Ranjit Kumar | Dayalbagh Educational Institute (original) (raw)

Papers by Ranjit Kumar

Dry deposition of S (s ulphur) as sulphate on white marble (natural surfaces) has been measured a... more Dry deposition of S (s ulphur) as sulphate on white marble (natural surfaces) has been measured at Dayalbagh, a suburban site of semi-arid region of Indi a, in winter season (December 1999-March 2000). Samples were collected by exposing the white marble for 24 h and analyzed by Dionex Dx-500 Ion Chromatograph system. Atmospheric concentration of S0 2 was 7.8 ± 2.0 !lg m-3 and particulate sulphate was 7.9 ± 1.8 !lg m-3. The dry d. eposition of S as sulphate has been found to be 0.19 ± 0.12 mg m-2 h-1. The percentage con tribution of the particulate su lphate (78.9) was hi gher than that of gas phase (21. 1). The calculated dry deposition velocity (Vd) of particulate sulph ate has been found to be 0.53 ± 0.27 em s-I. The Vd calculated by present method is lower than that reported by throughfall method, while Vct range is comparable to other methods like foliar extraction, micrometeorological and surrogate methods.

This paper deals with measurements of aerosol, their chemical properties and precursor trace gase... more This paper deals with measurements of aerosol, their chemical properties and precursor trace gases at Agra in the Indo-Gangetic plain during ISRO-GBP special aerosol land campaign II. Aerosol and trace gas sampling as well a meteorological parameters monitoring were carried out at Dayalbagh, a suburban site of Agra during campaign in December 2004 along with seven other stations in India. The average TSPM level was 441.2 µg m-3 and ranges between 60.8 µg m-3 and 1004.6 µg m-3 and was higher than National Ambient Air Quality Standard values of India. The high load SPM in this region may be probably due to industrial-vehicular emissions of sulphur and nitrogen oxides, transport of soil-sand dust from local agricultural field and Thar Desert of Rajasthan and long range transported pollutants. Meteorological study revealed that high wind speed and wind from North West direction influences the aerosol load as it may be long range transported. TSP load was higher during initial foggy and ...

Proceedings of the National Academy of Sciences, 2012

There is interest in the role of ammonia on Saturn’s moons Titan and Enceladus as the presence of... more There is interest in the role of ammonia on Saturn’s moons Titan and Enceladus as the presence of water, methane, and ammonia under temperature and pressure conditions of the surface and interior make these moons rich environments for the study of phases formed by these materials. Ammonia is known to form solid hemi-, mono-, and dihydrate crystal phases under conditions consistent with the surface of Titan and Enceladus, but has also been assigned a role as water-ice antifreeze and methane hydrate inhibitor which is thought to contribute to the outgassing of methane clathrate hydrates into these moons’ atmospheres. Here we show, through direct synthesis from solution and vapor deposition experiments under conditions consistent with extraterrestrial planetary atmospheres, that ammonia forms clathrate hydrates and participates synergistically in clathrate hydrate formation in the presence of methane gas at low temperatures. The binary structure II tetrahydrofuran + ammonia, structure ...

This communication presents simultaneous measurements of atmospheric concentration of gaseous SO ... more This communication presents simultaneous measurements of atmospheric concentration of gaseous SO 2 , NO 2 , HNO 3 and NH 3 at Dayalbagh, a suburban site and at St. John's, an urban site at Agra (India). The concentration of SO 2 , NO 2 , HNO 3 and NH 3 in vapour phase is 3.5 ± ± 1.4, 5.4 ± ± 1.5, 1.5 ± ± 0.8 and 10.5 ± ± 2.4 µ µg m-3 respectively at Dayalbagh, while at St John's corresponding values are 4.1 ± ± 1.2, 8.6 ± ± 1.8, 2.4 ± ± 1.0 and 6.6 ± ± 1.8 µ µg m-3 , respectively. The high concentration of SO 2 , NO 2 and HNO 3 at the St. John's site may be due to industries nearby and high vehicular traffic, while high concentration of NH 3 at the Dayalbagh site may be due to the stockyard nearby and also agricultural practices. Seasonally, SO 2 and NO 2 showed highest concentration in winter and lowest during the monsoon. This is because of high fuel usage during winter and trapping of the pollutants in the boundary layer due to frequent temperature inversions. HNO 3 showed highest concentration in summer, probably due to intense solar radiation and increased photochemical activity, followed by monsoon and winter. NH 3 showed highest values during the monsoon and lowest during the winter. The high concentration during monsoon may be due to more vegetation and favourable conditions for microbial activity.

Urban Climate, 2015

ABSTRACT This paper deals with measurements of aerosols, their chemical properties and precursor ... more ABSTRACT This paper deals with measurements of aerosols, their chemical properties and precursor trace gases at Agra in the Indo-Gangetic plain. The average TSPM level is 441.2 μg m−3 and ranges between 60.8 μg m−3 and 1004.6 μg m−3 which are higher than National Ambient Air Quality Standard Values of India. High wind speed from North West direction influences the aerosol load. TSPM load is higher during prefoggy/foggy days and lower during post foggy days. NH4+ concentration is highest followed by NO3−, SO42−, Cl−, K+, Ca2+, Na+, Mg2+ and F−. The high concentration of NH4+ may be probably due to nearby cattle yard, use of fertilizers and biogenic emissions. The concentration of trace gases SO2, NO2, HNO3 and NH3 are 20.8 μg m−3, 26.3 μg m−3, 1.6 μg m−3, 18.6 μg m−3, respectively. The transportation of urban plumes may be responsible for high concentration of SO2 and NO2. HNO3/NO3− ratio is less than unity. There was no correlation between SO2 and SO42−. The ratio of SO42− + NO3− + Cl−/NH4+ are 1.8 and 2.3, respectively indicate that acidifying components are not neutralized only by NH4+ ion.

Journal of Geophysical Research, 2003

to natural surfaces e.g., leaf of Ashok (Polyalthia longifolia) and Cassia (Cassia siamea), were ... more to natural surfaces e.g., leaf of Ashok (Polyalthia longifolia) and Cassia (Cassia siamea), were determined at Dayalbagh, a suburban site of semiarid region. Dry deposition flux was highest for Ca 2+ on both Ashok and Cassia while lowest for Na + on Ashok leaf and F À on Cassia leaf. Overall average dry deposition fluxes varied from 0.27 mg m À2 d À1 to 3.98 mg m À2 d À1. The deposition was comparatively higher to Cassia leaf than Ashok. The high deposition flux to Cassia leaf may be due to surface roughness as shown by scanning electron micrographs. The sum of major cations (Na + , K + , Ca 2+ , Mg 2+) and NH 4 + was higher than sum of major anions (F À , Cl À , NO 3 À and SO 4 2À). It indicates that dry deposition at present site is alkaline in nature and difference in the sum of major cations and major anions might be due to unmeasured carbonate and bicarbonate ions as well as organic anions (formate and acetate). Deposition flux of SO 4 2À and NO 3 À is relatively lower than Ca 2+ and Mg 2+. Seasonally dry deposition fluxes were higher in monsoon or summer for cationic species while for anionic species fluxes were higher in winter or monsoon. Average dry deposition velocity of major ions on Ashok and Cassia leaf varied from 0.41 to 2.36 cm s À1 , while seasonally values varied from 0.32 to 4.04 cm s À1. The variation in deposition velocity may be due to meteorological conditions and surface characteristics.

Journal of Atmospheric Chemistry, 2005

Environmental Science & Technology, 2006

This paper presents dry deposition of major ions on tropical foliage (leaves of Ashok (Polyalthia... more This paper presents dry deposition of major ions on tropical foliage (leaves of Ashok (Polyalthia longifolia) and Cassia (Cassia siamea)) at St. John&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s, Agra, an urban site of tropical India on nonrainy, nondewy, and nonfoggy days. The deposition flux was higher on Cassia leaf than Ashok leaf probably due to a rougher surface as shown by scanning electron microscopy. Dry deposition of cations varies from 0.46 to 12.16 mg m(-2) day(-1) while anions vary from 0.04 to 3.24 mg m(-2) day(-1). The percentage contribution of alkaline components is greater than that of acidic components, indicating the alkaline nature of dry deposition. Two-way analysis of variance results reveal significant seasonal variation only for K+, SO4(2-), and F-; however, values varied season to season for Na+, Ca2+, Mg2+, Cl-, NO3-, and NH4+ also. The large seasonal variation in deposition flux may be due to meteorological conditions, diameter of particles, and variation in atmospheric level. SO42- and NO3- show significant correlation, indicating their origin from similar sources while significant correlation between Ca2+ and Mg2+ implies their origin from soil. Poor correlation between Ca2+ and SO4(2-), Ca2+ and NO3-, and Mg2+ and SO4(2-) indicates that in addition to soil other sources also contribute to dry deposition. Low dry deposition fluxes of SO2- and NO3- compared to Ca2+ and Mg2+ may be due to low mass medium diameters of SO4(2-) and NO3- and may be due to uptake through the stomatal pores abundant on leaf surfaces. Factor analysis was employed to identify the sources. F-, Cl, SO4(2-), NO3-, and K+ are grouped together in the first factor, indicating their probable contribution from combustion, Ca2+, Mg2+, and NH4+ are grouped in factor II, which may be attributed to road dust and soil, and factor III includes mainly Na+ and F-, probably contributed from brick-kiln industries. Atmospheric concentrations of F-, Cl-, NOs-, SO4(2-), Na+, K+, Ca2+, Mg2+, and NH4+ were found to be 0.38, 2.28, 1.31, 2.74, 0.44, 0.59, 1.21, 1.2, and 2.29 microg m(-3), respectively.

Chemosphere, 2004

Dry deposition flux of major ions (Na+, K+, Ca2+, Mg2+, NH4+, F-, Cl-, NO3- and SO4(2-) to natura... more Dry deposition flux of major ions (Na+, K+, Ca2+, Mg2+, NH4+, F-, Cl-, NO3- and SO4(2-) to natural surfaces [guava (Psidium guyava) and peepal (Ficus religiosa) leaves] are determined at Rampur, a rural site of semi-arid region of India. Dry deposition flux is the highest for Ca2+ on guava leaves and for NH4+ on peepal leaves. Overall dry deposition flux is higher on guava leaves than of peepal leaves. The variation in deposition flux may be due to surface characteristics (surface roughness) and arrangement of leaves. Peepal leaves are arranged along the axis of the stem, whereas guava leaves are at right angles to the stem. The deposition flux of cations contributes 66% and 76% of dry deposition of all major ions on guava and peepal leaves, respectively as soil is major contributor towards dry deposition flux in tropical regions. ANOVA revealed no significant seasonal difference in deposition, although there is a trend for higher in winter. Deposition velocities of NH4+, NO3- and SO4(2-) are greater on guava leaves than peepal leaves, which can be attributed to the rougher surface of the guava leaf.

Indian Journal of Radio & …, 2008

Journal of Atmospheric Chemistry, 2002

Rainwater samples were collected for the monsoon period of 1988 and 1991–1996 at Dayalbagh (Agra)... more Rainwater samples were collected for the monsoon period of 1988 and 1991–1996 at Dayalbagh (Agra), a suburban site situated in semiaridregion. The mean pH was 7.01 ±1.03 well above 5.6, which is the reference pH. Concentration of Ca2+ was observed to be highest followed by Mg2+, NH4+,SO42-, Cl-,NO3-, Na+, F- and K+. The ratios of SO42- + NO3- andCa2+ +

Atmospheric Environment, 2003

This paper presents the measurements of gaseous SO 2 , NO 2 , HNO 3 and NH 3 and particulate NH 4... more This paper presents the measurements of gaseous SO 2 , NO 2 , HNO 3 and NH 3 and particulate NH 4 + , NO 3 À and SO 4 2À at Rampur, a rural site of semi-arid region of India and annual mean concentrations are 3.772.2, 7.373.7, 0.770.6 and 6.774.2 and 1.070.4, 1.171.3 and 2.671.6 mg m À3 , respectively. Seasonal variation with higher concentration in winter is observed for gaseous SO 2 , NO 2 , and NH 3 and particulate NH 4 +. The concentration of HNO 3 and particulate NO 3 À and SO 4 2À are higher in summer. Summer to winter ratio of HNO 3 and particulate NO 3 À are 3.8 and 1.8, respectively, showing seasonal variation is more pronounced in case of HNO 3 than particulate NO 3 À. The ratio of gaseous NH 3 to particulate NH 4 + (NH 3 /NH 4 +) is more than 1 probably due to basic nature of aerosol. Examination of equilibrium between gaseous NH 3 and HNO 3 and particulate NH 4 NO 3 shows observed equilibrium constant is lower than theoretical equilibrium constant in summer and vice versa in winter.

Major irritants of the environment are global warming, climate change, ozone depletion, acid rain... more Major irritants of the environment are global warming, climate change, ozone depletion, acid rain, visibility impairment etc. Aerosol and its constituents play an important role in climate change, and deposition of atmospheric components to the earth surfaces. Knowledge of chemistry of aerosols is required for the assessment of its role in the total deposition of acidity at the earth's surface

Aerosol and Air Quality Research

Atmospheric and Climate Sciences, 2012

This paper presents dry deposition flux and deposition velocity of atmospheric particles on white... more This paper presents dry deposition flux and deposition velocity of atmospheric particles on white marble and red stone at Dayalbagh, a suburban site of semi arid region, which is 10 km away from the industrial sector of the Agra city where due to agricultural practices vegetation predominates. The wind speed at Agra is mostly in the range of 1-2 m s −1 . The atmospheric calm conditions at Agra in summer, monsoon, and winter seasons are 47%, 35%, and 76%, respectively. Industrial areas of the city are away from Dayalbagh and are located in the NE, E, SE, and SW sectors. The main industrial activities, which are in operation in Agra city and its outskirts, are foundry and forging industry. The other industrial activities in Agra are rubber processing, lime oxidation and pulverization, chemicals, engineering and brick refractory kilns. Dry deposition samples were collected on dry days on white marble and red stone (0.224 m × 0.224 m × 0.02 m) using surface washing method. Both slabs were fixed to an iron stand (1.5 m height) at an angle of about 80 • from the horizontal and exposed for 24 h on the roof of the faculty building. The order of deposition flux on white marble is NH 4