Black Carbon and Elemental Carbon from Postharvest Agricultural-Waste Burning Emissions in the Indo-Gangetic Plain

We compare the mass concentrations of black carbon (BC) and elemental carbon (EC) from different emissions in the Indo-Gangetic Plain (IGP), using optical (Aethalometer; 880 nm) and thermooptical technique (EC-OC analyzer; 678 nm), respectively. The fractional contribution of BC mass concentration measured at two different channels (370 and 880 nm), OC/EC ratio, and non-sea-salt K+/EC ratios have been systematically monitored for representing the source characteristics of BC and EC in this study. The mass concentrations of BC varied from 8.5 to 19.6, 2.4 to 18.2, and 2.2 to 9.4 μg m−3 during October-November (paddy-residue burning emission), December–March (emission from bio- and fossil-fuel combustion) and April-May (wheat-residue burning emission), respectively. In contrast, the mass concentrations of EC varied from 3.8 to 17.5, 2.3 to 8.9, and 2.0 to 8.8 μg m−3 during these emissions, respectively. The BC/EC ratios conspicuously greater than 1.0 have been observed during paddy-residue burning emissions associated with high mass concentrations of EC, OC, and OC/EC ratio. The Ångström exponent (α) derived from Aethalometer data is approximately 1.5 for the postharvest agricultural-waste burning emissions, hitherto unknown for the IGP. The mass absorption efficiency (MAE) of BC and EC centers at ~1–4 m2 g−1 and 2-3 m2 g−1 during the entire study period in the IGP

Effects of Crop Residue Burning on Aerosol Properties, Plume Characteristics, and Long-Range Transport over Northern India

Aerosol emissions from biomass burning are of specific interest over the globe due to their strong radiative impacts and climate implications. The present study examines the impact of paddy crop residue burning over northern India during the postmonsoon (October-November) season of 2012 on modification of aerosol properties, as well as the long-range transport of smoke plumes, altitude characteristics, and affected areas via the synergy of ground-based measurements and satellite observations. During this period, Moderate Resolution Imaging Spectroradiometer (MODIS) images show a thick smoke/hazy aerosol layer below 2-2.5 km in the atmosphere covering nearly the whole Indo-Gangetic Plains (IGP). The air mass trajectories originating from the biomass-burning source region over Punjab at 500 m reveal a potential aerosol transport pathway along the Ganges valley from west to east, resulting in a strong aerosol optical depth (AOD) gradient. Sometimes, depending upon the wind direction and meteorological conditions, the plumes also influence central India, the Arabian Sea, and the Bay of Bengal, thus contributing to Asian pollution outflow. The increased number of fire counts (Terra and Aqua MODIS data) is associated with severe aerosol-laden atmospheres (AOD(500 nm) \u3e 1.0) over six IGP locations, high values of Angstrom exponent (\u3e1.2), high particulate mass 2.5 (PM2.5) concentrations (\u3e100-150 mu gm(-3)), and enhanced Ozone Monitoring Instrument Aerosol Index gradient (similar to 2.5) and NO2 concentrations (similar to 6 x 10(15) mol/cm(2)), indicating the dominance of smoke aerosols from agricultural crop residue burning. The aerosol size distribution is shifted toward the fine-mode fraction, also exhibiting an increase in the radius of fine aerosols due to coagulation processes in a highly turbid environment. The spectral variation of the single-scattering albedo reveals enhanced dominance of moderately absorbing aerosols, while the aerosol properties, modification, and mixing atmospheric processes differentiate along the IGP sites depending on the distance from the aerosol source, urban influence, and local characteristics

Optical and Radiative Properties of Aerosols over Two Locations in the North-West Part of India during Premonsoon Season

The present study examines the aerosol characteristics over two locations in the northwest region of India (Dehradun and Patiala) during premonsoon season of 2013. The average mass concentrations of particulates (PM10; PM2.5; PM1) were found to be 118±36, 34±11, and 19±10 µgm−3 and 140±48, 30±13, and 14±06 µgm−3 over Dehradun and Patiala, respectively. The average aerosol optical depth (AOD500 nm) is observed to be 0.62±0.11 over Dehradun and 0.56±0.21 over Patiala. Ångström exponent and fine mode fraction show higher values over Dehradun as compared to Patiala. The average mass concentration of black carbon was found to be 3343±546 ngm−3 and 6335±760 ngm−3 over Dehradun and Patiala, respectively. The diurnal pattern of BC is mainly controlled by boundary layer dynamics and local anthropogenic activities over both the stations. The average single scattering albedo (SSA500 nm) exhibited low value over Patiala (0.83±0.01) in comparison to Dehradun (0.90±0.01), suggesting the abundance of absorbing type aerosols over Patiala. The average atmospheric aerosol radiative forcing is +37.34 Wm−2 and +54.81 Wm−2 over Dehradun and Patiala, respectively, leading to atmospheric heating rate of 1.0 K day−1 over Dehradun and 1.5 K day−1 over Patiala

Highly time-resolved chemical speciation and source apportionment of organic aerosol components in Delhi, India, using extractive electrospray ionization mass spectrometry

In recent years, the Indian capital city of Delhi has been impacted by very high levels of air pollution, especially during winter. Comprehensive knowledge of the composition and sources of the organic aerosol (OA), which constitutes a substantial fraction of total particulate mass (PM) in Delhi, is central to formulating effective public health policies. Previous source apportionment studies in Delhi identified key sources of primary OA (POA) and showed that secondary OA (SOA) played a major role but were unable to resolve specific SOA sources. We address the latter through the first field deployment of an extractive electrospray ionization time-of-flight mass spectrometer (EESI-TOF) in Delhi, together with a high-resolution aerosol mass spectrometer (AMS). Measurements were conducted during the winter of 2018/19, and positive matrix factorization (PMF) was used separately on AMS and EESI-TOF datasets to apportion the sources of OA. AMS PMF analysis yielded three primary and two secondary factors which were attributed to hydrocarbon-like OA (HOA), biomass burning OA (BBOA-1 and BBOA-2), more oxidized oxygenated OA (MO-OOA), and less oxidized oxygenated OA (LO-OOA). On average, 40 % of the total OA mass was apportioned to the secondary factors. The SOA contribution to total OA mass varied greatly between the daytime (76.8 %, 10:00–16:00 local time (LT)) and nighttime (31.0 %, 21:00–04:00 LT). The higher chemical resolution of EESI-TOF data allowed identification of individual SOA sources. The EESI-TOF PMF analysis in total yielded six factors, two of which were primary factors (primary biomass burning and cooking-related OA). The remaining four factors were predominantly of secondary origin: aromatic SOA, biogenic SOA, aged biomass burning SOA, and mixed urban SOA. Due to the uncertainties in the EESI-TOF ion sensitivities, mass concentrations of EESI-TOF SOA-dominated factors were related to the total AMS SOA (i.e. MO-OOA + LO-OOA) by multiple linear regression (MLR). Aromatic SOA was the major SOA component during the daytime, with a 55.2 % contribution to total SOA mass (42.4 % contribution to total OA). Its contribution to total SOA, however, decreased to 25.4 % (7.9 % of total OA) during the nighttime. This factor was attributed to the oxidation of light aromatic compounds emitted mostly from traffic. Biogenic SOA accounted for 18.4 % of total SOA mass (14.2 % of total OA) during the daytime and 36.1 % of total SOA mass (11.2 % of total OA) during the nighttime. Aged biomass burning and mixed urban SOA accounted for 15.2 % and 11.0 % of total SOA mass (11.7 % and 8.5 % of total OA mass), respectively, during the daytime and 15.4 % and 22.9 % of total SOA mass (4.8 % and 7.1 % of total OA mass), respectively, during the nighttime. A simple dilution–partitioning model was applied on all EESI-TOF factors to estimate the fraction of observed daytime concentrations resulting from local photochemical production (SOA) or emissions (POA). Aromatic SOA, aged biomass burning, and mixed urban SOA were all found to be dominated by local photochemical production, likely from the oxidation of locally emitted volatile organic compounds (VOCs). In contrast, biogenic SOA was related to the oxidation of diffuse regional emissions of isoprene and monoterpenes. The findings of this study show that in Delhi, the nighttime high concentrations are caused by POA emissions led by traffic and biomass burning and the daytime OA is dominated by SOA, with aromatic SOA accounting for the largest fraction. Because aromatic SOA is possibly more toxic than biogenic SOA and primary OA, its dominance during the daytime suggests an increased OA toxicity and health-related consequences for the general public.</p

Performance Evaluation of Aodv and Dsr Routing Protocols for Vbr Traffic for 150

Mobile Ad hoc network (MANETs) is rapidly growing as an important area of wireless communication with the revolutionary inventions in the mobile devices. Efficient routing protocols make MANETs reliable. Despite the considerable simulation works, still more investigation is required in the performance evaluation of routing protocols for multimedia traffic especially Variable Bit Rate(VBR).In this paper, we will conduct a number of simulations for the performance evaluation of two popular routing protocols of MANET, namely AODV and DSR, for VBR multimedia traffic using Real Time Protocol(RTP).We will investigate the performance using four metrics-packet received, throughput, routing overhead and network load

Inter and Intra-Annual Variability in Aerosol Characteristics over Northwestern Indo-Gangetic Plain

This study reports the temporal characteristics of aerosols mass concentration (PM10, PM2.5, PM1), size distribution and optical depth from Dec-2011 to Nov-2013 over Patiala (30.33°N, 76.40°E, 249 a.s.l.), a site located in Indo-Gangetic Plain (IGP) in northwestern India, a region with highest population density in the world. PM10, PM2.5, and PM1 varied from 71 to 221, 27 to 92, and 17 to 75 µg/m3, respectively, with highest concentration of PM10 during summer of 2012, and PM2.5 and PM1 during autumn of 2013. These mass concentrations were significantly higher than National Ambient Air Quality (NAAQ) standards (PM10 = 60 and PM2.5 = 40 µg/m3), suggesting the poor quality of air over IGP. Both natural and anthropogenic sources were found to be responsible for poor air quality of IGP with more contribution from latter source as inferred from Ångström exponent (α380–870) and fine mode fraction (FMF: PM2.5/PM10) of aerosols, which have shown large temporal variability. The particle size distribution is skewed towards particles with size less than 1.00 µm and very few particles are having the size greater than 6.25 µm. Aerosol optical depth at 500 nm (AOD500) ranged from 0.36 to 0.64 and shows highest value during summer of 2012 (0.64 ± 0.09) and autumn of 2013 (0.64 ± 0.25) and minimum (0.36 ± 0.05) in spring of 2013, further reflecting the different effects of aerosols on climate during different seasons. The relation between AOD500 and PM mass has also been investigated, which has exhibited significant seasonality and AOD500 is more sensitive towards the concentration of PM1 rather than PM2.5 and PM10. These results give insight to the relativ

Effect of Seed Meals on Weed Control and Soil Physical Properties in Direct-Seeded Pumpkin

Mustard (Brassica sp.) seed meal (MSM) and sunflower (Helianthus annuus L.) seed meal (SSM) are the byproducts of the seed oil extraction process. They release biologically active allelochemicals that can provide a resource for supplemental nutrients and weed suppression in vegetable cropping systems. Our field experiment aimed to assess the phytotoxic impact of MSM and SSM on weeds and seedling establishment of direct-seeded pumpkin under semi-arid conditions and to study the impact of MSM and SSM on soil physical properties and soil water retention characteristics. The meals were incorporated into the soil 2 weeks before pumpkin planting at two rates (1150 and 2250 kg ha&minus;1). MSM at both rates reduced early season grass and broadleaf weeds by 75 to 82% and 69 to 76%, respectively, as compared to the untreated control. However, SSM at both rates provided 59 to 65% and 54 to 59% controls of narrow and broadleaf weeds, respectively. Both MSM and SSM provided significantly better weed control and pumpkin yield as compared to the untreated control, but higher pumpkin yield was recorded with a lower rate of MSM. In addition, soils amended by both the seed meals had higher saturated hydraulic conductivity, soil water content, and lower bulk density than the untreated control. Overall, our findings suggest that the use of both MSM and SSM as an organic adjuvant is effective in controlling weeds and improving soil physical properties; however, additional research is required to further evaluate these findings and improve the reliability of MSM and SSM for weed suppression following application to agricultural soils

Prosthodontic rehabilitation of AIDS Patients: An Overview

Procurement for high standard of oral hygiene is a cardinal requirement for any individual and dentists constantly aim to provide optimal treatment to their patients. However, when it comes to treat patients with immunocompromised diseases, particularly those attached with social stigma like AIDS/HIV, there remain doubts and hesitations. This may lead the dentists to break the ethical responsibility by abjuring or not providing adequate treatment to these patients. Such situations can easily be avoided with absolute knowledge and awareness among the oral health-care providers including prosthodontist regarding the disease process, its connotations and measures to be taken during their treatment. This article summarizes the fundamental points in the prosthodontic management of immunocompromised patients which in the opinion of the author may be easily consolidated in dental practice

Simulation of root zone soil water dynamics under cotton-silverleaf nightshade interactions in drip-irrigated cotton

The uncontrolled establishment of weeds in upland cotton (Gossypium hirsutum L.), especially perennial silverleaf nightshade (Solanum elaeagnifolium), reduces lint yield and quality of cotton primarily by competing with cotton to limit essential resources such as water. Quantitative insight into the effects of cotton-silverleaf nightshade interactions on the root water uptake (RWU) in cotton is needed to develop weed management systems, particularly based on the critical periods of competitive water uses. A field experiment was conducted during two consecutive cotton growing seasons (2019–2020) to evaluate root zone soil water dynamics in subsurface drip-irrigated cotton under three treatments: only cotton plants (CP), only silverleaf nightshade plants (SNP), and cotton-silverleaf nightshade plants grown together (CP-SNP). The numerical model HYDRUS (2D/3D) was calibrated and validated using experimental data under the CP, SNP, and CP-SNP systems. The results of numerical simulations suggested that the HYDRUS (2D/3D) provided an effective tool for helping to understand and predict soil water dynamics and RWU under the CP-SNP competitive interactions at different cotton growth stages. Simulations showed that actual RWU (i.e., transpiration) and evapotranspiration rates remained higher under the CP-SNP treatment during two consecutive growing seasons, and RWU and evapotranspiration rates were in the order of CP-SNP > SNP > CP. The temporal variations in cumulative transpiration, evaporation, and drainage fluxes revealed that RWU solely contributed to higher evapotranspiration rates under the CP-SNP system as the magnitudes and patterns of evaporation and drainage fluxes remained similar among all the treatments. The temporal variations in RWU patterns at different cotton growth stages suggested that higher competitive RWU under the CP-SNP system than CP and SNP occurred during cotton’s leaf development and flowering growth stages, indicating critical periods for competitive soil water uses. Weed control measures during these critical periods are essential to minimize competitive water uses under the CP-SNP system in semiarid environments