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- A review on sequential extraction of metals bound particulate matter and
their health risk assessment-
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Abstract: Abstract Sequential Extraction Procedure (SEP) is a method widely used to extract metals and metalloids from Particulate Matter (PM) based on their solubility in different reaction media. This extraction procedure is used to determine the actual mobility of metals present in the environment. A detailed discussion on the significance of sequential extraction analysis is also being given in this scientific document. This review includes different aspects related to the fractions obtained (exchangeable: F1, reducible: F2, oxidizable: F3, bound to organic matter: F4, and residual fraction: F5) during the SEP. The use of each reagent involved in the fractionation process of PM is also discussed briefly. Finally, the present up-to-date information given by different researchers in various fields of atmospheric chemistry along with the possible future developments is also part of this scientific review. The current review also focuses on the relation between SEP and mathematical expressions (bioavailability, source apportionment, and health risk assessment by the USEPA method). It is revealed from the previous studies that Cd and Zn are highly enriched, mobile as well as highly bioavailable in the environment and poses more risk to the human being. The Cr and As showed carcinogenic nature and hence pose carcinogenic diseases in humans. Whereas, Mn and As are non-carcinogenic in nature for children and adults and thereby both pose a non-carcinogenic disease threat to the population. PubDate: 2024-08-06
- Correction: India’s cultural heritage: Air quality effects amidst
COVID-19 lockdown and seasonal variability-
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PubDate: 2024-05-23 DOI: 10.1007/s10874-024-09459-w
- Analyzing air quality status at India’s heritage sites: Climate,
COVID-19 lockdown, and Solutions-
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Abstract: Abstract India, one of the most dynamic ancient civilizations, possesses a multitude of historical artifacts, with 37 of its notable architectural structures recognized as UNESCO World Heritage Sites. Yet, the ever-changing climate, especially air pollution, expedites the natural deterioration of historic sites and diminishes their aesthetic appeal, causing socio-economic damage. With this in mind, the current study aims to offer a logical scientific foundation for the implications of air pollution, seasonal shifts, and COVID-19 on 14 significant historical places in India during the year 2019-20. Delhi, among the cities most severely affected by atmospheric pollution, recorded an alarming air quality index (AQI) of 102–141, which can intensify the risk of cultural sites to corrode and deteriorate. Analysis reveals that the winter season had elevated levels of NO2 and particle pollution (PM2.5, PM10), whereas summer had the higher levels of O3. Throughout the 5-month lockdown period, ozone levels exhibited an elevation, contrasting with the reduction observed in other air parameters. Notably, there was a substantial 70% decrease in particulate matter concentration, which had previously remained stable over the course of the year. Variations in geographic locales and anthropogenic influences contribute significantly to the dose-response statistics, revealing an unprecedented elevation in corrosion risks to historical limestone and sandstone structures across target sites. Moreover, the research addresses available Governmental initiatives, and effective strategies designed to safeguard heritage sites against the corrosion and material degradation, offering a comprehensive exploration of protective measures. Thereby, the current research is centred on establishing a foundational understanding of the impact of air pollution on cultural heritage, utilizing a comparison to the year with the lowest air pollution levels, which can aid policymakers in enhancing risk management and implementing a robust national mandate for the preservation of cultural heritage sites against corrosion. PubDate: 2024-05-08 DOI: 10.1007/s10874-024-09458-x
- Quantification and source apportionment of atmospheric trace gases over
Dhaka, Bangladesh-
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Abstract: Abstract Five atmospheric trace gases were measured in Dhaka, Bangladesh, using an automated direct sensing gas monitoring system. The average concentrations of CO, NO, NO2, TVOC, and O3 were 2603.6 ± 1216.4, 281.5 ± 158.0, 182.7 ± 69.4, 10,068.2 ± 5296.1 and 36.6 ± 23.6 µg/m3. The measured trace gas concentrations demonstrated significant seasonal and monthly fluctuations, with NO and CO concentrations being the highest in winter, O3 and TVOC concentrations being the highest during the monsoon season, and NO2 concentrations being the highest during the pre-monsoon season. Air mass trajectories and wind rose plots during the monsoon were compared to the winter. It showed that air masses from the southeast and south had an impact on the quantity of most of the trace gases whilst they traveled over the Bay of Bengal throughout the monsoon period. In contrast, air masses from the northwestern region, north, and the west had a bigger effect on the rising amount of trace gases across the Indo Gangetic Plain (IGP) during the winter season. NO2 (182.7 µg/m3) had the maximum concentration of the gases measured and crossed the World Health Organization’s (WHO) annual recommended value. The source characteristics of NOx, TVCO, and O3 gases were determined using the positive matrix factorization (PMF 5.0) model. The combustion of fossil fuels and aerosols were found to be the major sources of NOx and O3, with aerosol formation being the primary source of TVOC concentration. PubDate: 2024-04-16 DOI: 10.1007/s10874-024-09457-y
- Toxic heavy metals in rainwater samples of Tehran
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Abstract: Abstract This study investigates the concentrations and spatial distribution of toxic heavy metals (Cd, Cu, Pb and Zn) through chemical analysis of rainwater samples collected in Tehran, Iran during winter and spring of 2022, characterized by different land use, emission sources, traffic conditions and population density. The average concentrations of the examined heavy metals at the five sampling sites were 52.9, 11.8, 14.6 and 0.93 μg l−1 for Zn, Pb, Cu and Cd, respectively. The concentrations of all heavy metals were significantly higher (p < 0.05) at the sampling points in central and south Tehran compared to sites in the west and north, due to different urban characteristics, higher pollution emission rates from the traffic and domestic sectors, and local wind patterns developed within the city. High traffic load in the central part of Tehran also escalates the heavy metal concentrations in this region. The significant correlations between the examined heavy metals at the five sites indicate common, local anthropogenic sources. The heavy metal concentrations were higher for rain samples collected in spring than in winter, likely associated with dilution processes in winter and the restriction measures due to COVID-19 pandemic. During the lockdown period, a drastic decrease in traffic load was observed in Tehran, confirming that motor vehicles is the main regulatory factor for air pollution and potential toxic elements in the city. PubDate: 2023-12-22 DOI: 10.1007/s10874-023-09454-7
- Aerosols in Northern Morocco (Part 3): the application of three
complementary approaches towards a better understanding of PM10 sources-
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Abstract: Abstract This study investigates the sources and characteristics of PM10 pollution in Tetouan city, Morocco, by employing a combination of chemical mass closure, source-receptor modelling (namely positive matrix factorization, PMF), and air mass trajectory statistical analyses (concentration weighted trajectory, CWT). It provides compelling evidence that using such a combination is a powerful approach for studying the composition and sources of PM10 in the Tetouan region. The PMF analysis identifies four PM10 sources, namely Vehicle Exhaust, Secondary Aerosols, Nitrate + Biomass Burning, and Fresh Sea Salt, with distinct seasonal contributions. CWT analysis reveals the Mediterranean Basin as the primary source region, with influences from populated areas in northern Morocco, southern Europe, and marine emissions. PM10 mass closure highlights the abundance of Dust, Particulate Organic Matter (POM), and Water-Soluble Inorganic Ions (WSI), accounting for the majority of the mass. The low OC/EC ratio advocates that carbonaceous aerosols primarily originate from local traffic emissions. Diagnostic of WSI ratios shows that the [NH4+]/[SO42−] ratio indicated an ammonium-poor environment and suggested an acidic nature of the PM10 aerosols, while the [SO42−]/[NO3−] ratio reflects the combined influence of stationary and mobile sources, with a partial contribution from industrial activities throughout the year. These findings are expected to shed light on the chemical composition, origin of emission sources, and transport pathways of PM10 in the region, contributing to the understanding of air pollution in the south western Mediterranean. PubDate: 2023-12-17 DOI: 10.1007/s10874-023-09455-6
- Spatio-temporal variability and possible source identification of criteria
pollutants from Ahmedabad-a megacity of Western India-
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Abstract: Abstract This study addresses the spatio-temporal variability and plausible sources of criteria air pollutants in the Western Indian city-Ahmedabad. The air pollutants PM10, PM2.5, O3, NO2, SO2, and CO have been analyzed at ten locations in Ahmedabad from 2017 to 2019. The seasonal variability indicates that the air pollutant concentration is highest during winter, followed by pre-monsoon, post-monsoon, and monsoon seasons. The concentration of PM2.5 (59.52 ± 16.68–89.72 ± 20.68) and PM10 (107.25 ± 30.43–176.04 ± 38.34) crosses the National Ambient Air Quality Standards (NAAQS) in all seasons. However, the seasonal difference from winter to pre-monsoon is not highly significant (p > 0.05), indicating that the pollution remains fairly similar during these two seasons. The spatial variability of air pollutants over Ahmedabad indicates that the concentration is highest in the south and central region of Ahmedabad and lowest at the east location. The Ventilation Coefficient (VC) has been used to understand the dispersion of air pollutants. The K-means clustering was performed to assess the locations within Ahmedabad with similar air pollutants sources followed by source identification using Principal Component Analysis-Multiple Linear Regression method (PCA-MLR) of 5 clusters. The different locations identified were industrial, residential, and traffic which mainly contribute to the air pollutants in Ahmedabad city. The health risk assessment indicates PMs are the leading pollutant and causing excess risk (ER > 1) at all the locations. With the help of the different statistical techniques, it helps in ascertaining the hotspots of air pollution in a region which will be beneficial in studying health exposure and for policymakers to adopt mitigation strategies. PubDate: 2023-12-14 DOI: 10.1007/s10874-023-09456-5
- Wet deposition of total nitrogen, dissolved organic carbon and heavy
metals investigating role of long-range transport at two sites in Delhi-
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Abstract: Abstract Precipitation is one of the significant phenomena for deposition of nitrogen, carbon and metal fractions. In the current study, Total Nitrogen (TN), Dissolved Organic Carbon (DOC) and metal concentrations were measured at two sites having distinct land use patterns in Delhi National Capital Region during different seasons in 2018 and 2019 to find out their potential sources. The TN mean concentration was found to be 16.0 mg/l and 7.0 mg/l at DG and JN site respectively. Whereas the DOC mean concentration was found to be 3.8 mg/l and 2.5 mg/l at DG and JN site respectively. The sequence for the metal concentrations was recorded as Ca > Na > Mg >K> Al > Cu > Fe > Mn > Zn > As for DG site whereas at JN site we recorded different sequence i.e., Ca > Al > Na > K > Mg > Fe > Mn > Zn > Cu > As. Different sources can be attributed to the influence of anthropogenic activities (agriculture, animal husbandry) on nitrogenous species, and biomass burning on dissolved organic carbon species. The wind rose plots indicated that the local and regional sources located in the south-eastern and north-western direction from the sites influenced the wet deposition of the species. Air-mass back trajectory analysis implied the influence of air masses originating from the Bay of Bengal during monsoon season while that of air masses originating from Haryana, Punjab and further north-west during winter season. Presently, very limited information is available on TN and DOC linking with heavy metals. The current study will be filling such gaps to further help nitrogen and carbon budgeting and linking nitrogen with climate change. The study has policy implications as well for north-central India especially for identifying and controlling local, trans-boundary and distance emission sources. The findings facilitate us to understand a holistic view of chemical composition of precipitation so that effective mitigation measures can be taken accordingly. PubDate: 2023-11-03 DOI: 10.1007/s10874-023-09453-8
- Impact of lockdown (COVID-19) and unlocking period on ambient air quality
and human health in Lucknow city, India-
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Abstract: Abstract Lucknow is one of the most polluted metro-city in India with increasing vehicular density and fuel consumption in the last three decades. The study was conducted during years 2019–2021 for measurement of fine particulate matter (PM2.5), nitrogen dioxide (NO2), sulphur dioxide (SO2), respirable particulate matter (PM10), and noise levels at nine selected sites; 4 residential, 4 commercial, and 1 industrial, encompassing prior-to-lockdown, during-lockdown, and after-lockdown periods. Values of PM10 for prior-to-lockdown, during-lockdown, and after-lockdown period ranged from 133.2 to 197.4, 77.0 to 135.0, and 91.4 to 148.0 µg/m3, respectively while values of PM2.5 were 66.5 to 93.6, 41.9 to 67.5 and 49.5 to 98.6 µg/m3, respectively. Corresponding values of SO2 ranged from 8.7 to 12.8, 5.5 to 7.6, and 11.4 to 17.6 µg/m3, respectively while values of NO2 were 24.6 to 57.0, 20.5 to 32.8, and 26.1 to 43.8 µg/m3, respectively. Order of the trace metals associated with PM2.5 is Co < Cd < As < Cr < Ni < Cu < Pb < Mn < K < Zn, Co < Cd < As < Cr < Cu < Ni < Pb < Mn < Zn < K and Cd < Co < As < Cr < Cu < Ni < Pb < Mn < K < Zn in the same periods. Statistical data evidenced that the air quality of the city witnessed drastic improvement during the COVID-19 pandemic. WHO AIRQ + was utilized to calculate attributable health risk and post-neonatal disease burden; showing 1447 ± 768 estimated number of cases attributable to ambient PM10 per lakh of population. Regulatory authorities need to establish new benchmarks for the prevention and management of public health risks for urban resilience and environmental management for episodic events in the near future. PubDate: 2023-08-02 DOI: 10.1007/s10874-023-09451-w
- Wintertime trends of particulate-bound polycyclic aromatic hydrocarbons
(PAHs) at north-east site of India: chemical characterization and source identification-
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Abstract: Particulate-bound Polycyclic Aromatic Hydrocarbons (PAHs) have been identified as pollutants of serious concern due to their severe health impacts on human and animal life. In the present work, 16 USEPA (United States Environmental Protection Agency) identified PAHs present in PM2.5 at Jorhat, India during the winter months (Jan-March, 2020) were analyzed. Apart from the temporal variability of these compounds, the impact of varying meteorological factors like temperature, wind speed, relative humidity, and planetary boundary layer height on PAHs concentration have also been studied. It has been observed that the effect of ambient air temperature and planetary boundary layer on PAHs concentration are significant compared to other meteorological parameters during the winter season. The average concentration of total PAHs during this period was 157.2 ± 127.7 ng/m3 with dominance of high molecular weight aromatics compared to the low molecular weight ones. Among all 16 PAHs studied, the contribution of benzo(b,j)fluoranthene (27.26%) to total PAHs concentration was found to be the highest followed by di-benzo(a,h)anthracene (10.37%). Source identification analysis using isomeric PAHs ratios indicated that crop residue burning, vehicular emission, coal, and wood combustion are the major emission sources of PAHs. A comparative study of PAHs emission at the present site with other northern cities of India has been performed and it is observed that vehicular emission contributing to PAHs is common to all cities but in Kolkata, wood and coal combustion were also responsible for PAHs emission. Biomass burning is also seen to be a contributor to Amritsar. Whereas in Jorhat, crop residue and coal/wood combustion are seen to be major contributors to PM2.5 bound PAHs unlike other cities. Graphical abstract PubDate: 2023-07-21 DOI: 10.1007/s10874-023-09450-x
- Statistical analysis of the variability of reactive trace gases (SO2, NO2
and ozone) in Greater Cairo during dust storm events-
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Abstract: Abstract The data of 17 air quality monitoring stations of Greater Cairo are used to perform a statistical analysis aiming to detect any heterogeneous surface effects of mineral dust on the distribution of reactive trace gases (SO2 NO2, and ozone) in. After a thorough quality check, the methodology consisted of i) selecting representative stations by agglomerative hierarchical clustering, ii) identifying dust events based on PM10 measurements, remote sensing observations, and meteorology, and iii) applying the non-parametric Kruskal Wallis (KW) hypothesis test to compare (at the 95% confidence level) trace gas concentrations during dust and non-dust events. The representative stations display either a background-like or a bimodal variability with concentrations (even that of the secondary product NO2) peaking at traffic rush hours but during dust storms all stations capture the signal of mineral dust advection. Eight wintertime and springtime dust cases are retained for the study. After the role of the confounding factors (i.e., ventilation index, relative humidity, and photolysis) has been carefully discussed and taken into account, the KW test shows that there is no significant reduction of the SO2, NO2 and ozone concentrations attributable to dust during 7 of the 8 events. The drop of the concentrations coinciding with the advection of dry dust-laden Saharan air masses is rather an effect of the dilution resulting from the combination of large wind speed and mixing layer height than of the heterogeneous uptake of these gases on the mineral dust surface. PubDate: 2023-07-14 DOI: 10.1007/s10874-023-09449-4
- Spatial variations in physico-chemical characteristics of PΜ2.5 in an
urban coastal city of India and associated health risks-
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Abstract: Abstract This paper investigates the chemical composition of Particulate Matter, Organic Carbon (OC), and Elemental Carbon (EC) in residential and traffic sites in Mumbai. The average PM2.5 and PM10 concentrations at the traffic site (Sakinaka) were 240 µg/m3 and 424 µg/m3, respectively. The observed levels of OC were 35 µg/m3, 22 µg/m3, and 15.5 µg/m3 at Sakinaka junction (high-density traffic), YP-Gate (low-density traffic), and Hostel Premise (Residential), respectively. The average OC/EC ratio value was high (4.5) at the residential site, indicating contributions from stationary combustion sources and secondary production of carbonaceous species to OC. The residential site has a higher percentage of low volatile OC fraction (57%) in total OC than the traffic sites. On the other hand, Sakinaka has a higher percentage of highly volatile OC fractions (36%) in total OC. The crustal-originated metals were dominating in all areas, but the concentration of metals from anthropogenic sources was highest at Sakinaka, i.e., As (381 ng/m3), Pb (352 ng/m3), Zn (679 ng/m3). The K/Al, Ca/Al, Mg/Al, and Fe/Al ratios were high in all the samples compared to the crustal ratio indicating biomass burning and traffic emission sources of these metals. PM originating from traffic was more enriched with heavy metals that are toxic to human health, increasing cancer risks (CR) through inhalation. The hazard quotient was above 1 at all the locations, and CR was above 1 × 10− 4, causing health risks. According to the dosimetry model, more PM was deposited in the lungs of traffic location occupants through inhalation, increasing the cancerous risk. PubDate: 2023-07-03 DOI: 10.1007/s10874-023-09448-5
- Significant abundances of alkaline components in the fine and coarse
aerosols over a tropical rain shadow location in peninsular India-
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Abstract: Abstract This paper reports the chemistry of fine (PM2.5) and coarse (PM10) aerosols sampled over a period of three years during 2018–2021 at a semi -arid tropical location in the rain shadow region of the peninsular India. The data is classified in to dry (December to May) and wet (June to November) periods. Scavenging effect due to rains have culminated in to less concentrations of both fine and coarse aerosols and their ionic components in the wet period. Significantly high concentrations of the crustal components such as Ca, Na, K and Mg from the local dust resulted in the alkaline pH in both dry and wet periods with Ca and Mg emerging as major neutralizing components. Overall, < 20% samples of both fine and coarse aerosols depicted acidic pH. Concentration of SO4 was comparatively more than NO3 indicating towards more presence of stationary sources (industrial/domestic emissions) than mobile (vehicular emissions) sources. Combustion generated and highly absorbing black carbon aerosols showed high concentration during the dry period. Local activities comprising residential, agricultural, vehicular and industrial emissions were the major sources of aerosols at Solapur however, the contribution from the distant sources were also found to contribute as inferred from the cluster analysis and concentration weighted trajectories (CWT). The observed abundances of the alkaline dust aerosols that could act as cloud condensation nuclei or ice nuclei will have important implications on the studies related to cloud aerosol precipitation interaction over this region. PubDate: 2023-05-27 DOI: 10.1007/s10874-023-09447-6
- Fate of 1,3-dioxolane in the troposphere: kinetics, mechanism with
theoretical support, and atmospheric implications-
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Abstract: The atmospheric fate of 1,3-dioxolane is assessed by measuring the OH and Cl initiated gas-phase oxidation kinetics, and exploring their mechanistic pathways. Absolute OH reaction rate coefficient of 1,3-dioxolane using laser photolysis-laser induced fluorescence technique is found to be (1.27 ± 0.03) × 10–11 cm3 molecule−1 s−1 at 298 ± 2 K and it is in good agreement with the measured relative value of (1.13 ± 0.12) × 10–11 cm3 molecule−1 s−1, using gas-chromatography. Relative value of Cl reaction rate coefficient with 1,3-dioxolane is found to be (1.64 ± 0.60) × 10–10 cm3 molecule−1 s−1. The tropospheric lifetime of 1,3-dioxolane is calculated to be about 22 h under ambient conditions. Interestingly, it reduces to about 8 h near marine boundary layer, where Cl reaction takes over the OH reaction. Such a short lifetime with respect to reaction with OH and Cl suggests the atmospheric impact of 1,3-dioxolane to be local. Formic acid, ethylene carbonate, and 1,2-ethanediol monoformate are observed as stable products in OH as well as Cl oxidation. 1,3-dioxolane may contribute as one of the sources of formic acid in the atmosphere. Theoretical calculations for the OH-initiated hydrogen abstraction of 1,3-dioxolane revealed that the reaction follows an indirect path through the formation of pre- and post-reaction complexes at entrance and exit channels, respectively with the lowest barrier height of 3.5 kcal/mol. Photochemical ozone creation potential of 1,3-dioxolane is calculated. PubDate: 2023-04-12 DOI: 10.1007/s10874-023-09446-7
- Variations in mixing states of organic aerosol composition and formation
of secondary organic aerosol at background region-
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Abstract: Abstract Investigation on organic particles was limited in the background regions of Yangtze River Delta (YRD) and little information has been obtained on organic particles of Lin’an (LA). In the present study, the morphology, composition, mixing state, and size of organic aerosols with diameter less than 1 µm were characterized at Lin’an from 20 March 2019 to 20 April 2019. In all samples, irregular types of organic matter (OM) particles were high fraction during morning (72.4%), afternoon (59.1%), and evening (52%), and most of them were internally mixed. In our study, we identified a higher fraction of internally mixed particles in evenings (85%), followed by afternoon (81%), and fewer mixed particles in mornings (68%), indicating particle growth during afternoon and evening. Further, the results show that fraction of organic coating particles was higher in evening (27.4%) and afternoon (12%) indicates strong photochemical processes and formation of secondary organic aerosol on the inorganic particles and new particles formation. Our study reveals that biomass burning in the morning and coal burning from heavy industries, power plants, and vehicles in surrounding urban regions in the afternoon and evenings significantly affected background air quality. PubDate: 2022-12-28 DOI: 10.1007/s10874-022-09445-0
- Remote sensing of aerosols due to biomass burning over Kanpur, Sao-Paulo,
Ilorin and Canberra-
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Abstract: Abstract Aerosol affect the climate in number of ways. In order to investigate these effects, we need a deep insight into aerosols optical, physical and radiative properties. So, to understand aerosols climatology, we investigate the properties of aerosols such as aerosol optical depth (AOD) (500 nm), Angstrom exponent (AE) (440–870 nm), single scattering albedo (SSA), refractive index (RI) and aerosols radiative forcing (ARF). For this purpose, we select four different AErosol RObotic NETwork (AERONET) sites located in four different continents; Kanpur, (India) Asia, Sao-Paulo, (Brazil) Southern America, IIorin, (Nigeria) Africa and Canberra, Australia. High AOD and AE is found (AOD = 0.90, AE = 1.31) in November at Kanpur and in September (AOD = 0.39, AE = 1.48) at Sao-Paulo. High AOD (1.06 and 1.12) over IIorin in January and February is found because of fog and haze. SSA shows decreasing trend with increasing wavelengths having minimum value (0.88 and 0.78 at 1020 nm) during the months of DJF and SON over Sao-Paulo and Canberra respectively. The highest value of SSA (~ 0.96) is found during the months of MAM over IIorin because of presence of coarse aerosols. The low value of SSA over Kanpur during DJF months shows dominance of fine urban/ biomass burning aerosols. Based on the values of AOD, AE and SSA, Canberra is the most pristine site. The estimated ARF values indicate that Kanpur and Ilorin sites exhibit higher TOA and BOA values as compared to Sao-Paulo. ARF at ATM is observed to be 7.4 Wm−2 higher during JJA months and 10.1 Wm−2 during SON months than MAM months over Kanpur. We have also observed lowest ARF efficiency (FeffBOA) of − 181 Wm−2 AOD−1550 nm during MAM months for Sao-Paulo while the highest value of − 297 Wm−2 AOD−1550 nm is observed during DJF months for Kanpur. PubDate: 2022-10-13 DOI: 10.1007/s10874-022-09444-1
- Water-soluble dicarboxylic acids, oxoacids and α-dicarbonyls in the
tropical aerosols in coastal megacity Mumbai: molecular characteristics and formation processes-
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Abstract: Abstract Daytime and nighttime PM10 samples were collected during summer (June) and winter (February) at a representative urban site in Mumbai, located on the western coast of Indian subcontinent. Samples were studied for molecular distribution of water-soluble dicarboxylic acids, oxoacids and dicarbonyls as well as total carbon (TC), water-soluble organic carbon (WSOC), inorganic ions along with specific markers (levoglucosan, K+) to better understand sources and formation processes of organic aerosols in Mumbai. The distribution of water-soluble organics was characterised by high abundance of oxalic acid (C2), followed by phthalic (Ph), terephthalic (tPh), azelaic (C9), malonic (C3), and succinic acids (C4). Positive correlations between C2, sulfate and glyoxal (ωC2) suggest secondary production of C2 predominantly via aqueous phase chemistry. C2 also showed positive correlation with K+ and levoglucosan indicating that biomass/biofuel burning is the potential source of diacids in the Mumbai aerosols. In addition, higher average contributions of total diacids to WSOC and OC in winter than in summer suggest that aerosols were aged i.e., photochemically well processed in winter in Mumbai. On the other hand, diurnal change in their ratios is observed with higher ratio in daytime samples than that of previous and succeeding nighttime samples, suggesting diacids are also influenced from local sources in both the seasons. This study demonstrates that biomass burning as well as biogenic sources are important sources influencing the distributions of aerosols in Mumbai. PubDate: 2022-10-08 DOI: 10.1007/s10874-022-09442-3
- Surface ozone changes during the COVID-19 outbreak in China: An insight
into the pollution characteristics and formation regimes of ozone in the cold season-
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Abstract: Abstract The countrywide lockdown in China during the COVID-19 pandemic provided a natural experiment to study the characteristics of surface ozone (O3). Based on statistical analysis of air quality across China before and during the lockdown, the tempo-spatial variations and site-specific formation regimes of wintertime O3 were analyzed. The results showed that the O3 pollution with concentrations higher than air quality standards could occur widely in winter, which had been aggravated by the emission reduction during the lockdown. On the national scale of China, with the significant decrease (54.03%) in NO2 level from pre-lockdown to COVID-19 lockdown, the maximum daily 8-h average concentration of O3 (MDA8h O3) increased by 39.43% from 49.05 to 64.22 μg/m3. This increase was comprehensively contributed by attenuated NOx suppression and favorable meteorological changes on O3 formation during the lockdown. As to the pollution states of different monitoring stations, surface O3 responded oppositely to the consistent decreased NO2 across China. The O3 levels were found to increase in the northern and central regions, but decrease in the southern region, where the changes in both meteorology (e.g. temperature drops) and precursors (reduced emissions) during the lockdown had diminished local O3 production. The spatial differences in NOx levels generally dictate the site-specific O3 formation regimes in winter, with NOx-titration/VOCs-sensitive regimes being dominant in northern and central China, while VOCs-sensitive/transition regimes being dominant in southern China. These findings highlight the influence of NOx saturation levels on winter O3 formation and the necessity of VOCs emission reductions on O3 pollution controls. PubDate: 2022-10-07 DOI: 10.1007/s10874-022-09443-2
- Temporary reduction in VOCs associated with health risk during and after
COVID-19 in Maharashtra, India-
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Abstract: Abstract A novel coronavirus has affected almost all countries and impacted the economy, environment, and social life. The short-term impact on the environment and human health needs attention to correlate the Volatile organic compounds (VOCs) and health assessment for pre-, during, and post lockdowns. Therefore, the current study demonstrates VOC changes and their effect on air quality during the lockdown. The findings of result, the levels of the mean for total VOC concentrations were found to be 15.45 ± 21.07, 2.48 ± 1.61, 19.25 ± 28.91 µg/m3 for all monitoring stations for pre-, during, and post lockdown periods. The highest value of TVOCs was observed at Thane, considered an industrial region (petroleum refinery), and the lowest at Bandra, which was considered a residential region, respectively. The VOC levels drastically decreased by 52%, 89%, 80%, and 97% for benzene, toluene, ethylbenzene, and m-xylene, respectively, during the lockdown period compared to the previous year. In the present study, the T/B ratio was found lower in the lockdown period as compared to the pre-lockdown period. This can be attributed to the complete closure of non-traffic sources such as industries and factories during the lockdown. The Lifetime Cancer Risk values for all monitoring stations for benzene for pre-and-post lockdown periods were higher than the prescribed value, except during the lockdown period. PubDate: 2022-08-17 DOI: 10.1007/s10874-022-09440-5
- Ionic composition, source identification of rainwater, and its
contribution to nutrient deposition in monsoon, over Sundarban Mangrove forest-
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Abstract: Abstract A detailed study on potential sources, variation, and environmental effects of the rainwater ions was carried out at Lothian Island, Sundarban mangrove forest, India, during the southwest monsoon (June–September) in 2019. On an event basis, the maximum rainwater precipitation was observed 17.65 mm Day −1 and a minimum of 1.02 mm Day −1. The maximum amount of total precipitation was recorded in the month of July (237 mm). The volume weighted mean (VWM) concentration shows that the total ionic composition was 93.7 μeq L−1, whereas the percentage contribution of the total ionic concentration is found to be 45.97% to anions and 54.02% to the cations. Temporal variation was observed between early (June- July) and late monsoon (August—September), which shows a high concentration of major ions in early monsoon and low concentration in late monsoon due to the washout of atmospheric particles with the frequent and increasing precipitation. The pH values of the 78% samples show neutral pH and neutralization factors (NF) followed a sequence of NFCa ˃NFMg ˃ NFNH4 with factors of 0.77, 0.34, and 0.14 indicating Ca2+ was the most potential species to balance the acidic ions (NO3−, SO42−) over the study area. Source apportionment study indicates the significant influence of marine actions (long-range transport by monsoonal wind from marine origin, Sea spray, salty soil profile of mangrove) as the major source of ions over Sundarban. The rate of nutrient wet deposition in the form of rainwater was estimated and average monsoonal nitrogen flux was observed 0.87 kg ha−1where NO3 contributes the most (0.60 kg ha−1). N and P deposition flux also showed a simultaneous pattern with the seasonal nutrient concentration of surrounding river water, which may be an indication of a possible contribution of atmospheric wet deposition in the spike of monsoonal nutrient concentration in river water. PubDate: 2022-08-17 DOI: 10.1007/s10874-022-09441-4
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