Aerosol Sources Research Articles

Long-term regional air pollution characteristics in and around Hyderabad, India: Effects of natural and anthropogenic sources

India is experiencing a rapid urban growth in recent decades modifying the regional air quality around urban agglomerations. Hyderabad, the capital city of Telangana state in India, has been experiencing significant urbanization of about 17 % growth in urban agglomeration over the past two decades. We investigated the long-term pollution characteristics along with the meteorology in and around Hyderabad (300 km × 300 km) using satellite-based remote sensing, and reanalysis data. Columnar aerosol loading was highest during the Spring while the positive trend was more during the Winter. The northeastern and southeastern parts of the study domain experienced higher aerosol loading. A significant increasing linear trend in AOD and PM2.5 is observed over the urban region as well as the northern and eastern parts. The NO2 and SO2 columnar concentrations showed considerable enhancement over the northeast sub-region where numerous thermal power plants are located, and over the urban centre. The SO2 concentration and SSA values were higher during the Autumn, while the NO2 values peaked along with lower SSA values during the Spring. The observed spatio-temporal features in air pollutants are further investigated using rainfall information, transport pathways, vegetation index, and fire events. Higher surface temperature and the polluted northeasterlies caused the comparative enhancement of NO2 concentration during Spring. The investigation on the NDVI and the fire events in different sub-regions points to the possibility of enhanced human settlement, and thereby the associated anthropogenic activities are notable over the West and South parts of Hyderabad. However, the presence of thermal power plants in the northeast and natural gas plants along the coast act as persistent regional sources for aerosols and pollutant gases irrespective of the wet removal.

Increased atmospheric PM2.5 events due to open waste burning in Qaanaaq, Greenland, summer of 2022

AbstractHigh levels of particulate matter (PM) are relevant to severe air pollution and can adversely impact human health. Maintaining healthy air quality for the residents of the Arctic region is essential to satisfy the no‐one‐left‐behind policy of the Sustainable Development Goals (SDGs) by the United Nations. In this study, we installed a PM2.5 measurement system in Qaanaaq, Greenland, and obtained the first continuous PM2.5 measurements from July 20, 2022 to August 13, 2022. We observed several increased PM2.5 events; relatively high PM2.5 levels persisted from August 8, 2022. On the same day, visible black smoke emitted from the Qaanaaq dump site originated from open waste burning. By confirming less transboundary air pollution contributions from remote aerosol source regions to Qaanaaq during the measurement period using NOAA's HYSPLIT backward trajectory analysis and NASA's MERRA‐2 aerosol re‐analysis, we confirmed that the increased PM2.5 was primarily due to local open waste burning with less contributions from transboundary air pollution. However, small contributions from biomass burning outside Greenland were plausible during the early measurement period. Additionally, NOAA's HYSPLIT dispersion calculations suggested possible aerosol depositions from local open waste burning to nearby sea areas, such as Baffin Bay. Although the hourly mean PM2.5 mass concentration was not alarmingly high during the measurement period, future studies should incorporate longer‐term continuous PM2.5 measurements along with other atmospheric chemical analyses to identify possible local air pollution sources in detail to ensure clean ambient air for the future in the Arctic. Our study provides quantitative evidence of the impact of open waste burning on air quality at a study site in Greenland, which could be crucial in developing air quality policies for this region in the Arctic.

Assessment of smoke plume height products derived from multisource satellite observations using lidar-derived height metrics for wildfires in the western US

Abstract. As wildfires intensify and fire seasons lengthen across the western US, the development of models that can predict smoke plume concentrations and track wildfire-induced air pollution exposures has become critical. Wildfire smoke plume height is a key indicator of the vertical placement of plume mass emitted from wildfire-related aerosol sources in climate and air quality models. With advancements in Earth observation (EO) satellites, spaceborne products for aerosol layer height or plume injection height have recently emerged with increased global-scale spatiotemporal resolution. However, to evaluate column radiative effects and refine satellite algorithms, vertical profiles of regionally representative aerosol properties from wildfires need to be measured directly. In this study, we conducted the first comprehensive evaluation of four passive satellite remote-sensing techniques specifically designed for retrieving plume height. We compared these satellite products with the airborne Wyoming Cloud Lidar (WCL) measurements during the 2018 Biomass Burning Flux Measurements of Trace Gases and Aerosols (BB-FLUX) field campaign in the western US. Two definitions, namely, “plume top” and “extinction-weighted mean plume height”, were used to derive the representative heights of wildfire smoke plumes, based on the WCL-derived vertical aerosol extinction coefficient profiles. Using these two definitions, we performed a comparative analysis of multisource satellite-derived plume height products for wildfire smoke. We provide a discussion related to which satellite product is most appropriate for determining plume height characteristics near a fire event or estimating downwind plume rise equivalent height, under multiple aerosol loadings. Our findings highlight the importance of understanding the sensitivity of different passive remote-sensing techniques on space-based wildfire smoke plume height observations, in order to resolve ambiguity surrounding the concept of “effective smoke plume height”. As additional aerosol-observing satellites are planned in the coming years, our results will inform future remote-sensing missions and EO satellite algorithm development. This bridges the gap between satellite observations and plume rise modeling to further investigate the vertical distribution of wildfire smoke aerosols.

Calcareous termite mounds in South Africa are ancient carbon reservoirs

Ecosystems that offer carbon sequestration by leaching bicarbonate to groundwater are valuable natural capital. One region that may offer this service is the west coast of South Africa. Over 20 % is covered by soil mounds (“heuweltjies”) up to 40 m diameter, 2 m high, inhabited by the southern harvester termite Microhodotermes viator and enriched in soil organic and inorganic carbon and soluble minerals. We aimed to generate radiogenic and stable isotope data for soils and groundwater in a region where these data are absent, to 1) verify the atmosphere-soil-groundwater link, and 2) resolve the timing and pattern of calcite dissolution and water infiltration in the landscape. Results show that soil and groundwater sulfate have the same marine aerosol source. Episodic calcite dissolution in mound centers, which increased during periods of global cooling, has been set against background input of marine aerosols since before the Last Glacial according to radiocarbon (14C) ages. Our data push back soil organic carbon 14C ages of inhabited termite mounds to 13-19 ka (kiloannum, thousand years before present), nest carbonate 14C ages to 33 ka, and mound soil carbonate 14C ages to 34 ka, making these the oldest active termite features ever dated. These ages are consistent with soil organic carbon and carbonate 14C ages of regional, non-mound, coastal petrocalcic horizons formed by accumulation of carbonate leached from their overlying aeolian dune fields. Harvesting activities of termites inject younger organic material around nests >1 m deep, leading to continuous renewal of important soil carbon reservoirs at depth. Termite bioturbation increases the system's ability to dissolve carbonate. The central, bioturbated part of the mounds have greater infiltration depths and greater calcite dissolution, whereas surrounding soils experienced more surface runoff. Calcareous termite mounds offer a mechanism to sequester CO2 through dissolution and leaching of soil carbonate-bicarbonate to groundwater.

Comparative analysis of CAMS aerosol optical depth data and AERONET observations in the Eastern Mediterranean over 19 years

Aerosol optical depth (AOD) is an essential metric for evaluating the atmospheric aerosol load and its impacts on climate, air quality, and public health. In this study, the AOD data from the Copernicus Atmosphere Monitoring Service (CAMS) were validated against ground-based measurements from the Aerosol Robotic Network (AERONET) throughout the Eastern Mediterranean, a region characterized by diverse aerosol types and sources. A comparative analysis was performed on 3-hourly CAMS AOD values at 550 nm against observations from 20 AERONET stations across Cyprus, Greece, Israel, Egypt, and Turkey from 2003 to 2021. The CAMS AOD data exhibited a good overall agreement with AERONET AOD data, demonstrated by a Pearson correlation coefficient of 0.77, a mean absolute error (MAE) of 0.08, and a root mean square error (RMSE) of 0.11. Nonetheless, spatial and temporal variations were observed in the CAMS AOD data performance, with site-specific correlation coefficients ranging from 0.57 to 0.85, the lowest correlations occurring in Egypt and the highest in Greece. An underestimation of CAMS AOD was noted at inland sites with high AOD levels, while a better agreement was observed at coastal sites with lower AOD levels. The diurnal variation analysis indicated improved CAMS reanalysis performance during the afternoon and evening hours. Seasonally, CAMS reanalysis showed better agreement with AERONET AODs in spring and autumn, with lower correlation coefficients noted in summer and winter. This study marks the first comprehensive validation of CAMS AOD performance in the Eastern Mediterranean, offering significant enhancements for regional air quality and climate modeling, and underscores the essential role of consistent validation in refining aerosol estimations within this complex and dynamic geographic setting.

Characteristics and Source Analysis of Carbonaceous Aerosols in PM2.5 in Huaxi District, Guiyang

Carbonaceous aerosol, as an important component of atmospheric aerosol, has a significant impact on atmospheric environmental quality, human health, and global climate change. To investigate the characteristics and sources of carbonaceous aerosol in atmospheric fine particulate matter (PM2.5) in Huaxi District of Guiyang, an in-situ observational study was conducted during different seasons in 2020, and the carbonaceous components of PM2.5 were measured using a thermal-optical carbon analyzer (DRI Model 2015). The results of the study showed that the average concentrations of PM2.5, total carbonaceous aerosol (TCA), organic carbon (OC), secondary organic carbon (SOC), and elemental carbon (EC) concentrations during the observation period were (39.7±22.3), (14.1±7.2), (7.6±3.9), (4.4±2.6), and (2.0±1.0) μg·m-3, respectively, and the mean value of OC/EC was (3.9±0.8). ρ(PM2.5), ρ(TCA), ρ(OC), ρ(SOC), and ρ(EC) showed a seasonal variation pattern with the highest in winter [(52.6±28.6), (17.0±9.6), (9.1±5.2), (6.1±3.9), and (2.4±1.2) μg·m-3, respectively] and the lowest in summer [(25.1±7.1), (11.6±3.6), (6.3±1.9), (3.7±1.2), and (1.6±0.6) μg·m-3, respectively]. The seasonal variation in OC/EC showed summer (4.2±0.8) > winter (3.8±0.9) > autumn (3.8±0.5) > spring (3.7±0.9), indicating the presence of SOC generation in all seasons in Huaxi District. SOC showed a significant correlation with OC (R2 =0.9), and the SOC concentration tended to increase with the increase in atmospheric oxidation. OC showed a good correlation with EC in all seasons, with the highest in autumn (R2 =0.9) and lower correlations in the other three seasons (R2 ranged from 0.74 to 0.75), indicating a common source. According to OC/EC ratio range, it was preliminarily determined that carbonaceous aerosol came from vehicle exhaust emissions, coal burning emissions, and biomass combustion emissions. In order to further quantify the contribution of major emission sources to carbonaceous aerosol, the results of this study using PMF to analyze the sources of carbonaceous aerosol showed that the main sources of carbonaceous aerosol in Huaxi District of Guiyang were coal combustion sources (29.3%), motor vehicle emission sources (21.5%), and biomass combustion sources (49.2%).

Pollution Characteristics, Source Apportionment, and Meteorological Response of Water-soluble Ions in PM2.5 in Xinxiang, North China

Pollution variation, source characteristics, and meteorological effects of water-soluble inorganic ions (WSIIs) in PM2.5 were analyzed in Xinxiang city, Henan Province. PM2.5 samples and their chemical components were monitored online by using URG-9000 in four seasons:winter (January, 2022), spring (April, 2022), summer (July, 2022), and fall (October, 2022). The results showed that the TWSIIs had the same seasonal fluctuations as PM2.5. The average seasonal concentrations of WSIIs ranged from 19.62-72.15 μg·m-3, accounting for more than 60% of PM2.5, demonstrating that WSIIs were the major components of PM2.5. The annual concentration value of NO3-/SO42- was 2.11, which showed an increasing trend, suggesting predominantly mobile sources for secondary inorganic aerosols (SNA). Further, the molar concentration value [NH4+]/[NO3-] was 1.95, demonstrating that agriculture emissions were the dominant contributors to atmospheric nitrogen. Furthermore, the backward trajectory analysis showed that the concentrations of Ca2+ and Mg2+ were higher when the northeasterly wind prevailed and the wind speed was high. High values of SOR and NOR were correlated with low temperatures and high relative humidity (T < 8℃, RH > 60%), demonstrating that more gaseous precursors were converted into sulfate and nitrate. At high temperatures (T > 24℃), there was no apparent high NOR value like that for SOR, mainly due to the decomposition of NH4NO3 at high temperatures. Finally, backward trajectories associated with the PMF-resolved results were used to explore the regional transport characteristics. The results illustrated that dust sources in the study areas were mainly influenced by air trajectories originating from the northwest regions, whereas secondary sulfate, secondary nitrate, and biomass sources contributed more to WSIIs when wind speed and altitude air masses were low in the area surrounding the observation site.

Pollution Characteristics and Source Apportionment of Black Carbon Aerosols during Spring in Beijing.

Black carbon (BC) aerosols are important for absorbing aerosols, affecting global climate change and regional air quality, and potentially harming human health. From March to May 2023, we investigated black carbon aerosol levels and air pollution in Beijing. Employing methods such as linear regression, Potential Source Contribution Function (PSCF) and Concentration-Weighted Trajectory (CWT), we analyzed the characteristics and sources of black carbon aerosols in the region. Results indicate that the light absorption coefficients of BC and BrC decrease with increasing wavelength, with BrC accounting for less than 40% at 370 nm. Daily variations in BC and PM2.5 concentrations exhibit similar trends, peaking in March, and BC displays a distinct bimodal hourly concentration structure during this period. Aethalometer model results suggest that liquid fuel combustion contributes significantly to black carbon (1.08 ± 0.71 μg·m-3), surpassing the contribution from solid fuel combustion (0.31 ± 0.2 μg·m-3). Furthermore, the significant positive correlation between BC and CO suggests that BC emissions in Beijing predominantly result from liquid fuel combustion. Potential source area analysis indicates that air masses of spring in Beijing mainly originate from the northwest (40.93%), while potential source areas for BC are predominantly distributed in the Beijing-Tianjin-Hebei region, as well as parts of the Shandong, Shanxi and Henan provinces. Moreover, this study reveals that dust processes during spring in Beijing have a limited impact on black carbon concentrations. This study's findings support controlling pollution in Beijing and improving regional air quality.

On the potential use of highly oxygenated organic molecules (HOMs) as indicators for ozone formation sensitivity

Abstract. Ozone (O3), an important and ubiquitous trace gas, protects lives from harmful solar ultraviolet (UV) radiation in the stratosphere but is toxic to living organisms in the troposphere. Additionally, tropospheric O3 is a key oxidant and a source of other oxidants (e.g., OH and NO3 radicals) for various volatile organic compounds (VOCs). Recently, highly oxygenated organic molecules (HOMs) were identified as a new compound group formed from the oxidation of many VOCs, making up a significant source of secondary organic aerosol (SOA). The pathways forming HOMs from VOCs involve autoxidation of peroxy radicals (RO2), formed ubiquitously in many VOC oxidation reactions. The main sink for RO2 is bimolecular reactions with other radicals, such as HO2, NO, or other RO2, and this largely determines the structure of the end products. Organic nitrates form solely from RO2 + NO reactions, while accretion products (“dimers”) form solely from RO2 + RO2 reactions. The RO2 + NO reaction also converts NO into NO2, making it a net source for O3 through NO2 photolysis. There is a highly nonlinear relationship between O3, NOx, and VOCs. Understanding the O3 formation sensitivity to changes in VOCs and NOx is crucial for making optimal mitigation policies to control O3 concentrations. However, determining the specific O3 formation regimes (either VOC-limited or NOx-limited) remains challenging in diverse environmental conditions. In this work we assessed whether HOM measurements can function as a real-time indicator for the O3 formation sensitivity based on the hypothesis that HOM compositions can describe the relative importance of NO as a terminator for RO2. Given the fast formation and short lifetimes of low-volatility HOMs (timescale of minutes), they describe the instantaneous chemical regime of the atmosphere. In this work, we conducted a series of monoterpene oxidation experiments in our chamber while varying the concentrations of NOx and VOCs under different NO2 photolysis rates. We also measured the relative concentrations of HOMs of different types (dimers, nitrate-containing monomers, and non-nitrate monomers) and used ratios between these to estimate the O3 formation sensitivity. We find that for this simple system, the O3 sensitivity could be described very well based on the HOM measurements. Future work will focus on determining to what extent this approach can be applied in more complex atmospheric environments. Ambient measurements of HOMs have become increasingly common during the last decade, and therefore we expect that there are already a large number of groups with available data for testing this approach.

Tropical tropospheric aerosol sources and chemical composition observed at high altitude in the Bolivian Andes

Abstract. The chemical composition of PM10 and non-overlapping PM2.5 was studied at the summit of Mt. Chacaltaya (5380 m a.s.l., lat. −16.346950°, long. −68.128250°) providing a unique long-term record spanning from December 2011 to March 2020. The chemical composition of aerosol at the Chacaltaya Global Atmosphere Watch (GAW) site is representative of the regional background, seasonally affected by biomass burning practices and by nearby anthropogenic emissions from the metropolitan area of La Paz–El Alto. Concentration levels are clearly influenced by seasons with minima occurring during the wet season (December to March) and maxima occurring during the dry and transition seasons (April to November). Ions, total carbon (EC + OC), and saccharide interquartile ranges for concentrations are 558–1785, 384–1120, and 4.3–25.5 ng m−3 for bulk PM10 and 917–2308, 519–1175, and 3.9–24.1 ng m−3 for PM2.5, respectively, with most of the aerosol seemingly present in the PM2.5 fraction. Such concentrations are overall lower compared to other high-altitude stations around the globe but higher than Amazonian remote sites (except for OC). For PM10, there is dominance of insoluble mineral matter (33 %–56 % of the mass), organic matter (7 %–34 %), and secondary inorganic aerosol (15 %–26 %). Chemical composition profiles were identified for different origins: EC, NO3-, NH4+, glucose, and C2O42- for the nearby urban and rural areas; OC, EC, NO3-, K+, acetate, formate, levoglucosan, and some F− and Br− for biomass burning; MeSO3-, Na+, Mg2+, K+, and Ca2+ for aged marine emissions from the Pacific Ocean; arabitol, mannitol, and glucose for biogenic emissions; Na+, Ca2+, Mg2+, and K+ for soil dust; and SO42-, F−, and some Cl− for volcanism. Regional biomass burning practices influence the soluble fraction of the aerosol between June and November. The organic fraction is present all year round and has both anthropogenic (biomass burning and other combustion sources) and natural (primary and secondary biogenic emissions) origins, with the OC/EC mass ratio being practically constant all year round (10.5 ± 5.7, IQR 8.1–13.3). Peruvian volcanism has dominated the SO42- concentration since 2014, though it presents strong temporal variability due to the intermittence of the sources and seasonal changes in the transport patterns. These measurements represent some of the first long-term observations of aerosol chemical composition at a continental high-altitude site in the tropical Southern Hemisphere.

20th Century Changes of DOC and Its 14C Signature Archived in Caucasus Ice‐Core: Implications for Past Sources of Organic Carbon Aerosol in South‐Eastern Europe

AbstractTo reconstruct the history of organic carbon (OC) aerosol over south‐eastern Europe, dissolved organic carbon (DOC) and its 14C signature (DO14C) were investigated along an ice core drilled at the Mount Elbrus (ELB) in Caucasus. In summer, compared to pre‐1945 levels, the DOC concentrations increased by 45% after 1960, the mean DO14C depletion in recent ELB ice relative to atmospheric 14CO2 of 32% being attributed to fossil‐fuel sources. DO14C content of ice deposited during the bomb‐peak era (1955–1980) closely followed atmospheric 14CO2 changes caused by atmospheric nuclear tests, suggesting the living biosphere as the main biogenic source of DOC in summer in this region. ELB data contrast with those previously obtained in summer Alpine (western Europe) ice in which a post‐1950 doubling of DOC was observed and attributed to enhanced emissions of organic compounds from vegetation in France. This regional difference is discussed with respect to changes of biogenic organic compound emissions in response to past change of use‐land and global warming. ELB data document, for the first time, changes of DOC and DO14C in winter mountain ice showing an increase by 44% of DOC levels associated with a 14C signature being 47% lower than that of atmospheric 14CO2 in ELB ice deposited after 1960. The 14C winter ELB ice record followed atmospheric 14CO2 changes with a delay of ∼3 years, suggesting that remaining emissions from the living biosphere, together with a small contribution from wood burning, are the main biogenic sources of DOC in winter in this region.

Chemical characterization of atmospheric aerosols at a high-altitude mountain site: a study of source apportionment

Abstract. The study of aerosols in high mountain regions is essential because particulate matter can play a role in altering the energy balance of high mountain regions, and aerosols can accelerate glacier melting in high mountain areas by darkening the ice surface, reducing its reflectivity (albedo). Studying aerosols in high mountain areas provides insights into long-range transport of pollutants, atmospheric dynamics, and climate change impacts. These regions can serve as valuable observatories for studying atmospheric processes. The main aim of this paper is to define the main sources of aerosols over an entire year of sampling at the Col Margherita Atmospheric Observatory (MRG; 46°22′0.059′′ N, 11°47′30.911′′ E; 2543 m a.s.l.), a high-altitude background site in the eastern Italian Alps. Here, we discuss the potential origins of more than 100 chemical markers (major ions, water-soluble organic compounds, trace elements, and rare earth elements) using different approaches. Some diagnostic ratios were applied, but source apportionment using positive matrix factorization (PMF) was used to define the main inputs of PM10 collected at this high-altitude site, resulting in the identification of four factors: (1) Saharan dust events, (2) long-range marine/anthropogenic influence, (3) biogenic sources, and (4) biomass-burning and anthropogenic emissions. It can be inferred that, despite the distant location of the Col Margherita site, both regional pollution and long-range anthropogenic pollution have discernible effects on this area.

Light absorption properties and source contributions of black and brown carbon in Guangxi, southern China

Black carbon (BC) and brown carbon aerosols (BrC) are primary light-absorbing carbonaceous aerosols that significantly influence the global and regional radiation balance, as well as air quality. Guangxi Zhuang Autonomous Region, as a primarily agricultural province of China and neighbouring Southeast Asia, is subjected to both local emissions and pollution transport from Southeast Asian biomass burning. To investigate the light absorption properties and source contributions of BC and BrC in this region, observations from a 7-wavelength Aethalometer are employed to estimate the light absorption properties of BC and BrC over the period from March to December 2020 in Nanning, China. This study focuses on analysing the absorption contributions of BC and BrC to the total absorption of carbonaceous aerosols, identifying their emission sources, and exploring the impact of long-range transport of biomass burning (BB) from Southeast Asia on BC and BrC based on backward trajectory and weighted concentration-weighted trajectories (WCWT) model. Our results show that the absorption Ångström exponent (AAE) of light-absorbing carbonaceous aerosols varies from 0.54 to 2.08, reflecting the presence of different absorbing aerosol sources with specific optical properties. The average absorption coefficients of BC and BrC at 370 nm, denoted as babs,BC(370) and babs,BrC(370), are 42.25 Mm−1 and 9.63 Mm−1, respectively, with the highest value observed in winter. The average absorption of BrC contributes 19% to the total absorption from light-absorbing carbonaceous aerosols, and this contribution decreases for high babs,BrC(370) values, with the highest value in summer at 20%. For the BC source apportionment using a site-specific AAE, fossil fuel combustion (FF) contributes 57%, with its highest proportion in summer (62%). Meanwhile, biomass burning (BB) accounts for 43%, with the greatest contribution in winter (58%). These results highlight the considerable role of BB in Guangxi. In terms of the BrC sources, secondary BrC (BrCsec) is responsible for 32% of the total light absorption of BrC at 370 nm, and is particularly characterized by a much higher level of 35% at night, meaning the dominant role of BrCsec in Nanning. The relative contribution of babs,BrC,sec(370) increases with a higher contribution of babs,BrC(370) to aerosol absorption. Compared with the BrCsec, primary BrC values are higher in spring and winter, due to the increased emissions from biomass burning. Based on the analysis of backward trajectory and WCWT, the increase in BC and BrC during March and April is mainly influenced by the long-range transport of BB from Southeast Asian countries, e.g., Laos and Thailand. Overall, the contributions of BB and FF emissions to BC are comparable in Guangxi, while BrC mainly formed from primary sources is significantly impacted by both local emissions and the long-range transport of BB. Studying the optical characteristics and emission sources in this region can promote the understanding of the radiative effect of light-absorbing carbonaceous aerosols under the joint contributions from biomass burning and industrial emissions.

Chemical characterization and sources of background aerosols in the eastern Mediterranean

Measurements of the composition of the gas and particulate phases were conducted from May 9 to June 4 of 2016 at the Finokalia (Greece) remote coastal site in the eastern Mediterranean, continuing the effort to track long term changes of the atmospheric chemical composition in the area. Finokalia is influenced by air masses arriving in the site from regional sources in Europe, Africa, and other locations. In this study, a series of instruments and analysis techniques were used for the first time at the Finokalia site to characterize the composition of the organic aerosol (OA). The PM1 was composed of ammonium sulfate/bisulfate (60%), followed by organics (35%) and black carbon (BC) (4%). The OA was highly oxidized with an average oxygen-to-carbon (O:C) ratio of 0.81. Source apportionment of high-resolution organic aerosol mass spectra via positive matrix factorization (PMF) identified four factors: less oxidized oxygenated organic aerosol (LO-OOA), more oxidized oxygenated organic aerosol (MO-OOA), marine-related oxygenated organic aerosol (marine-OOA) and hydrocarbon-like organic aerosol (HOA). The LO-OOA (O:C = 0.92) was the dominant factor for most of the campaign (51% of the PM1 OA), while the MO-OOA (O:C = 1.1) was responsible for 11% of the OA. The marine-OOA factor was also highly oxidized (O:C = 1.03), contributing on average 24% to the total OA and was found to be well correlated with sulfate (R2 = 0.83). The anthropogenic HOA factor (O:C = 0.36) was related to activities in the island of Crete. Its mass spectrum was quite similar (R2 = 0.86–0.95) to those of other HOA factors in the literature and its average concentration was 0.2 μg m−3 (14% of OA). High molecular weight compounds were found, suggesting the presence of oligomers in agreement with the presence of a highly oxidized quenching agent. Aromatic VOCs, like benzene, toluene, and xylenes were on average 0.17, 0.66 and 0.36 ppb, respectively with toluene concentrations indicating the presence of a local source despite the remote nature of the site. New particle formation (NPF) was observed during 26% of the days. The air masses during NPF events passed over the island of Crete and the Balkans and were characterized by a low condensation sink (5.9 ± 2.2 10−3 s−1). Nucleation mode particle concentrations during NPF days had an additional evening peak between 17:00 and 22:00, which was accompanied by an HOA peak implying the influence of a source of sub-25 nm particles in the extended area. These findings show that even a relatively remote site like Finokalia is occasionally affected by sources located tens of kilometers away, something that should be taken into account in the interpretation of past and future measurements in this location.

Innovative systems for the detection of air particles in the quarries of the Western Rif, Morocco

&lt;p&gt;In a world where climate change looms large the spotlight often shines on greenhouse gases, but the shadow of man-made aerosols should not be underestimated. These tiny particles play a pivotal role in disrupting Earth's radiative equilibrium, yet many mysteries surround their influence on various physical aspects of our planet. The root of these mysteries lies in the limited data we have on aerosol sources, formation processes, conversion dynamics, and collection methods. Aerosols, composed of particulate matter (PM), sulfates, and nitrates, hold significant sway across the hemisphere. Accurate measurement demands the refinement of in-situ, satellite, and ground-based techniques. As aerosols interact intricately with the environment, their full impact remains an enigma. Enter a groundbreaking study in Morocco that dared to compare an internet of thing (IoT) system with satellite-based atmospheric models, with a focus on fine particles below 10 and 2.5 micrometers in diameter. The initial results, particularly in regions abundant with extraction pits, shed light on the IoT system's potential to decode aerosols' role in the grand narrative of climate change. These findings inspire hope as we confront the formidable global challenge of climate change.&lt;/p&gt;

Atmospheric aerosol chemistry and source apportionment of PM10 using stable carbon isotopes and PMF modelling during fireworks over Hyderabad, southern India

This study examined the influence of fireworks on atmospheric aerosols over the Southern Indian city of Hyderabad during festival of Diwali using mass closure, stable carbon isotopes and the EPA-PMF model. Identification of chemical species in day and night time aerosol samples for 2019 and 2020 Diwali weeks showed increased concentrations of NH4+, NO3−, SO42−, K+, organic carbon (OC), Ba, Pb and Li, which were considered as tracers for fireworks. PM10 source apportionment was done using inorganic (trace elements, major ions) and carbonaceous (organic and elemental carbon; OC & EC) constituents, along with stable isotopic compositions of TC and EC. K+/Na+ ∼1 and K+nss/OC > 0.5 indicated contribution from fireworks. High NO3−, NH4+, Na+, Cl− and SO42− suggested the presence of deliquescent salts NaCl, NH4NO3 and (NH4)2SO4. TAE/TCE >1 suggested H+ exclusion, indicating possible presence of H2SO4 and NH4HSO4 in the aerosols. Ba, Pb, Sb, Sr and Fe increased by 305 (87), 12 (11), 12 (3), 3 (2) and 3 (4) times on Diwali nights, compared to pre-Diwali of 2019 (2020), and are considered as metallic tracers of fireworks. δ13CTC and δ13CEC in aerosols closely resembled that of diesel and C3 plant burning emissions, with meagre contribution from firecrackers during Diwali period. The δ13CEC was relatively depleted than δ13CTC and δ13COC. For both years, δ13COC-EC (δ13COC - δ13CEC) were positive, suggesting photochemical aging of aerosols during long-range transport, while for pre-Diwali 2019 and post-Diwali 2020, δ13COC-EC were negative with high OC/EC ratio, implying secondary organic aerosols formation. High toluene during Diwali week contributed to fresh SOA formation, which reacted with precursor 12C, leading to 13C depletions. Eight-factored EPA-PMF source apportionment indicated highest contribution from residue/waste burning, followed by marine/dust soil and fireworks, while least was contributed from solid fuel/coal combustion.

A new software toolkit for optical apportionment of carbonaceous aerosol

Abstract. Instruments measuring aerosol light absorption, such as the Aethalometer and the Multi-Wavelength Absorbance Analyzer (MWAA), have been extensively used to characterize optical absorption of atmospheric particulate matter. Data retrieved with such instruments can be analysed with mathematical models to apportion different aerosol sources (Aethalometer model) and components (MWAA model). In this work we present an upgrade to the MWAA optical apportionment model. In addition to the apportionment of the absorption coefficient babs in its components (black carbon and brown carbon) and sources (fossil fuels and wood burning), the extended model allows for the retrieval of the absorption Ångström exponent of each component and source, thereby avoiding initial assumptions regarding these parameters. We also present a new open-source software toolkit, the MWAA model toolkit (MWAA_MT), written in both Python and R, that performs the entire apportionment procedure.

Composition and sources of carbonaceous aerosol in the European Arctic at Zeppelin Observatory, Svalbard (2017 to 2020)

Abstract. We analyzed long-term measurements of organic carbon, elemental carbon, and source-specific organic tracers from 2017 to 2020 to constrain carbonaceous aerosol sources in the rapidly changing Arctic. Additionally, we used absorption photometer (Aethalometer) measurements to constrain equivalent black carbon (eBC) from biomass burning and fossil fuel combustion, using positive matrix factorization (PMF). Our analysis shows that organic tracers are essential for understanding Arctic carbonaceous aerosol sources. Throughout 2017 to 2020, levoglucosan exhibited bimodal seasonality, reflecting emissions from residential wood combustion (RWC) in the heating season (November to May) and from wildfires (WFs) in the non-heating season (June to October), demonstrating a pronounced interannual variability in the influence of WF. Biogenic secondary organic aerosol (BSOA) species (2-methyltetrols) from isoprene oxidation was only present in the non-heating season, peaking in July to August. Warm air masses from Siberia led to a substantial increase in 2-methyltetrols in 2019 and 2020 compared to 2017 to 2018. This highlights the need to investigate the contribution of local sources vs. long-range atmospheric transport (LRT), considering the temperature sensitivity of biogenic volatile organic compound emissions from Arctic vegetation. Tracers of primary biological aerosol particles (PBAPs), including various sugars and sugar alcohols, showed elevated levels in the non-heating season, although with different seasonal trends, whereas cellulose had no apparent seasonality. Most PBAP tracers and 2-methyltetrols peaked during influence of WF emissions, highlighting the importance of measuring a range of source-specific tracers to understand sources and dynamics of carbonaceous aerosol. The seasonality of carbonaceous aerosol was strongly influenced by LRT episodes, as background levels are extremely low. In the non-heating season, the organic aerosol peak was as influenced by LRT, as was elemental carbon during the Arctic haze period. Source apportionment of carbonaceous aerosol by Latin hypercube sampling showed mixed contributions from RWC (46 %), fossil fuel (FF) sources (27 %), and BSOA (25 %) in the heating season. In contrast, the non-heating season was dominated by BSOA (56 %), with lower contributions from WF (26 %) and FF sources (15 %). Source apportionment of eBC by PMF showed that FF combustion dominated eBC (70±2.7 %), whereas RWC (22±2.7 %) was more abundant than WF (8.0±2.9 %). Modeled BC concentrations from FLEXPART (FLEXible PARTicle dispersion model) attributed an almost equal share to FF sources (51±3.1 %) and to biomass burning. Both FLEXPART and the PMF analysis concluded that RWC is a more important source of (e)BC than WF. However, with a modeled RWC contribution of 30±4.1 % and WF of 19±2.8 %, FLEXPART suggests relatively higher contributions to eBC from these sources. Notably, the BB fraction of EC was twice as high as that of eBC, reflecting methodological differences between source apportionment by LHS and PMF. However, important conclusions drawn are unaffected, as both methods indicate the presence of RWC- and WF-sourced BC at Zeppelin, with a higher relative BB contribution during the non-heating season. In summary, organic aerosol (281±106 ng m−3) constitutes a significant fraction of Arctic PM10, although surpassed by sea salt aerosol (682±46.9 ng m−3), mineral dust (613±368 ng m−3), and typically non-sea-salt sulfate SO42- (314±62.6 ng m−3), originating mainly from anthropogenic sources in winter and from natural sources in summer.

A Review on Anthropogenic Biomass Burning: Emission of Aerosol Pollutants, Impact on Climate Change, Human Health and its Mitigation Strategies

Biomass burning is a complex process, encircling chemical and physical responses covering, transmission of mass and warmth. A large number of investigations were accumulated on the significant emissions from various kinds of anthropogenic biomass burning in the recent decade. In India, an increasing trend of biomass burning is an important cause to release a large volume of reactive gases with other impurities and intensify the level of invisible particles into the troposphere, which affects humans health and leads to the probable alteration of the weather and global climate. The present review looks at the interpretations for a diverse investigation of distinct body and monitoring interventions, pertinent to our country, relating to the significance of particulate matter emissions, sources of aerosols and their health implications. This study also discusses numerous persuaded investigations, conducted on the impact of aerosol, attributed to climate change and also points out precise matters such as spatio-temporal variability of fire occurrences detected in India. Furthermore, the present study reveals that substantial quantities of data, along with a variety of enhanced simulation models and investigational validations, are essential for the development of efficient mitigation strategies with the objective of protecting the environment of the Indian Peninsula.

Optical properties and simple forcing efficiency of the organic aerosols and black carbon emitted by residential wood burning in rural central Europe

Abstract. Recent years have seen an increase in the use of wood for energy production of over 30 %, and this trend is expected to continue due to the current energy crisis and geopolitical instability. At present, residential wood burning (RWB) is one of the most important sources of organic aerosols (OAs) and black carbon (BC), posing a significant risk to air quality and health. Simultaneously, as a substantial aerosol source, RWB also holds relevance in the context of aerosol radiative effects and climate. While BC is recognized for its large light absorption cross-section, the role of OAs in light absorption is still under evaluation due to their heterogeneous composition and source-dependent optical properties. Existing studies that characterize wood-burning aerosol emissions in Europe primarily concentrate on urban and background sites and focus on BC properties. Despite the significant RWB emissions in rural areas, these locations have received comparatively less attention. The present scenario underscores the imperative for an improved understanding of RWB pollution, aerosol optical properties, and their subsequent connection to climate impacts, particularly in rural areas. We have characterized atmospheric aerosol particles from a central European rural site during wintertime in the village of Retje in Loški Potok, Slovenia, from 1 December 2017 to 7 March 2018. The village experienced extremely high aerosol concentrations produced by RWB and near-ground temperature inversion. The isolated location of the site and the substantial local emissions made it an ideal laboratory-like place for characterizing RWB aerosols with low influence from non-RWB sources under ambient conditions. The mean mass concentrations of OA and BC were 35 µg m−3 (max⁡=270 µg m−3) and 3.1 µg m−3 (max⁡=24 µg m−3), respectively. The mean total particle number concentration (10–600 nm) was 9.9×103 particles cm−3 (max⁡=59×103 particles cm−3). The mean total light absorption coefficients at 370 and 880 nm measured by an AE33 Aethalometer were 120 and 22 Mm−1 and had maximum values of 1100 and 180 Mm−1, respectively. The aerosol concentrations and absorption coefficients measured during the campaign in Loški Potok were significantly larger than reported values for several urban areas in the region with larger populations and a larger extent of aerosol sources. Here, considerable contributions from brown carbon (BrC) to the total light absorption were identified, reaching up to 60 % and 48 % in the near-UV (370 nm) and blue (470 nm) wavelengths. These contributions are up to 3 times higher than values reported for other sites impacted by wood-burning emissions. The calculated mass absorption cross-section and the absorption Ångström exponent for RWB OA were MACOA,370nm=2.4 m2 g−1, and AAEBrC,370-590nm=3.9, respectively. Simple-forcing-efficiency (SFE) calculations were performed as a sensitivity analysis to evaluate the climate impact of the RWB aerosols produced at the study site by integrating the optical properties measured during the campaign. The SFE results show a considerable forcing capacity from the local RWB aerosols, with a high sensitivity to OA absorption properties and a more substantial impact over bright surfaces like snow, typical during the coldest season with higher OA emissions from RWB. Our study's results are highly significant regarding air pollution, optical properties, and climate impact. The findings suggest that there may be an underestimation of RWB emissions in rural Europe and that further investigation is necessary.