Characterization of ionic composition of TSP and PM10 during the Middle Eastern Dust (MED) storms in Ahvaz, Iran

Suspended particulate matter promotes epithelial-to-mesenchymal transition in alveolar epithelial cells via TGF-β1-mediated ROS/IL-8/SMAD3 axis

Epidemiological evidence presents that dust storms are related to respiratory diseases, such as pulmonary fibrosis (PF). However, the precise underlying mechanisms of SPM-elicited adverse effects still need to be investigated. Epithelial-mesenchymal transition (EMT) process is a characteristic of PF. We discussed whether suspended particulate matter (SPM) is involved in EMT induction via transforming growth factor-β1 (TGF-β1). In this study, a detailed elemental analysis (55 elements), particle size, and morphology were determined. To investigate the toxicity of SPM, an MTT test was performed to detect cell viability. Next, A549 cells were exposed to selected concentrations of SPM (20 and 40 µg/mL) for single and repeated exposures. The DCFH-DA assay showed that exposure to SPM could produce reactive oxygen species (ROS). The ELISA assay demonstrated increased levels of interleukin-8 (IL-8) and TGF-β1 in the supernatant. Western blot was used to detect the expression of proteins associated with EMT and the SMAD3-dependent pathway. Results of western blot demonstrated that E-cadherin was reduced, whereas p-SMAD3, vimentin, and α-smooth muscle actin were elevated. Our findings indicated that SPM triggered EMT by induction of oxidative stress, inflammation, and the TGF-β1/SMAD3 pathway activation.

Atmospheric environment characteristic of severe dust storms and its impact on sulfate formation in downstream city

This study comprehensively investigated the impact of dust storms (DSs) on downstream cities, by selecting representative DS events. In this paper, we discussed the characteristics of meteorological conditions, air pollutants, PM2.5 components, and their influence on sulfate formation mechanisms. During DSs, strong winds, reaching speeds of up to 10 m/s, led to significant increases in PM10 and PM2.5, with maximum concentrations of 2684.5 and 429 μg/m3, respectively. Primary gaseous pollutants experienced substantial reductions, with decline rates of 48.1, 34.9, 36.8, and 9.0 % for SO2, NO2, NH3, and CO, respectively. Despite a notable increase in PM2.5 concentrations, only 7.6 % of the total mass of PM2.5 was attributed to ionic and carbonaceous components, a much lower value than observed before the DSs (77.3 %). Concentrations of Fe, Ti, and Mn exhibited increases by factors of 6.5-14.1, 10.4-17.0, and 1.6-4.7, respectively. In contrast to the significant decrease of >76.2 % in nitrogen oxidation ratio (NOR), sulfur oxidation ratio (SOR) remained at a relatively high level, displaying a strong positive correlation with high concentrations of Fe, Mn, and Ti. Quantitative analysis revealed an average increase of 0.187 and 0.045 μg/m3 in sulfate from natural sources and heterogeneous generation, respectively. The heterogeneous reaction on mineral dust was closely linked to atmospheric humidity, radiation intensity, the form of metal existence, and concentrations of it. High concentrations of titanium dioxide and iron‑manganese oxides in mineral dust promoted heterogeneous oxidation of SO2 through photocatalysis during the daytime and metal ion catalysis during the nighttime. This study establishes that the metal components in mineral dust promote heterogeneous sulfate formation, quantifies the yield of sulfate generated as a result, and provides possible mechanisms for heterogeneous sulfate formation.

Intrinsic and extrinsic techniques for quantification uncertainty of an interpretable GRU deep learning model used to predict atmospheric total suspended particulates (TSP) in Zabol, Iran during the dusty period of 120-days wind

Total suspended particulates (TSP), as a key pollutant, is a serious threat for air quality, climate, ecosystems and human health. Therefore, measurements, prediction and forecasting of TSP concentrations are necessary to mitigate their negative effects. This study applies the gated recurrent unit (GRU) deep learning model to predict TSP concentrations in Zabol, Iran, during the dust period of the 120-day wind (3 June - 4 October 2014). Three uncertainty quantification (UQ) techniques consisting of the blackbox metamodel, heteroscedastic regression and infinitesimal jackknife were applied to quantify the uncertainty associated with GRU model. Permutation feature importance measure (PFIM), based on the game theory, was employed for the interpretability of the predictive model's outputs. A total of 80 TSP samples were collected and were randomly divided as training (70%) and validation (30%) datasets, while eight variables were used in the TSP prediction model. Our findings showed that GRU performed very well for TSP prediction (with r and Nash Sutcliffe coefficient (NSC) values above 0.99 for both datasets, and RMSE of 57 μg m-3 and 73 μg m-3 for training and validation datasets, respectively). Among the three UQ techniques, the infinitesimal jackknife was the most accurate one, while all the observed and predicted TSP values fell within the continence limitation estimated by the model. PFIM plots showed that wind speed and air humidity were the most and least important variables, respectively, impacting the predictive model's outputs. This is the first attempt of using an interpretable DL model for TSP prediction modelling, recommending that future research should involve aspects of uncertainty and interpretability of the predictive models. Overall, UQ and interpretability techniques have a key role in reducing the impact of uncertainties during optimization and decision making, resulting in better understanding of sophisticated mechanisms related to the predictive model.

Isotopic comparison of ammonium between two summertime field campaigns in 2013 and 2021 at a background site of North China

Ammonia (NH3) is the primary atmospheric alkaline gas, playing a crucial role in the atmospheric chemistry. Recently, non-agricultural emissions have been identified as the dominant sources of NH3 in urban areas. However, few studies have quantified the contributions of different sources to regional NH3. This study conducted two summertime field observations in 2013 and 2021 at a background site of North China to comprehensively explore the regional variations in concentration, nitrogen isotope composition (δ15N), and sources of ammonium (NH4+). The results indicate that NHx (NHx = NH3 + NH4+) concentration has increased in 2021, but the fNH4+ (NH4+/ NHx) has decreased significantly. The δ15N-NH4+ values show a significant increase, ranging from -4.7 ± 8.1 ‰ to +12.0 ± 2.4 ‰. The increase can be attributed to two primary factors: changes in fNH4+ resulting from the reduction of atmospheric acid gases and alterations in the sources of NH3. Bayesian simulation analysis reveals substantial variations in NH3 sources between 2013 and 2021 observations. Non-agricultural sources have significantly increased their contribution to NHx concentration, with vehicle exhaust and NH3 slip experiencing growth rates of 187 % and 104 %, respectively. Our results confirm the dominate contribution of non-agricultural sources to regional NH3 at the present stage and propose relevant mitigation strategies, which would provide essential insights for reducing NH3 emissions in North China.

Integrative assessment of urban dust polycyclic aromatic hydrocarbons using ground and satellite data in Iran

Recently, for quick urbanization and industrialization, pollutants, especially urban dust, have posed many threats to the human environment. Polycyclic aromatic hydrocarbons (PAHs) are regarded as the main dangerous pollutants that are widespread, persistent, and carcinogenic. The present work aimed to investigate the contamination and sources of PAHs, as well as to assess the risk of cancer for 16 priority PAHs, in urban dust samples in Ahvaz, Isfahan, and Shiraz cities in Iran. We measured PAH concentrations by gas chromatography-mass spectrometry (GC-MS). The average concentrations of the 16 PAHs in Ahvaz, Isfahan, and Shiraz were 6215.11, 7611.03, and 7810.37 μg kg-1, respectively. The domination of low-molecular-weight (LMW) PAHs was observed in Ahvaz, while maximum contribution was observed for high-molecular-weight (HMW) PAHs in Esfahan and Shiraz. For PAHs' source identification, diagnostic ratio, correlation analysis, clustering, and positive matrix factorization (PMF) model were used. PAHs had a combustion (coal and wood, oil, fossil fuels) and gasoline/diesel engine emissions in all cities. Comparative studies suggest that the PAH compounds' level is higher in the research area than in other countries, except for China and India. Also, the pollution of urban dust PAHs has increased over time compared to previous studies in the same cities. The cancer risk from exposure to dust contaminated with PAHs was assessed using the Incremental Lifetime Cancer Risk (ILCR) model. According to the findings, a high risk of exposure to cancer was observed in Ahvaz, Isfahan, and Shiraz. However, compared to adults, children are at higher risk of cancer in their daily lives via dermal contact and unconscious ingestion. Based on the ILCR values, the risk of cancer is in the order of Shiraz > Isfahan > Ahvaz. To assess air pollutants and their effects on urban dust, TROPOMI onboard the Sentinel-5P data were used in the studied cities during 2018-2021. The results show that Ahvaz has different high levels of CO compared to the other 2 cities. Also, Isfahan has different high levels of NO2 compared to the other 2 cities, but Shiraz has different low levels of O3. According to satellite time series data, the trend of the Aerosol Absorbing Index (AAI) has been increasing, while there was a decreasing trend in AAI from the beginning of the COVID-19 pandemic until 12 months later. Therefore, the natural and anthropogenic sources of urban dust PAHs have been increasing in all studied cities. Our findings show that PAH compounds in urban dust pose a significant threat to human health. Therefore, strategic management and planning are vital in reducing urban dust pollution.

High time-resolved variations of proteins in PM2.5 during haze pollution periods in Xi'an, China

Proteinaceous matter is an important component of PM_2.5, which can cause adverse health effects and also influence the air quality and climate change. However, there is little attention to high time-resolved variations and potential role of aerosol proteins during haze pollution periods. In this study, PM_2.5 samples were first collected by a medium flow sampler in autumn and winter in Xi'an, China. Then three high time-resolved monitoring campaigns during haze pollution periods were conducted to determine the evolving characteristics of total protein concentration and explore the interactive relationship between protein and other chemical compositions. The results showed that the average protein concentration in PM_2.5 in Xi'an (5.46 ± 3.32 μg m^-3) was higher than those in most cities of China, and varied by seasons and air pollution conditions. In particular, the protein concentration in PM_2.5 increased with the increase of air quality index (AQI). The continuous variations of aerosol proteins during the haze pollution periods further showed that PM_2.5, atmospheric humidity and long-distance air mass transport exerted the significant impacts on the protein components in aerosols. Based on the present observation, it is suggested that aerosol proteins might affect the generation of secondary aerosols under haze weather conditions. The present results may provide a new possible insight into the variations and the role of aerosol proteinaceous matter during the formation and development of haze pollution.

Temporal profiles of ambient air pollutants and associated health outcomes in two polluted cities of the Middle East

Dust storms and particulate matters had been increased due to climate change in the Middle East. On the other hand, urbanization and industrialization raised levels of gaseous air pollutants in all big cities. In the current study, air pollution information collected from Environmental Protection Agency of Khuzestan and Tehran containing hourly O₃, NO₂, CO, SO₂, PM₁₀ and PM_2.5 concentrations between 2014 and 2015. This study evaluated the air quality of these two cities by Air Quality Index (AQI). As a result, mean concentrations of O₃, NO₂, PM₁₀ and PM_2.5 were higher in Ahvaz than Tehran while Tehran was more pollutant in terms of CO and SO₂. Diurnal variations of O₃ in weekend were the only trend located above weekday variations along the daytimes. Hourly variations of all pollutants changed with a wider range of concentrations in Ahvaz. Diurnal peaks of all pollutants showed their highest level on Monday as the busiest day in mega city, Tehran with the exception of SO₂. PM_2.5 was the worst and limiting pollutant for both cities. Accordingly, winter was the most polluted season by 77 and 33 μg m^-3 in Ahvaz and Tehran, respectively. Number of clean days was significantly lower in Ahvaz (no-day) than mega city, Tehran (<17 days). The number of unhealthy days was also presented significantly higher in Ahvaz (>186 days). Although, annual PM_2.5 concentrations were more in Ahvaz, the higher at-risk population in Tehran caused more health endpoints in the capital of Iran. Consequently, both cities should have their own especial pattern to control air pollution and attributed health damages.

Analysis and Sources Identification of Atmospheric PM10 and Its Cation and Anion Contents in Makkah, Saudi Arabia

In this paper, atmospheric water-soluble cation and anion contents of PM10 are analysed in Makkah, Saudi Arabia. PM10 samples were collected at five sites for a whole year. PM10 concentrations (µg/m3) ranged from 82.11 to 739.61 at Aziziyah, 65.37 to 421.71 at Sanaiyah, 25.20 to 466.60 at Misfalah, 52.56 to 507.23 at Abdeyah, and 40.91 to 471.99 at Askan. Both daily and annual averaged PM10 concentrations exceeded WHO and Saudi Arabia national air quality limits. Daily averaged PM10 concentration exceeded the national air quality limits of 340 µg/m3, 32% of the time at Aziziyah, 8% of the time at Sanaiyah, and 6% of the time at the other three sites. On average, the cations and anions made a 37.81% contribution to the PM10 concentrations. SO42−, NO3−, Ca2+, Na+, and Cl− contributed 50.25%, 16.43%, 12.11%, 11.12%, and 8.70% to the total ion concentrations, respectively. The minor ions (F−, Br−, Mg2+, NO2−, and PO43−) contributed just over 1% to the ion mass. Four principal components explained 89% variations in PM10 concentrations. Four major emission sources were identified: (a) Road traffic, including emission from the exhaust, wear-and-tear, and the resuspension of dust particles (F−, SO42−, NO3−, Ca2+, Na+, Mg+, Br−, Cl−, NO2−, PO43−); (b) Mineral dust (Cl−, F−, Na+, Ca2+, Mg2+, PO43−); (c) Industries and construction–demolition work (F−, SO42−, Ca2+, Mg2+); and (d) Seaspray and marine aerosols (Cl−, Br−, Mg2+, Na+). Future work would include an analysis of the metal contents of PM10 and their spatiotemporal variability in Makkah.

Mineralogical, geochemical, and textural characteristics of soil and airborne samples during dust storms in Khuzestan, southwest Iran

Dust storms are frequent phenomena in Khuzestan Province, southwest Iran, leading to environmental hazards and deleterious impacts on human health. This work analyzes mineralogic and geochemical characteristics of dust sediments at the source regions and in deposition areas in southwest Iran during three dust-storm events in winter and spring 2018. Twenty soil and airborne dust samples were collected and analyzed for compositions of dust at different distances from the source regions in Iraq and southwest Iran, aiming to assess the source characterization and possible mixing processes in the atmosphere. The grain size distributions were also analyzed at specific sites. The results show that about 50 % of the volume size distribution corresponds to particle sizes of above 20 μm, indicating local/regional dust storms of coarse to giant particles. XRD analysis indicates that calcite is the dominant mineral in all the samples, with a high quartz and dolomite fraction. The most abundant major compounds are SiO₂ and CaO, while Cl, Ba, Sr, Pb, Ni, Zn, Cr, V are the main trace elements. The enrichment factor (EF) analysis showed that apart from Th, Nb, Ce, and V, all the other elements (Pb, Zn, Cr, etc.) have an anthropogenic origin or represent high amounts of pollutant contamination. High levels of elemental enrichment are attributable to intensive pollution in Khuzestan Province and at sampling sites due to fossil-fuel combustion, gas and petroleum drilling activities. Moreover, based on the geo-accumulation index (Igeo), all samples are found to be contaminated by heavy metals due to prior war-related materiel, oil and gas extraction, and emissions from polluting industries.

Long-Term Variability of Dust Events in Southwestern Iran and Its Relationship with the Drought

Dust storms represent a major environmental challenge in the Middle East. The southwest part of Iran is highly affected by dust events transported from neighboring desert regions, mostly from the Iraqi plains and Saudi Arabia, as well as from local dust storms. This study analyzes the spatio-temporal distribution of dust days at five meteorological stations located in southwestern Iran covering a period of 22 years (from 1997 to 2018). Dust codes (06, 07, 30 to 35) from meteorological observations are analyzed at each station, indicating that 84% of the dust events are not of local origin. The average number of dust days maximizes in June and July (188 and 193, respectively), while the dust activity weakens after August. The dust events exhibit large inter-annual variability, with statistically significant increasing trends in all of five stations. Spatial distributions of the aerosol optical depth (AOD), dust loading, and surface dust concentrations from a moderate resolution imaging spectroradiometer (MODIS) and Modern-Era Retrospective analysis for Research and Applications (MERRA-2) retrievals reveal high dust accumulation over southwest Iran and surrounding regions. Furthermore, the spatial distribution of the (MODIS)-AOD trend (%) over southwest Iran indicates a large spatial heterogeneity during 2000–2018 with trends ranging mostly between −9% and 9% (not statistically significant). 2009 was the most active dust year, followed by 2011 and 2008, due to prolonged drought conditions in the fertile crescent and the enhanced dust emissions in the Iraqi plains during this period. In these years, the AOD was much higher than the 19-year average (2000 to 2018), while July 2009 was the dustiest month with about 25–30 dust days in each station. The years with highest dust activity were associated with less precipitation, negative anomalies of the vegetation health index (VHI) and normalized difference vegetation index (NDVI) over the Iraqi plains and southwest Iran, and favorable meteorological dynamics triggering stronger winds.

Vulnerability mapping and risk analysis of sand and dust storms in Ahvaz, IRAN

In this work, a sand and dust storm vulnerability mapping (SDS-VM) approach is developed to model the vulnerability of urban blocks to SDS using GIS spatial analysis and a range of geographical data. The SDS-VM was carried out in Ahvaz, IRAN, representing one of the most dust-polluted cities in West Asia. Here, vulnerability is defined as a function of three components: exposure, sensitivity, and adaptive capacity of the people in the city blocks to sand and dust storms. These components were formulated into measurable indicators (i.e. GIS layers) including: PM_2.5, wind speed, distance from dust emission sources, demographic statistics (age, gender, family size, education level), number of building floors, building age, land surface temperature (LST), land use, percentage of literate population, distance from health services, distance from city facilities (city center, shopping centers), distance from infrastructure (public transportation, main roads and highways), distance from parks and green spaces, and green area per capita. The components and the indicators were weighted using analytical hierarchy process (AHP). Different levels of risks for the components and the indicators were defined using ordered weighted averaging (OWA). Urban SDS vulnerability maps at different risk levels were generated through spatial multi-criteria data analysis procedure. Vulnerability maps, with different risk levels, were validated against field-collected data of 781 patients hospitalized for dust-related diseases (i.e. respiratory, cardiovascular, and skin). Results showed that (i) SDS vulnerability map, obtained from the developed methodology, gives an overall accuracy of 79%; (ii); regions 1 and 5 of Ahvaz are recognized with the highest and lowest vulnerabilities to SDS, respectively; and (iii) ORness equal to 0 (very low risk) is the optimum SDS-VM risk level for decision-making to mitigate the harmful impacts of SDS in the deposition areas of Ahvaz city.

Reapportioning the sources of secondary components of PM2.5: A combined application of positive matrix factorization and isotopic evidence

Secondary particles account for a considerable proportion of fine particles (PM_2.5) and reasonable reapportioning them to primary sources is critical for designing effective strategies for air quality improvement. This study developed a method which can reapportion secondary sources of PM_2.5 solved by positive matrix factorization (PMF) to primary sources based on the isotopic signals of nitrate, ammonium and sulfate. Actual PM_2.5 data in Beijing were used as a case study to assess the feasibility and capacity of this method. In the case, 20 chemical components were used to apportion PM_2.5 sources and source contributions of nitrate were applied to reapportion secondary source to primary sources. The model performance was also estimated by radiocarbon measurement (¹⁴C) of organic (OC) and elemental (EC) carbons of eight samples. The PMF apportioned seven sources: the secondary source (36.1%), vehicle exhausts (18.7%), industrial sources (13.6%), biomass burning (11.4%), coal combustion (8.10%), construction dust (7.93%) and fuel oil combustion (4.24%). After the reapportionment of the secondary source, vehicle exhausts (28.7%) contributed the most to PM_2.5, followed by biomass burning (25.1%) and industrial sources (18.9%). Fossil oil combustion and coal combustion increased to 8.00% and 11.4%, respectively, and construction dust contributed the least. The average gap between contributions of identified sources to OC and EC and the ¹⁴C measurements decreased 2.5 ± 1.2% after the reapportionment than 13.2 ± 10.8%, indicating the good performance of the developed method.

Human health risk assessment for toxic elements in the extreme ambient dust conditions observed in Sistan, Iran

This study evaluates the bioaccessibility and health risks related to heavy metals (Cd, Cr, Co, Cu, Mn, Ni, Pb, Zn and metalloid As) in airborne dust samples (TSP and PM_2.5) in Zabol, Iran during the summer dust period, when peak concentration levels of PM are typically observed. High bioaccessibilities of carcinogenic metals in PM_2.5 (i.e. 53.3%, 48.6% and 47.6% for Ni, Cr and As, respectively) were calculated. The carcinogenic and non-carcinogenic health risks were assessed for three exposure pathways (inhalation, ingestion and dermal contact), separately for children and adults. Non-carcinogenic inhalation risks were very high (Hazard Index: HI > 1) both for children and adults, while the carcinogenic risks were above the upper acceptable threshold of 10^-4 for adults and marginally close (5.0-8.4 × 10^-5) for children. High carcinogenic risks (>10^-4) were found for the ingestion pathway both for children and adults, while HI values > 1 (8.2) were estimated for children. Carcinogenic and non-carcinogenic risk estimates for dermal contact were also above the limits considered acceptable, except for the carcinogenic risk for children (7.6 × 10^-5). Higher non-carcinogenic and carcinogenic risks (integrated for all elements) were associated with the inhalation pathway in adults and children with the exception of carcinogenic risk for children, where the ingestion route remains the most important, while As was linked with the highest risks for nearly all exposure pathways. A comparative evaluation shows that health risks related with toxic elements in airborne particles in Sistan are among the highest reported in the world.

Climate change and health in Iran: a narrative review

BACKGROUND

The consequences of climate change are highly impeding the achievement of Sustainable Development Goals (SDGs) anywhere, especially in low and middle-income countries. While climate change scales up, its health-related risks increase, which in turn leads to cause new challenges for public health. As a second largest country of the Eastern Mediterranean Region of World Health Organization, Iran is highly vulnerable to the effects of climate change.

PURPOSE

This study seeks the notion of health risks and challenges of climate change in Iran and provide potential evidence-based remedies to prevent and diminish such destructive effects.

METHODS

A comprehensive literature in various computerized databases was conducted, and numerous published original research and review articles about climate change status and evidences of adverse health consequences of climate change in Iran were reviewed.

RESULTS

The evidence suggests that the expected health challenges related to climate change in Iran are: rising temperatures; frequent extreme weather events; reduction of air quality; food-borne, water-borne, and vector-borne diseases; mental health and well-being consequences; and the increasing trend of natural disasters and deaths associated with climatological hazards.

CONCLUSIONS

By considering the growing burden of diseases associated with climate variability in Iran as well as the interdisciplinary nature of climate change and health issues, an integrated, multi-sectoral, and comprehensive approach for identification, prioritization, and implementation of adaptation options is required by Ministry of Health and Medical Education as a custodian of public health in order to enhance the resiliency and adaption against adverse health effects of climate change.

An investigation into the use of < 38 µm fraction as a proxy for < 10 µm road dust particles

It is well documented that a large portion of urban particulate matters is derived from road dust. Isolating particles of RD which are small enough to be inhaled, however, is a difficult process. In this study, it is shown for the first time that the < 38 µm fraction of road dust particles can be used as a proxy for road dust particles < 10 µm in bioaccessibility studies. This study probed similarities between the < 10 and < 38µm fractions of urban road dust to show that the larger of the two can be used for analysis for which larger sample masses are required, as is the case with in vitro analysis. Road dust, initially segregated to size < 38 µm using sieves, was again size segregated to < 10 µm using water deposition. Both the original < 38 µm and the separated < 10 µm fractions were then subject to single particle analysis by SEM-EDX and bulk analysis by ICP-OES for its elemental composition. Dissolution tests in artificial lysosomal fluid, representative of lung fluid, were carried out on both samples to determine % bioaccessibility of selected potentially harmful elements and thus probe similarities/differences in in vitro behaviour between the two fractions. The separation technique achieved 94.3% of particles < 10 µm in terms of number of particles (the original sample contained 90.4% as determined by SEM-EDX). Acid-soluble metal concentration results indicated differences between the samples. However, when manipulated to negate the input of Si, SEM-EDX data showed general similarities in metal concentrations. Dissolution testing results indicated similar behaviour between the two samples in a simulated biological fluid.

Elemental and magnetic analyses, source identification, and oxidative potential of airborne, passive, and street dust particles in Asaluyeh County, Iran

One of the most important environmental issues in arid and semi-arid regions is deposition of dust particles. In this study, airborne, passive, and street dust samples were collected in Asaluyeh County, in August 2017, September 2017, and February 2018. The PM_2.5 and PM₁₀ concentrations for the sampling period ranged between 19.7 and 76.0 μg/m³ and 47.16-348 μg/m³ with an average of 46.4 μg/m³ and 143 μg/m³, respectively. Monthly dust deposition rates ranged from 5.2 to 26.1 g/m² with an average of 17.85 g/m². Positive Matrix Factorization (PMF) applied to the dust compositional data indicated that Sb, Zn, Pb, Mo, Cu, and As come from anthropogenic sources while Al, Fe, Ti, Mn, Ni, Cr, and Co originate mostly from geogenic sources. The PMF results indicated that the geogenic material was the major source of passive and airborne dust samples. Elemental compositions were similar for passive dust and local surface soil. Frequency-dependent magnetic susceptibility (χ_If and χ_fd%) showed that the local soil is entisol. Isothermal remanent magnetization (IRM_-100mT/IRM_1T) versus saturation IRM (SIRM) demonstrated that the background sample contains ferrimagnetic minerals, but with increasing SIRM, the concentration of soft magnetic magnetite-like phases increases and the magnetic particles are larger. Mrs./Ms. versus Bcr/Bc indicated that the magnetic particles sizes were probably between 120 and 1000 nm. Eu values and the mean Eu/Eu* and La/Al values clearly show that the airborne dust is most affected by oil industries, while passive dust samples primarily originated from local surface soils. These assumptions were confirmed by Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model results. The samples display a moderate level of oxidation towards ascorbic acid (OP_AA) and glutathione (OP_GSH). Regarding the passive and airborne dust samples, backward Generalized Estimating Equations (GEE) modeling results display a significant positive relationship between geogenic material and oxidative potential (OP). It includes many redox-active transition metals. Alternatively, the street dust OP is strongly related to geogenic and industrial sources and OP_AA is marginally related to urban sources. It was shown that measured magnetic parameters can be used for OP estimation.

Health risk assessment and source apportionment of polycyclic aromatic hydrocarbons associated with PM10 and road deposited dust in Ahvaz metropolis of Iran

The objective of this study was to compare the characteristics of polycyclic aromatic hydrocarbons (PAHs) in PM₁₀ and road dust samples, as well as to identify and quantify the contributions of each source profile using the positive matrix factorization (PMF) receptor model. Health risk assessment was carried out using toxic equivalency factors and incremental lifetime cancer risk (ILCR), which quantitatively estimate the exposure risk for age-specific groups. PM₁₀ samples were collected on PTFE filters in the metropolitan area of Ahvaz. Road dust samples were also collected from all over the urban areas with different land uses. Total PAH concentrations in PM₁₀ and road dust samples were 0.5-25.5 ng/m³ and 49.3-16,645 µg/kg, respectively. Pyrene was the highest PAH in the PM₁₀ profile, whereas fluoranthene became the highest PAH in the road dust. Abundance of benzo[ghi]perylene at PM₁₀ and road dust samples suggested a source indicator for traffic emissions. The results demonstrate that in 36.5% of samples, PM₁₀ concentrations exceed the maximum concentration level recommended by EPA. A multiple linear regression model was used to estimate the influence of meteorological parameters (temperature, wind speed, and relative humidity) on buildup of PAHs. All of PAH species show higher concentrations during the cold and typical days rather than the dust event days and warm periods. PMF analysis showed that vehicular emissions (50.6%) and industrial activities (especially steel industries) (30.4%) were first two sources of PAHs bounded with PM₁₀, followed by diesel emissions (11.6%) and air-soil exchange (7.4%). For road dust samples, three common sources were also identified: vehicular traffic (48%), industrial activities (42.3%), and petrogenic sources (9.7%), in line with that of diagnostic molecular ratios results. According to the results of health risk assessment model, the ILCR of exposure to PAHs associated with PM₁₀ and road-deposited dust was higher than the guidelines of USEPA, indicating high carcinogenic risk.

Chemical and organic characteristics of PM2.5 particles and their in-vitro cytotoxic effects on lung cells: The Middle East dust storms in Ahvaz, Iran

There are very few reports about the effect of PM_2.5 particles carried by the Middle East dust storms on lung cells. This study aimed to investigate the chemical properties and in-vitro cytotoxic effects of PM_2.5 extracts. Water-soluble fraction and organic solvent-extractable components of the samples collected from the city of Ahvaz, Khuzestan Province, Iran, during the normal and dust storm days of the winter of 2016 were analyzed and then applied on the human lung epithelial cell line (A549). The chemical properties and the cytotoxicity were analyzed by ICP-OES and Lactase Dehydrogenase (LDH) assay, respectively. The results of the independent t-test showed significantly higher mean cytotoxicity in the samples of normal days than that of dust storm days. It could be due to the fact that the cells were exposed to the same amount of water-soluble extract, whether it be from a normal day or a dust storm day, and since the normal air of Ahvaz is severely affected by traffic and industrial pollutants, its normal day samples showed stronger cytotoxic effect. The results of the Kruskal-Wallis test showed that cytotoxic effect increased with the particulate concentration. The highest cytotoxicity levels observed at 62, 125, and 250 μg/mL concentrations after 24-h incubation were 17% (belonging to a dust storm day), 37% (belonging to a normal day), and 47% (belonging to a dust storm day), respectively Since PAH compounds were measured in the particulate phase, their amount was naturally correlated with the quantity of particulates. However, it was observed that the samples of normal days contained the species with stronger human carcinogens ΣPAHs = 0.82 ng/m³.The results of one-way ANOVA showed a significant difference between the incubation times regarding the resulted cytotoxicity levels. In general, as the incubation duration increased, so did the cytotoxicity level. Although normal day particulates had a greater cytotoxic effect on A549 cell line, dust storm days are associated with higher levels of health risk; simply because during dust storms, people inhale much larger amounts of particulates.

Source Apportionment of Total Suspended Particles (TSP) by Positive Matrix Factorization (PMF) and Chemical Mass Balance (CMB) Modeling in Ahvaz, Iran

There is a compelling need for apportionment of pollutants' sources to facilitate their reduction through proper management plans. The present study was designed to determine the contribution of each possible source of total suspended particles in Ahvaz's ambient air using positive matrix factorization (PMF), chemical mass balance (CMB), and the SPECIATE database. The sampling program undertaken followed EPA's guidelines and finally resulted in 74 samples. The concentration of 33 elemental and 10 ionic species were measured during a whole year. Three modeling approaches were applied: PMF, the integrated use of PMF and CMB, and the integrated use of the SPECIATE database and CMB. Six sources were derived by PMF: crustal dust (30.6%), industrial and mining activities (25.4%), motor vehicles (23.4%), marine aerosols (11.5%), secondary inorganic aerosols (5.7%), and road dust (3.4%). The contributions of sources from PMF-CMB approach were crustal dust (32.9%), industrial and mining activities (20.9%), motor vehicles (19.7%), marine aerosols (11.1%), secondary inorganic aerosols (9.2%), and road dust (9.36%). Seven sources were derived by SPECIATE-CMB approach: crustal dust (23.2%), industrial and mining activities (20.1%), motor vehicles (17.5%), marine aerosols (12.4%), secondary inorganic aerosols (4.8%), road dust (5.3%), and "nondetermined sources" factor (16.7%). Despite the different contributions of sources, there is a noticeable consistency between the results of these approaches. Furthermore, because of the approved performance of combined receptor models in previous studies and the presence of sufficient data on the number of species and samples, the results of the PMF-CMB approach are possibly the most realistic among those of the three applied approaches.

Combining Positive Matrix Factorization and Radiocarbon Measurements for Source Apportionment of PM2.5 from a National Background Site in North China

To explore the utility of combining positive matrix factorization (PMF) with radiocarbon (¹⁴C) measurements for source apportionment, we applied PM_2.5 data collected for 14 months at a national background station in North China to PMF models. The solutions were compared to ¹⁴C results of four seasonally averaged samples and three outlier samples. Comparing the most readily interpretable PMF solutions and ¹⁴C results revealed that PMF modeling was well able to capture the source patterns of PM_2.5 with two and three irrelevant source classifications for the seasonal and outlier samples. The contribution of sources that could not be classified as either fossil or non-fossil sources in the PMF solution, and the errors between the modeled and measured concentrations weakened the effectiveness of the comparison. Based on these two factors, we developed an index for selecting the most suitable ¹⁴C measurement samples for combining with the PMF model. Then we examined the potential for coupling PMF modeling and ¹⁴C data with a constrained PMF run using the ¹⁴C data as a priori information. The restricted run could provide a more reliable solution; however, the PMF model must provide a flexible dialog to input the priori restrictions for executing the constraint simulation.

Physicochemical characterization of ambient PM2.5 in Tehran air and its potential cytotoxicity in human lung epithelial cells (A549)

As air pollution is a major problem in Tehran, this study aimed to investigate the physicochemical characterization of the water-soluble and organic contents of ambient PM_2.5 in Tehran and determine its in vitro toxicological impact on human lung epithelial cells (A549). A total of 11 sampling stations were selected, including three categories: traffic, urban, and suburban. All sampling was carried out in the spring and summer of 2015. Ion chromatography (IC), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and GC-MS were used to analyze ionic compounds, heavy metals, and polycyclic aromatic hydrocarbons (PAHs), respectively, and an ELISA reader was used for cytotoxicity analysis. The most prevalent ionic species found for all three categories was SO₄^2-. PAH concentrations were 43.45±32.71, 50.51±37.27, and 29.13±33.29ng/m³ for traffic, urban, and suburban stations, respectively. For all sampling stations, Al and Fe had the highest values among the investigated heavy metals. Cell viability measurements, carried out using the MTT assay, showed that all three categories of samples cause cytotoxicity, although the urban station samples showed higher cytotoxicity than those from the other stations (p˂0.05). Based on the results of the present study, organic compounds and insoluble particles could be the main causes of cytotoxicity.

Elemental and carbonaceous characterization of TSP and PM10 during Middle Eastern dust (MED) storms in Ahvaz, Southwestern Iran

Middle Eastern dust (MED) storms carry large amounts of dust particles to the Southern and Western cities of Iran. This study aimed to characterize the elemental and carbonaceous composition of total suspended particles (TSP) and PM₁₀ in Ahvaz, Iran. TSP and PM₁₀ samples were collected using two separate high-volume air samplers. The sampling program was performed according to EPA guidelines and resulted in 72 samples. Twenty-eight elements and two carbonaceous components in TSP and PM₁₀ were measured. Over the entire study period, the mean concentration (SD) of TSP and PM₁₀ was 1548.72 μg/m³ (1965.11 μg/m³) and 1152.35 μg/m³ (1510.34 μg/m³), respectively. The order of concentrations of major species were Si > Al > Ca > OC > Na > B > Zn > Mn > K > Mg and Si > Ca > Al > Na > OC > B > K > Mn > Cu > Mg for TSP and PM₁₀, respectively. Almost all elements (except for Cd, Cr, and Cu) and carbonaceous components (except for organic carbon) had dust days/non-dust days (DD/NDD) ratios higher than 1, implying that all components are somehow affected by dust storms. Crustal elements constituted the major portion of particles for both TSP and PM₁₀ in both DDs and NDDs. The enrichment factor of elements such as Ca, Fe, K, Mg, Na, and Ti was near unity. Species such as Al, Ca, Fe, K, Na, Si, and EC had high correlation coefficients in both TSP and PM₁₀ (except for EC). In conclusion, Ahvaz is exposed to high concentrations of TSP and PM₁₀ during the MED period. Immediate actions must be planned to decrease the high concentrations of particulate matter in Ahvaz's ambient air.

National and sub-national age-sex specific and cause-specific mortality and disability-adjusted life years (DALYs) attributable to household air pollution from solid cookfuel use (HAP) in Iran, 1990-2013

National and sub-national mortality, years of life lost due to premature mortality (YLLs), years lived with disability (YLDs) and disability-adjusted life years (DALYs) for household air pollution from solid cookfuel use (HAP) in Iran, 1990-2013 were estimated based on the Global Burden of Disease Study 2013 (GBD 2013). The burden of disease attributable to HAP was quantified by the comparative risk assessment method using four inputs: (1) exposure to HAP, (2) the theoretical minimum risk exposure level (TMREL), (3) exposure-response relationships of related causes (4) disease burden of related causes. All across the country, solid fuel use decreased from 5.26% in 1990 to 0.15% in 2013. The drastic reduction of solid fuel use leaded to DALYs attributable to HAP fell by 97.8% (95% uncertainty interval 97.7-98.0%) from 87,433 (51072-144303) in 1990 to 1889 (1016-3247) in 2013. Proportion of YLLs in DALYs from HAP decreased from 95.7% in 1990 to 86.6% in 2013. Contribution of causes in the attributable DALYs was variable during the study period and in 2013 was in the following order: ischemic heart disease for 43.4%, chronic obstructive pulmonary disease for 24.7%, hemorrhagic stroke for 9.7%, lower respiratory infections for 9.3%, ischemic stroke for 7.8%, lung cancer for 3.4% and cataract for 1.8%. Based on the Gini coefficient, the spatial inequality of the disease burden from HAP increased during the study period. The remained burden of disease was relatively scarce and it mainly occurred in seven southern provinces. Further reduction of the disease burden from HAP as well as compensation of the increasing spatial inequality in Iran could be attained through an especial plan for providing cleaner fuels in the southern provinces.

Comparison of normal and dusty day impacts on fractional exhaled nitric oxide and lung function in healthy children in Ahvaz, Iran

Children are the vulnerable group at risk of adverse health effects related to air pollution due to dust storm in Ahvaz. The purpose of this study was to compare the values of fractional exhaled nitric oxide (FENO) and lung functions as parameters of adverse health effects of particulate matter (PM) in dusty and normal (non-dusty) days in elementary schoolchildren. The study was conducted among elementary school students in Ahvaz. The healthy elementary schoolchildren (N = 105) were selected from different districts for FENO and lung function sampling during the dusty and normal days. The values of PM₁₀ and PM_2.5 during dusty days were higher than during normal days. Mean values of FENO during the normal and dusty days were 14.23 and 20.3 ppb, respectively, and the difference between these values was statistically significant (p < 0.05). Lung function results showed a statistically significant difference between the mean values of forced vital capacity during the dusty and normal days (p < 0.05). The results revealed a significant difference both in the values of inflammatory biomarker and in the lung function tests in dusty and normal days. Based on our results, fractional exhaled nitric oxide could be a useful short-term biomarker of particulate pollution effect coupled with spirometry.

Chemical composition of PM10 and its in vitro toxicological impacts on lung cells during the Middle Eastern Dust (MED) storms in Ahvaz, Iran

Reports on the effects of PM10 from dust storm on lung cells are limited. The main purpose of this study was to investigate the chemical composition and in vitro toxicological impacts of PM10 suspensions, its water-soluble fraction, and the solvent-extractable organics extracted from Middle Eastern Dust storms on the human lung epithelial cell (A549). Samples of dust storms and normal days (PM10 < 200 μg m(-3)) were collected from December 2012 until June 2013 in Ahvaz, the capital of Khuzestan Province in Iran. The chemical composition and cytotoxicity were analyzed by ICP- OES and Lactase Dehydrogenase (LDH) reduction assay, respectively. The results showed that PM10 suspensions, their water-soluble fraction and solvent-extractable organics from both dust storm and normal days caused a decrease in the cell viability and an increase in LDH in supernatant in a dose-response manner. Although samples of normal days showed higher cytotoxicity than those of dust storm at the highest treated dosage, T Test showed no significant difference in cytotoxicity between normal days and dust event days (P value > 0.05). These results led to the conclusions that dust storm PM10 as well as normal day PM10 could lead to cytotoxicity, and the organic compounds (PAHs) and the insoluble particle-core might be the main contributors to cytotoxicity. Our results showed that cytotoxicity and the risk of PM10 to human lung may be more severe during dust storm than normal days due to inhalation of a higher mass concentration of airborne particles. Further research on PM dangerous fractions and the most responsible components to make cytotoxicity in exposed cells is recommended.

Disturbance effects of PM₁₀ on iNOS and eNOS mRNA expression levels and antioxidant activity induced by ischemia-reperfusion injury in isolated rat heart: protective role of vanillic acid

Myocardial infarction is the acute condition of myocardial necrosis that occurs as a result of imbalance between coronary blood supply and myocardial demand. Air pollution increases the risk of death from cardiovascular diseases (CVDs). The aim of this study was to investigate the effects of particulate matter (PM) on oxidative stress, the expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) messenger RNA (mRNA) level induced by ischemia-reperfusion injury, and the protective effects of vanillic acid (VA) in the isolated rat heart. Male Wistar rats were randomly divided into eight groups (n = 10), namely control, VAc, sham, VA, PMa (0.5 mg/kg), PMb (2.5 mg/kg), PMc (5 mg/kg), and PMc + VA groups. Particles with an aerodynamic diameter <10 μm (PM10) was instilled into the trachea through a fine intubation tube. Two days following the PM10 instillation, the animal's hearts were isolated and transferred to a Langendorff apparatus. The hearts were subjected to 30 min of global ischemia followed by 60 min of reperfusion. The activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), xanthine oxidase (XOX), and lactate dehydrogenase (LDH) were measured using special kits. Reverse transcription polymerase chain reaction (RT-PCR) was used to determine levels of iNOS and eNOS mRNA. An increase in left ventricular end-diastolic pressure (LVEDP), S-T elevation, and oxidative stress in PM10 groups was observed. Ischemia-reperfusion (I/R) induction showed a significant augment in the expression of iNOS mRNA level and a significant decrease in the expression eNOS mRNA level. This effect was more pronounced in the PM groups than in the control and sham groups. Vanillic acid caused a significant decrease in LVEDP, S-T elevation, and also a significant difference in eNOS mRNA expression level, antioxidant enzymes, iNOS mRNA expression level, and oxidative stress occurred on myocardial dysfunction after I/R in isolated rat hearts. This study showed that PM10 exposure had devastating effects on the myocardial heart, oxidative stress, and eNOS and iNOS mRNA expression levels. Vanillic acid was able to improve these parameters. Vanillic acid as a potent antioxidant could also provide protection against particulate matter-induced toxicity.

The effect of sand storms on acute asthma in Riyadh, Saudi Arabia

OBJECTIVE

Major sand storms are frequent in the Middle East. This study aims to investigate the role of air particulate matter (PM) level in acute asthma in children in Riyadh, Saudi Arabia.

METHODS

An aerosol spectrometer was used to evaluate PM < 10μm in diameter (PM10) and PM < 2.5 μm in diameter (PM2.5) concentrations in the air every 30 minutes throughout February and March 2012 in Riyadh. Data on children 2-12 years of age presenting to the emergency department of a major children's hospital with acute asthma during the same period were collected including their acute asthma severity score.

RESULTS

The median with interquartile range (IQR) levels of PM10 and PM2.5 were 454 μg/m(3) (309,864) and 108 μg/m(3) (72,192) respectively. There was no correlation between the average daily PM10 levels and the average number of children presenting with acute asthma per day (r = -0.14, P = 0.45), their daily asthma score (r = 0.014, P = 0.94), or admission rate ( r= -0.08, P = 0.65). This was also true for average daily PM2.5 levels. In addition, there was no difference in these variables between days with PM10 >1000 μg/m(3), representing major sand storms, plus the following 5 days and other days with PM10< 1000 μg/m(3).

CONCLUSION

Sand storms, even major ones, had no significant impact on acute asthma exacerbations in children in Riyadh, Saudi Arabia. The very high levels of PM, however, deserve further studying especially of their long-term effects.

Investigation on the lung function of general population in Ilam, west of Iran, as a city exposed to dust storm

BACKGROUND

Dust storm is one of the most important natural sources of air pollution in the Middle East that has caused a major concern in recent years. The aim of this study was to evaluate the respiratory tract function of people living in Ilam city (Iran) during dust storm.

METHODS

A sample size of 250 people was selected and the cluster sampling was randomly used from 13 health centers in Ilam city. Pulmonary function test (PFT) was determined via a standard spirometry apparatus. Vital capacity (VC), Forced Vital capacity (FVC), FVC in first second (FEV1), FEV1/VC, FEV1/FVC, peek expiratory flow (PEF), forced expiratory flow (FEF25-75%), forced expiratory flow (FEF25-75%), forced expiratory flow (FEF75-85%), forced mid flow time (FMFT) and maximum voluntary ventilation (MVV) were measured.

RESULTS

Mean values of respiratory capacities measured in all participants excluding FEV1/VC and FMFT were less than predicted mean values by ECCS reference. 21.6% of the population suffered from obstructive lesions. This value among males (24.1%) was more than females (19.6%). This could be related to more exposure (outdoor jobs) of males with dust storms.

CONCLUSION

The results also showed a negative significant relationship between duration of inhabitance in Ilam city and all respiratory capacities. Further studies are needed for confident confirmation of whether reduction of respiratory capacities among Ilamian people is only related to dust storms.

Identification and quantification of shipping emissions in Bohai Rim, China

Rapid development of port and shipbuilding industry in China has badly affected the ambient air quality of coastal zone due to shipping emissions. A total of 60 ambient air samples were collected from background site of Tuoji Island in Bohai Sea strait. The air samples were analyzed for PM2.5, organic carbon (OC), element carbon (EC), inorganic elements, and water-soluble ions. The maximum concentration of PM2.5 was observed during spring (73.6 μg·m(-3)) compared to winter (39.0 μg·m(-3)) with mean of 54.6 μg·m(-3). Back trajectory air mass analysis together with temporal distribution of vanadium (V) showed that V could be the typical tracer of shipping emissions at Tuoji Island. Furthermore, the ratios of vanadium to nickel (V/Ni), vanadium to lead (V/Pb) and vanadium to zinc (V/Zn) also suggest shipping emissions at Tuoji Island. The annual average primary PM2.5 estimate of shipping emissions was 0.65 μg·m(-3) at Tuoji Island, accounting for 2.94% of the total primary PM2.5, with a maximum of 3.16% in summer and a minimum of 2.39% in autumn.

Integrated assessment of air pollution in tehran, over the period from september 2008 to september 2009

BACKGROUND

Air pollution is a major problem in urban\industrial areas, like Tehran, and has several impacts on human health. This study aimed at assessing concentrations of criteria air pollutants (CO, SO(2), NO(2), O(3), PM(10)) in Tehran, extracting patterns of hourly, daily, weekly, and monthly variations of concentrations, and making comparisons to National Standards and WHO Guidelines.

METHODS

Air quality data were taken from Air Quality Control Corporation and 5 sampling stations (out of 13) were selected for analysis according to data availability. Microsoft Excel 2003 was used for data analysis and plotting the charts.

RESULTS

Patterns of temporal variation (hourly, daily, weekly, and monthly) of air pollutant concentrations were extracted. In some cases extracted patterns matched with the patterns proposed by other researchers. Pollutant concentrations were compared to National Standards and WHO Guidelines and it was observed that in most of the days, we exceeded the limit values.

CONCLUSION

Air pollution in Tehran is quite high and there are many days that we exceed the standards; therefore appropriate control strategies are needed. Although the number of sampling stations is high enough to be representative of whole city, it is proposed that an independent sampling station is setup to check the validity of the measurements.