainty interval [UI] 240-275) LRI incident episodes in males and 232 million (217-248) in females. In the same year, LRIs accounted for 1·30 million (95% UI 1·18-1·42) male deaths and 1·20 million (1·07-1·33) female deaths. Age-standardised incidence and mortality rates were 1·17 times (95% UI 1·16-1·18) and 1·31 times (95% UI 1·23-1·41) greater in males than in females in 2019. Between 1990 and 2019, LRI incidence and mortality rates declined at different rates across age groups and an increase in LRI episodes and deaths was estimated among all adult age groups, with males aged 70 years and older having the highest increase in LRI episodes (126·0% [95% UI 121·4-131·1]) and deaths (100·0% [83·4-115·9]). During the same period, LRI episodes and deaths in children younger than 15 years were estimated to have decreased, and the greatest decline was observed for LRI deaths in males younger than 5 years (-70·7% [-77·2 to -61·8]). The leading risk factors for LRI mortality varied across age groups and sex. More than half of global LRI deaths in children younger than 5 years were attributable to child wasting (population attributable fraction [PAF] 53·0% [95% UI 37·7-61·8] in males and 56·4% [40·7-65·1] in females), and more than a quarter of LRI deaths among those aged 5-14 years were attributable to household air pollution (PAF 26·0% [95% UI 16·6-35·5] for males and PAF 25·8% [16·3-35·4] for females). PAFs of male LRI deaths attributed to smoking were 20·4% (95% UI 15·4-25·2) in those aged 15-49 years, 30·5% (24·1-36·9) in those aged 50-69 years, and 21·9% (16·8-27·3) in those aged 70 years and older. PAFs of female LRI deaths attributed to household air pollution were 21·1% (95% UI 14·5-27·9) in those aged 15-49 years and 18·2% (12·5-24·5) in those aged 50-69 years. For females aged 70 years and older, the leading risk factor, ambient particulate matter, was responsible for 11·7% (95% UI 8·2-15·8) of LRI deaths.

INTERPRETATION

The patterns and progress in reducing the burden of LRIs and key risk factors for mortality varied across age groups and sexes. The progress seen in children younger than 5 years was clearly a result of targeted interventions, such as vaccination and reduction of exposure to risk factors. Similar interventions for other age groups could contribute to the achievement of multiple Sustainable Development Goals targets, including promoting wellbeing at all ages and reducing health inequalities. Interventions, including addressing risk factors such as child wasting, smoking, ambient particulate matter pollution, and household air pollution, would prevent deaths and reduce health disparities.

FUNDING

Bill & Melinda Gates Foundation.

R. Morrison L, Bean de Hernández A, Rakic S, AlOmran M, Alsukait RF, Herbst CH, AlBalawi S. Effective options for addressing air quality– related environmental public health burdens in Saudi Arabia

Air pollution poses major disease burdens globally and accounts for approximately 10% of deaths annually through its contribution to a variety of respiratory, cardiovascular, and other diseases. The burden of disease is particularly acute in Saudi Arabia, where a mix of anthropogenic and natural sources of air pollution threatens public health. Addressing these burdens requires careful study of the costs and effectiveness of available technologies and policies for reducing emissions (mitigation) and avoiding exposure (adaptation). To help evaluate these options, we conduct a semi-systematic literature review of over 3,000 articles published since 2010 that were identified by searches of literature focused on pollution mitigation and pollution adaptation. We identify a wide variety of effective mitigation and adaptation technologies and find that cost-effectiveness information for policy design is highly variable in the case of mitigation, both within and across pollution source categories; or scarce, in the case of adaptation. While pollution control costs are well studied, policy costs differ; these may vary more by location because of factors such as technology operating conditions and behavioral responses to adaptation initiatives, limiting the generalizability of cost-effectiveness information. Moreover, potential cost advantages of multipollutant control policies are likely to depend on the existing mix of pollution sources and controls. While the policy literature generally favors more flexible compliance mechanisms that increase the cost of polluting to reflect its costs to society, important policy design factors include policy co-benefits, distributional concerns, and inter-regional harmonization. In addition to these key themes, we find that further study is needed both to improve the availability of cost information for adaptation interventions and to localize technology and policy cost estimates to the Saudi context.

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Literature review of environmental public health technology and policy options.

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Air pollution mitigation options have considerable cost variation.

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Air pollution adaptation options lack thorough cost effectiveness evaluation.

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Policy effectiveness will depend heavily on local conditions and design.

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Saudi Arabia requires a mix of mitigation and adaptation public health options.

Effects of the COVID-19 lockdown and recovery on People's mobility and air quality in the United Arab Emirates using satellite and ground observations

The stringent COVID-19 lockdown measures in 2020 significantly impacted people's mobility and air quality worldwide. This study presents an assessment of the impacts of the lockdown and the subsequent reopening on air quality and people's mobility in the United Arab Emirates (UAE). Google's community mobility reports and UAE's government lockdown measures were used to assess the changes in the mobility patterns. Time-series and statistical analyses of various air pollutants levels (NO₂, O₃, SO₂, PM₁₀, and aerosol optical depth-AOD) obtained from satellite images and ground monitoring stations were used to assess air quality. The levels of pollutants during the initial lockdown (March to June 2020) and the subsequent gradual reopening in 2020 and 2021 were compared with their average levels during 2015-2019. During the lockdown, people's mobility in the workplace, parks, shops and pharmacies, transit stations, and retail and recreation sectors decreased by about 34%-79%. However, the mobility in the residential sector increased by up to 29%. The satellite-based data indicated significant reductions in NO₂ (up to 22%), SO₂ (up to 17%), and AOD (up to 40%) with small changes in O₃ (up to 5%) during the lockdown. Similarly, data from the ground monitoring stations showed significant reductions in NO₂ (49% - 57%) and PM₁₀ (19% - 64%); however, the SO₂ and O₃ levels showed inconsistent trends. The ground and satellite-based air quality levels were positively correlated for NO₂, PM₁₀, and AOD. The data also demonstrated significant correlations between the mobility and NO₂ and AOD levels during the lockdown and recovery periods. The study documents the impacts of the lockdown on people's mobility and air quality and provides useful data and analyses for researchers, planners, and policymakers relevant to managing risk, mobility, and air quality.

Analyzing the severity of coronavirus infections in relation to air pollution: evidence-based study from Saudi Arabia

COVID-19 is one of the major pandemics in history. It has caused various health problems to majority of countries in the world. Several researchers have examined and developed studies regarding concerns on air pollution being considered a major risk factor causing respiratory infections. Such infections are carried out by microorganisms, thus further affecting the immune system. The present study involves the relationship between air pollutants and the total COVID-19 infections along with the estimation of death rates in several regions of Saudi Arabia. The major goal of this study comprises the analysis of the relationship between air pollutants concentration, such as PM10, NO₂, CO, SO₂, and O₃, and the widespread outbreak of COVID-19. This scenario involves the transmission, number of patients, critical cases, and death rates. Results show that the estimation of recorded COVID-19 cases was in the most polluted regions; the mortality rate and critical cases were also more distinct in these regions than in other regions in Saudi Arabia. The finding of this study demonstrates a positive correlation between the mean values of PM10, NO₂, CO, and SO₂ pollutants. The results represent the significant relationship between air pollution resulting from a high concentration of NO₂ and COVID-19 infections and deaths. In addition, a null hypothesis of the relation between other pollutants and COVID-19 infections cannot be rejected. The study also indicates a significant correlation between the means of NO₂ and CO and the total number of critical cases. Negative correlations are obtained between the mean of O₃ and the total number of cases, total deaths, and critical case per cumulative days.

The nexus between in-car aerosol concentrations, ventilation and the risk of respiratory infection

We examined the trade-offs between in-car aerosol concentrations, ventilation and respiratory infection transmission under three ventilation settings: windows open (WO); windows closed with air-conditioning on ambient air mode (WC-AA); and windows closed with air-conditioning on recirculation (WC-RC). Forty-five runs, covering a total of 324 km distance on a 7.2-km looped route, were carried out three times a day (morning, afternoon, evening) to monitor aerosols (PM_2.5; particulate matter < 2.5 μm and PNC; particle number concentration), CO₂ and environmental conditions (temperature and relative humidity). Ideally, higher ventilation rates would give lower in-car pollutant concentrations due to dilution from outdoor air. However, in-car aerosol concentrations increased with ventilation (WO > WC-AA > WC-RC) due to the ingress of polluted outdoor air on urban routes. A clear trade-off, therefore, exists for the in-car air quality (icAQ) versus ventilation; for example, WC-RC showed the least aerosol concentrations (i.e. four-times lower compared with WO), but corresponded to elevated CO₂ levels (i.e. five-times higher compared with WO) in 20 mins. We considered COVID-19 as an example of respiratory infection transmission. The probability of its transmission from an infected occupant in a five-seater car was estimated during different quanta generation rates (2-60.5 quanta hr^-1) using the Wells-Riley model. In WO, the probability with 50%-efficient and without facemasks under normal speaking (9.4 quanta hr^-1) varied only by upto 0.5%. It increased by 2-fold in WC-AA (<1.1%) and 10-fold in WC-RC (<5.2%) during a 20 mins trip. Therefore, a wise selection of ventilation settings is needed to balance in-car exposure in urban areas affected by outdoor air pollution and that by COVID-19 transmission. We also successfully developed and assessed the feasibility of using sensor units in static and dynamic environments to monitor icAQ and potentially infer COVID-19 transmission. Further research is required to develop automatic-alarm systems to help reduce both pollutant exposure and infection from respiratory COVID-19 transmission.

Does democracy improve environmental quality of GCC region? Analysis robust to cross-section dependence and slope heterogeneity

Since the developed world's economic prosperity has been heavily reliant on excessive fossil-based energy consumption, it has posed severe environmental quality challenges. This research attempts to revisit the relationship between income and anthropogenic emissions in the context of the environmental Kuznets curve (EKC) theory by considering electric power consumption, urbanization, and democratic accountability index in the Gulf Cooperation Council (GCC) region. It employs annual frequency panel data from 1990 through 2019 and three alternative advanced econometric estimation techniques. The main findings are as follows: Firstly, the EKC results for the whole sample strongly support the proposition of an inverse U-shaped connection between anthropogenic emissions and affluence in the long run. Secondly, the country-specific results confirm EKC only in Saudi Arabia and Bahrain, while the remaining countries demonstrate a U-shaped connection. Thirdly, the democratic accountability promoted anthropogenic emissions implying that it failed to contribute to environmental protection. It means that democratic setup in the GCC region performs poorly in accomplishing climate change mitigation and Sustainable Development Goals (SDGs). Fourthly, electric power consumption and urbanization impart positive and negative impacts on anthropogenic emission, respectively. These findings are found robust across the fully modified ordinary least square (FMOLS), bias-corrected LSDV (least squares dummy variable) (LSDV), and pooled mean group (PMG) estimators. Finally, Dumitrescu-Hurlin panel causality shows that (i) income and urbanization establish a two-way causality with the anthropogenic emissions. (ii) However, a unidirectional causal connection is revealed from electric power consumption and democratic accountability index to anthropogenic emissions. The findings suggest that the GCC region should prioritize environmental protection and SDGs across the political aims' recipe since it would direct the region on the path of climate change mitigation.

Characterization and exposure assessment to urban air toxics across Middle Eastern and North African countries: a review

Middle East and North African (MENA) countries over the decades are experiencing rapid industrial and infrastructural growth combined with being the global hub of oil and gas industries. These economic transformations are associated with release of air pollutants including urban air toxics (UAT) through industrial, traffic, and constructional activities into ambient urban environments. UAT concentrations levels may exacerbate in most MENA countries considering high number of vehicular traffic populations and petrochemical industries which are one of the main sources of this pollutant. Therefore, the main objective of the study is to review major findings of UAT levels in urban areas across thirteen (13) MENA countries. The study characterizes various measured UAT, assesses their concentrations in ambient environment, and identifies their major sources of emissions by reviewing more than 100 relevant UAT papers across the selected MENA countries. It was found that benzene, heavy metals, formaldehyde, and dioxin-like compounds are the most reported UAT. The study concluded that road traffic, fuel stations, and petrochemical industries were identified as the main sources of ambient UAT levels. It was further reported that most of the studies were based on short-term ambient environment with limited studies in indoor environments. Therefore, it is highly recommended that future research should focus on innovative health impact assessment and epidemiological studies from exposure to UAT levels. Also embarking on sustainable mitigation approaches through urban greenery, eco-industrial estates infrastructural developments, and renewable energy shares will reduce UAT levels and improve human health.

Identification of public health priorities, barriers, and solutions for Kuwait using the modified Delphi method for stakeholder consensus

The rapid modernization and economic developments in Kuwait, have been accompanied by substantial lifestyle changes such as unhealthy diet and physical inactivity. These modifiable behaviours have contributed to increased rates of non-communicable diseases including diabetes and cardiovascular diseases. Delphi Consensus Method was implemented in the current study to draw stakeholders from all sectors together to develop a consensus on the major public health priorities, barriers and solutions. The process involves administration of a series of questions to selected stakeholders through an iterative process that ends when a consensus has been reached among participants. Results of the iteration process identified obesity, diabetes, cardiovascular diseases along with lack of enforcement of laws and regulation as priority health issues. Results also identified lack of national vision for the development of a public health system, lack of multidisciplinary research investigating sources of disease and methods of prevention and improving efficiency with existing resources in implementation and efficiency as the main barriers identified were. Solutions suggested included investing in healthcare prevention, strengthening communication between all involved sectors through intersectoral collaboration, awareness at the primary healthcare setting and use of electronic health records. The results offer an important opportunity for stakeholders in Kuwait to tackle these priority health issues employing the suggested approaches and solution.

A Review on Atmospheric Analysis Focusing on Public Health, Environmental Legislation and Chemical Characterization

Atmospheric pollution has been considered one of the most important topics in environmental science once it can be related to the incidence of respiratory diseases, climate change, and others. Knowing the composition of this complex and variable mixture of gases and particulate matter is crucial to understand the damages it causes, help establish limit levels, reduce emissions, and mitigate risks. In this work, the current scenario of the legislation and guideline values for indoor and outdoor atmospheric parameters will be reviewed, focusing on the inorganic and organic compositions of particulate matter and on biomonitoring. Considering the concentration level of the contaminants in air and the physical aspects (meteorological conditions) involved in the dispersion of these contaminants, different approaches for air sampling and analysis have been developed in recent years. Finally, this review presents the importance of data analysis, whose main objective is to transform analytical results into reliable information about the significance of anthropic activities in air pollution and its possible sources. This information is a useful tool to help the government implement actions against atmospheric air pollution.

PM10-bound trace elements in the Great Lakes Basin (1988-2017) indicates effectiveness of regulatory actions, variations in sources and reduction in human health risks

Limited studies focus on the effectiveness of regulatory actions on changes in sources and temporal trends of human health risks for trace elements in atmospheric particles < 10 μm (PM₁₀). To address this knowledge gap, PM₁₀ samples were collected at three stations in the Great Lakes Basin over a thirty-year time span and analyzed for 19 representative elements. Temporal trends of trace elements in PM₁₀ were derived using the Digital Filtration Technique and sources of these elements were determined using multiple statistical techniques, namely enrichment factor analysis, positive matrix factorization (PMF) and potential source contribution function (PSCF). Non-carcinogenic and carcinogenic risks by chronic exposure were assessed using US EPA reference concentrations and inhalation unit risk. Our results showed a strong relationship between element concentrations and local populations, which suggested that the emissions of trace elements were anthropogenically-related and was confirmed by the enrichment factor analysis. The concentrations of most elements were significantly decreasing with halving times ranging from 10 to 48 years in response to national and international regulatory actions. Specific origins of atmospheric trace elements were from the copper refining industry, refuse incineration, coal combustion, vehicle emissions, oil/coal-fired power plants, and crustal/soil dust. Potential source region analysis indicates dominant sources south of the sampling sites in the US, associated with a higher population and more industrial and transportation activities. The possibility of non-cancer health effects due to inhalation were mostly within acceptable levels. However, potential cancer risk posed by inhalation of some elements cannot be ignored, with values approaching or higher than the acceptable level. Considering that the sampling locations are remote and regionally-representative, our finding emphasizes the importance of continued monitoring of metals in air to assess the effectiveness of control strategies.

Evaluation of vehicular pollution levels using line source model for hot spots in Muscat, Oman

A detailed investigation was carried out to assess the concentration of near-road traffic-related air pollution (TRAP) using a dispersion model in Muscat. Two ambient air quality monitoring (AQM) stations were utilized separately at six locations near major roadways (each location for 2 months) to monitor carbon monoxide (CO) and nitrogen oxides (NOx). The study aimed to measure the concentration of near-road TRAP in a city hot spots and develop a validated dispersion model via performance measures. The US Environmental Protection Agency (US EPA) Line Source Model was implemented in which the pollutant emission factors were obtained through Comprehensive Modal Emission Model (CMEM) and COmputer Programme to calculate Emissions from Road Transport (COPERT) model. Traffic data of all vehicle categories under normal driving conditions including average vehicle speed limits and local meteorological conditions were included in the modeling study. The analysis of monitoring data showed that hourly (00:00 to 23:00) concentrations of CO were within the US EPA limits, while NOx concentration was exceeded in most locations. Also, the measured pollutant levels were consistent with hourly peak and off-peak traffic volumes. The overall primary statistical performance measures showed that COPERT model was better than CMEM due to the high sensitivity of CMEM to the local meteorological factors. The best fractional bias (0.47 and 0.39), normalized mean square error (0.44 and 0.50), correlation coefficient (0.64 and 0.70), geometric mean bias (1.07 and 1.57), and geometric variance (2.00 and 2.32) were obtained for CO and NOx, respectively. However, the bootstrap 95% CI estimates over normalized mean square error, fractional bias, and correlation coefficient for COPERT and CMEM were found to be statistically significant from 0 in the case of combined model comparison across all the traffic locations for both CO and NOx. In overall, certain roads showed weak performance mainly due to the terrain features and the lack of reliable background concentrations, which need to be considered in the future study.

A primary school driven initiative to influence commuting style for dropping-off and picking-up of pupils

The use of cars for drop-off and pick-up of pupils from schools is a potential cause of pollution hotspots at school premises. Employing a joint execution of smart sensing technology and citizen science approach, a primary school took an initiative to co-design a study with local community and researchers to generate data and provide information to understand the impact on pollution levels and identify possible mitigation measures. This study was aimed to assess the hotspots of vehicle-generated particulate matter ≤2.5 μm (PM_2.5) and ≤10 μm (PM₁₀) at defined drop-off/pick-up points and its ingress into a nearby naturally ventilated primary school classroom. Five different locations were selected inside school premises for measurements during two peak hours: morning (MP; 0730-0930 h; local time), evening (EP; 1400-1600 h), and off-peak (OP; 1100-1300 h) hours for comparison. These represent PM measurements at the main road, pick-up point at the adjoining road, drop-off point, a classroom, and the school playground. Additional measurements of carbon dioxide (CO₂) were taken simultaneously inside and outside (drop-off point) the classroom to understand its build-up and ingress of outdoor PM. The results demonstrated nearly a three-fold increase in the concentrations of fine particles (PM_2.5) during drop-off hours compared to off-peak hours indicated the dominant contribution of car queuing in the school premises. Coarse particles (PM_2.5-10) were prevalent in the school playground, while the contribution of fine particles as a result of traffic congestion became more pronounced during drop-off hours. In the naturally ventilated classroom, the changes in indoor PM_2.5 concentrations during both peak hours (0.58 < R² < 0.67) were followed by the outdoor concentration at the drop-off point. This initiative resulted in valuable information that might be used to influence school commuting style and raise other important issues such as the generally fairly high PM_2.5 concentrations in the playground and future classroom ventilation plans.

Organic pollutants in indoor dust from Ecuadorian Amazonia areas affected by oil extractivism

Fifty-five household dust samples collected within six settlements surrounding oil production complexes along the Ecuadorian Amazonia were analysed to evaluate the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs), phthalates, alkylphenols (APs), bisphenol A (BPA), nicotine, organophosphorus flame retardants (OPFRs), polychlorinated biphenyls (PCBs), legacy organochlorine pesticides (OCs) and organophosphorus pesticides. Studied areas are mainly affected by gas flares emissions and oil spilling coming from extractivist operations and pesticides used in agriculture. Median ΣPAHs values ranged from 739 to 1182 ng g^-1 and up to 52% of the PAH dust concentrations were associated to petrogenic activities from crude oil extraction, according to diagnostic ratios. ΣPAHs and toxic equivalents based on benzo[a]pyrene concentration (ΣTEQ_BaP, ng g^-1) suggested similar toxicities among the different areas. Individual lifetime cancer risk (ILCR_dust) was calculated for ingestion and dermal contact exposure routes and a non-acceptable total carcinogenic risk of up to 10^-4 (one case per ten thousand people) was found for newborns from 0 to 3 years-old in Pimampiro area. Plasticisers and OPFRs were present in dust at maximum median concentrations of 332,507 ng g^-1 (DEHP), 5,249 ng g^-1 (DBP), 1,885 ng g^-1 (BPA), 871 ng g^-1 (TBOEP) and 122 ng g^-1 (TEHP). Some dust samples from Ecuadorian houses had high maximum levels of legacy and modern pesticides such as chlorpyrifos (up to 44,176 ng g^-1), 4,4'-DDT (12,958 ng g^-1), malathion (34,748 ng g^-1) and α+β-endosulfan (10,660 ng g^-1) attributed to inappropriate use and storage of the pesticides. Finally, nicotine was seldom detected (36 ng g^-1). The sources and risks of these compounds are discussed based on the activities carried out in the study areas and attending to an additional non-cancer risk assessment which showed high hazard quotients (HQ) and hazard indexes (HI) for DEHP, DBP, 4,4'-DDT, malathion, chlorpyrifos, naphthalene and benzo[a]pyrene in newborns and children up to 16 years-old.

Incidence of Respiratory Symptoms for Residents Living Near a Petrochemical Industrial Complex: A Meta-Analysis

The air pollution emitted by petrochemical industrial complexes (PICs) may affect the respiratory health of surrounding residents. Previous meta-analyses have indicated a higher risk of lung cancer mortality and incidence among residents near a PIC. Therefore, in this study, a meta-analysis was conducted to estimate the degree to which PIC exposure increases the risk of the development of nonmalignant respiratory symptoms among residents. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to systematically identify, select, and critically appraise relevant research. Finally, we identified 16 study groups reporting 5 types of respiratory symptoms: asthma, bronchitis, cough, rhinitis, and wheezing. We estimated pooled odds ratios (ORs) using random-effect models and investigated the robustness of pooled estimates in subgroup analyses by location, observation period, and age group. We determined that residential exposure to a PIC was significantly associated with a higher incidence of cough (OR = 1.35), wheezing (OR = 1.28), bronchitis (OR = 1.26), rhinitis (OR = 1.17), and asthma (OR = 1.15), although the latter two associations did not reach statistical significance. Subgroup analyses suggested that the association remained robust across different groups for cough and bronchitis. We identified high heterogeneity for asthma, rhinitis, and wheezing, which could be due to higher ORs in South America. Our meta-analysis indicates that residential exposure to a PIC is associated with an increased risk of nonmalignant respiratory symptoms.

Analysis of air quality characteristics of Beijing-Tianjin-Hebei and its surrounding air pollution transport channel cities in China

Beijing-Tianjin-Hebei (BTH) and its surrounding areas are very important to air pollution control in China. To analyze the characteristics of BTH and its surrounding areas of China, we collected 5,641,440 air quality data from 161 air monitoring stations and 37,123,000 continuous monitoring data from air polluting enterprises in BTH and surrounding cities to establish an indicator system for urban air quality portraits. The results showed that particulate matter with aerodynamic diameters of <2.5 μm (PM_2.5), particulate matter with aerodynamic diameters of <10 μm (PM₁₀) and SO₂ improved significantly in 31 cities from 2015 to 2018, but ozone deteriorated. Air quality in BTH and the surrounding areas showed obvious seasonal characteristics, among which PM_2.5, PM₁₀, SO₂, and NO₂ showed a "U" type distribution from January to December, while O₃ had an "inverted U" distribution. The hourly changes in air quality revealed that peaks of PM_2.5, PM₁₀ and NO₂ appeared from 8:00 to 10:00, while those for O₃ appeared at 15:00-16:00. The exposure characteristics of the 31 cities showed that six districts in Beijing had the highest air quality population exposure, and that exposure levels in Zhengzhou, Puyang, Anyang, Jincheng were higher than the average of the 31 investigated cities. Additionally, multiple linear regression revealed a negative correlation between meteorological factors (especially wind and precipitation) and air quality, while a positive correlation existed between industrial pollution emissions and air quality in most of BTH and its surrounding cities.

Human health damages related to air pollution in China

In recent years, air pollution in China has posed serious threats to human health. In this study, we investigate the relationship between air pollution and residents' health by nesting the household registration data of the China Migrant Dynamic Survey in 2014 with city characteristic data and pollution data. The results indicated that an increase in the concentration of air pollution significantly reduced residents' health levels. After using the instrumental variable (IV)-Oprobit model to solve endogenous problem, we have found that the negative impact of air pollution on residents' health remained significant. Moreover, the lag term of environmental indexes was introduced and found that air pollution significantly increased health risk. The results also demonstrated that the impact of air pollution on human health was heterogeneous. Men and urban residents were more sensitive to air pollution and more adversely affected. In addition to air pollution, the study found that, among the influencing factors at the individual level, males' health was better than females' health, and education positively impacted on residents' health. The health effects were consistent with the theoretical predictions of the Grossman model. The financial expenditure and medical input were negatively correlated with residents' health levels. Based on the results, we suggest the Chinese government should implement rigorous air pollution laws and regulations.

Characterization of BTEX group of VOCs and inhalation risks in indoor microenvironments at small enterprises

Concentrations of BTEX group (benzene, toluene, ethylbenzene and xylene) were measured in indoor and outdoor environments at four printing shops and two photocopy centers in Sakaka city, KSA. Fifty four BTEX samples were collected using passive diffusion monitors (SKC VOC 575) and analyzed by GC-MS. The results showed that toluene was the most prevailing compound within the BTEX group and its indoor levels were much higher than outdoor. The average indoor concentrations (μg/m³) ranged from 2.45 to 14.66, 81.59 to 955.65, 11.19 to 97.35, 35.66 to 291.88 and 3.90 to 28.39 for benzene, toluene, ethylbenzene, m/p-xylene and o-xylene, respectively. The indoor/outdoor ratios of concentrations of BTEX species were more than one in most cases, indicating the effect of indoor emission sources. Based on (Toluene/Benzene) ratios, all sites were affected by the traffic emissions. Ventilation efficiency, ink type and outdoor pollutant concentration are responsible for results disparity. Cancer and non-cancer risks were assessed in the indoor environments by calculating the lifetime cancer risk (LCR) and hazard ratio (HR), respectively. For benzene and ethylbenzene measured concentrations, LCR values were more than the acceptable USEPA risk level of 1 × 10^-6. HR values for BTEX species were in general lower than the threshold limit of one.

Indoor air pollution and exposure assessment of the gulf cooperation council countries: A critical review

Indoor air pollution is one of the human health threat problems in the Gulf Cooperation Council (GCC) countries. In these countries, due to unfavorable meteorological conditions, such as elevated ambient temperature, high relative humidity, and natural events such as dust storms, people spend a substantial amount of their time in indoor environments. In addition, production of physical and biological aerosols from air conditioners, cooking activities, burning of Arabian incense, and overcrowding due to pilgrimage programs are common causes of low quality indoor air in this region. Thus, due to infiltration of outdoor sources as well as various indoor sources, people living in the GCC countries are highly exposed to indoor air pollutants. Inhalation of indoor air pollutants causes mortalities and morbidities attributed to cardiorespiratory, pulmonary, and lung cancer diseases. Hence, the aim of this review study is to provide a summary of the major findings of indoor air pollution studies in different microenvironments in six GCC countries. These include characterization of detected indoor air pollutants, exposure concentration levels, source identifications, sustainable building designs and ventilation systems, and the mitigation strategies. To do so, >130 relevant indoor air pollution studies across the GCC countries were critically reviewed. Particulate matters (PM₁₀ and PM_2.5), total volatile organic compounds (TVOCs), carbon dioxide (CO₂), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and heavy metals were identified as the reported indoor air pollutants. Apart from them, indoor Radon and bioaerosols were studied only in specific GCC countries. Thus, future studies should also focus on the investigation of emerging indoor air pollutants, such as ultrafine and nanoparticles and their associated health effects. Furthermore, studies on the mitigation of indoor air pollution through the development of advanced air purification and ventilation systems could improve the indoor air quality (IAQ) in the GCC region.

Dispersion and deposition estimation of fugitive iron particles from an iron industry on nearby communities via AERMOD

Emission of fugitive iron particles from anthropogenic sources can have significant effects on the human health and the environment. In this study, a regulatory air pollutant dispersion model (AERMOD) was implemented to predict the dispersion and deposition of fugitive iron particles towards a mid-sized residential area in Sultanate of Oman. The performance of the model was validated using air, soil, and dust fall samples. PM₁₀ was found as the most abundant iron particles in the soil samples. The results showed that the maximum daily concentration level of fugitive iron particles simulated through AERMOD was 7.19 μg/m³. Statistical analysis, including fractional bias (FB), normalized mean square error (NMSE), and predicted/observed ratio (Pred./Obs.), showed a reliable agreement in accuracy and precision between the datasets (for air samples FB = 0.024, NMSE = 0.001, Pred./Obs. = 0.976; for dust fall samples FB = -0.004, NMSE = 0.000, Pred./Obs. = 1.004). However, uncertainties and differences were from the external sources, such as other industries in the region. The results presented that the concentration levels were below the national and international guidelines proposed by the US Environmental Protection Agency (USEPA) and Omani Ambient Air Quality Standards (OAAQS). The methodology followed and the developed dispersion model can be generalized to other industries from which the dispersion of fugitive metal particles need to be evaluated as a potential route for human exposure. Graphical abstract ᅟ.