Composition Of PM2 Research Articles

Temporal variations of short-term effects of particulate matter on hospital admissions in the most densely populated city in Thailand

Short-term effects of ambient particulate matter (PM) on daily hospital admissions have been comprehensively elucidated, but very few studies evaluated the temporal variations of ambient PM associated with hospital admissions, especially in developing countries. This study aimed to explore the temporal changes of the short-term effects of PM10 on hospital admissions in Bangkok, Thailand from 2006 to 2014. The overdispersed Poisson regression model was applied to related daily PM10 concentrations to daily cardiovascular and respiratory hospital admissions by adjusting for temperature, humidity, long-term trend and seasonality, day of the week, public holiday, and population dynamics. The temporal variations of the effects of PM10 on hospital admissions were assessed by adding an interaction term between PM10 concentration and predefined time periods into the model. The relative risks per 10 μg/m3 increase in PM10 were 1.0092 (95% CI: 1.0046, 1.0138) for cardiovascular admissions at lag 0–3 day and 1.0209 (95% CI: 1.0145, 1.0273) for respiratory admissions at lag 0–7 day over the entire study period. Despite non-homogenous decreasing trends in annual PM10 concentrations during the study period, the effects of PM10 on cardiovascular and respiratory admissions remained significant and even showed an increasing trend for cardiovascular admissions. Specifically, the relative risks of cardiovascular admission per 10 μg/m3 increase in PM10 were 1.0050 (95% CI: 0.9965, 1.0135), 1.0086 (95% CI: 1.0000, 1.0174), and 1.0103 (95% CI: 1.0041, 1.0165) for the period of 2006–2008, 2009–2011, and 2012–2014, respectively (p-value for interaction <0.01). This finding indicated that estimated effects of PM10 on cardiovascular admissions significantly changed over time, speculating that the composition of PM10 might have changed and introduced the alterations of overall toxicity of PM10. Therefore, the efforts on air pollution control need to be continued to reduce health effects of PM10 in the future.

Health Impact Assessment of Volcanic Ash Inhalation: A Comparison With Outdoor Air Pollution Methods.

This paper critically appraises the extrapolation of concentration‐response functions (CRFs) for fine and coarse particulate matter, PM2.5 and PM10, respectively, used in outdoor air pollution health impact assessment (HIA) studies to assess the extent of health impacts in communities exposed to volcanic emissions. Treating volcanic ash as PM, we (1) consider existing models for HIA for general outdoor PM, (2) identify documented health effects from exposure to ash in volcanic eruptions, (3) discuss potential issues of applying CRFs based on the composition and concentration of ash‐related PM, and (4) critically review available case studies of volcanic exposure scenarios utilizing HIA for outdoor air pollution. We identify a number of small‐scale studies focusing on populations exposed to volcanic ash; exposure is rarely quantified, and there is limited evidence concerning the health effects of PM from volcanic eruptions. That limited evidence is, however, consistent with the CRFs typically used for outdoor air pollution HIA. Two health assessments of exposure to volcanic emissions have been published using population‐ and occupational‐based CRFs, though each application entails distinct assumptions and limitations. We conclude that the best available strategy, at present, is to apply outdoor air pollution risk estimates to scenarios involving volcanic ash emissions for the purposes of HIA. However, due to the knowledge gaps on, for example, the health effects from exposure to volcanic ash and differences in ash composition, there is inherent uncertainty in this application. To conclude, we suggest actions to enable better prediction and assessment of health impacts of volcanic emissions.

Identification of wintertime carbonaceous fine particulate matter (PM2.5) sources in Kaunas, Lithuania using polycyclic aromatic hydrocarbons and stable carbon isotope analysis

Abstract The study aimed at demonstrating the application of PAHs and δ13C indoor and outdoor measurements towards resolving airborne carbonaceous particle sources in wintertime. Concurrent outdoor and indoor measurements of PM2.5 and size-resolved (PM0.056-2.5) particulate matter were conducted at 6 one-family houses in Kaunas, Lithuania during January–March 2013. PM2.5 and size-resolved filter samples were analyzed for total carbon (TC) and stable carbon isotopic composition by elemental analyzer connected to isotope ratio mass spectrometer. Moreover, the indoor-outdoor concentrations of 10 selected polycyclic aromatic hydrocarbons (PAHs) in PM2.5 were quantified. The simultaneous stable carbon isotope ratio and PAHs diagnostic ratio analysis enabled to identify main anthropogenic sources (traffic, biomass burning, and coal combustion) of PM2.5. Our study indicated that during winter period outdoor PM2.5 in Kaunas were mainly derived from biomass burning (solid fuel stoves) and vehicular emissions. Whereas indoor particulate matter had different stable carbon isotope composition of TC indicating the existence of pollution sources which was likely cooking emissions. The differences of indoor/outdoor stable carbon isotope composition in PM2.5 and size-resolved aerosol particles supported the existence of distinct TC sources and suggested that cooking emissions inside the house could strongly affect δ13C values.

First systematic review on PM-bound water: exploring the existing knowledge domain using the CiteSpace software

Aerosol water is a master component of atmospheric aerosols and a medium that enables all aqueous-phase reactions occurring in the atmosphere. This integral chemical compound of suspended aerosol particles (PM) has become one of the hottest issues in recent years. To look for scientific productivity in the area of PM-bound water research a bibliometric analysis was performed. Most actual literature regarding aerosol and particulate bound water and implications of the research in this field was downloaded from WOS database using 1996–2018 timespan. Different bibliographic statistics were used to get a general profile of leading authorships, institutions, countries and mainstream journals providing most highly cited articles in the field. Using the CiteSpace software it was possible to identify past trends and possible future directions in measuring aerosol bound water. The search terms used in the database were {“aerosol” AND “water” OR “chemical mass balance”} AND {“particulate matter” OR “PM-bound water” OR “hygroscopic”}. The answers to the following questions were found: which authors, countries, institutions and aerosol journals to the greatest degree influenced PM-bound water research?. The network of co-occurring noun phrases was extracted from the set of publications, followed by co-citation analysis. The network was also clustered by top terms which gave a clear picture of topics most often undertaken. Finally the publication meeting eligibility criteria were looked for chemical compounds most frequently determined in PM-bound water research, which help to indicate works where quantitative assessment of PM-bound water was performed. Obtained results indicate that the paper with the greatest citation burst was Tang and Munkelwitz (J Geophys Res Atmos 99(D9):18801–18808, 1994). The largest number of articles in this specific field was published in Atmospheric Chemistry and Physics. An absolute leader in the quantity of publications among all research institutions is National Aeronautics Space Administration NASA. Meteorology and Atmospheric sciences is the discipline most occupied by highly cited journals in this field. Clustering results indicate that the research has mainly focused on hygroscopic measurement of aerosol, hygroscopic growth of particles; aerosol liquid water, and hygroscopic behavior. Most articles rather points PM-bound water as an artifact in organic carbon and ions measurements without detailed analysis of its contents or probable origin. The number of publications in each cluster of the build network is relatively high, which indicate that scholars have formed a rather consistent studies in the theme of aerosol-bound water. Despite a relevant role played by aerosol-bound water in atmospheric processes a quantitative description of its contents is rather rarely found in the literature (with the total number of only 23 papers concerning PM-bound water contents). In terms of yield, USA, China and Italy ranked highest, playing a propelling role in the research on PM-bound water. Future trends in PM-bound water research should be directed to a quantitative measurements of its contents; source apportionment, chemical composition of PM—modulating its hygroscopicity and therefore cloud formation processes, and the assessment of artefacts influencing the quality of PM-bound water measurements. Those areas should be especially developed in future studies and scientific projects concerning atmospheric water.

Using Low-Cost Measurement Systems to Investigate Air Quality: A Case Study in Palapye, Botswana

Exposure to particulate air pollution is a major cause of mortality and morbidity worldwide. In developing countries, the combustion of solid fuels is widely used as a source of energy, and this process can produce exposure to harmful levels of particulate matter with diameters smaller than 2.5 microns (PM2.5). However, as countries develop, solid fuel may be replaced by centralized coal combustion, and vehicles burning diesel and gasoline may become common, changing the concentration and composition of PM2.5, which ultimately changes the population health effects. Therefore, there is a continuous need for in-situ monitoring of air pollution in developing nations, both to estimate human exposure and to monitor changes in air quality. In this study, we present measurements from a 5-week field experiment in Palapye, Botswana. We used a low-cost, highly portable instrument package to measure surface-based aerosol optical depth (AOD), real-time surface PM2.5 concentrations using a third-party optical sensor, and time-integrated PM2.5 concentration and composition by collecting PM2.5 onto Teflon filters. Furthermore, we employed other low-cost measurements of real-time black carbon and time-integrated ammonia to help interpret the observed PM2.5 composition and concentration information during the field experiment. We found that the average PM2.5 concentration (9.5 µg∙m−3) was below the World Health Organization (WHO) annual limit, and this concentration closely agrees with estimates from the Global Burden of Disease (GBD) report estimates for this region. Sulfate aerosol and carbonaceous aerosol, likely from coal combustion and biomass burning, respectively, were the main contributors to PM2.5 by mass (33% and 27% of total PM2.5 mass, respectively). While these observed concentrations were on average below WHO guidelines, we found that the measurement site experienced higher concentrations of aerosol during first half our measurement period (14.5 µg∙m−3), which is classified as “moderately unhealthy” according to the WHO standard.

Impacts of PM2.5 Chemical Composition on Aerosol Light Extinction During the Xi’an International Horticultural Expo of China

In this study, we investigated the impacts of PM2.5 chemical composition on aerosol light extinction during the Xi’an International Horticultural Expo of China. The average mass concentration of PM2.5 was 118.1 ± 57.3 µg m-3 during the entire campaign with 23.1% and 40.7% contributed by carbonaceous aerosols and water-soluble inorganic ions. The average light extinction was 957.7 ± 643.5 Mm-1, of which &gt;90% was contributed by the particle light scattering. The light extinction was 1.6 times larger during polluted period than the unpolluted period. The diurnal pattern of the measured light scattering was associated with the anthropogenic activities of daily life and the daily variation of boundary-layer height. Based on the IMPROVE equation, (NH4)2SO4 was the largest contributor to light extinction (35.3%) during the Xi’an International Horticultural Expo, followed by organic matter (33.7%), NH4NO3 (20.5%), EC (6.3%), and fine soil (4.0%). The light extinction produced by (NH4)2SO4, organic matter, and NH4NO3 were 1.8 – 2.5 times larger during polluted period than the unpolluted period. The results indicated that (NH4)2SO4 was the most important chemical composition in PM2.5 affecting the aerosol light extinction during the Xi’an International Horticultural Expo.

Source Apportionment of Coarse Particulate Matter (PM10) in Yangon, Myanmar.

The Republic of the Union of Myanmar is one of many developing countries facing concerns about particulate matter (PM). Previously, a preliminary study of PM2.5 in 2018 suggested that the main source of PM in Yangon, the former capital, was vehicle emissions. However, this suggestion was not supported by any chemical composition data. In this study, to fill that gap, we quantitatively determined source contributions to coarse particulate matter (PM10) in Yangon, Myanmar. PM10 samples were collected in Yangon from May 2017 to April 2018 and chemically analyzed to determine composition. Chemical composition data for these samples were then used in the Chemical Mass Balance (CMB) model to identify the major sources of particulate matter in this area. The results indicate that PM10 composition varies seasonally according to both meteorological factors (e.g., precipitation and temperature) and human activities (e.g., firewood and yard waste burning). The major sources of PM in Yangon annually were dust, secondary inorganic aerosols (SIA), and secondary organic aerosols (SOA), while contributions from biomass burning were more important during the winter months.

Chemical composition and source characterization of PM10 in urban areas of Lahore, Pakistan

This study aims to assess the physicochemical characteristics of the particulate matter ≤10 µm (PM10) at both congested and non-congested areas of Lahore, the second-largest city of Pakistan. PM10 samples from 10 urban sites in Lahore were analysed for source apportionment. The techniques of scanning electron microscopy/energy dispersive spectrometry (SEM/EDX) and inductively coupled plasma-optical emission spectroscopy (ICP-OES) were used to determine the morphology and the chemical composition of PM10. Thirteen elements including toxic metals were consequently detected and quantified: Ca (48.1%), Zn (17.0%), Fe (13.3%), Al (8.2%), Mg (6.6%), Pb (5.5%), Mn (0.4%), Cu (0.3%), Ba (0.17%), Cd (0.15%), Ni (0.04%), Cr (0.01%) and Co (0.008%). The results showed that the daily PM10 concentration was 6%–9% higher than the World Health Organization’s guideline values at all urban sites of Lahore. The congested sites showed higher contents than the non-congested areas for most of the elements, including Cd (41.8%), Cr (35.0%), Zn (19.7%), Cu (12.7%), Ni (6.2%), Ca (3.4%), Ba (1.2%), Mg (1.2%) and Al (0.07%). The non-congested areas showed higher contents only for Pb (0.07%) and Co (4.3%). The principal component analysis indicated that 72% of PM10 originates from road dust and vehicular sources, and 38% from industrial sources.

Development of a cost effective passive sampler to quantify the particulate matter depositions on building materials over time

Air pollution represents a serious risk for the preservation of open-air Cultural Heritage. The increased on Particulate Matter contamination may contribute to trigger the sulphating process of porous building materials and to add new ions, which may react and change the original composition of the materials. Because of this, the knowledge of PM composition near monuments or buildings over time is becoming an important issue in conservation strategies. In this work, a simple and cost-efficient passive sampler is proposed to quantify the PM being deposited over building material surfaces per area and time of exposure. The passive sampler described in this work, consisting on retainers specially designed for XRF analysis, is used for the first time as a simple way for characterising the surrounding atmospheric contamination caused by PM, without the need of other commonly employed more expensive PM active samplers such as cascade impactors. The particles trapped in this way can then be easily analysed by means of Scanning Electron Microscopy coupled to Energy Dispersive Spectrometer (SEM-EDS), Micro Energy Dispersive X-Ray Fluorescence Spectrometry (μ-EDXRF) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). In the studied case, the Galleries of Punta Begoña, the identification of sulphates deposition add new ions to the building materials, the marine aerosol affects significantly to the reinforcement of the concrete and the important deposition of Fe particles may be responsible of triggering the sulphating process in this historical building. The PM passive sampler and the characterisation methodology proposed in this work can be extensively applied to other situations where PM characterisation is required.

Chemical Composition of PM10 in 16 Urban, Industrial and Background Sites in Italy

Italy is characterized by a very variable configuration in terms of altitude, proximity to the sea, latitude and the presence of industrial plants. This paper summarizes the chemical characterization of PM10 obtained from 38 sampling campaigns carried out in 16 sites in Italy during the years 2008–2018. Chemical determinations include all macro-components (six macro-elements, eight ions, elemental carbon and organic carbon). The sum of the individual components agrees well with the PM10 mass. The chemical composition of the atmospheric aerosol clearly reflects the variety in the Italian territory and the pronounced seasonal variations in the meteoclimatic conditions that characterize the country. Macro-sources reconstruction allowed us to identify and evaluate the strength of the main PM10 sources in different areas. On 10 sampling sites, the soluble and insoluble fractions of 23 minor and trace elements were also determined. Principal Component Analysis was applied to these data to highlight the relationship between the elemental composition of PM10 and the characteristics of the sampling sites.

Understanding PM2.5 concentration and removal efficiency variation in urban forest park-Observation at human breathing height.

To increase our knowledge of PM2.5 concentrations near the surface in a forest park in Beijing, an observational study measured the concentration and composition of PM2.5 in Beijing Olympic Forest Park from 2014 to 2015. This study analyzed the meteorological factors and removal efficiency at 1.5 m above the ground (human breathing height) over the day in the forest. The results showed that the average concentrations of PM2.5 near the surface peaked at 07:00–09:30 and reached their lowest at 12:00–15:00. Besides, the results showed that the annual concentration of PM2.5 in the forest was highest during winter, followed by spring and fall, and was lowest during summer. The main chemical components of PM2.5 near the surface in the forest were SO42− and NO3−, which accounted for 68.72% of all water-soluble ions that we observed. The concentration of PM2.5 in the forest had a significant positive correlation with relative humidity and a significant negative correlation with temperature. The removal efficiency near the surface showed no significant variation through the day or year. In the forest, the highest removal efficiency occurred between 07:00 and 09:30 in summer, while the lowest occurred between 09:30 and 12:00 in winter.

Is There Something in the Air? Sources, Concentrations and Ionic Composition of Particulate Matter (PM2.5) in an Industrial Coastal City in Southern Brazil

Rio Grande (RS, Brazil) is a coastal municipality in which the climatic conditions are driven mainly by the wind regime. The city harbours important port and industrial activities that may affect residential areas. In this sense, the main goal of the present study was to investigate, for the first time, concentrations and ion composition of the atmospheric particulate matter (PM 2.5) in this peculiar city. Air samplers were installed in both urban and urban-industrial zones from October 2009 to May 2011, filtering particles < 2.5 μm one to three times a month. PM 2.5 concentrations and their ionic composition (Na+, Mg2+, Ca2+, K+, NH4+, F−, Cl−, NO3−, NO2−, SO42− and PO43−) were determined, as well as the contribution of natural (originated from the sea salt) and anthropogenic ions in the samples. PM 2.5 concentrations ranged from 6.74 to 88.14 μg m−3 in the urban-industrial area and from 11.24 to 53.44 g m−3 in the urban zone, exceeding quality criteria established by WHO and CONAMA in more than 50% of the samples collected, in both areas. Ion analysis in PM 2.5 evidenced a strong contribution of ions coming from industrial sources in the composition of PM 2.5, both in the industrial and the urban zone.

Chemical nature and sources of fine particles in urban Beijing: Seasonality and formation mechanisms

To mitigate air pollution in China, a legislative ‘Air Pollution Prevention and Control Action Plan’ has been implemented by the Chinese government since 2013. There is, however, a lack of investigations for long-term trends in the composition, sources and evolution processes of PM1 (particulate matter with diameter less than 1 μm) after the implementation. To evaluate the effectiveness of these control measures, we present a year-long real-time measurement of the chemical composition of PM1 at an urban site in Beijing from November 2014 to November 2015, and the results are compared with previous studies from 2008 to 2013 to gain insights into the variations of the chemical composition and sources of PM1 in Beijing. Large seasonal differences were observed in the mass concentrations of PM1 species and general declining trend was observed in the last seven years. Specifically, the annual averages of mass concentrations in 2014–2015 decrease by 16–43% (PM1), 23–43% (organic aerosol, OA), 38–68% (sulfate), 26–51% (nitrate), 18–33% (ammonium) and 27–38% (chloride) compared to those from 2008 to 2013. During winter and summer, the seasonal mass concentrations of sulfate and nitrate show more significant declines especially in summer 2008 (79% and 81%) and summer 2011 (76% and 77%). The nitrate-to-sulfate ratio is higher in 2014–2015 (1.5 ± 0.6) than that in 2013 (1.0 ± 0.3), largely due to significant reduction in SO2 emissions, suggesting that nitrate is becoming more important than sulfate in particulate pollution in Beijing. OA is the dominant PM1 fraction (>45%) in all seasons and the mass concentrations/contributions of both primary and secondary OA show different seasonality. As for the more oxidized oxygenated OA (MO-OOA) and less oxidized oxygenated OA (LO-OOA), the contributions of MO-OOA are much higher than those of LO-OOA (27–62% vs. 6–26%) in both high-pollution and low-pollution days. Aqueous-phase processes are found to facilitate the formation of MO-OOA while photochemical oxidation formation is a major contributor of LO-OOA in winter, and photochemical oxidation plays a major role in the formation of MO-OOA in summer and fall. The current study provides a comprehensive seasonal comparison of chemical composition and formation of PM1 in Beijing and a pacesetter in tackling PM pollution for other equally polluted megacities, after implementation of more stringent control measures after 2013.

Chemical and isotopic characteristics of PM10 over the Bay of Bengal: Effects of continental outflow on a marine environment

Pollutants transport from South and Southeast Asia can profoundly affect the marine atmospheric boundary layer (MABL) over the Bay of Bengal (BoB). This study presents chemical and stable isotopic composition of PM10 collected at Port Blair Island (11.6°N, 92.7°E) located in the middle of the BoB during the late northeast monsoon (February–April), a period when the BoB receives considerable continental outflow. These samples (n = 50) were analysed for major ions, carbonaceous species, trace metals, and isotopic composition of total C, N, and S components. Mass concentration of PM10 ranged from 24 to 65 μg m−3 during the study period. The dominance of continental inputs over a marine realm was evident by a significant amount of non-sea-salt (nss)-SO42− (range: 1.8 to 16.9 μg m−3), which accounts for ~65% of the total water-soluble inorganic constituents. The impact of anthropogenic emissions was further evident from the widespread depletion of chloride (range: 57–100%, avg.: 98 ± 7%) from sea-salt aerosols. Carbonaceous species (elemental carbon and organic matter) contributed nearly 35% to PM10. Further, average δ13C (−25.6‰ ± 0.5) and δ34S (4.5‰ ± 1.3) values observed over the marine study region were similar to those found in typical urban environments. δ15N values (13.7‰ ± 5.1) show the significant presence of combustion sources along with the effect of atmospheric processing. Aerosol δ13C values correlate positively with the ratio of water-soluble organic carbon to total organic carbon, indicating the aging of organic aerosols during the transport. Chemical and isotopic data suggest that both biomass burning (BB) and fossil fuel burning (FFB) contributed to ambient PM10 with relatively more contribution of BB during February to early March and that of FFB during late March to middle of April. In aggregate, this study provides newer insights into sources of carbonaceous species and their chemical processing in MABL of BoB.

Characteristics and Sources Apportionment of Fine Particulate Matter in a Typical Coastal City During the Heating Period

To clarify the pollution characteristics and sources of PM2.5 in Weihai during the heating period, PM2.5 samples from ambient air were collected at three routine air quality monitoring sites from January to March 2018. The OC, EC, water-soluble ions, and elements in PM2.5 were analyzed, and the sources of PM2.5 were identified using the PMF model. The results showed that the average daily mass concentration of PM2.5 was (33.80±22.45) μg·m-3, and the NO3-, NH4+, SO42-, OC, and EC were the main components of PM2.5. As a coastal city, the Cl- ratio was relatively high in PM2.5. Meanwhile, the compositions of PM2.5 were affected by the emission of pollutants with local industrial characteristics. Both NO3-/SO42- and OC/EC showed that mobile sources had a high contribution during the heating period. The acid-base ions in water-soluble ions showed that PM2.5 is weakly alkaline, and NH4+ is excessive. NH4+ mainly existed in the form of NH4NO3 and (NH4)2SO4. During the polluted period, the concentration of secondary pollutants significantly increased, and the mass concentrations of NH4+, NO3-, SO42-, OC, and EC were 4.21, 5.27, 3.23, 2.02, and 1.81 times that of the cleaning period, respectively. The PMF model showed that secondary aerosols were the major source of PM2.5, accounting for 32.4%-36.0% of PM2.5. The contributions of vehicle exhaust, coal combustion, biomass burning, and dust were 15.6%-18.9%, 12.1%-17.8%, 9.0%-10.4%, and 8.6%-11.3%, respectively, while the contributions of process emission (2.1%-8.3%), non-road mobile sources (2.4%-3.7%), and sea salt (3.5%-5.6%) were less.

Understanding the emission pattern and source contribution of hazardous air pollutants from open burning of municipal solid waste in China

The open burning of municipal solid waste (MSW) is common in China. Therein, low–temperature anoxic combustion results in the emission of hazardous air pollutants. This study employed a dilution sampling system to conduct open burning testing on MSW samples from different functional urban areas. Additionally, modified combustion efficiency was used to distinguish smoldering and flaming combustion in two of the most common open burning practices in China: pile–up burning and barrel burning. The sampled pollutants included gaseous pollutants (e.g., CO2, CO, SO2, and NOx) and fine particles (PM2.5). This study also analyzed the carbonization compounds, 9 water–soluble ions, and 8 toxic heavy metals in PM2.5. Emission factors of air pollutants from open burning of different MSW compositions and burning modes were determined. The composition of PM2.5 from MSW open burning comprised average 43.9%, 22.5%, and 0.4% of organic carbon (OC), water–soluble ions, and toxic heavy metals (THMs), respectively. OC was found to be the primary component of PM2.5. Based on localized emission factor database, the emissions and source contribution of open burning of MSW in China were quantified. The open burning of MSW can contribute averaged 8.7%, 16.7%, 3.8%, 1.3% of PM2.5, OC, THMs, and gaseous air pollutants of reported emissions of anthropogenic sources, respectively. This work can complement current anthropogenic emission inventory and assist policy–making.

Validation of PM2.5 model particle through physicochemical evaluation and atherosclerotic plaque formation in ApoE-/- mice.

PM2.5 particles are regarded as prominent risk factors that contribute to the development of atherosclerosis. However, the composition of PM2.5 is rather complicated. This study aimed to provide a model particle that simulates the behavior of actual PM2.5, for subsequent use in exploring mechanisms and major complications arising from PM2.5. To establish model particles of PM2.5, a series of monodisperse SiO2 microspheres with different average grain diameters were mixed according to the size distribution of actual PM2.5. The organic carbon (OC) was removed from PM2.5 and coated onto the SiO2 model particle, to formulate simulant PM2.5. Results showed that the size distribution of the model particle was highly approximate to that of the PM2.5 core. The polycyclic aromatic hydrocarbon (PAHs) composition profile of the simulated PM2.5 were approximate to PM2.5, and loading efficiency was approximately 80%-120%. Furthermore, compared to the control, SiO2-only model particle had negligible cytotoxicity on cell viability and oxidative stress of HUVECs, and marginal effect on the lipid metabolism and atherosclerotic plaque formation in ApoE-/- mice. In contrast, simulated PM2.5 exhibited similar cytotoxic and detrimental effects on lipid metabolism and atherosclerotic plaque formation with actual PM2.5. Traffic-related PM2.5 had negative effects on endothelial function and led to the formation of atherosclerosis via oxidative stress. The simulated PM2.5 simulated the outcomes of actual PM2.5 exposure. Here, we show that SiO2 particle model cores coated with OC could significantly assist in the evaluation of the effects of specific organic compositions bound on PM2.5, specifically in the context of environmental health and safety.

Variability of air pollutants, and PM composition and sources at a regional background site in the Balearic Islands: Review of western Mediterranean phenomenology from a 3-year study

The present study discloses the results of a comprehensive 3-years campaign (2010−2012) of air pollution measurements over an regional island background area (Can Llompart-Balearic Islands, Spain), contextualized with other measurements in the western Mediterranean region.Gaseous pollutants and particulate matter fractions were measured in real time; and PM10 and PM1 daily samples were obtained regularly from which chemical analyses were performed. Furthermore, during three intensive observation periods, real-time concentrations of particle number, black carbon and ammonia were additionally measured.Our results display particular diurnal and seasonal patterns for certain pollutants such as O3 and particle number concentration.Our study reveals that concentrations of air pollutants and aerosol chemical composition are rather similar all over the central and western Mediterranean basin. The most abundant chemical components in PM10 were mineral dust, followed by organic matter, sea spray and SO42−; in PM1 organic matter and SO42− dominated, with significant contribution of mineral dust.Furthermore, a source apportionment Positive Matrix Factorization analysis was conducted. Natural sources exert most of the impact on the coarse-mode fraction, while most of fine-mode aerosols are linked to anthropogenic sources coming from local, regional or long range transport emissions.Prevalence of Atlantic air masses in 2010 had a positive effect in air quality, lowering mineral dust, SO42− and EC concentrations. On the contrary, the high incidence of African dust and regional recirculation situations during the 2012 warm season favoured an overall PM load increase governed by mineral dust, SO42− and trace elements associated to dust aerosols.The continuous increase in tourists in the Balearic Islands, and in general all around the Mediterranean, is clearly changing air quality patterns: while urban air pollution has strongly decreased since 2010, such downward trend is less pronounced at the regional scale, thus related to crescent sources such as maritime and air transport.

Size Distributions, Microstructures, and Elemental Compositions of PM2.5 from Two Coal-Fired Fluidized-Bed Boilers Equipped with Fabric Filters

PM2.5 is one of the main atmospheric pollutants in China, and coal burning is the main emission source of PM2.5. At present, PM2.5 emission characteristics of the coal-fired fluidized-bed boiler ar...

Contribution of Volcanic and Fumarolic Emission to the Aerosol in Marine Atmosphere in the Central Mediterranean Sea: Results from Med-Oceanor 2017 Cruise Campaign

This work studied the contribution of the geogenic sources volcanoes and fumaroles to the aerosol in marine atmosphere in the central Mediterranean basin. For this purpose, in the framework of the Med-Oceanor measurement program, we carried out a cruise campaign in the summer of 2017 to investigate the impact to the aerosol of the most important Mediterranean volcanoes (Mount Etna, Stromboli Island, and Marsili Seamount) and solfatara areas (Phlegraean Fields complex, Volcano Islands, Ischia Island, and Panarea submarine fumarole). We collected PM10 and PM2.5 samples in 12 sites and performed chemical characterization to gather information about the concentration of major and trace elements, elemental carbon (EC), organic carbon (OC), and ionic species. The use of triangular plots and the calculation of enrichment factors confirmed the interception of volcanic plume. We integrated the outcomes from chemical characterization with the use of factor analysis and SEM/EDX analysis for the source apportionment. Anthropogenic and natural sources including shipping emissions, volcanic and fumarolic load, as well as sea spray were identified as the main factors affecting aerosol levels in the study area. Furthermore, we performed pattern recognition analysis by stepwise linear discriminant analysis to seek differences in the composition of PM10 and PM2.5 samples according to their volcanic or solfatara origin.