| 1. |
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- 2017
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In: Physical Review D. - 2470-0010 .- 2470-0029. ; 96:2
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Journal article (peer-reviewed)
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| 2. |
- Bisht, D. S., et al.
(author)
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Tethered balloon-born and ground-based measurements. of black carbon and particulate profiles within the lower troposphere during the foggy period in Delhi, India
- 2016
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 573, s. 894-905
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Journal article (peer-reviewed)abstract
- The ground and vertical profiles of particulate matter (PM) were mapped as part of a pilot study using a Tethered balloon within the lower troposphere (1000 m) during the foggy episodes in the winter season of 2015-16 in New Delhi, India. Measurements of black carbon (BC) aerosol and PM <2.5 and 10 mu m (PM2.5 &PM-10 respectively) concentrations and their associated particulate optical properties along with meteorological parameters were made. The mean concentrations of PM2.5, PM10, BC370 (nm), and BC880 nm were observed to be 146.8 +/- 42.1, 245.4 +/- 65.4, 30.3 +/- 122, and 24.1 +/- 103 mu g m(-3), respectively. The mean value of PM2.5 was similar to 12 times higher than the annual US-EPA air quality standard. The fraction of BC in PM2.5 that contributed to absorption in the shorter visible wavelengths (BC370 nm) was-21%. Compared to clear days, the ground level mass concentrations of PM2.5 and BC370 nm particles were substantially increased (59% and 24%, respectively) during the foggy episode. The aerosol light extinction coefficient (sigma(ext)) value was much higher (mean: 610 Mm(-1)) during the lower visibility (foggy) condition. Higher concentrations of PM2.5 (89 mu g m(-3)) and longer visible wavelength absorbing BC880 am (25.7 mu g m(-3)) particles were observed up to 200 m. The BC880 nm and PM2.5 aerosol concentrations near boundary layer (1 km) were significantly higher (similar to 1.9 and 12 mu g m(-3)), respectively. The BC (i.e BCtot) aerosol direct radiative forcing (DRF) values were estimated at the top of the atmosphere (TOA), surface (SFC), and atmosphere (ATM) and its resultant forcing were- 75.5 Wm(-2) at SFC indicating the cooling effect at the surface. A positive value (20.9 Wm(-2)) of BC aerosol DRF at TOA indicated the warming effect at the top of the atmosphere over the study region. The net DRF value due to BC aerosol was positive (96.4 Wm(-2)) indicating a net warming effect in the atmosphere. The contribution of fossil and biomass fuels to the observed BC aerosol DRF values was -78% and-22%, respectively. The higher mean atmospheric heating rate (2.71 K clay(-1)) by BC aerosol in the winter season would probably strengthen the temperature inversion leading to poor dispersion and affecting the formation of clouds. Serious detrimental impacts on regional climate due to the high concentrations of BC and PM (especially PM2.5) aerosol are likely based on this study and suggest the need for immediate, stringent measures to improve the regional air quality in the northern India.
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| 3. |
- Tiwari, Suresh, et al.
(author)
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Assessment of PM2.5 and PM10 over Guwahati in Brahmaputra River Valley : Temporal evolution, source apportionment and meteorological dependence
- 2017
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In: Atmospheric Pollution Research. - : Elsevier BV. - 1309-1042. ; 8:1, s. 13-28
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Journal article (peer-reviewed)abstract
- Temporal evolution, source apportionment and transport pathways of particulate matter (PM2.5 and PM10) are analysed over Guwahati, located in the Brahmaputra River Valley (BRV), as a function of meteorological dynamics. During the study period (July 2013-June 2014), the mean PM2.5 and PM10 mass concentrations were found to be 52 +/- 37 and 91 +/- 60 mu g m (-3), respectively, both exhibiting higher concentrations during DecembereMarch and very low during summer. The annual mean ratio of PM2.5/ PM10 was 0.57 +/- 0.11, varying from 0.24 to 0.86, suggesting dominance of anthropogenic vs natural emissions during winter and spring, respectively. Diurnal variation reveals higher PM concentrations during morning (similar to 9: 00 local time (LT)) and evening (similar to 23: 00 LT) and lowest around similar to 14: 00 to 17: 00 LT due to influence of dilution processes and higher mixing-layer height over the region. Bivariate plots and Conditional Bivariate Probability Function (CBPF) analysis showed that the highest PM2.5 and PM10 concentrations are mostly associated with weak northwestern winds (< 1.5 ms (- 1)) in all seasons except spring, when the highest PM10 are for southwestern winds above 4-6 ms(- 1), indicating dust transport from SW Asia. Analysis reveals that the local emissions, transported aerosols, along with seasonallychanged air masses, meteorology and boundary-layer dynamics control the concentrations, evolution and fractions of PM over BRV. The turbid air masses transported over Guwahati mostly from western and southwestern directions contribute to higher PM concentrations, either carrying anthropogenic pollution from Indo-Gangetic Plains or locally and LRT dust from BRV and western India, respectively.
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| 4. |
- Tiwari, Suresh, et al.
(author)
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Observations of ambient trace gas and PM10 concentrations at Patna, Central Ganga Basin during 2013-2014 : The influence of meteorological variables on atmospheric pollutants
- 2016
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In: Atmospheric research. - : Elsevier BV. - 0169-8095 .- 1873-2895. ; 180, s. 138-149
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Journal article (peer-reviewed)abstract
- Atmospheric pollutants including ozone (O-3), sulfur dioxide (SO2), oxides of nitrogen (NOx), carbon monoxide (CO), and inhalable particulate matter (PM10) were measured in the central Indo-Gangetic Basin (IGB) at Patna, India, from 1st March 2013 to 31st December 2014, and significant variability was observed in the temporal patterns of these pollutant concentrations. The mean O-3, SO2, NO, NO2, CO (trace gases: TG), and PM10 (PM) concentrations were 14.5 +/- 4.8, 5.9 +/- 4.8, 23.1 +/- 22, 20.6 +/- 14.6 ppb, 1.5 +/- 0.7 ppm, and 192.0 +/- 132.8 ng/m(3), respectively, over the study period. The highest concentrations of these species were during the post-monsoon and winter seasons except O-3 and SO2 that showed the highest concentrations during the pre-monsoon. The lowest concentrations of TG and PM were observed during the monsoon season as a result of scavenging by rain. NO and NO2 along with PM concentrations decreased by similar to 76,19, and 63% when the wind speed (WS) was >0.5 m/s. However, for O-3, an opposite trend was observed with similar to 14% higher concentrations. The WS was negatively correlated with PM during the winter (-0.48) and post-monsoon (-0.32) seasons. In order to investigate the source region of TG and PM, 5-day air mass back trajectories were computed. The dominance of the air masses (92, 53, and 49%) were from the IGB is highly polluted during the winter, pre-monsoon, and post-monsoon, respectively. The TG and PM were observed much higher during these periods. During the biomass burning period (post-monsoon), the trajectory analysis showed that the TG and PM concentrations were around three-fold higher (flow from the IGB) than the other seasons. To improve air quality over IGB, the mitigation measures should be designed to reduce emissions from both local and regional sources.
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| 5. |
- Bharmoria, Pankaj, 1985, et al.
(author)
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Protein-olive oil-in-water nanoemulsions as encapsulation materials for curcumin acting as anticancer agent towards MDA-MB-231 cells
- 2021
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 11:1, s. 9099-9099
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Journal article (peer-reviewed)abstract
- The sustainable cellular delivery of the pleiotropic drug curcumin encounters drawbacks related to its fast autoxidation at the physiological pH, cytotoxicity of delivery vehicles and poor cellular uptake. A biomaterial compatible with curcumin and with the appropriate structure to allow the correct curcumin encapsulation considering its poor solubility in water, while maintaining its stability for a safe release was developed. In this work, the biomaterial developed started by the preparation of an oil-in-water nanoemulsion using with a cytocompatible copolymer (Pluronic F 127) coated with a positively charged protein (gelatin), designed as G-Cur-NE, to mitigate the cytotoxicity issue of curcumin. These G-Cur-NE showed excellent capacity to stabilize curcumin, to increase its bio-accessibility, while allowing to arrest its autoxidation during its successful application as an anticancer agent proved by the disintegration of MDA-MB-231 breast cancer cells as a proof of concept.
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| 6. |
- Bikkina, Srinivas, et al.
(author)
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Air quality in megacity Delhi affected by countryside biomass burning
- 2019
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In: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 2:3, s. 200-205
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Journal article (peer-reviewed)abstract
- South Asian megacities are strong sources of regional air pollution. Delhi is a key hotspot of health-and climate-impacting black carbon (BC) emissions, affecting environmental sustainability in densely populated northern India. Effective mitigation of BC impact is hampered by highly uncertain emission source estimates. Here, we use dual-carbon isotope fingerprints (delta C-13/Delta C-14) of BC to constrain the seasonal source variability in Delhi. These measurements show that lower BC concentrations in summer are predominantly from fossil fuel sources (similar to 83%). However, large-scale open burning of post-harvest crop residue/wood in nearby rural regions is contributing to severe haze pollution in Delhi during winter and autumn (similar to 42 +/- 17%). Hence, the common conception that megacities affect their surroundings is here amended or seasonally reversed. Therefore, to combat the severe air pollution problems in Delhi and the environmental quality of northern India, current urban efforts need to be complemented with countryside regional mitigation.
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| 7. |
- Rao, P. S. P., et al.
(author)
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Sources of chemical species in rainwater during monsoon and non-monsoonal periods over two mega cities in India and dominant source region of secondary aerosols
- 2016
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 146, s. 90-99
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Journal article (peer-reviewed)abstract
- Samples of rainwater (RW) were collected to characterize the chemistry and sources in two representative megacities at Pune (Southwest) and Delhi (Northern) India from 2011 to 2014 across two seasons: monsoon (MN) and non-monsoon (NMN). Collected RW samples were analyzed for major chemical constituents (F-, Cl-, SO42-, NO3-, NH4+, Na+, K+, Ca2+, and Mg2+), pH and conductivity. In addition, bicarbonate (HCO3-) was also estimated. The mean pH values of the RW were >6 at Pune and <6 at Delhi and 4% and 26% were acidic, respectively. The mean sum of all measured ionic species in Pune and Delhi was 304.7 and 536.4 mu ep/l, respectively, indicating that significant atmospheric pollution effects in these Indian mega cities. Both the Ca2+ and SO42- were the dominant ions, accounting for 43% (Pune) and 54% (Delhi) of the total ions. The sum of measured ions during the NMN period was greater than the NM period by a factor of 1.5 for Pune (278.4: NM and 412.1: NMN mu eq/l) and a factor of about 2.5 for Delhi (406 and 1037.7 mu eq/l). The contributions of SO42- and NO3- to the RW acidity were similar to 40% and 60%, respectively, at Pune and correspondingly, 36% and 64% at Delhi. The concentrations of secondary aerosols (SO42- and NO3-) were higher by a factor of two and three when the air masses were transported to Pune from the continental side. At Delhi, the concentrations of SO42-, NO3-, Ca2+, and Mg2+ were significantly higher when the air masses arrive from Punjab, Haryana, and Pakistan indicating the greater atmospheric pollution over the Indo-Gangetic Plain. Positive matrix factorization was applied to the source apportionment of the deposition fluxes of these ions. Three factors were obtained for Pune and four for Delhi. The sources at Pune were secondary aerosols from fossil fuel combustion, soil dust, and marine, whereas, at Delhi, the sources were soil, fossil fuel combustion, biomass burning, and industrial chlorine.
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| 8. |
- Tiwari, Suresh, et al.
(author)
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Atmospheric heating due to black carbon aerosol during the summer monsoon period over Ballia : A rural environment over Indo-Gangetic Plain
- 2016
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In: Atmospheric research. - : Elsevier BV. - 0169-8095 .- 1873-2895. ; 178, s. 393-400
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Journal article (peer-reviewed)abstract
- Black carbon (BC) aerosols are one of the most uncertain drivers of global climate change. The prevailing view is that BC mass concentrations are low in rural areas where industrialization and vehicular emissions are at a minimum. As part of a national research program called the Ganga Basin Ground Based Experiment-2014 under the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) Phase-III of Ministry of Earth Sciences, Government of India, the continuous measurements of BC and particulate matter (PM) mass concentrations, were conducted in a rural environment in the highly-polluted Indo-Gangetic Plain region during 16th June to 15th August (monsoon period), 2014. The mean mass concentration of BC was 4.03 (+/- 0.85) mu g m(-3) with a daily variability between 2.4 and 5.64 mu g m(-3), however, the mean mass PM concentrations [near ultrafine (PM1.0), fine (PM2.5) and inhalable (PM1.0)] were 29.1(+/- 16.2), 34.7 (+/- 19.9) and 43.7 (+/- 283) mu g m(-3), respectively. The contribution of BC in PM1.0 was approximately 13%, which is one of the highest being recorded. Diurnally, the BC mass concentrations were highest (mean: 5.89 mu g m(-3)) between 20:00 to 22:00 local time (LT) due to the burning of biofuels/biomass such as wood, dung, straw and crop residue mixed with dung by the local residents for cooking purposes. The atmospheric direct radiative forcing values due to the composite and BC aerosols were determined to be +78.3, +44.9, and +45.0 W m(-2) and +42.2, +35.4 and +34.3 W m(-2) during the months ofJune, July and August, respectively. The corresponding atmospheric heating rates (AHR) for composite and BC aerosols were 2.21,1.26 and 1.26; and 1.19, 0.99 and 0.96 K day(-1) for the month ofJune, July and August, respectively, with a mean of 1.57 and 1.05 K day(-1) which was 33% lower AHR (BC) than for the composite particles during the study period. This high AHR underscores the importance of absorbing aerosols such as BC contributed by residential cooking using biofuels in India. Our study demonstrates the need for immediate, effective regulations and policies that mitigate the emission of BC particles from domestic cooking in rural areas of India.
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| 9. |
- Tiwari, S., et al.
(author)
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Simultaneous measurements of black carbon and PM2.5, CO, and NOx variability at a locally polluted urban location in India
- 2015
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In: Natural Hazards. - : Springer Science and Business Media LLC. - 0921-030X .- 1573-0840. ; 75:1, s. 813-829
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Journal article (peer-reviewed)abstract
- Black carbon, which is a by-product of incomplete combustion of carbon containing fuels, can alter atmospheric radiation property and make adverse impacts on human health. This paper shows the comparative study of particles and associated gaseous pollutants measurements at five observatories dispersed across central part of megacity Delhi, India, with high-temporal resolution (5 min) measurements. The mean +/- SD concentrations of black carbon (BC), fine particles (PM2.5), carbon monoxide (CO), and oxides of nitrogen (NOx) of the all five stations were 13.4 +/- 10, 149.6 +/- 109 mu g m(-3), 3.4 +/- 2 ppm, and 81.8 +/- 79 ppb, respectively. The mean mass concentration of PM2.5 was approximately four times and ten times in excess of annual average standards of Indian air quality (40 mu g m(-3)) and USEPA (15 mu g m(-3)) levels. Highest BC mass concentrations were recorded during winter (December) due to consistent with a shallower atmospheric boundary layer, lower wind speeds, and possibly larger biofuel burning in the coldest period. Also, the strong diurnal dynamics in boundary layer height had a large impact on the ground-level concentrations of all the pollutants. A significant difference in the emissions of atmospheric pollutants was observed over Delhi during weekdays and weekends during study period. There was a strong diurnal effect on BC and the other pollutants, presumably with mixing height as a strong driver. The 24-h cycle is characterized throughout the study by maximum concentrations around midnight and lowest concentrations at 1500-1700 hours local time (LT), with a local maximum between 0800 and 1000 hours LT, presumably due to morning rush hour. While the amplitude of the BC excursion was a factor of 2-3, the mixing height decreased by a factor of 12-14 from day to night. This monitoring program contributed to insights into the levels and dynamics of atmospheric pollutants in the New Delhi megacity over a 5-month period. The concentrations are varying over several timescales, consistent with both atmospheric mixing and variations in presumed emission source strengths.
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