PM10 Fraction Research Articles

SCIENTIFIC SUBSTANTIATION OF ENVIRONMENTAL MONITORING SYSTEMS AT THE REGIONAL LEVEL USING THE EXAMPLES OF PM2.5, PM10 AND OZONE IN WARTIME CONDITIONS

SCIENTIFIC SUBSTANTIATION OF ENVIRONMENTAL MONITORING SYSTEMS AT THE REGIONAL LEVEL USING THE EXAMPLES OF PM2.5, PM10 AND OZONE IN WARTIME CONDITIONS

Health risk assessment of toxic elements in sedimentable dust from landfills

Four monitoring campaigns of sedimentable dust were provided from two large non-sanitary landfills (Zrenjanin and Novi Sad) in Serbia during 2021. Particle size analysis by laser diffraction and inductively coupled plasma-optical emission spectrometry were carried out in order to obtain the particle size distribution (PSD) and the toxic elements (TEs) concentrations. The health risk assessment of the landfill employees was performed according to the United States Environmental Protection Agency methods based on TEs concentrations. The PSD results demonstrated that the majority of sedimentable dust samples mass were not concentrated neither within PM2.5 neither within PM10 fraction. Analysis revealed high concentration of TEs at both landfills: an extremely high concentrations of Cr and Zn in samples from Zrenjanin landfill was detected. Health risk potential of elements was as follows for both landfills: Cr > Co > Pb > Ni > Zn > Cu. According to the results, maximal hazard index for landfill employees in Zrenjanin (0.197) and Novi Sad (0.113) showed that non-cancer risk was very low. For both landfill sites, cancer risk was highest for Cr (2.75?10-5 for Zrenjanin and 2.02?10-7 for Novi Sad), though still within the defined threshold for tolerable cancer risk.

The Use of Multilayer Perceptrons to Model PM2.5 Concentrations at Air Monitoring Stations in Poland

The biggest problem facing air protection in Poland is the high levels of suspended particular matter concentrations. Air monitoring reports show that air quality standards, related to PM10 and PM2.5 concentrations, are exceeded every year in many Polish cities. The PM2.5 aerosol fraction is particularly dangerous to human and animal health. Therefore, monitoring the level of PM2.5 concentration should be considered particularly important. Unfortunately, most monitoring stations in Poland do not measure this dust fraction. However, almost all stations are equipped with analyzers measuring PM10 concentrations. PM2.5 is a fine fraction of PM10, and there is a strong correlation between the concentrations of these two types of suspended dust. This relationship can be used to determine the concentration of PM2.5. The main purpose of this analysis was to assess the accuracy of PM2.5 concentration prediction using PM10 concentrations. The analysis was carried out on the basis of long-term hourly data recorded at several monitoring stations in Poland. Artificial neural networks in the form of a multilayer perceptron were used to model PM2.5 concentrations.

Merenje kvaliteta vazduha u aglomeraciji Bor u 2022. godini u periodu rekonstrukcije topionice bakra u Boru

This paper presents the results of the air quality measurements in the agglomeration of Bor in the period June-December 2022, in which the Copper Smelter in Bor was not working due to the works on reconstruction and increasing the capacity for copper concentrate processing. Based on an analysis of the existing measuring points and concentrations of pollutants, measured in the local and national air quality monitoring network in the territory of the Bor agglomeration, as well as the possible impact of the new mining and metallurgical facilities in the company Serbia ZiJin Copper Bor, the additional locations, where the measurements were performed, were selected. The air quality measurement results show that there was no exceedance of the hourly and daily limit values for gaseous pollutants, nor were there an exceedance of the limit value for the mean daily concentration of lead in the suspended particles of the PM10 fraction, as well as the target values for the concentrations of cadmium and nickel in PM10. The arsenic concentration in PM10 at the measuring point of PU Bor was above the target annual value for 3 days. The maximum measured mean daily value of arsenic concentration in PM10 at this measuring point was 11.3 ng/m3 . Based on a complete insight into the results of air quality measurements in the Bor agglomeration in 2022, it can be concluded that the dominant share of concentration of SO2 , CO, as well as the concentration of arsenic, cadmium, and lead in PM10, originates from the gaseous pollutant emissions from the Copper Smelter Bor in the period when it operates. It was established that at the measuring point MMI Bor, the nitrogen oxide emissions from traffic mostly affect the level of nitrogen oxides in the air. Also, the measurement results indicate that the operation of the Smelter in 2022 did not significantly contribute to the concentration increase of suspended PM10 particles in the agglomeration of Bor, and that during the period of operation of the Copper Smelter in 2022, no copper concentrates with increased nickel content were processed.

Relevance of Pyrolysis Products Derived from Sewage Sludge for Soil Applications

The recovery of sludge produced in the wastewater treatment process in WWTPs is often limited by the high content of toxic forms of contaminants of both an inorganic and organic nature. One of the options for the effective treatment of the world’s ever-increasing quantities of sewage sludge is the pyrolysis process. Thermochemical conversion of sewage sludge is emerging as a promising method for treating these heterogeneous and highly complex wastes with increasing research work. Pyrolysis-treated sewage sludge (PM) prepared at 603–615 °C was characterized by pH, EC, and CHN-S analysis; total and bioavailable concentrations of P and heavy metals (Cd, Cu, Fe and Zn); fractionation of bound forms of P and heavy metals in the material and determination of the presence of polycyclic aromatic hydrocarbons (PAHs). The studied material was subjected to ecotoxicological tests (Daphnia pulex L.) and cultivation tests (Lactuca sativa L.). Elemental analysis revealed the concentrations of heavy metals in PM: Fe (137,600 mg/kg), Zn (2602 mg/kg), Cu (582 mg/kg), Cr (107 mg/kg), Pb (87 mg/kg), Ni (67 mg/kg), As (<1 mg/kg), Hg (<2 mg/kg) and Cd (<1 mg/kg). The highest values of extractability of the investigated heavy metals from PM were found in the cases of Zn (HCl) and Fe (Mehlich 3), both values not exceeding 500 mg/kg. BCR sequential extraction showed the major concentrations of Cu and Fe were predominantly bound in the residual fraction (F4) and Zn in the reducible fraction (F2) of PM. The results of heavy metal bioavailability suggest that the addition of PM does not negatively affect the growth of lettuce biomass and the metal contents of plant tissues. Based on the results obtained, the pyrolysis material prepared from municipal sewage sludge seems to be a promising and innovative soil additive and a potential alternative to conventional inorganic fertilizers.

Contamination levels and source apportionment of potentially toxic elements in size-fractionated road dust of Moscow.

The distributions of potentially toxic elements (PTEs) among PM1, PM1-10, PM10-50, and PM50-1000 fractions of the road dust were studied in the western and eastern parts of Moscow, impacted mainly by the road transport and the industrial sector, respectively. The partitioning of PTEs in road dust can provide more precise information on pollution sources and its further interpretation regarding human health risks. The concentrations of PTEs were analyzed by mass and atomic emission inductively coupled plasma spectrometry. Differences in the results between the western and eastern parts of the city were caused by the dissimilarity between traffic and industrial emissions. The source apportionment of the PTEs was carried out using absolute principal component analysis with multiple linear regressions (PCA/APCS-MLR). The contribution from anthropogenic sources was significant to PM1 and PM1-10 particles. In coarser fractions (PM10-50, PM50-1000), it decreased due to the input with the wind-induced resuspension of soil and rock particles. In the eastern part of the city, the accumulation of PTEs (especially Mo, Sb, Cd, Sn, Bi, Co, and As) is the most active in PM1-10, while in the western part, it is most pronounced in PM1 (especially Pb, Cu, Cr, and W) which is associated with differences in the size of particles coming from traffic and industrial sources. In the eastern part of Moscow, in comparison with the western part, the contribution from industrial sources to the accumulation of PTEs in all particle size fractions was higher by 10-30%. In the western part of Moscow, the finest particles PM1 and PM1-10 demonstrate the trend of rising pollution levels with the increase in road size, while in the eastern part of the city, only coarse particles PM50-1000 show the same trend. In the fractions PM1 and PM1-10 of road dust, a significant contribution was made by anthropogenic sources; however, its role decreased in the coarse fractions-PM10-50 and especially in PM50-1000-due to the influence of roadside soils and their parent material.

Physico-chemical properties and transboundary transport of PM2.5 in Bien Hoa City, Dong Nai Province, Southeastern Vietnam.

Air pollution is one of the most concerning environmental issues, wherein PM2.5 concentration plays an important role. This study monitored and evaluated the PM2.5 concentration trends in Bien Hoa City, Dong Nai Province, Vietnam. Twenty 24-h PM2.5 samples were continuously collected during the rainy (15 Oct. to 25 Oct. 2021) and dry (19 Mar. to 29 Mar. 2022) seasons. The PM2.5 samples were analyzed by scanning electron microscopy to determine the surface pattern and size distributions were analyzed using ImageJ software. The water-soluble fractions of 15 trace metal(oid)s concentrations (Al, Cu, Ni, K, Ca, Co, Mn, Cr, As, Zn, Pb, Cd, Na, Fe, and Mg) bound to PM2.5 were analyzed by inductively coupled plasma-mass spectrometry. The results showed that the 24-h fine fraction PM2.5 concentrations were 24.1 ± 12.2μg/m3 and 63.0 ± 18.7μg/m3 in the rainy and dry seasons, respectively. The results indicate that the size distributions of the particles of 2.0-2.5μm are minor, and the majority are ultrafine particles with aerodynamic diameter ≤ 1.0μm. Overall, the mass concentration level of the water-soluble fraction of trace metal(oid)s in PM2.5 in the rainy season was higher than that in the dry season. Among these, Ca, K, and Na were the most abundant earth crustal elements in PM2.5 in the rainy and dry seasons, accounting for 85% and 41.2% of the total trace element concentrations, respectively. The major sources of PM2.5 are local and regional sources of thermal power plants, industrial parks, and waterborne transportation (domestic rivers and marine). The activities undertaken to remove Agent Orange (e.g., soil excavation, transportation, and rotary kiln incinerators) at the Bien Hoa airbase area also cause increases in the PM2.5 level in the atmosphere of Bien Hoa City.

A study on the chemical profile and the derived health effects of heavy-duty machinery aerosol with a focus on the impact of alternative fuels

The combustion of petroleum-based fossil fuels is associated with a high environmental burden. Several alternative fuels, including synthetic fuels (e.g., gas-to-liquid, GTL) and biofuels (e.g., rapeseed methyl ester, RME) have been studied in the last few years. While the advantages for the environment (sustainability of biofuels) are well known, research on the resulting health effects from combustion aerosols of these alternative fuels is still scarce. Consequently, we investigated the chemical combustion profile from three distinct fuel types, including a petroleum-based fossil fuel (B0) and two alternative fuels (GTL, RME) under real exposure conditions. We sampled particulate matter (PM2.5, PM0.25) and the gas phase from heavy-duty machinery and evaluated the general pattern of volatile and semi-volatile organic compounds, elemental and organic carbon as well as a range of transition metals in the size segregated PM and/or gas phase. The use of comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry enabled us to classify distinct methylated PAHs in the PM samples and its high abundance, especially in the fine fraction of PM. We found that (methylated) PAHs were highly abundant in the PM of B0 compared to GTL and RME. Highest concentrations of targeted aromatic species in the gas phase were released from B0. In summary, we demonstrated that GTL and RME combustion released lower amounts of chemical compounds related to adverse health effects, thus, the substitution of petroleum-based fuels could improve air quality for human and the environment.

Multiparametric assessment of the microclimate of livestock premises by the method of continuous automatic registration

Introduction. The relevance of work is due to the need for constructive transformation of the AАEE-7 multi-block measuring system into a mono-block one. This is required for microclimate research in livestock premises, according to the methodological provisions. The work on the development of a laboratory sample of a mono-block analyzer is being carried out in Ukraine for the first time. The purpose of the research was to implement a method of continuous automatic recording of measurements of the microclimate of livestock premises. In addition, it was supposed to reduce the cost and reduce the number of technical means of measurement. It was also supposed to simplify the process of setting up measurements to increase the productivity of scientists and technologists. Research methods. Analytical, mathematical, physical, economic research methods are applied. In addition, the methods of designing and programming electronic devices are applied. On the basis of previous developments and materials of scientific works of periodical publications, the advantages of the measuring system "Analyzer of air environment electronic mono-block" (AАEE-M) are substantiated. A laboratory sample of the device with software was made (developer Cherkasy Research Station of Bioresources NAAS). The algorithm of the multiparameter method of continuous automatic registration and assessment of the microclimate of premises using AАEE-M has been developed. Research results. It was determined that the devices of the main Ukrainian manufacturers PJSC "Ukranalit" and LLC "Complex Automated Systems" and foreign companies "Delta Ohm" and "Luma Sense Technologies A/S" do not fully meet the requirements of microclimate monitoring, according to the existing methodology. The main innovative advantage of AАEE-M is the possibility of automatic registration of daily fluctuations of at least ten parameters of the microclimate, with a time interval of 6 minutes. This applies, in particular, to small particles of suspended dust of PM1, PM2.5 and PM10 fractions and low volumetric concentrations of polluting gases CO2, NH3, H2S, CH4. The technical advantage of the measuring system is based on the fact that it is characterized by a 30 % lower mass compared to the Ecolab prototype. In addition, it has 9 times longer battery life, wireless communication, and the possibility of remote transmission of measurement results. Conclusions. For the operation of the AАEE-M measuring system, a methodology for assessing microclimate parameters using the method of continuous automatic registration has been developed. The economic advantage of AАEE-M is that it is 4.4 times cheaper compared to the prototype. Also, it is cheaper by 22.9 %, compared to the previous multi-block modification of the measuring system. Key words: measuring system, parametric, evaluation, microclimate, livestock premises, method of determination.

Determination of particulate matter fractions pm2.5, pm10 and co2 in urban schools in Imphal, India

Measurements were carried out to determine the PM2.5, PM10 and, CO2 levels in schools located in the urban areas of Imphal, Manipur. The particulate matters (PM2.5 and PM10) were monitored gravimetrically with standardised particulate samplers, while the CO2 in the air was measured by gas chromatography. Average PM2.5 and PM10 concentration in the classrooms was 41.0 ± 9.0 µg/m3 and 79.4 ± 20.2 µg/m3, respectively, and it was comparatively higher than the outdoor concentration of 34.8 ± 8.0 µg/m3 and 64.7 ± 18.9 µg/m3, respectively. The average concentration of CO2 in the indoor and outdoor air was 1250.6 ± 131.3 ∙ 103 µg/m3 and 885.7 ± 94.7 ∙103 µg/m3. The highest levels of PM2.5 (58.3 µg/m3), PM10 (112.5 µg/m3) and CO2 (1457.5 ∙ 103 µg/m3) were recorded indoors, in a school located at the heart of the city, whereas the lowest levels of PM2.5 (25.0 µg/m3), PM10 (45.8 µg/m3) and CO2 (1045.7 ∙ 103 µg/m3) were recorded in a school located away from the city centre. The levels of PM2.5 and PM10 in the air were found to exceed the permissible limits prescribed by the National Ambient Air Quality Standards in more than half of the sampling. There was a strong positive correlation between indoor and outdoor pollutant concentrations.

Significance of sources and size distribution on calibration of low-cost particle sensors: Evidence from a field sampling campaign

Low-cost sensors (LCS) are gathering the interest of researchers and monitoring agencies worldwide due to their compact size and economic feasibility. However, the data recorded by LCS is often of low quality owing to its calibration dependencies and biases. An intensive field sampling campaign was conducted at five sites inside the IIT Bombay campus to understand the fundamental issues associated with LCS. PA-II and OPC-N2 LCS were collocated with BAM-1020 and OPS- 3330 at the sampling locations for inter-comparison. LCS shows a good correlation with BAM-1020 at sites where the contributing sources produce more particles in the 1–2.5 μm size range than particles in below 1 μm (PM1) and 2.5–10 μm size range. The performance decreased with an increase in mass fractions of PM1 and PM10. The overall performance of both PA-II (R2 = 0.72) and OPC-N2 (R2 = 0.73) are comparable. Both PA-II and OPC-N2 have substandard performance with R2 in the range of 0.30–0.39 and 0.42–0.53 at the construction and main gate site respectively. Comparing the two calibration approaches used in this study indicates the importance of including size distribution parameters in the calibration of LCS. The calibration models were developed for each site and were compared with the general model developed for PA-II and OPC-N2. Results indicate that the site-specific models are in better agreement with the reference instrument than the general calibration model. The number concentration recorded by PA-II was poorly correlated with OPS-3330, especially for particles >1 μm and vice versa for OPC-N2. The particle count for PM > 2.5 μm recorded by PA-II is predominantly zero, which is inconsistent with the mass concentration data recorded by the sensor. The size distribution results indicate that LCS assumes a universal monotonically decreasing function of number concentration with respect to the particle diameter. It is one of the critical problems with LCS measurements as any error in the number measurement is increased 3-fold in the mass conversion. This study shows the need for site-specific robust calibration of LCS based on the particle size distribution and provides a direction in their development.

Heavy Metals and Metalloids in Soils, Road Dust, and Their PM10 Fractions in Sebastopol: Levels, Sources, and Pollution Risk

Heavy Metals and Metalloids in Soils, Road Dust, and Their PM10 Fractions in Sebastopol: Levels, Sources, and Pollution Risk

On the influence of VOCs on new particle growth in a Continental-Mediterranean region

A field campaign has been performed in the Madrid region to study the VOC influence in the growth of new particles in ambient air. A number of instruments have been deployed to characterize the main pollutant gases and particle properties and composition. The measurements were performed simultaneously at three sites (rural, urban background and urban traffic influenced) in the period 1–17 July 2019. The sites: Tres Cantos (rural), CIEMAT (urban background) and Leganés (urban traffic) were located within the Madrid airshed. Particle size distributions, mass concentrations at fractions PM10, PM2.5 and PM1, black carbon, VOCs species and gaseous pollutants (NOx and O3) were obtained in the sites. Some supplementary measurements were obtained in at least one of the sites: meteorological parameters, non-refractory submicron aerosol species and vertical profiles of aerosol optical properties. It has been observed that the new particle formation (NPF) events, nucleation and subsequent growth, happened at a regional scale, although differently among the sites. In the rural site, fewer events than expected were observed because of the high temperatures that affected the BVOC emissions. In the urban background site, the highest number of events was reached. In this station, it is common to receive air masses from the nearby forest and from the urban area, producing a mix of conditions with high BVOC and AVOC concentrations. In the urban traffic site, several NPF cases appeared, being a site dominated by AVOCs. Among the BVOCs measured in the three stations, the most common were α-Pinene and Limonene. Among the AVOCs measured, aromatics and linear hydrocarbon compounds for C10 and above were found. The linear group was found to be predominant during the NPF event days in the urban background site. This work provides new insights about the aerosol-forming precursors and growth of new particles in the Madrid region.

Interaction integral method for thermal fracture of nonhomogeneous magneto-electro-elastic materials

This paper focuses on the thermal fracture performance of magneto-electro-elastic (MEE) materials and proposes a new interaction integral (I-integral) method for extracting the key fracture parameters, including stress intensity factors (SIFs), electric displacement intensity factor (EDIF) and magnetic induction intensity factor (MIIF). After introducing the integrals along the interfaces with mismatched thermal properties, the I-integral is strictly proved to be independent of the integration domain size. This domain-independence is numerically validated for nonhomogeneous and discontinuous MEE materials (relative deviation <1%). Through the combination with the extended finite element method (XFEM), the developed I-integral method is employed to study thermal crack problems of MEE materials. The results show that the I-integral can achieve high numerical accuracy in determining the intensity factors. The thermal boundary condition of crack surface affects the intensity factors significantly. Finally, this paper focuses on the thermal fracture of laminated and fiber reinforced MEE composites. As for MEE composites (BaTiO3/CoFe2O4), the SIFs increase as the volume fraction of PM (CoFe2O4). Reducing the percentage of piezomagnetic phase can enhance the fracture resistance of MEE multiphase composites. At the identical volume fraction of components, the fracture resistance of fiber-reinforced MEE composites is generally better than that of laminated MEE composites and the PE-fiber composite exhibits greater fracture resistance than the PM-fiber composite.

Nonnegligible pathogenic exposure risk of coarse part of PM10 in non-open environments

In non-open environments, pathogenic microorganisms are more likely to invade the human respiratory tract due to their limited diffusion in the environment, which has received little attention. In this study, we explored the distribution characteristics of particulate matter (PM) in non-open environments, and included sewage treatment plants and farms, which are occupational exposure risks, and G-series high-speed trains and waiting rooms, which are crowded. The results showed orders of magnitude differences in PM and microbial concentrations and the DNA/PM values of adsorption in the different non-open spaces. The concentration of PM with a size in the 4.7–10.0 μm range was higher than those of PM in the 1.1–4.7 μm and 0.43–1.1 μm ranges in all three types of places, accounting for 74.64%, 46.59%, and 51.49%, respectively. The DNA/PM value for the 1.1–4.7 μm range was higher than those for PM in the other two ranges in all three types of places at 0.175, 3.78 × 10−3, and 9.98 ng/μg, respectively. Although the relative abundances of Class II potentially pathogenic bacteria with sizes ranging from 1.1 to 4.7 μm were higher in all three types of places, the total abundance and the relative abundance of identified pathogenic microorganisms with sizes ranging from 4.7 to 10.0 μm were higher in all three types of places. Here, in non-open spaces, the pathogen exposure risk associated with PM10, particularly the coarse fraction of PM10, deserves special attention. Infectious diseases caused by aerosol transmission of pathogens in non-open environments should receive more attention and require further investigation in the future.

Spatio-temporal statistical analysis of PM1 and PM2.5 concentrations and their key influencing factors at Guayaquil city, Ecuador

Guayaquil, Ecuador, is in a tropical area on the equatorial Pacific Ocean coast of South America. Since 2008 the city has been increasing its population, vehicle fleet and manufacturing industries. Within the city there are various industrial and urban land uses sharing the same space. With regard to air quality there is a lack of government information on it. Therefore, the research’s aim was to investigate the spatio-temporal characteristics of PM1 and PM2.5 concentrations and their main influencing factors. For this, both PM fractions were sampled and a bivariate analysis (cross-correlation and Pearson's correlation), multivariate linear and logistic regression analysis was applied. Hourly and daily PM1 and PM2.5 were the dependent variables, and meteorological variables, occurrence of events and characteristics of land use were the independent variables. We found 48% exceedances of the PM2.5-24 h World Health Organization 2021 threshold’s, which questions the city’s air quality. The cross-correlation function and Pearson’s correlation analysis indicate that hourly and daily temperature, relative humidity, and wind speed have a complex nonlinear relationship with PM concentrations. Multivariate linear and logistic regression models for PM1-24 h showed that rain and the flat orography of cement plant sector decrease concentrations; while unusual PM emission events (traffic jams and vegetation-fires) increase them. The same models for PM2.5-24 h show that the dry season and the industrial sector (strong activity) increase the concentration of PM2.5-24 h, and the cement plant decrease them. Public policies and interventions should aim to regulate land uses while continuously monitoring emission sources, both regular and unusual.

Factors influencing aerosol and precipitation ion chemistry in urban background of Moscow megacity

In-depth study of aerosol and precipitation ion chemistry was carried out in order to cover an existing data gap in the seasonal-dependent ionic data in Moscow urban background atmosphere. Literature about atmospheric pollution in this megacity is, indeed, still poor, despite its peculiar climatological characteristics that make it a very interesting site for atmospheric research. Particulate matter (PM) and precipitation were collected at Moscow urban background during spring of 2018, summer, and autumn of 2019. Aerosol inorganic ions are characterized for the whole period, carboxylic acids and sugars for summer. Inorganic ions constitute a major PM10 fraction of 27% in autumn, it drops down to 16.5% in summer. Dominance of secondary inorganic aerosol (SIA) over all the other inorganic ion species is determined. Na+ and Ca2+ shows the largest variability between seasons, with maximum in summer and spring, respectively. Excess of anions in autumn is indicated by ion balance while adding carbonates, spring and summer aerosol is found electroneutral. Chloride depletion phenomenon follows the snow melt and remobilization of salt applied to roads for deicing, demonstrating the biggest impact in summer. Degree of neutralization of ammonia as sulfate and nitrate is found by the correlation between the concentration of NH4+ and calculated from SO42− and NO3−. Inorganic fraction in PM10 is higher (16.5%) than total carboxylic acids (3.5%), and total sugars and anhydrosugars (0.8%). Concentration polar plots show ion variation jointly with wind speed and wind direction and the source origin. Highest SIA concentrations relate a cluster of the prevalent air mass transportation and indicate the source in the northwestern direction in spring and summer. K+ acts as a marker of fires in spring and summer as well as of the domestic biomass burning in the region around a megacity in autumn. Source apportionment of inorganic ion and BC by Varimax analysis reveals major sources namely SIA, soil resuspension, biomass burning, deicing salt, and fossil fuel combustion. In summer, organic ions, anhydrosugars, and sugars shows additional impact of photochemistry and biological activities. Rainfall is heavier in summer than in autumn, with pH of acid rain during spring and summer. The highest concentrations for almost all ions were observed in spring, except HCO3−. Precipitation composition is described with aerosol wet removal by seasonal variability of SIA scavenging factors, decreasing in summer and increasing in autumn and spring.

Intrinsic Characteristics and Biological Effects of Standard Reference Indoor Dust SRM® 2585 and Its Inhalable Subfractions PM10 and PM2.5

Standard Reference Material® (SRM®) 2585 can be considered as a model sample of settled indoor dust. At least 168 adsorbed chemicals were identified and quantified, generating a complex and potentially toxic mixture. Inhalable fractions PM10 and PM2.5 were isolated and compared to SRM® 2585 for their intrinsic properties and their respiratory toxicity using pertinent normal human bronchoepithelial (NHBE) cells. The intrinsic oxidative potential (OP) of SRM® 2585 and its subfractions was measured in acellular conditions, together with ROS generation and endotoxin content. For SRM® 2585 and PM10, cellular responses were evaluated on NHBE cells after 72 h exposure (1.1 to 110 µg/mL). The presence of endotoxins associated with an intrinsic prooxidant potential did not lead to the induction of an inflammatory response. Interestingly, cytokine production was decreased, strongly for IL-1β and to a lesser extent for IL-6. Only PM10 induced an acute toxicity. In parallel, mutagenicity was evaluated from organic extracts. Mutagenic profiles indicated the concomitant presence of nitro-PAHs in addition to the previously reported PAHs. This could be of concern for long-term health effects in a context of chronic exposure.

Discovering oxidative potential (OP) drivers of atmospheric PM10, PM2.5, and PM1 simultaneously in North-Eastern Spain

Ambient particulate matter (PM) is a major contributor to air pollution, leading to adverse health effects on the human population. It has been suggested that the oxidative potential (OP, as a tracer of oxidative stress) of PM is a possible determinant of its health impact. In this study, samples of PM10, PM2.5, and PM1 were collected roughly every four days from January 2018 until March 2019 at a Barcelona urban background site and Montseny rural background site in northeastern Spain. We determined the chemical composition of samples, allowing us to perform source apportionment using positive matrix factorization. The OP of PM was determined by measuring reactive oxygen species using dithiothreitol and ascorbic acid assays. Finally, to link the sources with the measured OP, both a Pearson's correlation and a multiple linear regression model were applied to the dataset. The results showed that in Barcelona, the OP of PM10 was much higher than those of PM2.5 and PM1, whereas in Montseny results for all PM sizes were in the same range, but significantly lower than in Barcelona. In Barcelona, several anthropogenic sources were the main drivers of OP in PM10 (Combustion + Road Dust + Heavy Oil + OC-rich) and PM2.5 (Road Dust + Combustion). In contrast, PM1 -associated OP was driven by Industry, with a much lower contribution to PM10 and PM2.5 mass. Meanwhile, Montseny exhibited no clear drivers for OP evolution, likely explaining the lack of a significant difference in OP between PM10, PM2.5, and PM1. Overall, this study indicates that size fraction matters for OP, as a function of the environment typology. In an urban context, OP is driven by the PM10 and PM1 size fractions, whereas only the PM1 fraction is involved in rural environments.

Seasonal changes and respiratory deposition flux of PM2.5 and PM10 bound metals in Dhaka, Bangladesh

Due to rapid urbanization and fast economic development, aerosol pollution is a serious environmental issue, especially in Bangladesh. Based on bioaccessibility and respiratory deposition doses (RDD), health risks of PM2.5 and PM10 bound 15 (fifteen) metals were investigated at fourteen urban sites (roadside, marketplace, industrial, and commercial areas). Sampling campaigns were conducted over four seasons (winter, summer, rainy, and autumn) from December 2020 to November 2021. A beta attenuation mass analyzer measured particulate matter concentrations in ambient air. The metals in PM fractions were analyzed by X-ray fluorescence spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). The airborne trace metals (Cd, As, Zn, Pb, Cr, Cu, Ni) with high enrichment factors indicate anthropogenic sources. The positive matrix factorization (PMF) categorized these elements as originating from automobile exhaust, industrial emissions, and solid waste/coal combustion, whereas the geologic elements came from earth crust/soil dust. During the winter, most of the air mass trajectories arrived from India across the land (82%) and Indo Gangetic Plain (IGP) region to the sampling sites, which may have aided in the transport of pollutants. The deposition flux of metals illustrated that compared to PM2.5, PM10 deposited a higher amount of metals in the upper airways (81.96%).In comparison, PM2.5 accumulates more elevated amounts of metals in alveolar regions (11.77%), due to the ability of fine particles to penetrate deeper into the lower pulmonary region. Among age groups, an adult inhales a higher amount of metals than a child, on average 0.103 mg and 0.08 mg of metals per day via PM2.5, respectively. Acute health impacts are caused by the deposited cancer-causing metals in alveolar tissue, which circulates through the bloodstream and affects several organs. Prolonged exposure to these carcinogenic metals poses significant health risks.