Search

The COVID-19 pandemic has affected severely the economic structure and health care system, among others, of India and the rest of the world. The magnitude of its aftermath is exceptionally devastating in India, with the first case reported in January 2020, and the number has risen to ~31.3 million as of July 23, 2021. India imposed a complete lockdown on March 25, which severely impacted migrant population, industrial sector, tourism industry, and overall economic growth. Herein, the impacts of lockdown and unlock phases on ambient atmospheric air quality variables have been assessed across 16 major cities of India covering the north-to-south stretch of the country. In general, all assessed air pollutants showed a substantial decrease in AQI values during the lockdown compared with the reference period (2017–2019) for almost all the reported cities across India. On an average, about 30–50% reduction in AQI has been observed for PM2.5, PM10, and CO, and maximum reduction of 40–60% of NO2 has been observed herein, while the data was average for northern, western, and southern India. SO2 and O3 showed an increase over a few cities as well as a decrease over the other cities. Maximum reduction (49%) in PM2.5 was observed over north India during the lockdown period. Furthermore, the changes in pollution levels showed a significant reduction in the first three phases of lockdown and a steady increase during subsequent phase of lockdown and unlock period. Our results show the substantial effect of lockdown on reduction in atmospheric loading of key anthropogenic pollutants due to less-to-no impact from industrial activities and vehicular emissions, and relatively clean transport of air masses from the upwind region. These results indicate that by adopting cleaner fuel technology and avoiding poor combustion activities across the urban agglomerations in India could bring down ambient levels of air pollution at least by 30%.

Abstract Recent research has focused on nanoparticles. Aedes albopictus is a potential vector that transmits fatal diseases. Recently, Phyto-reduced silver nanoparticles (AgNPs) were shown to be mosquito larvicides. This study aimed to synthesize silver nanoparticles using Diospyros montana leaf extract, characterize them, and test their efficacy as larvicide and pupicide against Ae. albopictus mosquitoes, determine their duration of effectiveness as a larvicide, identify plant compounds that help to synthesize nanoparticles, and assess their effects on non-target organisms. Quercetin, luteolin, kaempferol, gallocatechin gallate, epigallocatechin gallate, and capsaicin are among the novel reducing and capping agents found in D. montana leaf through LCMS analysis. The color shift and distinctive peak in UV–Vis spectroscopy made it simple to see how biogenic AgNPs were produced by converting Ag+ ions into Ag0. Substantial negative value (− 19.10 mv) of zeta potential demonstrated the long-term stability of AgNPs. A moderate range (8.72 − 50.75 nm) of particle size distribution pattern was obtained using the DLS technique. SEM and TEM images depicted the quasi-spherical (or polyhedral) and spherical shape of the nanoparticles, having approximately 16.75 nm average size. Synthesized AgNPs had a low LC90 value (

Abstract Larvae of the elephant mosquitoes, Toxorhynchites spp. (Diptera: Culicidae) are predacious on larvae of other mosquito species and some small aquatic organisms; this predatory behavior can be applied in (mosquito) vector control. The present study examined the feeding behavior of Toxorhynchites splendens on Aedes albopictus in relation to search area [volume of water (X1)] and prey density (X2), prey instars, predatory preference and larvae's functional response on variable prey densities. Experiments were conducted to determine changes in the feeding activity of T. splendens with different search areas and showed that rate of prey consumption was inversely proportional to the search area as evidenced by a negative value of X1 in the regression equation and positively related to prey density. The non-linear polynomial logistic regression estimated a significant linear parameter (P1 0.05), expressing that all the instars of prey were equally susceptible to the predator. Toxorhynchites splendens preferred to consume Ae. albopictus larvae rather than Tubifex when supplied together as a food source.