Explore the vast range of titles available.

Wintertime non-refractory submicron particulate matter (NR-PM 1 ) species were measured in Delhi with an Aerodyne Aerosol Chemical Speciation Monitor (ACSM) during February–March 2018. The average NR-PM 1 mass concentration throughout the study was 58.0 ± 42.6 µg m −3 , where the contribution of organic aerosol (OA) was 69% of the total NR-PM 1 . In Delhi, chloride (10%) was the main inorganic contributor, followed by ammonium (8%), sulfate (7%), and nitrate (6%), contrasting with the prevalence of sulfate in most urban environments. Source apportionment analysis of the OA identified five major factors, including three primary contributors: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), cooking-related OA (COA) and two secondary contributors: oxygenated primary OA (OPOA), and more-oxidized oxygenated OA (MO-OOA). A 19% rise in OPOA concentration was observed during high chloride episodes, suggesting the potential role of chloride in the atmospheric chemical transformation of OA. Traffic emissions significantly contribute to ambient OA, accounting for at least 41% of the total OA mass. Furthermore, the OA exhibited low oxidation levels regardless of its source. The f 44 : f 43 analysis revealed slower atmospheric oxidization of OA compared to other urban locations worldwide. Further investigations, including chamber experiments tailored to the Delhi atmosphere, are necessary to elucidate the atmospheric oxidants and the genesis of secondary OA alongside primary emissions.

Low-cost sensors based on the optical particle counter (OPC) are increasingly being used to collect particulate matter (PM) data at high space and time resolution. In spite of their huge explorative potential, practical guidelines and recommendations for their use are still limited. In this work, we outline a few best practices for the optimal use of PM low-cost sensors based on the results of an intensive field campaign performed in Bologna (44°30′ N, 11°21′ E; Italy) under different weather conditions. Briefly, the performances of a series of sensors were evaluated against a calibrated mainstream OPC with a heated inlet, using a robust approach based on a suite of statistical indexes capable of evaluating both correlations and biases in respect to the reference sensor. Our results show that the sensor performance is sensibly affected by both time resolution and weather with biases maximized at high time resolution and high relative humidity. Optimization of PM data obtained is therefore achievable by lowering time resolution and applying suitable correction factors for hygroscopic growth based on the inherent particle size distribution.

This study assesses temporal variability and source contributions of PM 1 (particles with aerodynamic diameter ≤ 1.0 µm) samples (n=51; November 2009-February 2010) from an urban location at Kanpur (26.30°N; 80.13°E; 142 m above mean sea-level) in the Indo-Gangetic Plain (IGP). A study period from November to February is preferred owing to massive loading of particulate matter in entire IGP. PM 1 varies from 18 to 348 (Avg±SD: 113±72) µg m −3 in this study. A total of 11 trace metals, five major elements and four water-soluble inorganic species (WSIS) have been measured. Mass fraction of total metals (∑metals=trace+major) centres at 18±14 %, of which nearly 15 % is contributed by major elements. Furthermore, ∑WSIS contributes about 26 % to PM 1 mass concentration. Abundance pattern among assessed WSIS in this study follows the order: ≈ > > Cl − . The K-to-PM 1 mass fraction (Avg: 2 %) in conjunction with air-mass back trajectories (AMBT) indicates that the prevailing north-westerly winds transport biomass burning derived pollutants from upwind IGP. A recent version of positive matrix factorisation (PMF 5.0) has been utilised to quantify the contribution of fine-mode aerosols from various sources. The contribution from each source is highly variable and shows a strong dependence on AMBT. Events with predominant contribution from biomass burning emission (>70 %) indicate origin of air-masses from source region upwind in IGP. One of the most interesting features of our study relates to the observation that secondary aerosols (contributing as high as ~60 % to PM 1 loading) are predominantly derived from stationary combustion sources ( / ratio: 0.30±0.23). Thus, our study highlights a high concentration of PM 1 loading and atmospheric fog prevalent during wintertime can have a severe impact on atmospheric chemistry in the air-shed of IGP.

The article evaluates air pollution by particulate matter (PM) in indoor and outdoor air in one of the Polish health resorts, where children and adults with respiratory diseases are treated. The highest indoor PM concentrations were recorded during the winter season. Therefore, the maximum average daily concentration values in indoor air for the PM 10 , PM 2.5 , and PM 1 fractions were 50, 42 and 23 µg/m 3 , respectively. In the case of outdoor air, the highest average daily concentrations of PM 2.5 reached a value of 40 µg/m 3 . The analyses and backward trajectories of episodes of high PM concentrations showed the impact of supra-regional sources and the influx of pollutants from North Africa on the variability of PM concentrations. The correlation between selected meteorological parameters and PM concentrations shows the relationship between PM concentrations and wind speed. For example, the correlation coefficients between PM 1 (I) and PM 1 (O) concentrations and wind speed were − 0.8 and − 0.7 respectively. These factors determined episodes of high PM concentrations during winter periods in the outdoor air, which were then transferred to the indoor air. Elevated concentrations in indoor air during summer were also influenced by chimney/gravity ventilation and the appearance of reverse chimney effect.

Tetraselmis sp. is a widespread marine green alga capable of both dissolved organic carbon (DOC) and bacterial ingestion, making it a potentially important contributor to carbon fluxes in microbial food webs. Mixotrophy can enhance survival under nutrient or light limitation, yet how DOC availability influences phagotrophic activity in marine green algae remains poorly understood. Here, we experimentally examined the interaction between osmotrophy and phagotrophy in Tetraselmis sp. under low-light and dark conditions across different dissolved organic carbon levels. Bacterial ingestion rates were quantified using live fluorescently labeled bacteria (FLB), enabling direct assessment of feeding responses. Carbon utilization assays showed that Tetraselmis sp. can assimilate a broad range of organic substrates, with glucose preferentially utilized under low-light conditions. Increasing glucose concentrations (0.1, 1, and 10 g L⁻¹) significantly suppressed bacterial ingestion, with ingestion rates declining from 2.34 to 0.17 bacteria cell⁻¹ h⁻¹ under low-light conditions and from 1.48 to 0.16 bacteria cell⁻¹ h⁻¹ in darkness. Together, these results demonstrate that DOC availability directly regulates phagocytosis, suggesting a trade-off between osmotrophic uptake and phagotrophic feeding. Our findings refine current frameworks of algal mixotrophy by highlighting the interaction among multiple trophic strategies and underscore the trophic plasticity of marine green algae in shaping carbon transfer within microbial food webs.

Despite extensive efforts in ​​reducing emissions related to road traffic, industrial, and household activities, the problem of exceeding standard levels of particulate matter (PM) still affects many areas in Europe. The monitoring data for the PM 1 , PM 2.5 , PM 10 , PM 10 − 18 , as well as the particle number, at urban background site in Zabrze (Southern Poland) over a 3-year period (Jun 2022 – May 2025) are presented within this paper. The main goal of the study was to analyse the concentrations of and contributions of various fractions of the total suspended particulates (TSP), together with the assessment of their time variability and their role in air pollution of an urban area. It was found that the annual average levels of both PM 2.5 and PM 10 remained high compared to the values recorded at many European measurement stations. Moreover, for a large part of the research period, daily PM 2.5 and PM 10 concentrations were above the revised daily standard (~ 30% and ~ 17%, respectively). During the study, a total of 109 exceedances of the level of 50 µg m − 3 were identified, of which 84 were classified as episode days (26 events in total). Regardless of the averaging period, PM 2.5 —especially PM 1 —constituted the dominant part of the TSP with a particularly high share in the winter months and in episodes (~ 80%). Therefore, the obtained results indicate the need to include PM 1 measurements in routine air quality monitoring and the necessity to establish exposure limits for this fraction, especially in areas where the PM 2.5 limit values ​​are frequently exceeded.

Population aging poses significant public health challenges in China. Emerging studies have linked air pollution to physiological aging, yet evidence regarding particulate matter with an aerodynamic diameter ≤ 1 μm (PM 1 ) remains sparse. This two-wave panel study included 5391 Chinese adults aged 45–80 to explore the effects of long-term exposure to PM 1 on biological aging acceleration. The Klemera−Doubal method (KDM) was employed to estimate biological aging acceleration (KDM-BAA) using 11 clinical biomarkers at both the 2011 baseline and the 2015 follow-up survey. Multivariate linear models with natural cubic splines were performed to estimate the association between PM 1 exposure and KDM-BAA changes from baseline to follow-up. Sensitivity analyses and stratified analyses were also performed. The exposure–response curve indicated that exposure to ambient PM 1 was significantly positively associated with changes in KDM-BAA, with the association becoming substantially stronger when PM 1 exposure exceeded the median exposure level of 32.5 μg/m 3 . Per 10 μg/m 3 increment in PM 1 exposure was associated with an acceleration of 1.55 (95% CI: 0.79, 2.31) years in KDM-BAA. Elderly adults over 60 years and smokers demonstrated greater susceptibility to the aging effects of ambient PM 1 exposure, whereas leisure engagement was observed to have a beneficial effect in mitigating the aging response of PM 1 exposure. Long-term exposure to ambient PM 1 may accelerate biological aging among middle-aged and older adults in China, especially in the elderly. These findings highlight the urgency for policies aimed at mitigating PM 1 pollution to promote healthy aging within an increasingly aging population.

The main objective of this research was the determination of the geochemical and mineralogical properties of particulate matter: TSP (total suspended particles) and, especially PM1 (particles with aerodynamic diameter not greater than 1 µm) suspended in the air of a selected urban area in southern Poland. Identification of the emission sources of metals and metalloids bound in TSP and PM1 as well as the assessment of potential risk of urban ambient air to human health using hazard indices was an additional aim of this investigation. The daily TSP and PM1 quartz fiber filters collected during heating season were subjected to mass magnetic susceptibility (χ) measurements, SEM (Scanning Electron Microscopy) observations and geochemical analyses. Obtained results revealed that the concentration of TSP and PM1 well correlated with their mass-specific magnetic susceptibility. The good relationship between the PM concentration and χ suggests that magnetic susceptibility measurements can be a good proxy of low-level atmospheric dust pollution. The rank order of potentially toxic elements (PTE) based on average concentration was Ba > Zn > Al > Fe > Pb > Mn > Ti > Cu > Cr > Ni >As > Cd > V > Tl, both for TSP and PM1. PM1/TSP ratios for PTE concentrations and χ were around or slightly above unity, which indicated that PM1 was the main carrier of PTE (with the exception of cadmium, copper and lead) and technogenic magnetic particles. The non-carcinogenic and carcinogenic risks were confirmed by very high values of human health indices.

The importance of air quality monitoring has been strongly demonstrated in numerous scientific studies. This study, carried out in an intense circular intersection, brings additional arguments that the monitoring of the fine particles like PM1 and PM2.5 that influence in more than 80% the concentration of PM10 particles must be measured at several points. Few were the cases [approx. 20%] in which the increase of PM10 concentrations is given by particles with diameters from 2.5 to 10 μm, most likely caused by the re-suspension of dust particles. Grimm Aerosol Technik Germany and SC INOESY SRL conducted a campaign for monitoring the air quality [PM1, PM2.5, PM10] in Iasi, Stone Bridge area, from 8 to 22 February 2018. The monitoring point was located close (150 m) to the APMIS-01 station of the National Environmental Protection Agency.

We investigated aerosol optical properties, mass concentration and chemical composition over a 1 year period (from March 2006 to February 2007) at an urban site in Southern Spain (Granada, 37.18°N, 3.58°W, 680 m above sea level). Light‐scattering and absorption measurements were performed using an integrating nephelometer and a MultiAngle Absorption Photometer (MAAP), respectively, with no aerosol size cut‐off and without any conditioning of the sampled air. PM10 and PM1 (ambient air levels of atmospheric particulate matter finer than 10 and 1 microns) were collected with two high volume samplers, and the chemical composition was investigated for all samples. Relative humidity (RH) within the nephelometer was below 50% and the weighting of the filters was also at RH of 50%. PM10 and PM1 mass concentrations showed a mean value of 44 ± 19 μg/m3 and 15 ± 7 μg/m3, respectively. The mineral matter was the major constituent of the PM10–1 fraction (contributing more than 58%) whereas organic matter and elemental carbon (OM+EC) contributed the most to the PM1 fraction (around 43%). The absorption coefficient at 550 nm showed a mean value of 24 ± 9 Mm−1 and the scattering coefficient at 550 nm presented a mean value of 61 ± 25 Mm−1, typical of urban areas. Both the scattering and the absorption coefficients exhibited the highest values during winter and the lowest during summer, due to the increase in the anthropogenic contribution and the lower development of the convective mixing layer during winter. A very low mean value of the single scattering albedo of 0.71 ± 0.07 at 550 nm was calculated, suggesting that urban aerosols in this site contain a large fraction of absorbing material. Mass scattering and absorption efficiencies of PM10 particles exhibited larger values during winter and lower during summer, showing a similar trend to PM1 and opposite to PM10–1. This seasonality is therefore influenced by the variations on PM composition. In addition, the mass scattering efficiency of the major aerosol constituents in PM10 were also calculated applying the multilinear regression (MLR) analysis. Among all of them, the most efficient in terms of scattering was sulfate ion (7 ± 1 m2g−1) while the least efficient was the mineral matter (0.2 ± 0.3 m2g−1). On the other hand, we found that the absorption process was mainly dominated by carbonaceous particles. Key Points Chemical composition and optical properties of urban aerosols have been analyzed Non marine sulfate, nitrate and OM presented high mass scattering efficiencies Carbonaceous particles dominated the absorption process