Ashwini Kumar

• Ph.D
• Senior Researcher at CSIR-National Institute of Oceanography, India

Our understanding of surface ocean and lower atmosphere processes in the Indian Ocean (IO) region shows significant knowledge gaps mainly due to the paucity of observational studies. The IO basin is bordered by landmasses and an archipelago on 3 sides with more than one-quarter of the global population dwelling along these coastal regions. Therefor...

Microplastics (MPs) in the atmosphere can undergo long-range transport from emission regions to pristine terrestrial and oceanic ecosystems. Due to their inherent toxic and hazardous characteristics, MPs pose serious risks to both human well-being and the equilibrium of ecosystem. The present study outlines the comprehensive characterization, spann...

Cirrus clouds are highly reflective clouds that play an important role in the atmospheric radiative balance and contribute to climate change. We present the seasonal distribution of cirrus cloud occurrence, characteristics and evolution over a coastal station (Goa, 15.4°N, 73.8°E, 40 m above MSL) in India using ground-based micro pulse lidar and ra...

The acidity of atmospheric particles can promote specific chemical processes that result in the production of extra condensed phases from lesser volatile species (secondary fine particulate matter), change the optical and water absorption characteristics of particles, and enhance trace metal solubility that can function as essential nutrients in nu...

The interactions between aerosol and cloud play a vital role in global climate change and associated with one of the largest uncertainties. In last few decades, due to unique geographical location, Northern Indian Ocean (NIO) gains significant scrutiny among the scientific communities. The in-depth understanding of aerosols and their interaction wi...

Atmospheric dust deposition in the North Indian Ocean, particularly in the Arabian Sea significantly impacts phytoplankton productivity. Importantly, the steady increase in Sea Surface Temperature (SST) of the Arabian Sea may intensify oligotrophy and the significance of atmospheric dust input for phytoplankton growth may escalate in the future. Fu...

Atmospheric aerosol over the Arabian Sea is significantly impacted by the long-range transported mineral dust from the surrounding continents. This transported mineral dust is hypothesized and tested during several studies to see the impacts on the surface ocean biogeochemical processes and subsequently to the Carbon cycle. It is, thus important to...

Cirrus clouds are highly reflective clouds that play an important role in the atmospheric radiative balance and hence contribute to climate change. We present seasonal distribution of cirrus cloud occurrence, their characteristics and evolution over a coastal station (Goa, 15.4 o N, 73.8 o E, 40m above MSL) in India, using ground-based Micro Pulse...

The Arabian Sea is one of the highest productive zones in the global oceans and possesses several highly interesting biogeochemical features including open-ocean upwelling, monsoon reversal of currents, persistent oxygen minimum zone. These features collectively attracted oceanographers from all over the world. This dynamic land-locked basin has be...

Water-soluble species constitute a significant fraction (up to 60–70%) of the total aerosol loading in the marine atmospheric boundary layer (MABL). The “indirect” effects, that is, climate forcing due to modification of cloud properties depend on the water-soluble composition of aerosols. Thus, the characterization of aerosols over the MABL is of...

One of the major pathways for dust supply to surface water of the Arabian Sea is via wet deposition, which is significant during southwest Monsoon (June-September). Aeolian dust supplies macro and micronutrients, which can impact on several marine biogeochemical processes. Here we report, major elements and rare earth elements (REEs) content as wel...

This poster present, 1-year long aerosol chemical composition data of PM10 and PM2.5 at a costal location in the Northeastern Arabian Sea. Owing to high population density and rapid industrialization, Indian subcontinent is considered as one of the major hotspots for anthropogenic emissions which further make adjoining marine region vulnerable to t...

The Arabian Sea, one of the most biologically productive oceanic regions, receive significant amount of nutrients through aeolian dust deposition which have potential to modulate surface water biogeochemical processes. Identification of dust sources is important to assess role of dust deposition to surface water biogeochemistry. Here we report geoc...

The Arabian Sea is an enclosed basin surrounded by land and is prone to receive large amount of aeolian dust from the continent. This can significantly impact surface water biogeochemical processes. In this study, an attempt has been made to quantify the amount of dust transported from Middle East region to Indian subcontinent (sampling site is Goa...

Major/crustal elements (Al, Ca, Mg, K and Fe) and trace metals (Mn, Cr, Cu, Pb, Zn, and Ni) in atmospheric particulate matter at three sites in Goa (a coastal city in the Eastern Arabian Sea) were assessed during winter (December) and summer (March-May) months of 2015. A significant spatial and temporal variability was observed in PM10 mass concent...

The first International Indian Ocean Expedition (IIOE; conducted in the early 1960s) was one of the greatest interna- tional, interdisciplinary oceanographic research efforts. It involved 46 research vessels (under 14 different flags) that carried out an unprecedented number of hydrographic surveys (and repeat sur- veys) of the entire Indian Ocean...

Flavonoids represent an important bioactive component in plants. Accumulation of flavonoids often occurs in plants subjected to abiotic stresses including the adaptation of plants to the environment and in overcoming their stress conditions. This fact makes their analysis and determination an attractive field in food science since they can give int...

Atmospheric fine-mode particulate matter (PM2.5), collected during January to December 2007 at a high-altitude site (Mt. Abu, 24.6°N, 72.7°E, 1680 m asl) in the western India, have been analysed for carbonaceous and inorganic species to assess their temporal variability and the influence of emissions and transport processes, particularly from the I...

Due to the high toxicity of endocrine disruptors (EDs), studies are being undertaken to design effective techniques for separation and detection of EDs in various matrices. Recently, research activities in this area have shown that a diverse range of chromatographic techniques are available for the quantification and analysis of EDs. Therefore, on...

The Bodélé Depression (Chad) in the central Sahara/Sahel region of Northern Africa is the most important source of mineral dust to the atmosphere globally. The Bodélé Depression is purportedly the largest source of Saharan dust reaching the Amazon Basin by transatlantic transport. Here, we have undertaken a comprehensive study of surface sediments...

Early studies by Prospero and colleagues [1] have shown that African dust reaches all across the Atlantic and into the Caribbean. It may contribute to fertilizing the Amazon rainforest [2,3,4], in addition to enhancing the ocean biological productivity via delivery of iron, a key nutrient element[5]. Radiogenic isotope ratios (Sr, Nd, Pb) are robus...

The Bodélé Depression, located in Chad in the Southern Sahara, is one of the most prominent dust emission regions. Despite evidence of large dust storms emanating from the Bodélé region, geochemical tracer studies have not been able to identify unambiguously the signature of dust emitted from this region. This is partly due to the lack of isotope d...

The chemical composition (involving water-soluble inorganic constituents, crustal elements and carbonaceous species) of size-segregated aerosols (PM10 and PM2.5), collected from the marine atmospheric boundary layer (MABL) of the Bay of Bengal (BoB) during 27th Dec' 08–28th Jan' 09, has been studied to ascertain the factors controlling the spatio-t...

The chemical composition of aerosol over the Arabian Sea was investigated during December 2007. Elemental Carbon (EC), Organic Carbon (OC), water soluble organic and inorganic constituents and crustal elements (Al, Fe, Ca, and Mg) were measured in total suspended particulate samples (TSP) collected from marine boundary layer of the Arabian Sea when...

A method for the simultaneous determination of quinolones in water and urine samples by microextraction in a sorbent-packed syringe (MEPS) with LC is described. MEPS is a new miniaturized SPE technique that can be used with chromatographic instruments without any modifications. In MEPS, approximately 1 mg of the solid packing material is inserted i...

Ambient aerosols collected from the marine atmospheric boundary layer of the Bay of Bengal and the Arabian Sea have been studied to assess the fractional solubility of aerosol iron, defined as Fews (%) = Fews/FeTot × 100; where FeTot is total aerosol iron and Fews is water soluble iron. The mass concentration of FeTot over the two oceanic regions i...

A simple, fast, selective and very sensitive method based on sample preparation by the relatively new technique of microextraction in a packed syringe (MEPS) and analysis by liquid chromatography (LC) and gas chromatography-mass spectrometry (GC-MS) for the simultaneous determination of antidepressant drugs (amitriptyline, imipramine, clomipramine,...

The continental outflow from Indo-Gangetic Plain and south-east Asia dominates the widespread dispersal of pollutants over tropical Bay of Bengal (BoB) during the late NE-monsoon (January–March). It is thus pertinent to assess the impact on marine atmospheric boundary layer of BoB. The chemical data, based on analyses of size-segregated (PM<sub>2.5...

Abstract Our long-term study provides an unequivocal evidence for near-quantitative (80–100%) depletion of chloride from sea-salts in the marine atmospheric boundary layer (MABL) of tropical Bay of Bengal. During the late NE-monsoon (Jan-Mar), continental outflow from south and south-east Asia dominate the wide-spread dispersal of pollutants over t...

In this report, a new approach for the fast determination of hydrazine compounds (hy) in complex matrices is presented. The experimental protocol is based on poly(methylmethacrylate) (PMMA) microchip separations with contactless conductivity detection using a compact portable device, which integrates all separation and detection components. Three h...

This study presents a fast, accurate and sensitive technique using gas chromatography-mass spectrometry (GC-MS) for the identification and quantification of N-acyl homoserine lactones (AHLs) in the extracts of bacterial strain of Pseudomonas aeruginosa and sputum sample of a cystic fibrosis patient. This method involves direct separation and determ...

A new method for the efficient extraction and determination of volatile aliphatic amines by means of single-drop microextraction (SDME) in combination with microchip electrophoresis and contactless conductivity detection has been developed. An experimental approach for interfacing real world samples with chip electrophoresis is presented. The metho...

The relative influence of source categories of aerosols that affect atmospheric extinction is analyzed by evaluating the potential source contribution function (PSCF) based source regions of the positive matrix factorization (PMF) estimated factors against satellite retrievals of aerosol index and active fires and combining with emission inventory...

Much progress has been made in pesticide analysis over the past decade, during this time hyphenated techniques involving highly efficient separation with sensitive detection have become the techniques of choice. Among these, methods based on separation with mass spectrometric detection have resulted in greater likelihood of identification and are a...

The determination of the amines in the environment is very important. In this review, different methods for the analysis of the amines in the environment are discussed. Different aspects of the toxicity of the amines are discussed in detail. Methods for the sampling of the amines in air, soil, and water are discussed. Though there different techniq...

Spatiotemporal heterogeneity in aerosol radiative forcing and heating rate have been studied over Bay of Bengal and Arabian Sea during premonsoon (March–May 2006) using aerosol optical depth (AOD), total mass, aerosol chemical composition, and radiative transfer model. Mean 0.5 μm AOD over Bay of Bengal and Arabian Sea is 0.36 and 0.25, respectivel...

ABSTRACTA systematic 1-yr chemical data for the fine mode (PM2.5) air-borne particulate matter, collected from a high-altitude site (Mt. Abu, 22.7°N, 74.6°E, 1680 m asl) in a semi-arid region of western India, reveal characteristic temporal variability in the abundance of mineral dust and fractional solubility of aerosol Fe (referred as water-solub...

We present a comprehensive one-year data set on water-soluble ionic species in PM2.5 (fine) and PM10–2.5 (coarse) aerosols from a high-altitude site (Mt. Abu, 24.6 °N, 72.7 °E, 1680 m asl) in high-dust region of western India. The water-soluble ionic composition (WSIC) varied from 1.0 to 19.5 μg m−3 in the fine mode and constitutes 50, 39 and 31% o...

Solid-phase microextraction (SPME) has gained widespread acceptance for analyte-matrix separation and preconcentration. SPME is a simple, effective adsorption/desorption technique that eliminates the need for solvents or complicated apparatus for concentrating volatile or non-volatile compounds in liquid samples or headspace. SPME is compatible wit...

Size-segregated aerosol samples (PM2.5 and PM10) were collected during Jan–Dec-2007 from a high-altitude site located in a semi-arid region (Mt. Abu, 24.6 °N, 72.7 °E, 1680 m asl) in order to asses the temporal variability in the abundance of atmospheric mineral dust and its elemental composition over western India. The mass concentrations of fine...

Hyphenation of analytical techniques is a promising trend due to their wide applicability. This article explains the hyphenation of solid phase micro-extraction to capillary electrophoresis. Different modes of solid phase microextraction (SPME) are reported to increase sensitivity of the methods. Various advantages and problems that occurred during...

A new approach for the extraction and determination of myricetin and quercetin by using SPME-HPLC-UV system has been developed. The method involves adsorption of flavonoids on CAR/TPR fiber followed by desorption in the desorption chamber of SPME-HPLC interface using citrate buffer (0.001 M):acetonitrile (70:30) as mobile phase and UV detection at...

A solid-phase microextraction (SPME) method followed by separation with high-performance liquid chromatography and subsequent UV detection was developed for the determination of norfloxacin and enrofloxacin. The simple and sensitive preconcentration technique uses 280 nm wavelength in mobile phase of citrate buffer (0.01 M), pH 3.8, prepared in wat...

The chemical characteristics of aerosols in the Arabian Sea–atmospheric boundary layer (AABL) have been studied during the spring inter-monsoon (April and May 2006) based on the analysis of water-soluble constituents (Na+, NH4+, K+, Mg2+, Ca2+, Cl−, NO3−, and SO42−), crustal elements (Al, Fe, and Ca), and carbonaceous species (EC and OC). The total...

The chemical composition of aerosols in the Marine Atmospheric Boundary Layer (MABL) of Bay of Bengal (BoB) and Arabian Sea (AS) has been studied during the spring and inter-monsoon (March-May 2006) based on the analysis of water soluble constituents (Na+, NH4+, K+, Mg2+, Ca2+, Cl−, NO3− and SO42−), crustal elements (Al, Fe, and Ca) and carbonaceou...

Solid phase microextraction (SPME) is an innovative, solvent free technology that is fast, economical and versatile. SPME is a fiber coated with a liquid (polymer), a solid (sorbent) or a combination of both. The fiber coating takes up the compounds from the sample by absorption in the case of liquid coatings or adsorption in the case of solid coat...

A simple and highly sensitive high pressure liquid chromatographic (HPLC-UV) method has been developed for the determination of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, in mobile phase citrate buffer (0.001 M) of pH 4.5 prepared in water (X), methanol (Y), and ACN (Z) using gradient at a flow rate of 1.0 mL/min by direct UV absorbanc...

The majority of quinolones of clinical use belong to the subset of fluoroquinolones, which have a fluoro group attached the central ring system, typically at the 6-position. Fluoroquinolones are widely used in human and veterinary medicine. In recent times there has been significant development in the field of fluoroquinolones and many new analogue...

A new approach has been developed for the extraction and determination of aldehydes such as veratraldehyde, m-nitrobenzaldehyde, cinnamaldehyde, benzaldehyde, and p-chlorobenzaldehyde by using solid-phase microextraction (SPME) and high-performance liquid chromatography with UV detection (HPLC/UV). The method involves adsorption of the aldehydes on...

Methods developed for the analysis of explosives by SPME coupled to HPLC are reviewed with special emphasis on determination and monitoring in environmental samples such as soil and water. Analysis of explosives by using SPME-HPLC as analytical technique is comparatively a new method on which a special attention is focused nowadays. It saves time,...

Specific conductivity of aqueous electrolyte solution of anticonvulsant gabapentin (2-[1-(aminomethyl)cyclohexyl]ethanoicacid) has been determined in the temperature range of 303-338 K. The critical micelle concentrations (cmc), ionization degree () and the counterion binding of the micelle (, were estimated from the dependence of specific condu...