Concentrations, transport characteristics, and health risks of PM2.5-bound trace elements over a national park in central India.

Fine particulate matter (PM2.5) mass and its chemical constituents were measured over Van Vihar National Park (VVNP) in Bhopal, central India. Fine PM collected over two years onto Teflon filters using a Mini-Vol® sampler were analyzed for trace elements using an Energy Dispersive X-ray fluorescence (ED-XRF) spectrometer. The temporal behaviour, dry deposition fluxes and transport pathways of elements, in addition to their health risks were examined in this study. S, K, Si, Al, Ca, and Fe accounted for most of the PM2.5-bound trace elements (~88% on average). Pronounced seasonality was observed for major elements (S, K, and Cl) and reconstructed soil (estimated as the sum of oxides of crustal elements, i.e., Si, Al, Ca, Fe, and Ti), with winter and post-monsoon season highs, potentially due to source strengths and favourable metrology during these seasons. The synoptic meteorology during these seasons favoured the fetch of particles from highly polluted regions such as the Indo-Gangetic Plain. The estimated average dry depositional flux of each element in this study was comparable to those measured/estimated for each of these species over other urban areas. The sum of the dry deposition flux for crustal elements (1301.9 ± 880.7 µg m-2 d-1) was in agreement with global dust cycle models. Air-parcel trajectory cluster analysis revealed that S, K, and Cl were influenced by biomass and coal burning in predominantly in central, and northwestern India, while reconstructed soil was influenced by air masses from the Arabian and Thar deserts. Finally, human exposure risk assessment to carcinogens (As, Cr, Cd, Pb and Ni) and non-carcinogens (Cu, Zn, Mn, V, Hg, Se and Al) revealed that no significant risk was posed by these elements. The assessment in this study was a screening for severe adverse effects, rather than a speciated health assessment. Thus, over the study region, monitoring, health risk assessment and mitigation measures, where needed, must be enhanced to ensure that trace elements induced health effects continue to be within safe levels.

Influence of fireworks emission on aerosol aging process at lower troposphere and associated health risks in an urban region of eastern central India.

To study the influence of fireworks in atmospheric aerosols and their effect on health during the extreme firework days, fireworks tracer metals and carbonaceous species in size-distributed aerosols in the lower troposphere at Raipur in eastern central India were investigated during the 2018 Deepawali festival. Aerosol samples were collected, before Deepawali period (BDP, n = 5), during Deepawali period (DDP, n = 5) and after Deepawali period (ADP, n = 5). Bimodal size-distribution with intense fine mode peak was found for Na during DDP. Bimodal distribution with fine mode intense peak was found for K during DDP. The bimodal size distribution of K was found common for other events because of biomass burning emissions, whereas high intense peak during DDP indicated mixed sources from biomass burning and fireworks. During DDP, K and Ca were well correlated (r2 = 0.93) together. Strong metal-metal correlations were found between the following pairs, Zn-Fe, Cu-Fe and Cu-Ca, which indicated the similar firecrackers burning source. The atmospheric aging of aerosols was also found significantly high during fireworks days. Aging of aerosols were higher because of heterogeneous reactions of SO2 and NOx on aerosols directly emitted from fireworks. The observed high values of inhalation dose of elemental carbon during DDP period imposed higher risk of respiratory diseases. This study has provided carbonaceous fractions composition data as a tool to detect the aging processes of fireworks in ultra-fine, fine and coarse mode particles during the extreme firework days. Inhalation doses were calculated to establish potential influence on human health.

Colorimetric and smartphone-integrated paper device for on-site determination of arsenic (III) using sucrose modified gold nanoparticles as a nanoprobe.

An optical colorimetric and smartphone-integrated paper device (SIPD) is demonstrated for determination of As (III) in water and soil samples using sucrose modified gold nanoparticles (AuNPs/Suc) as a nanoprobe. The mechanism for determination of As(III) is experimentally validated by performing UV-Vis, transmission electron microscope (TEM), Fourier transforms infra-red spectroscopy (FTIR) and dynamic light scattering (DLS) measurements. The density function theory (DFT) calculations using B3LYP with 6-311G (2d,2p) and LANL2DZ basis sets is used to theoretically prove the mechanism for determination of As(III). In addition, the paper fabricated with AuNPs/SuC was used as a nanoprobe for quantitative determination of As(III) using smartphone and ImageJ software. Calibration plot was linear over 10-800 µgL-1 for colorimetric determination of As(III) with limit of detection (LOD) of 4 µgL-1 acquired when the absorbance ratio obtained at 594 nm/515 nm. The linearity range of 50-3000 µgL-1 with LOD of 20 µgL-1 was determined using smartphone-integrated paper device. AuNPs/Suc is successfully employed for determination of As (III) from contaminated water and soil samples in colorimetry and SIPD. Graphical abstractColorimetric and Smartphone-integrated paper device used for selective detection of arsenic from contaminated water samples using sucrose modified gold nanoparticles (AuNPs/Suc) as a sensing probe.

A KBr-impregnated paper substrate as a sample probe for the enhanced ATR-FTIR signal strength of anionic and non-ionic surfactants in an aqueous medium.

Herein, we report a KBr-impregnated paper substrate as a sample probe to enhance the attenuated total reflection-Fourier transform infrared (ATR-FTIR) signal strength of anionic surfactants (AS) and non-ionic surfactants (NS) in an aqueous solution. The mechanism for the sensing of AS and NS is based on the strong interaction of surfactants with the silicate groups (SiO4 4-) of the KBr-impregnated paper substrate. The role of SiO4 4- on the surface of the paper is to enhance the adsorption of AS and NS, resulting in improved IR signal intensities for the target analytes. The improved signal intensity at 1253 cm-1 (SO4 2-, symmetric stretching) for AS and 1114 cm-1 (C-O-C, stretching vibration) for NS were selected for quantification. SEM-EDX was employed to determine the elemental compositions of pre- and post-adsorbed AS and NS on glass fibre filter paper (GFF). The linear range for the determination of AS and NS was 10-100 µg L-1 with a method detection limit (MDL) of 4 µg L-1 and method quantification limit (MQL) of 12 µg L-1. The good relative recovery of 71.4-109.7% and the interference studies showed the selectivity of the method for the determination of AS and NS in environmental water and commodity samples. The advantages of this method include its cost-effectiveness, enhanced sensitivity, disposability and accessibility of the paper substrate.

Citrate-capped gold nanoparticles as a sensing probe for determination of cetyltrimethylammonium surfactant using FTIR spectroscopy and colorimetry.

A novel, facile, and low-cost method was developed for determination of cetyltrimethylammonium (CTA+) cationic surfactant in water samples using diffuse reflectance Fourier transform IR (FTIR) spectroscopy and colorimetry. Cetyltrimethylammonium bromide was chosen as a model compound to demonstrate the optimization of the method for determination of CTA+ in water samples. The absorption peak at 3015.96 cm-1 (for CTA+) was enhanced when gold nanoparticles were used as a chemical sensor in diffuse reflectance FTIR spectroscopy, and this absorption peak was used for determination of CTA+. Alternatively, the color change from wine red (525 nm) to blue (740 nm) and the redshift of the localized surface plasmon resonance band in the visible region were used as a sensing probe for determination of CTA+. A linear calibration curve for determination in water samples was obtained in the range from 10 to 100 ng mL-1 with a limit of detection of 3 ng mL-1 by diffuse reflectance FTIR spectroscopy and in the range from 20 to 400 ng mL-1 with a limit of detection of 7 ng mL-1 by colorimetry. The advantageous features of the methods are their simplicity, rapidity, and sensitivity for the determination of CTA+ in water samples. Graphical abstract.

Application of functionalized silver nanoparticles as a biochemical sensor for selective detection of lysozyme protein in milk sample.

Silver nanoparticles (AgNPs) functionalized with glutamic acid (GA) was used as a biochemical sensing probe in colorimetry for detection of lysozyme protein in milk samples. The method is based on the color change of AgNPs/GA from yellow to reddish-yellow differentiated with naked eyes for qualitative determination and red shift of localized surface plasmon resonance (LSPR) absorption signal intensity of AgNPs/GA in visible region used for quantitative determination of lysozyme. The control experiments were performed to demonstrate the electrostatic force of interactions between AgNPs/GA and protein molecule. A wide linear range of 3-150 nM with limit of detection of 1.5 nM was acquired for quantitative determination of lysozyme using AgNPs/GA as a biochemical sensing probe. The advantages of using AgNPs/GA as a biochemical sensing probe are simple, label-free and economic for determination of lysozyme from milk samples.

A direct DRS-FTIR probe for rapid detection and quantification of fluoroquinolone antibiotics in poultry egg-yolk.

We report a novel diffuse reflectance-Fourier transforms infrared (DRS-FTIR) spectral monitoring of fluoroquinolone antibiotics such as ciprofloxacin (CIP) and norfloxacin (NOR) for their quantification in poultry egg-yolks. To the best of our knowledge, this is the first report to describe the rapid quantitative determination of fluoroquinolone antibiotics in poultry egg samples using DRS-FTIR. The characteristic absorption peaks obtained at 1627 and 1026 cm-1 were used for optimization and determination of CIP and NOR, respectively. The linearity range obtained for the determination of CIP and NOR in egg samples was 0.05-0.50 ng mL-1 with limit of detection and limit of quantification of 0.032 and 1.551 ng mL-1 and 0.028 and 0.194 ng mL-1, respectively. Good recoveries were obtained in the range of 83.1-102.3% from poultry eggs samples using DRS-FTIR method. The advantages of the DRS-FTIR method are its simplicity, sensitivity and suitability for high-throughput analysis towards the food samples.

PM10 and PM2.5 chemical source profiles with optical attenuation and health risk indicators of paved and unpaved road dust in Bhopal, India.

Size classified (PM10 and PM2.5) paved and unpaved road dust chemical source profiles, optical attenuation and potential health risk from exposure to these sources are reported in this study. A total of 45 samples from 9 paved road and 6 unpaved road sites located in and around Bhopal were re-suspended in the laboratory, collected onto filter substrates and subjected to a variety of chemical analyses. In general, road dust was enriched (compared to upper continental crustal abundance) in anthropogenic pollutants including Sb, Cu, Zn, Co, and Pb. Organic and elemental carbon (OC/EC) in PM10 and PM2.5 size fractions were 50-75% higher in paved road dust compared to their counterparts in unpaved road dust. Further, the results suggest that when it is not possible to include carbon fractions in source profiles, the inclusion of optical attenuation is likely to enhance the source resolution of receptor models. Additionally, profiles obtained in this study were not very similar to the US EPA SPECIATE composite profiles for PM10 and PM2.5, for both sources. Specifically, the mass fractions of Si, Fe, OC, and EC were most different between SPECIATE composite profiles and Bhopal composite profiles. An estimate of health indicators for Bhopal road dust revealed that although Cr was only marginally enriched, its inhalation may pose a health risk. The estimates of potential lifetime incremental cancer risk induced by the inhalation of Cr in paved and unpaved road dust (PM10 and PM2.5) for both adults and children were higher than the baseline values of acceptable risk. These results suggest that road dust Cr induced carcinogenic risk should be further investigated.

Molecular markers in ambient aerosol in the Mahanadi Riverside Basin of eastern central India during winter.

Organic molecular markers are important atmospheric constituents. Their formation and sources are important aspects of the study of urban and rural air quality. We collected PM10 aerosol samples from the Mahanadi Riverside Basin (MRB), a rural part of eastern central India, during the winter of 2011. PM10 aerosols were characterized for molecular markers using ion chromatography. The concentration of PM10 ranged from 208.8 to 588.3 µg m(-3) with a mean concentration of 388.9 µg m(-3). Total concentration of anhydrosugars, sugar alcohols, primary sugars, and oxalate were found to be 3.25, 5.60, 10.52, and 0.37 µg m(-3), respectively, during the study period. Glucose was the most abundant species followed by levoglucosan and mannitol. Significant positive correlation between the molecular markers, anhydrosugars, sugar alcohols, primary sugars, and oxalic acid confirmed that biomass burning, biogenic activity, and re-suspension of soil particles were the main sources of aerosol in the eastern central India study area.

Seasonal air quality profile of size-segregated aerosols in the ambient air of a central Indian region.

Seasonal distribution trends of size-segregated aerosols i.e. submicron (PM1), fine (PM2.5) and coarse (PM2.5-10) and their relationship with meteorological variables employing correlation analysis were studied in the ambient air of central India from July 2009 to June 2010. The annual mean concentrations of PM1, PM2.5 and PM2.5-10 were found to be 65.7, 135.0 and 118.5 µg m(-3), respectively. The annual mean PM2.5 concentration is three times higher than the National Ambient Air Quality Standards of India (NAAQS). Higher concentrations of PM1, PM2.5 and PM2.5-10 were found during winter due to enormous biomass burning especially during night time due to the use of combustible goods like fire wood and dung cake in the open space by the peoples to keep themselves warm and lower concentrations were observed during monsoon when there were high precipitations. PM2.5 showed high positive correlation with PM1 (r = 0.69) and moderate correlation with PM2.5-10 indicating that variation in PM2.5 mass is governed by the variation in PM1 mass or vice versa.

Mass loading of size-segregated atmospheric aerosols in the ambient air during fireworks episodes in eastern Central India.

The effects of combustion of the fire crackers on the air quality in eastern Central India were studied for the first time during Diwali festival. This case study analyzes the size distribution and temporal variation of aerosols collected in the rural area of eastern Central India during pre-diwali, Diwali and post-diwali period for the year of 2011. Fifteen aerosol samples were collected during the special case study of Diwali period using Andersen sampler. The mean concentrations of PM10 (respirable particulate matter) were found to be 212.8 ± 4.2, 555.5 ± 20.2 and 284.4 ± 5.8 during pre-diwali, Diwali and post-diwali period, respectively. During Diwali festival PM10 concentration was about 2.6 and 1.9 times higher than pre-diwali and post-diwali period, respectively. PM2.5 (fine) and PM1 (submicron) concentrations during Diwali festival were more than 2 times higher than pre-diwali and post-diwali.

Aerosol size distribution and seasonal variation in an urban area of an industrial city in central India.

To study the size distribution and seasonal variations of atmospheric aerosols, size-segregated aerosol samples were collected from July 2009 to June 2010 using the nine-stage cascade impactor aerosol sampler in Durg City, India. The aerosol particles exhibited bimodal size distribution on mass concentration with a peak at 2.5-4.4 µm size ranges in the coarse mode and 2.1-2.5 µm size ranges in the fine mode. The aerosol mass and size distribution during monsoon were found unimodal distribution with a peak in the coarse mode, while they showed trimodal distributions during winter with all three peaks appearing in the fine mode. The annual mean concentration of PM(10) aerosol was found to be 253.5 ± 99.4 µg/m(3), which is four times higher as compared to the annual guideline of National Ambient Air Quality Standards (NAAQS) of India prescribed by the Central Pollution Control Board (CPCB), India. The highest aerosol mass concentrations were found during winter due to enormous biomass burning, while the lowest concentrations were observed during monsoon due to heavy rainfall. Air quality index values calculated in this study showed that 35% of the days were unhealthy for sensitive people, 35% were unhealthy or very unhealthy, while 3.3% were found as hazardous in Durg City, India.