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STATUS OF GROUNDWATER QUALITY IN LUDHIANA DISTRICT OF PUNJAB, INDIA

2026-05-01T00:00:00Z

Title: STATUS OF GROUNDWATER QUALITY IN LUDHIANA DISTRICT OF PUNJAB, INDIA Authors: GOYAL, DEEPALI; Singh, S.K. (SUPERVISION); Haritash, A.K. (CO-SUPERVISOR) Abstract: The present study provides an integrated assessment of groundwater quality in Ludhiana district, Punjab, based on 152 groundwater samples characterized by 18 physicochemical parameters. These were synthesized into a Drinking Water Quality Index (WQI) to evaluate potable suitability. The WQI classification shows that 2.6% of samples are “excellent” and 57.9% “good,” whereas 32.9%, 4.0%, and 2.6% fall into “poor,” “very poor,” and “unsuitable” categories, respectively, indicating spatially heterogeneous degradation in groundwater quality. Hydrogeochemical characterization, supported by facies diagrams, ionic diagnostics, saturation indices, and multivariate statistics, indicates that groundwater chemistry is primarily governed by carbonate and silicate weathering, with active cation exchange. Saturation indices show that groundwater is generally supersaturated with respect to calcite, dolomite, and aragonite, and undersaturated with respect to halite, fluorite, and sylvite. Spatial variability in nitrate and other key parameters reflects localized agricultural and urban influences, while IDW interpolation in QGIS has been used to generate spatial distribution maps of major ions. In the present study, irrigation suitability has been evaluated using salinity, sodicity, and carbonate–bicarbonate hazard indices, including EC, %Na, SAR, and PI. In addition, an Irrigation Water Quality Index (IWQI) is computed using EC, SAR, Na⁺, Cl⁻, and HCO₃⁻ concentrations. Salinity classification indicates that 62.5% of samples fall within the “medium” EC range (250–750 µS/cm), while 37.5% fall within the “high” category. Hazard assessment indicates that 75% of samples fall within the excellent-to-permissible range based on %Na, 97.4% belong to the S1 class (low sodicity) based on SAR, and all samples fall within PI Classes I–II. However, IWQI based classification indicates irrigation constraints, with 21.7% of samples under “severe restriction” (IWQI < 40), 37.5% under “high restriction” (40–55), 33.6% under “moderate restriction” (55–70), and only 7.2% under “low restriction” (70–85). IDW based GIS mapping delineates zones of elevated irrigation risk, particularly in eastern Samrala and Khanna, parts of Ludhiana II and Machhiwara, and southern to western xvi Pakhowal and Sidhwan Bet, whereas low-restriction pockets are confined to limited villages such as Sherpur Kalan, Bardeke, Hathur, and Dholanwal. An ANN-based predictive model for IWQI is developed using the multilayer perceptron architecture in IBM SPSS with standardized inputs. The optimal network includes five input neurons (EC, SAR, Na⁺, Cl⁻, HCO₃⁻), two hidden layers, and one sigmoid-activated output neuron, trained using batch learning and gradient-descent backpropagation. The model achieved RMSE values of 0.09 for training and 0.07 for testing, indicating strong predictive performance and close agreement between observed and simulated IWQI values. Sensitivity analysis shows that Cl⁻ has the highest normalized importance (100%), followed by SAR (59.7%), Na⁺ (58.5%), HCO₃⁻ (53.1%), and EC (27.2%), confirming the dominant influence of salinity and sodicity on irrigation water quality. Additionally, nitrate distribution has been examined to distinguish regional hydrogeological controls from localized anthropogenic influences. The weak statistical association between nitrate concentration and hydraulic parameters indicates that regional groundwater flow is not the principal control on nitrate occurrence. The lack of a coherent downgradient nitrate plume suggests that nitrate distribution is governed mainly by localized recharge and anthropogenic inputs. A conservative nitrate-transport scenario simulated by coupling the calibrated transient MODFLOW flow model with MT3D-USGS shows a decline in mean nitrate concentration from 8.86 mg/l in Year 1 to 6.51 mg/l in Year 10 (~27% reduction), contraction of the >45 mg/l footprint from ~1.70% to ~0.88%, and a reduction in peak concentrations to a maximum simulated value of ~69.95 mg/l after 10 years.

STUDY OF AEROSOLS IN INDOOR - OUTDOOR MICROENVIRONMENTS FOR URBAN HOUSEHOLDS OF DELHI

2026-02-01T00:00:00Z

Title: STUDY OF AEROSOLS IN INDOOR - OUTDOOR MICROENVIRONMENTS FOR URBAN HOUSEHOLDS OF DELHI Authors: SHARMA, MONIKA; Mishra, Rajeev Kumar (SUPERVISOR); Khare, Mukesh (CO-SUPERVISOR) Abstract: Rapid urbanization increases the population density in urban regions, which compromises the standard of living. Indoor air quality in urban regions is a serious concern. To understand the indoor air quality in residential homes of one of the India’s most polluted cities, Delhi. This is a region where detailed studies remain scarce, especially in residential context. This study analyzed the concentration of indoor particulate matter and particle number concentration in urban clusters where significant socioeconomic differences exist within the same geographical domain. To understand the indoor air quality in residential homes of one of the India’s most polluted city, Delhi. This is a region where detailed studies remain scarce, especially in residential context. This study also estimated the seasonal variations of indoor and outdoor particle number concentrations in different socioeconomic household conditions in the urban city Delhi. This study investigated the impact of festival activities on household indoor air quality in megacity Delhi. The study included different phases and activities during the festival and normal conditions and analysed the impact of different emissions. The portable aerosol spectrometer was employed to measure quasi-ultrafine, sub-fine, fine, and coarse particle concentrations in the kitchen, bedroom, and outdoor conditions. Indoor air quality is crucial for the well-being of residents, as people spend 80% of their time indoors. Particulate matters (PM10, PM2.5, and PM1) were measured in two major indoor microenvironments (kitchen and bedroom) along with outdoors of the selected households during winter, summer, and monsoon seasons. Four major income groups were considered for the study. A poorly ventilated kitchen was found to have higher concentrations of PM10 (247 μg/m3), PM2.5 (200 μg/m3), and PM1 (153 μg/m3), respectively. Indoor, PM1 contributed ~40 to 85 % to PM10. During winter, the seasonal mean I/O ratio of PM10, PM2.5, and PM1 ranged between 1.1 and 1.8 in bedroom and between 0.8 and 2.2 in kitchen. The influence of outdoor particulate matter concentration on indoor air was observed to be high during winter, followed by summer and monsoon. The higher concentration in kitchen leads to an exposure of 0.10 μg, and in bedroom, it was 0.11 μg for adults with a higher breathing rate. The exposure depends on the xi concentration and exposure time. The PM2.5 depositions were found more in the lower lung regions. The findings of the study revealed that quasi-ultrafine (250 to 500 nm) particle concentration was high (2.1×106 #cm-3) in urban poor households during the winter season. Indoor quasi-ultrafine particle concentration ranged between ~105–106 #cm-3 in the kitchen and bedroom. In a properly ventilated kitchen, a significant reduction in indoor particle number concentration (1.2×106 #cm-3 to 7.1×105 #cm-3) was observed. The number concentration of coarse particles was found to be the lowest (< 1.1×103 #cm- 3) among other sizes. However, indoor sources resulted in a higher I/O ratio of 40. Lower- income group kitchens exhibited a higher number concentration of different-sized particles, which also influenced bedroom concentration. During the festival period, the indoor ultrafine particle concentration was found to be 6.7 × 104 #cm-3, which was the highest observed indoor concentration throughout the study. The particle number concentration of the nanoparticles in indoor environment ranged from 104 to 105 #cm-3. Ultrafine size range particles contributed up to 85% to the total particle numbers. Fireworks contributed to higher particle numbers in indoors, followed by cooking, dusting, and worshiping. The size distribution pattern of the particles emitted during cooking activities and fireworks were found to be different. Particle size range 10 to 30 nm contributed 31 % to total particle numbers on fireworks day, whereas on a normal day, it contributed only 13 %. During a normal day, 100 to 1000 nm size particles contributed ~50 % to the total particle numbers. The diurnal pattern of the indoor environment was different to the outdoor. The outdoor fireworks activities also influenced indoor pollutants with respect to trace metals, which makes the indoor air quality more toxic and affects the occupants' health. Indoor particle number concentration (PNC) varies significantly in different microenvironments. Cooking, dusting, and incense stick burning are major indoor activities that generate different-sized particle numbers. The number concentration of the quasiultrafine particles (qUFP) was found to be a maximum of (106 #cm-3), followed by subfine (105 #cm-3), fine (104 #cm-3), and coarse (103 #cm-3) particles. The winter season exhibits a higher decay period of particles in indoor. The number concentration of xii particles observed during nighttime was higher than the concentration during daytime. The particles generated during cooking took more time to decay, up to 320 minutes, followed by dusting (120 to 300 minutes) and incense stick usage (< 200 minutes). Roasting, stir frying, and gravy preparation emit a higher concentration of qUFP (4 to 5×106 #cm-3) and sub-fine (6 to 8×105 #cm-3) particles. More fine particles were generated during stir-frying (3×104 #cm-3) and coarse particles (2×103 #cm-3) were emitted at high levels during roasting. The boiling method of cooking generates a very less number of qUFP and subfine particles (< 105 #cm-3). The measured particle number concentration linearly correlated with particulate matter, and the influence of indoor sources was found to be more in the studied microenvironments. Indoor number concentrations were found to be higher than in the outdoor environment. Households with good infrastructure conditions were found to have less influence on one microenvironment than another. Improving indoor air quality relies not only on sources but also on ventilation status, built infrastructure, occupants’ behaviour, and the influence of outdoor air. Since people spend the majority of their time indoors, it will be more vulnerable to residents. Indoor pollution in households needs to be mitigated and regulated for a better standard of living.

A COMPARATIVE STUDY ON SIZE SEGREGATED ULTRAFINE PARTICLE CONCENTRATION AND ITS TEMPORAL DISTRIBUTION IN URBAN AND BACKGROUND REGIONS

2025-11-01T00:00:00Z

Title: A COMPARATIVE STUDY ON SIZE SEGREGATED ULTRAFINE PARTICLE CONCENTRATION AND ITS TEMPORAL DISTRIBUTION IN URBAN AND BACKGROUND REGIONS Authors: MOHAN, VIGNESH Abstract: In developing countries like India, air pollutants have become a serious issue. Industrialization and urbanization have greatly boosted the Indian economy. On the other hand, they have also brought about a drastic change in the environment. Due to various natural and anthropogenic activities, different pollutants are released into the atmosphere. Air pollution is still a major problem faced by the whole world, resulting in 6.2 million deaths throughout the world and 6,20,000 premature deaths in India alone. The alarming increase in air pollutants, with its intensity on the higher side, has resulted in numerous health issues and lung diseases, including chronic respiratory disorders, pneumonia, acute asthma, and shortness of breath. Although technological advancements have improved our understanding of ultrafine particles and air quality, many environmental conditions and scientific problems remain unresolved. Ultrafine particles in the atmosphere are formed due to natural and anthropogenic activities, including photochemical reactions and combustion processes. Atmospheric aerosols persist in solid or liquid form and significantly impact a region’s air quality, contributing to climate change and affecting human health. The concentration of the ultrafine particles in a region is highly dependent on the intensity of the emission sources, represented by the number concentration. The ultrafine particle concentration is quantified in terms of particle number concentration (PNC) per unit volume of air, expressed as the number of particles per cubic centimeter (cm3). Ultrafine particles are considered a universal carrier of a wide variety of toxic chemicals to humans. The deposition of particles in the human respiratory system varies based on the size of the particles, which are categorized into nucleation, Aitken, and accumulation modes. Also, the concentration of these particles signifies the emission sources in a particular region. These can enter the deeper regions of the respiratory system, such as the alveoli, and can be transported to the circulatory system, allowing them to reach any organ in the body. This study analyzes the year-long measurements of particle number size distribution (10.21-1090.23 nm) in 2022 in the urban traffic corridor of the megacity Delhi. The study examined particle number concentration in the ultrafine (<100 nm) and accumulation (100-1000 nm) ranges during both day and night, in terms of the source's intensity, emission patterns, and local meteorological conditions. Further, the ultrafine particles (< 100 nm) are separated into three mode size fractions xi (Nnuc, Natk, and Nacc) were also considered, and the data set was analyzed for the different meteorological periods and day and night time in terms of sources and type of emission (from CNG, petrol, and diesel vehicular exhaust) and meteorology. Nucleation mode particles (Nnuc, 10-30 nm) contributed ~50% during the daytime in the summer period due to increased fresh traffic emissions. During the daytime, particle concentration was dominated by smaller sizes, such as nucleation mode particles (Nnuc, 30-100 nm), while at nighttime, the particles were found in the Aitken and Accumulation (Nacc, 100-1000 nm) modes. Nnuc and Natk were reduced by ~45% and 4% at night, while Nacc increased by ~34%. The mean normalized particle number size distribution confirmed these findings, showing clearly that Nnuc dominated during the daytime, especially during peak rush hours, and at night, particle concentration increased up to the size of 300 nm particles. The particle number size distribution and the changes experienced in the percentage concentration of the different particle size ranges highlight the role of engine exhaust emissions in the atmospheric particles contributed in urban areas. The study's findings help identify the intensity and behavior of different sources during the day and nighttime, which can inform policy formulation and decision-making to mitigate air quality and its associated health impacts. The study measured and analysed the particle number concentration of particles ranging from 10 nm to 800 nm in urban and background sites. The aim of the study is to estimate the role of anthropogenic sources in urban regions in terms of number concentration. The study finds that the particle number concentration in an urban site is ~8 times higher than in the background sites. At the urban site, the Aitken and Nucleation modes contributed more to the total particle concentration, whereas at the background site, it was the Aitken and Accumulation modes. The annual average concentrations at the urban and background sites were 2.5 x 104, 2.9 x 103 cm-3, respectively. Aitken-mode particles dominated both in the urban and background sites, with the lowest concentrations observed in the summer (6.4 x 102 cm-3) and monsoon periods (1.09 x 102 cm-3), respectively. The diurnal concentration illustrates the role of transportation emissions at the urban site and the natural process of particle condensation at the background site. The long-range transportation of sources indicates that during the winter and autumn seasons, the westerly and north-westerly winds bring biomass burning emissions smoke to the urban region, which is less visible xii in the background conditions. Road traffic emissions are often identified as the leading source of ultrafine particles in urban environments. However, recent international studies have revealed that in cities with elevated solar radiation, the occurrence of new particle formation events may also significantly contribute to the levels of ultrafine particles. To assess the frequency and effects of these events, a comprehensive study was carried out in Delhi from January to December 2022. The analysis showed that the highest mean concentration of total particle number concentration (Ntot) followed the order of Post- Monsoon > Winter > Monsoon > Summer. The Aitken particle contribution (Natk) to Ntot was approximately 52% on event days and 46% on non-event days. Throughout the year, 23 new particle formation (NPF) events were identified, accounting for 6% of the total days, which included 2 nocturnal and 21 midday occurrences. During the nocturnal events, ammonia levels increased by about 34%, which aids in the growth of newly formed particles. The remaining NPF events predominantly occurred during daylight hours, when solar radiation was a crucial factor in particle generation. The highest growth rates were observed in winter (12.07 ± 1.07 nm h-1), while the condensation sink (cs) was highest in the post-monsoon period (0.087 ± 0.039 s-1). The presence of larger pre-existing particles during the post-monsoon season appeared to hinder formation rates but enhance particle growth. An increase in particle numbers was associated with a decrease in the condensation sink throughout the day. Winds from the northwest direction were conducive to new particle formation, coinciding with increased solar radiation and temperature, alongside a decrease in relative humidity. In summary, although traffic remains the predominant source of ultrafine particles (UFP) in urban areas, urban nucleation events also represent a significant source of UFP. A future decline in traffic-related particle concentrations is expected; however, an increase in nucleation events in urban areas is likely due to the reduced capacity of urban condensation sinks. The festival of Diwali, characterized by extensive fireworks displays in India, significantly contributes to the increase of atmospheric particles over a brief period, thereby compromising air quality. Implementing short-term measures, such as prohibiting the use of firecrackers during these celebrations, can enhance urban air quality. This study examined particle number concentrations ranging from 10 nm to xiii 1000 nm during the years 2021 and 2022. A notable decrease in particle number concentration was recorded, dropping from 3.8 x 104 cm-3 to 3.1 x 104 cm-3, following the ban on firecrackers in Delhi. The concentration range shifted from 105 cm-3 to 104 cm-3. The analysis of various size categories, Nucleation (10 nm to 30 nm), Aitken (30 nm to 100 nm), and Accumulation (100 nm to 1000 nm), revealed that on Diwali day, Accumulation mode particles accounted for approximately 60% to 83% of the total particle number concentration. Furthermore, the total inhalable particle concentration exposure on Diwali day was reduced by about 18%, equating to 1.6 million particles per day. The findings of this study indicate that significant reductions in emissions within urban environments can be achieved through effective policy implementation and active citizen engagement. Lowering particle emissions is crucial for enhancing air quality, minimizing health risks, and promoting sustainability. The overarching sustainability objectives emphasize the necessity of clean air for all, while health improvements in polluted areas represent achievable interim goals through the execution of appropriate mitigation strategies, which also contribute to combating climate change.

STUDY OF NANO-SIZE PARTICLE DYNAMICS IN URBAN ROAD MICROENVIRONMENT IN DELHI

2025-05-01T00:00:00Z

Title: STUDY OF NANO-SIZE PARTICLE DYNAMICS IN URBAN ROAD MICROENVIRONMENT IN DELHI Authors: RAJAGOPAL, KANAGARAJ Abstract: Due to rapid urbanization, Delhi experiences frequent pollution events, and the particulate matter load exceeds the prescribed limit often. This study analyzes nanoparticle (10 to 1090 nm) during different emission scenarios, seasonal and meteorological conditions in two phases: April to June 2021 (Period I) and October to November 2021 (Period II). Period I experienced around 31% less concentration of particles (~2.4 × 104 cm-3 ) due to lockdown restrictions and, on the other hand, particle concentration increased by 35% compared to normal conditions due to the sudden rise in firework emissions in Period II. Except for the post-Diwali phase (104 cm-3 to 105 cm-3 ), the concentrations lie between 103 cm-3 and 105 cm-3 . The Aitken modes contribute 10 to 30% of total concentration in both periods. Particles in nucleation and accumulation modes contribute 30 to 40%, 20 to 30%, 15 to 25%, and 35 to 50% in Periods I and II, respectively. Concentration and behavior of nano particles in different seasons (winter, spring, summer, monsoon, and autumn) are examined, for the first time. Concentration of particles is classified into four different sizes as Nnuc (10 to 30 nm, nucleation), Nsatk (30 to 50 nm, small Aitken), Nlatk (50 to 100 nm, large Aitken), and Nacc (100 to 1000 nm, accumulation mode), and the total (10 to 1000 nm) particle number concentration (PNC) as Ntotal. PNC ranges between 104 cm-3 and 106 cm-3 over Delhi during the year, and the highest concentration occurs in winter. Winter concentration is 2 times higher than monsoon, summer, autumn and spring concentrations, respectively. Nnuc, Nsatk, Nlatk and Nacc and their respective contributions to total PNC exhibit significant seasonal variations. During winter Nlatk and Nacc contribute more to total PNC due to coagulation, with Nacc alone contributing >40% to total PNC. Nnuc, Nsatk, and Nlatk are higher in spring and summer during mid-day due to nucleation and/or ultrafine particle burst events. The direct primary emissions from engine exhaust produce a prominent double hump structure during morning and evening ix peak hours in winter and autumn. PNC and their contributions exhibit day-night variations as they are influenced by emission sources and variations in meteorological parameters (wind speed, relative humidity, temperature, solar radiation and boundary layer height) between day and night. Carbon monoxide correlates positively with Nacc in all seasons (R2~0.5) as fossil fuel emission is predominant source for gases and particles in study environment. The concentration of UFP size range particles is dominantly higher (70 to 80%) during peak hours than the non-peak hours. The variations in particle number concentration depend on the intensity and emissions of sources during peak, and non peak hours. UFP contributes ~60 to 80% to the total particle number concentration in the urban roadside microenvironment, and its contribution increases during peak hours. During the winter season, the average total particle number concentration was observed to be maximum (4.1 × 104 cm-3 ) with a higher surface area of particles of 3.5 × 10-3 mm2m 3 . Compared to the monsoon season, the concentration of NOX was 5 times higher in winter. The boundary layer height in the study region ranged from 600 to 2400 m during different seasons, and the maximum ventilation coefficient was observed to be >3000 m2s-1 during summer. Precipitation reduced the concentration of particles by half, from 2.2 x 104 to 1.1 x 104 cm-3 , due to wet scavenging. The study revealed that the concentrations of particles depend not only on primary emissions but also are influenced by local meteorology and other co-emitted pollutants. The Multiple Path Particle Dosimetry (MPPD) model simulated values show that the order of deposition goes as alveoli > bronchiole > bronchus. The deposition in the study area ranges between 10 and 18 million nanoparticles during different hours of the day, whereas the estimated inhalable particles vary between 0.5 to 1 billion. The concentration of total inhalable particles and the actual particles deposited in the lung varies. The seasonal sequence of deposition of nanoparticles is winter > monsoon > summer > autumn > spring. The x deposition of nanoparticle in adults is 30 to 40% higher than in children and infants, and further, the deposition is higher in the alveolar region than in the bronchiole and trachea regions. About 90% of the particles get deposited in the alveolar regions, 6 to 8% in the bronchiole region, and 2% in the trachea region. The estimated deposition of nanoparticles for an individual working 8 hours a day in the near road conditions is 338 µg/year in Delhi. The deposition increases almost linearly as a function of time, and is 3 times higher (1016 µg/year) for a person residing near the road throughout the day (24 h). The deposition fraction of particles ranges between 0.05 and 0.10 µg/day in alveolar region, <0.05 µg/day in the bronchiole region, and lies between 0.02 and 0.04 µg/day in the trachea. The nanoparticles deposited in the respiratory system can lead to the development of various diseases such as asthma, chronic obstructive pulmonary disease, and can lead to carcinogenicity. Number concentration-based studies are essential for estimating the potential impacts on human health due to air pollution. The study provides information regarding vehicle emission-based particle concentration under various emission scenarios in urban cities, which is crucial for estimation of emissions, health impact assessment, future policy formulation and strategy measures. These quantitative results on seasonal variations of air pollutants together with the knowledge on seasonal variations in meteorological parameters and atmospheric dynamics provide a foundation which can positively contribute to the planning and devising mitigation measures aimed at improving air quality and public health. The study provides new insights on inhalable particle concentration during the day that are crucial for strategy development, emission mitigation, and health hazard assessment for the citizens. Understanding the dynamics of atmospheric nanoparticles in urban roadside environments provides on the deposition of nanoparticles in humans residing near roadside conditions are crucial to estimate the xi human health risk potential, and to formulate mitigation measures for exposure reduction which can result in a better and sustainable future.