Bringing revolution through quadcopter technology in the field of supplying medicine in the Himalayan regions of Uttarakhand: Case example of Pithoragarh.

BACKGROUND: Quadcopters are used in various forms in the civil arena, from crop insurance to agricultural drones, as loudspeakers for announcing government guidelines, resilience tools in infrastructure monitoring, real-time vehicle detection, etc. However, the usage of quadcopters and hexacopters in supplying medical aid to inhospitable and far-flung terrains is being studied and researched in less detail throughout the globe. AIM: This paper focuses on the basics of quadcopter technology in supplying medicines and its advantages to the affected patients who get life-saving medicines from earlier inaccessible roads. The efficacy of quadcopters in terms of time, economy, and manpower in supplying essential and inescapable medical supplies is exponentially high, especially in the Pithoragarh Region of Uttarakhand State, where the villages are not connected to the roads. METHODS: The road structure of the hilly terrain of Uttarakhand, India, was studied in detail to know the state of people who do not get access to life-saving drugs due to the non-availability of roads near them. RESULTS: The result informs us that the quad/hexacopter if used in abundance can provide a glimmer of hope to people in remote places. CONCLUSION: The quadcopter can provide hope to the residents of the Pithoragarh district of Uttarakhand, India, located in far-flung places devoid of basic medical facilities.

High rise in carbonaceous aerosols under very low anthropogenic emissions over eastern Himalaya, India: Impact of lockdown for COVID-19 outbreak.

The present study has been conducted to investigate the relative changes of carbonaceous aerosols (CA) over a high altitude Himalayan atmosphere with and without (very low) anthropogenic emissions. Measurements of atmospheric organic (OC) and elemental carbon (EC) were conducted during the lockdown period (April 2020) due to global COVID 19 outbreak and compared with the normal period (April 2019). The interesting, unexpected and surprising observation is that OC, EC and the total CA (TCA) during the lockdown (OC: 12.1 ± 5.5 µg m-3; EC: 2.2 ± 1.1 µg m-3; TCA: 21.5 ± 10 µg m-3) were higher than the normal period (OC: 7.04 ± 2.2 µg m-3; EC: 1.9 ± 0.7 µg m-3; TCA: 13.2 ± 4.1 µg m-3). The higher values for OC/EC ratio too was observed during the lockdown (5.7 ± 0.9) compared to the normal period (4.2 ± 1.1). Much higher surface O3 during the lockdown (due to very low NO) could better promote the formation of secondary OC (SOC) through the photochemical oxidation of biogenic volatile organic compounds (BVOCs) emitted from Himalayan coniferous forest cover. SOC during the lockdown (7.6 ± 3.5 µg m-3) was double of that in normal period (3.8 ± 1.4 µg m-3). Regression analysis between SOC and O3 showed that with the same amount of increase in O3, the SOC formation increased to a larger extent when anthropogenic emissions were very low and biogenic emissions dominate (lockdown) compared to when anthropogenic emissions were high (normal). Concentration weighted trajectory (CWT) analysis showed that the anthropogenic activities over Nepal and forest fire over north-east India were the major long-distant sources of the CA over Darjeeling during the normal period. On the other hand, during lockdown, the major source regions of CA over Darjeeling were regional/local. The findings of the study indicate the immense importance of Himalayan biosphere as a major source of organic carbon.

Relative role of black carbon and sea-salt aerosols as cloud condensation nuclei over a high altitude urban atmosphere in eastern Himalaya.

The present study is an attempt to investigate the relative role of black carbon (BC) and sea-salt aerosols on the CCN activation over a high altitude station, Darjeeling (27.1° N and 88.15° E, 2200 m asl) at eastern Himalaya. Aerosols (CN, CCN, BC and PM2.5) were measured during premonsoon and monsoon in 2017 and 2018. A unique sampling strategy and a novel methodology were adopted that enabled us to quantitatively and separately determine the contributions of local emissions (LE), valley wind transport (VWT) and long-range transport (LRT) to BC aerosols and their role in CCN activation. On the other hand, the contributions of transported sea-salt (NaCl) aerosols to CCN activation were also determined when they interact with the local anthropogenic soluble species and when they do not. CCN (0.5% super-saturation) concentrations were found to be increased when BC aerosols were more aged (~ 80 cm-3 and 218 cm-3 increase in CCN for 1 µg m-3 increase in BCLE and BCLRT with activation ratios of 0.17 and 0.55 respectively). Local anthropogenic acidic species (SO42-/H2SO4 (g) and NO3-/HNO3 (g)) interact with NaCl resulting to Cl- depletion. Cl- depletion was increased with the increase in NO3- + SO42-(45% for1 µg m-3increase in NO3- + SO42-) that in turn sharply decreased the AR of NaCl (0.04 for 1% increase in Cl- depletion). On the other hand, higher the NO3- + SO42-, higher were the CCN activation of transported BC which could be due to the soluble coating on BC. The important and interesting fact is that when transported and interacted with anthropogenic soluble species, BC aerosols (though hydrophobic) act as much better CCN than NaCl (though hydrophilic).

Identification of most preferable reaction pathways for chloride depletion from size segregated sea-salt aerosols: A study over high altitude Himalaya, tropical urban metropolis and tropical coastal mangrove forest in eastern India.

Depletion of chloride from sea-salt aerosols affects their hygroscopicity, cloud condensation nuclei activity as well as microphysical and chemical properties of aerosols and clouds modifying earth-atmosphere radiative balance. Here, we proposed five possible reaction pathways through which the inorganic acids (H2SO4 and HNO3) could deplete chloride from sea-salt aerosols. We determined "maximum potential contribution" (MPC) of each acid and compared the MPC with actual chloride depletion. This step-by-step approach enables us to identify the most preferable reaction pathway(s) for coarse, superfine, accumulation and ultrafine aerosols over a Himalayan station (Darjeeling), a tropical urban station (Kolkata) and a tropical mangrove forest at the north-east coast of Bay of Bengal (Sundarban) in India. Over Kolkata and Darjeeling, locally generated acids reacted with transported sea-salts. Over Sundarban, the locally generated sea-salts from the Bay of Bengal reacted with the acids of biomass burning plume transported from Eastern Ghat and continental haze transported from upper Indo-Gangetic Plain. The average chloride depletion in PM10 ranged between 70 and 74% over Sundarban and 31-34% over Kolkata and Darjeeling. We observed that HNO3(g) depleted the larger (>1 µm) chlorides whereas H2SO4(g) depleted the smaller (<1 µm) chlorides over Kolkata and Darjeeling. However, in addition to H2SO4(g) and HNO3(g), some other species could be involved in chloride depletion over Sundarban mainly during winter. The study reveals that Sundarban acts as the major sink of the inorganic acids transported from Eastern Ghat biomass burning plume inhibiting their further advection towards inland regions.

Nanoparticle-based 'turn-on' scattering and post-sample fluorescence for ultrasensitive detection of water pollution in wider window.

Ultrasensitive detection of heavy metal ions in available water around us is a great challenge for scientists since long time. We developed an optical technique that combines Rayleigh scattering of UV light (365 nm) and post-sample fluorescence detection from colloidal silver (Ag) nanoparticles (NPs) having a surface plasmon resonance (SPR) band at 420 nm. The efficacy of the technique is tested by the detection of several model toxic ions, including mercury, lead, and methylmercury in aqueous media. The light scattering from the Hg-included/inflated Ag NPs at 395 nm was observed to saturate the light sensor even with ppm-order concentrations of Hg ions in the water sample. However, the pollutant is not detected at lower concentrations at this wavelength. Instead, the fluorescence of a high-pass filter (cut-off at 400 nm) at 520 nm is applied to detect pollutant concentrations of up to several hundreds of ppm in the water sample. We also detected lead and methylmercury as model pollutants in aqueous media and validated the efficacy of our strategy. Finally, we report the development of a working prototype based on the strategy developed for efficient detection of pollutants in drinking/agricultural water.

Below-cloud scavenging of size-segregated aerosols and its effect on rainwater acidity and nutrient deposition: A long-term (2009-2018) and real-time observation over eastern Himalaya.

The major removal pathway of atmospheric aerosols is the below cloud scavenging. The present study is the first-ever in the world, where long-term (2009-2018) as well as real-time observations on the below-cloud scavenging of ultrafine (<0.4 µm), superfine (0.4-1.0 µm) and coarse mode (>1 µm) aerosols have been made. The study was conducted with 919 rain events over a high altitude Himalayan station (27.01 °N, 88.15 °E, 2200 m amsl) in India. The other factors were normalized in order to investigate the "rain only" effect and therefore 919 rain events were screened and finally 165 events were studied. We determined threshold values of the rain rate (and duration) above which aerosols are scavenged in very high proportion (>75%) irrespective of the duration (and rain rate). These threshold values decrease as the aerosol size increases. For example, threshold rain rate decreases from ~17 mm h-1 to ~8 mm h-1 as the aerosol size increases from ultrafine to coarse mode. We also showed that how the rainwater acidity and the deposition flux of major inorganic nutrients (NH4+ + NO3- + SO42-) vary with the rain rate and duration. We observed that the rains either >12 mm h-1 or >80 min are all acidic. Maximum nutrients were accumulated in the ultrafine aerosols and hence the spectrum of the deposition flux of the nutrients (with rain rate and duration) was similar to the scavenging spectrum of ultrafine aerosol. Such long-term database enables us to quantitatively predict the aerosol scavenging, acid rains and nutrient deposition which showed excellent agreement with the observed results. Such quantitative prediction would in turn help the researchers to predict the rain-induced changes in air quality as well as any bio-geo chemical parameter. The present study bears paramount importance in Himalayan context as well as any ecologically-rich regions.

Impacts of photochemical ageing on the half-lives and diagnostic ratio of polycyclic aromatic hydrocarbons intrinsic to PM2.5 collected from 'real-world' like combustion events of wood and rice straw burning.

The present experimental study describes the characteristics of polycyclic aromatic hydrocarbons (PAHs) emitted with PM2.5 particles during wood and rice straw burning as well as impacts of photochemical ageing on the half lives of particulate PAHs and their diagnostic ratio values. The photochemical degradation kinetics experiments were carried out by exposing the PM2.5 to light and synthetic air flow. Pseudo first order rate constants were calculated based on PAH loss as a function of exposure time. Relatively quick degradation of lighter PAHs (3-rings) [(0.2-0.5)h-1] than heavier PAHs (4-6 rings) [(0.0005-0.03)h-1] indicates substantial impact of PAH-substrate interaction through π-π stacking with the carbonaceous substrates. Moreover, our results showed distinct PAH diagnostic ratios (DR) for wood and rice straw burnings which, however, change with time due to photochemical degradation. The later may add uncertainties in the applications of DR values for source apportionment. Furthermore, considerably large half lives (100-3000 h) of the carcinogenic PAHs as estimated under ambient solar radiation may cause poor and adverse air quality in long range and therefore demands immediate regulations against uncontrolled biomass burning.

Factors controlling the long-term (2009-2015) trend of PM2.5 and black carbon aerosols at eastern Himalaya, India.

A first-ever long-term (2009-2015) study on the fine particulate matter (PM2.5) and black carbon (BC) aerosol were conducted over Himalaya in order to investigate the characteristics, temporal variations and the important factors regulating the long-term trend. The study was conducted over a high altitude station, Darjeeling (27°01'N, 88°15'E, 2200 m asl) representing a typical high altitude urban atmosphere at eastern Himalaya in India. The average concentrations of PM2.5 and BC over a period of seven years were 25.2 ±â€¯5.6 µg m-3 (ranging between 2.2 and 220.4 µg m-3) and 3.4 ±â€¯0.7 µg m-3 (0.4 to 15.6 µg m-3) respectively. We observed decreasing trends in both PM2.5 (49% at a rate of 170 ng m-3 month-1) and BC (34% at the rate of 20 ng m-3 month-1) mass concentration over this region from 2009 to 2015. We extensively studied the impact of micrometeorological parameters on the long-term trend in PM2.5 and BC through the correlation analysis. The significant changes in boundary layer dynamics over this region played a major role in the decreasing trend of aerosols. The concentration weighted trajectory analysis revealed that the important contributory long-distant source regions for PM2.5 and BC over eastern Himalaya were Indo Gangetic Plane and Nepal. The contributions from these regions were found to be decreased significantly from 2009 to 2015. Investigations on the fire counts associated with the forest fire, and open burning activities through the satellite observations revealed that the decreasing trend in PM2.5 and BC over eastern Himalaya is well correlated to the decreasing trend in the fire counts over IGP and Nepal. We also explored that the changes and up gradation of the domestic fuel at the Indo Gangetic Plane regions in recent years not only improved the regional air quality but also affected the atmospheric environment over the eastern part of Himalaya.

Hygroscopic Coating of Sulfuric Acid Shields Oxidant Attack on the Atmospheric Pollutant Benzo(a)pyrene Bound to Model Soot Particles.

Substantial impacts on climate have been documented for soot‒sulfuric acid (H2SO4) interactions in terms of optical and hygroscopic properties of soot aerosols. However, the influence of H2SO4 on heterogeneous chemistry on soot remains unexplored. Additionally, oxidation rate coefficients for polycyclic aromatic hydrocarbons intrinsic to the atmospheric particles evaluated in laboratory experiments seem to overestimate their degradation in ambient atmosphere, possibly due to matrix effects which are hitherto not mimicked in laboratory experiments. For the first time, our kinetics study reports significant influence of H2SO4 coating on heterogeneous ozonation of benzo(a)pyrene (BaP) deposited on model soot, representative to atmospheric particles. The approximate specific surface area of model soot (5 m2g-1) was estimated as a measure of the availability of surface molecules to a typical gaseous atmospheric oxidant. Heterogeneous bimolecular reaction kinetics and Raman spectroscopy studies suggested plausible reasons for decreased BaP ozonation rate in presence of H2SO4: 1. decreased partitioning of O3 on soot surface and 2. shielding of BaP molecules to gaseous O3 by acid-BaP reaction or O3 oxidation products.

An integrated campaign for investigation of winter-time continental haze over Indo-Gangetic Basin and its radiative effects.

An outflow of continental haze occurs from Indo-Gangetic Basin (IGB) in the North to Bay of Bengal (BoB) in the South. An integrated campaign was organized to investigate this continental haze during December 2013-February 2014 at source and remote regions within IGB to quantify its radiative effects. Measurements were carried out at three locations in eastern India; 1) Kalas Island, Sundarban (21.68°N, 88.57°E) - an isolated island along the north-east coast of BoB, 2) Kolkata (22.57°N, 88.42°E) - an urban metropolis and 3) Siliguri (26.70°N, 88.35°E) - an urban region at the foothills of eastern Himalayas. Ground-based AOD (at 0.5 µm) is observed to be maximum (1.25±0.18) over Kolkata followed by Siliguri (0.60±0.17) and minimum over Sundarban (0.53±0.18). Black carbon concentration is found to be maximum at Kolkata (21.6±6.6 µg·m(-3)) with almost equal concentrations at Siliguri (12.6±5.2 µg·m(-3)) and Sundarban (12.3±3.0 µg·m(-3)). Combination of MODIS-AOD and back-trajectories analysis shows an outflow of winter-time continental haze originating from central IGB and venting out through Sundarban towards BoB. This continental haze with high extinction coefficient is identified up to central BoB using CALIPSO observations and is found to contribute ~75% to marine AOD over central BoB. This haze produces significantly high aerosol radiative forcing within the atmosphere over Kolkata (75.4 Wm(-2)) as well as over Siliguri and Sundarban (40 Wm(-2)) indicating large forcing over entire IGB, from foothills of the Himalayas to coastal region. This winter-time continental haze also causes about similar radiative heating (1.5 K·day(-1)) from Siliguri to Sundarban which is enhanced over Kolkata (3 K·day(-1)) due to large emission of local urban aerosols. This high aerosol heating over entire IGB and coastal region of BoB can have considerable impact on the monsoonal circulation and more importantly, such haze transported over to BoB can significantly affect the marine hydrological cycle.

Effect of dust and anthropogenic aerosols on columnar aerosol optical properties over Darjeeling (2200 m asl), eastern Himalayas, India.

BACKGROUND: The loading of atmospheric particulate matter (aerosol) in the eastern Himalaya is mainly regulated by the locally generated anthropogenic aerosols from the biomass burning and by the aerosols transported from the distance sources. These different types of aerosol loading not only affect the aerosol chemistry but also produce consequent signature on the radiative properties of aerosol. METHODOLOGY/PRINCIPAL FINDINGS: An extensive study has been made to study the seasonal variations in aerosol components of fine and coarse mode aerosols and black carbon along with the simultaneous measurements of aerosol optical depth on clear sky days over Darjeeling, a high altitude station (2200 masl) at eastern Himalayas during the year 2008. We observed a heavy loading of fine mode dust component (Ca(2+)) during pre-monsoon (Apr-May) which was higher by 162% than its annual mean whereas during winter (Dec-Feb), the loading of anthropogenic aerosol components mainly from biomass burning (fine mode SO(4)(2-) and black carbon) were higher (76% for black carbon and 96% for fine mode SO(4)(2-)) from their annual means. These high increases in dust aerosols during pre-monsoon and anthropogenic aerosols during winter enhanced the aerosol optical depth by 25 and 40%, respectively. We observed that for every 1% increase in anthropogenic aerosols, AOD increased by 0.55% during winter whereas for every 1% increase in dust aerosols, AOD increased by 0.46% during pre-monsoon. CONCLUSION/SIGNIFICANCE: The natural dust transport process (during pre-monsoon) plays as important a role in the radiation effects as the anthropogenic biomass burning (during winter) and their differential effects (rate of increase of the AOD with that of the aerosol concentration) are also very similar. This should be taken into account in proper modeling of the atmospheric environment over eastern Himalayas.

Aerosol chemistry over a high altitude station at northeastern Himalayas, India.

BACKGROUND: There is an urgent need for an improved understanding of the sources, distributions and properties of atmospheric aerosol in order to control the atmospheric pollution over northeastern Himalayas where rising anthropogenic interferences from rapid urbanization and development is becoming an increasing concern. METHODOLOGY/PRINCIPAL FINDINGS: An extensive aerosol sampling program was conducted in Darjeeling (altitude approximately 2200 meter above sea level (masl), latitude 27 degrees 01'N and longitude 88 degrees 15'E), a high altitude station in northeastern Himalayas, during January-December 2005. Samples were collected using a respirable dust sampler and a fine dust sampler simultaneously. Ion chromatograph was used to analyze the water soluble ionic species of aerosol. The average concentrations of fine and coarse mode aerosol were found to be 29.5+/-20.8 microg m(-3) and 19.6+/-11.1 microg m(-3) respectively. Fine mode aerosol dominated during dry seasons and coarse mode aerosol dominated during monsoon. Nitrate existed as NH(4)NO(3) in fine mode aerosol during winter and as NaNO(3) in coarse mode aerosol during monsoon. Gas phase photochemical oxidation of SO(2) during premonsoon and aqueous phase oxidation during winter and postmonsoon were the major pathways for the formation of SO(4)(2-) in the atmosphere. Long range transport of dust aerosol from arid regions of western India was observed during premonsoon. The acidity of fine mode aerosol was higher in dry seasons compared to monsoon whereas the coarse mode acidity was higher in monsoon compared to dry seasons. Biomass burning, vehicular emissions and dust particles were the major types of aerosol from local and continental regions whereas sea salt particles were the major types of aerosol from marine source regions. CONCLUSIONS/SIGNIFICANCE: The year-long data presented in this paper provide substantial improvements to the heretofore poor knowledge regarding aerosol chemistry over northeastern Himalayas, and should be useful to policy makers in making control strategies.