The total waste generation in India reported for 2015 is highly uncertain (51-300 Tgy(-1)), primarily because observational data from rural regions within India is lacking. This makes it difficult to constrain rural waste generation rates. Official government data (51 Tg) denies the existence of rural waste generation in India. The rural data gap makes it difficult to construct accurate open waste burning emission inventories and plan waste management infrastructure. Our study presents activity data from understudied rural regions across India and establishes a relationship between waste generation and household income for both urban and rural India. We use this relationship to create a 0.1 degrees x 0.1 degrees gridded waste generation and waste treatment dataset and construct an open waste burning emission inventory for India (OWBEII) for the year 2020, after segregating both the rural and urban population into 5 income group with the help of socioeconomic data from the national health surveys. We find that out of 192 (102-231) Tgy(-1) waste generated in 2020, 74 (30-92) Tgy(-1) was burned in the open. Open waste burning is a widely established practice of waste disposal in developing nations and emits particulate matter (285-1401 Ggy(-1) PM2.5 and 322-1486 Ggy(-1) PM10), a suite of carcinogens (19-82 Ggy(-1) benzene) and very reactive VOCs, which act as precursors to tropospheric ozone and secondary aerosol formation. The anthropogenic emissions of formaldehyde (a Group 1 carcinogen) from this source are 5.7 times larger than India's currently recognized total anthropogenic budget of formaldehyde in the EDGARv4.3.2 emission inventory.

This study uses two newly developed statistical source apportionment models, MuSAM and MuReSAM, to perform quantitative statistical source apportionment of PM10 at multiple receptor sites in South Hessen. MuSAM uses multi-site back trajectory data to quantify the contribution of long-range transport, while MuReSAM uses wind speed and direction as proxy for regional transport and quantifies the contribution of regional source areas. On average, between 7.8 and 9.1 μg/m3 of PM10 (∼50%) at receptor sites in South Hessen is contributed by long-range transport. The dominant source regions are Eastern, South Eastern, and Southern Europe. 32% of the PM10 at receptor sites in South Hessen is contributed by regional source areas (2.8–9.41 μg/m3). This fraction varies from <20% at remote sites to >40% for urban stations. Sources located within a 2 km radius around the receptor site are responsible for 7%–20% of the total PM10 mass (0.7–4.4 μg/m3). The perturbation study of the traffic flow due to the closing and reopening of the Schiersteiner Brücke revealed that the contribution of the bridge to PM10 mass loadings at two nearby receptor sites increased by approximately 120% after it reopened and became a bottleneck, although in absolute terms, the increase is small.

Angstrom exponent measurements of equivalent black carbon (BCeq) have recently been introduced as a novel tool to apportion the contribution of biomass burning sources to the BCeq mass. The BCeq is the mass of ideal BC with defined optical properties that, upon deposition on the aethalometer filter tape, would cause equal optical attenuation of light to the actual PM2.5 aerosol deposited. The BCeq mass hence is identical to the mass of the total light-absorbing carbon deposited on the filter tape. Here, we use simultaneously collected data from a seven-wavelength aethalometer and a high-sensitivity proton-transfer reaction mass spectrometer installed at a suburban site in Mohali (Punjab), India, to identify a number of biomass combustion plumes. The identified types of biomass combustion include paddy- and wheat-residue burning, leaf litter, and garbage burning. Traffic plumes were selected for comparison. We find that the combustion efficiency, rather than the fuel used, determines αabs, and consequently, the αabs can be ∼1 for flaming biomass combustion and >1 for older vehicles that operate with poorly optimized engines. Thus, the absorption angstrom exponent is not representative of the fuel used and, therefore, cannot be used as a generic tracer to constrain source contributions.

In most municipalities in India, the collection, transportation and disposal of municipal solid waste deviates from the mass flow envisaged by the municipal agencies and planning authorities. While multiple studies have focused on the environmental problems arising due to uncontrolled waste dumping and combustion, we present a qualitative study of the efforts towards resource conservation and recycling by various actors involved, and a quantitative estimate of the amount of material recovered at various stages.Both the informal sectors (garbage collectors, waste pickers, waste dealers, small stores and itinerant merchants) and the households in India, play a vital role in recovering consumer waste. In order to have an in-depth understanding, a case study has been performed to better understand the contribution of households, garbage collectors and itinerant waste merchants towards recovering consumer waste. Our study shows that consumer waste is far more efficiently recovered in India than what has been reported in literature until now. The waste recovery takes place in multiple-stages and the final waste that reaches the municipal corporation mostly comprises of biodegradable waste, inerts and highly non-recyclable waste.Households, itinerant waste merchants and garbage collectors in India jointly recover 1.2-2.4 million tonnes of newspapers, 2.4-4.3 million tonnes of cardboard and mixed paper, 6.5-8.5 million tonnes of plastic, more than1.3 million tonnes of glass, more than 2.6 million tonnes of metal waste and 4-6.2 million tonnes of other recyclable material per year. Overall, 30-60% of all paper and cardboard, 50-80% of all plastic and close to 100% of all glass bottles produced in India are recycled. (C) 2015 Elsevier B.V. All rights reserved.

A phased array acoustic atmospheric wind profiler has been developed. The system has the capability to remotely measure atmospheric horizontal and vertical winds from 70 m to 770 m within the earths atmospheric boundary layer. This system is being operated at the National Physical Laboratory (NPL), which is located in the middle of a highly noisy environment of the city of Delhi. Moreover, due to the rich green surroundings, there are plenty of birds whose calls make measurements at acoustic frequencies very difficult. In spite of the above two limitations, the system has been successfully used to make wind measurements in the height range of 70 m to 455 m.

The ion and electron F region plasma measurements made by the ion and electron Retarding Potential Analyzers (RPAs) onboard the Indian satellite SROSS-C2, have yielded excellent data set over the Indian region for more than half a solar cycle, after the SROSS-C2 launch in May 1994. The absolute ion density, ion temperature, and ion composition parameters are derived from these in situ measurements and used by many workers. In this paper the absolute values of ion density derived from the ion RPA measurements are compared and evaluated with the measurements made by ground-based ionosondes located in the Indian region and close to the SROSS-C2 orbital path. It is shown that a slight adjustment in efficiency factor of the ion RPA sensor brings the in situ measurements much closer to those obtained from the ground-based ionosonde measurements taking into account the model calculations. It may be mentioned that this is a correction to the ion density measurement by SROSS-C2 by a fixed proportion (14-11.4%). The effect of change in efficiency factor on the ion current, which is used to deduce the ion number density, is demonstrated and discussed.

Two identical planar blunt probes of stainless steel material, biased with a bipolar ramp voltage, are used to measure the stratospheric polar conductivities to altitudes of 34 km. One probe (DP) is mounted closer to the gondola, looking downwards and shielded from sunlight, while the other (SP) is mounted looking sideways, away from the gondola. The daytime observations of positive ions in the 29–34 km altitude range with SP, and of negative ions at 34 km with DP, show photoelectric contaminations induced by solar UV radiations in the 190–230 nm band. These contaminations are found to be due to photoemissions from the SP probe steel surface and from the carbon paint that coats the surface of the gondola, respectively. It is found that, a segment of the photocurrent contaminated I–V curve, recorded with SP at higher negative probe potentials, is linear, and it can give the ambient positive polar conductivity.

Ionospheric F-region is very dynamic and highly depends on the solar cycle. In the present study almost half of the solar cycle from January 1995 to December 2000 (from solar minimum to solar maximum) satellite data were used. The data were recorded with the help of Retarding Potential Analyzer (RPA) payload aboard Indian SROSS-C2 satellite at an average altitude of 500 km over the Indian region. The data analysis shows that the nighttime average ionospheric electron and ion temperatures show a positive correlation with solar activity. However, the sunrise peak values show anti-correlation with solar activity. Further the ratio of sunrise average peak value and nighttime average show a negative correlation with the solar activity, both for electron and ion temperatures. A sudden enhancement at sunrise has been observed during all seasons, in both electron and ion temperatures. Comparison of the measured ionospheric electron and ion temperatures with the predicted values from the international reference ionosphere (IRI) reveals that the peak during sunrise hours is slightly underestimated by the IRI model.

On December 11, 1967 at 05:21LT, an immense earthquake of magnitude 6.7 struck Koyna, the Indian province of Maharashtra. Its epicenter was located at geographic latitude 17.37°N and longitude 73.75°E with depth of about 3km. Ground based measurements show variation in the critical frequency of ionospheric F2 layer (foF2) before and after the shock. In the present study the behavior of F2-region of ionosphere has been examined over the equatorial and low latitudinal region ionosphere during the month of December 1967 around the time of Koyna earthquake. For this purpose, the ionospheric data collected with the help of ground-based ionosondes installed at Hyderabad (located close to the earthquake epicenter) Ahmedabad, Trichirapulli, Kodaikanal and Trivendrum have been utilized. The upper and lower bound of Interquartile range (IRQ) are constructed to monitor the variations in foF2 other than day-to-day and diurnal pattern for finding the seismo-ionospheric precursors. Some anomalous electron density variations are observed between post midnight hours to local pre-noon hours at each station. These anomalies are strongly time dependent and appeared a couple of days before the main shock. The period considered in this study comes under the quiet geomagnetic conditions. Hence, the observed anomalies (which are more than the usual day-to-day variability) over all stations are likely to be associated with this imminent earthquake. The possible mechanism to explain these anomalies is the effect of seismogenic electric field generated just above the surface of earth within the earthquake preparation zone well before the earthquake due to emission of radioactive particles and then propagated upward, which perturbs the F-region ionosphere.

To study the occurrence characteristics of equatorial spread-F irregularities and their latitudinal extent, simultaneous digital ionosonde data (January-December 2001) from Trivandrum (8.2 degrees N), Waltair (17.7 degrees N) and Delhi (28.6 degrees N) and 4 GHz scintillation data from Sikandarabad (26.8 degrees N) and Chenglepet (10.4 degrees N), and 250 MHz scintillation data from Bhopal (23.2 degrees N) for equinoxes period are analysed. It is noted that except summer months, occurrence of spread F is always maximum at Trivandrum, minimum at Delhi and moderate at Waltair. During equinoxes and winter months. Their occurrences at higher latitude station are always conditional to their prior occurrences at lower latitudes indicating their association with the generation of equatorial plasma bubble and associated irregularities. Scintillation occurrences also follow the similar pattern. During the summer months, the spread-F occurrences are highest at equatorial location Trivandrum, moderate at Delhi and minimum at Waltair and seem to be caused by irregularities generated locally especially over Delhi.To gain forecasting capability, night-to-night occurrences of spread-F/scintillation at these locations are examined in relation to post sunset rise of h'F and upward ExB drift velocity over the magnetic equator using Trivandrum ionosonde data. It is noted that except the summer months, the spread-F at Trivandrum, Waltair and Delhi are observed only when equatorial ExB (h'F) is more than about 15 m/s (325 km), 20 m/s (350 km) and 25 m/s (375 km), respectively. With these threshold values their corresponding success rate of predictions are more than 90%, 50% and 15% at the respective locations. Whereas in the case of GHz scintillations near equator are observed only when ExB (h'F) is more than 15 m/s (325 km), whereas for low latitude, the same should be 30 m/s (400 km) and their success rate of prediction is about 90% and 30%, respectively. The intensity of 4 GHz scintillation at low latitude is also found to be positively correlated with equatorial upward ExB drift velocity values, whereas correlation is poor with that of equatorial scintillations. In conclusions, near magnetic equator threshold values of ExB or h'F can be successfully used for the night-to-night prediction of spread-F/scintillations occurrences, whereas these are necessary but not sufficient for their prediction at higher latitudes. For that some other controlling parameters like background electron density, neutral winds, gravity waves, etc. should also be examined. (c) 2007 Elsevier Ltd. All rights reserved.

Major crops subject to field burning of crop residue (FBCR) generated an estimated 284 Tg of residue in India, of which 40% was contributed by wheat in the year 2000. About 7.5% of this total generated wheat straw was subjected to on-site burning, that is expected to emit large amounts of trace gases and particulate matter (PM) to the atmosphere, whose country-specific estimates and emission factors (EFs) are presently not available. An in situ experiment for wheat straw burning was undertaken for developing India specific EFs. The EFs of CO2, CH4, CO, N2O, NOx, NO and NO2 were found to be 1787±36, 3.6±2.7, 28.1±20.1, 0.74±0.46, 1.70±1.68, 0.78±0.71 and 0.56±0.47gkg-1, whereas those for organic carbon (OC), black carbon (BC) and total carbon (TC) were 0.3±0.1, 0.2±0.1, and 0.5±0.2gkg-1, respectively. Although these EFs have been generated from a single field experiment nevertheless they address important information gap on FBCR in the region. Further, the total emissions of CH4, CO2, CO, N2O, NOx, NO, NO2, OC, BC and TC from wheat straw burning in India for the year 2000 was estimated as 68±51, 34435±682, 541±387, 14±9, 33±32, 15±14, 11±9, 6±2, 3±1 and 10±4 Gg, respectively.

The diurnal, seasonal and latitudinal variation of electron density (Ne) measured by the Indian SROSS C2 satellite from December 1994 to January 1997 at low and equatorial latitudes along 75°E meridian are investigated. The satellite covered the latitude belt of 31°S to 34°N and longitude range of 40°E to 100°E at an average altitude of ∼500km. Electron density is minimum before sunrise and reaches the diurnal maximum in the afternoon hours. A secondary enhancement is observed in the sunset hours of June solstice. The well-known equatorial ionization anomaly is found to be asymmetric at the altitude tracked by the satellite in this period of low solar activity (mean sunspot number=13.9). The location of the crest of the anomaly varies with season. There are seasonal and latitudinal variations of Ne. Further, electron density is found to be positively correlated with the strength of the equatorial electrojet. Comparison of measured density with that predicted by the International Reference Ionosphere (IRI) reveals that the IRI overestimates Ne at about all local times and in all seasons. The IRI also fails to produce the secondary enhancement of electron density.

Characteristics of trace gases (O3, CO, CO2, CH4 and N2O) and aerosols (particle size of 2.5 micron) were studied over the Arabian Sea, equatorial Indian Ocean and southwest part of the Bay of Bengal during the monsoon transition period (October–November, 2004). Flow of pollutants is expected from south and southeast Asia during the monsoonal transition period due to the patterns of wind flow which are different from the monsoon period. This is the first detailed report on aerosols and trace gases during the sampled period as the earlier Bay of Bengal Experiment (BOBMEX), Arabian Sea Monsoon Experiment (ARMEX) and Indian Ocean Experiments (INDOEX) were during monsoon seasons. The significant observations during the transition period include: (i) low ozone concentration of the order of 5 ppbv around the equator, (ii) high concentrations of CO2, CH4 and N2O and (iii) variations in PM2.5 of 5–20μg/m3.

The local time, seasonal and solar activity variations of electron temperature Te measured by the SROSS C2 satellite at equatorial and low latitudes during the low to moderate solar activity period of 1994–1998 are investigated. The mean height of the satellite is ∼500km and covered the latitude belt of 31°S–34°N and the longitude range of 40–100°E. Results show that Te varies between 700 and 900K during nighttime (20:00–04:00 LT), rises sharply in the sunrise period (04:00–06:00 LT) to reach a level of 3500–5000K within a couple of hours and then falls between 07:00 and 10:00 LT to a daytime (10:00–14:00 LT) average of 1600–2000K. A secondary maximum is observed around 16:00–18:00 LT in the June solstice in all years and in the equinoxes in the years of moderate activity. The morning enhancement is more pronounced in the equinoxes. Electron temperature during the day was found to be higher in spring compared to that in autumn. Within the solstices, the amplitude of the morning enhancement is higher in winter compared to that in summer. The afternoon enhancement in summer decreases as the solar activity increases. Both day and nighttime Te bears a positive correlation with solar activity. The observed Te was also compared with the values predicted by the International Reference Ionosphere, IRI. Comparison reveals that the IRI predicts nighttime Te well within 100K of measured temperature. But, in the morning and afternoon, which are periods of enhanced temperature, IRI underestimates Te in all seasons irrespective of solar activity. Daytime predicted Te is lower than the measured values when solar activity is low. The difference between measurement and prediction during daytime decreases as the solar activity increases.

Analyzing the 2 months ionospheric electron content (IEC) data acquired during a high solar activity period from a network of a stations whose sub-ionospheric points at 420km were located within ± 1° of 84° meridian and covering a latitude belt of 3–21°N (magnetic), it has been shown that following sunset a fresh equatorial anomaly develops in continuation to the decaying daytime equatorial anomaly (DEA) in the low latitude belt. The occurrence of this post-sunset equatorial anomaly (PEA) is although a regular phenomenon but large day-to-day variations are seen in its strength (crest to trough ratio) and the latitude extent, PEA develops fully within 2–3h of sunset and then decays. During its development crest of anomaly clearly shows a pole-ward movement and during decay it shows substantial equator-ward movement. While the trough of PEA is always seen over the magnetic equator, the crest of fully developed anomaly may be seen to lie at latitudes anywhere between 12°N and 21°N magnetic or more on different days. Thus the development and decay of PEA produce large latitudinal disturbance of F-region plasma in the lower latitude belt in the post-sunset hours and the occurrence of various low latitude phenomenon observed in IEC, e.g. post-sunset IEC decreases at equatorial latitudes, post-sunset IEC enhancements at 12°N or higher latitudes, pre-midnight IEC enhancements at equatorial latitudes, etc., have been attributed to the systematic development and decay of PEA. Also, the occurrence and development of PEA has been found to play an important role in the onset of equatorial plasma bubble associated ionospheric irregularities and their latitudinal growth. The equatorial ionization anomaly (EIA) is primarily caused by the ExB drifts whereas meridional winds in association with E×B drifts also seems to play some role in determining the crest of PEA.

Ionospheric response to the seismic events has been studied in the present paper by analyzing the variation in electron temperature during the occurrence of earthquake. The ionospheric electron temperature data recorded by the RPA payload aboard the Indian SROSS-C2 satellite during the period from January 1995 to December 1996 were used. Six earthquake events recorded during this period were used to analyze the temperature anomalies related to earthquake events. The details of these events are obtained from USGS earthquake data information website.