Dilip Ganguly

Indian Institute of Technology Delhi | IIT Delhi · Centre for Atmospheric Sciences

India has set ambitious solar energy targets to meet its climate commitments. However, climate change, already evident in the country, poses significant challenges to solar power generation. Therefore, assessing the impact of climate change on future photovoltaic potential in India is essential. This study evaluates the mid-century (2041–2050) sola...

High time-resolution aerosol measurements across various regions of the Indo-Gangetic Plain (IGP) are essential due to its dense population, intense industry, pollution episodes, agriculture, health impacts, and climate implications. However, absence of studies in Central IGP (C-IGP) limits the comprehensive understanding, as research has been prim...

The oxidative potential (OP) of particulate matter (PM) is a major driver of PM-associated health effects. In India, the emission sources defining PM-OP, and their local/regional nature, are yet to be established. Here, to address this gap we determine the geographical origin, sources of PM, and its OP at five Indo-Gangetic Plain sites inside and o...

The apparent volatility of atmospheric organic aerosol (OA) particles is determined by their chemical composition and environmental conditions (e.g., ambient temperature). A quantitative, experimental assessment of volatility and the respective importance of these two factors remains challenging, especially in ambient measurements. We present molec...

The apparent volatility of atmospheric organic aerosol (OA) particles is determined by their chemical composition and environmental conditions (e.g., ambient temperature). A quantitative, experimental assessment of volatility and the respective importance of these two factors remains challenging, especially in ambient measurements. We present molec...

India aims for ambitious solar energy goal to fulfill its climate commitment but there are limited studies on solar resource assessment considering both environmental and land availability constraints. The present work attempts to address this issue using satellite-derived air pollution, radiation, and land use data over the Indian region. Surface...

Atmospheric pollution in urban regions is highly influenced by oxidants due to their important role in the formation of secondary organic aerosol (SOA) and smog. These include the nitrate radical (NO3), which is typically considered a nighttime oxidant, and the chlorine radical (Cl), an extremely potent oxidant that can be released in the morning i...

Aerosols undergo significant changes due to water uptake under high RH conditions, leading to changes in physical, optical, and chemical properties. Detailed assessment and investigation are needed to understand better aerosol liquid water content (ALWC) characteristics in highly polluted regions like Delhi. Therefore, in this study, we examined th...

Atmospheric pollution in urban regions is highly influenced by oxidants due to their important role in the formation of secondary organic aerosol (SOA) and smog. These include the nitrate radical (NO3), which is typically considered a night-time oxidant, and the chlorine radical (Cl), an extremely potent oxidant that can be released in the morning...

Natural and anthropogenic biomass burning are among the major sources of particulate pollution worldwide that afects air quality, climate and human health. Delhi, one of the world’s most populated cities, experiences severe haze events caused by particulate pollution during winter, but the underlying pathways remain poorly understood. Here we obser...

Comprehensive evaluation of aerosol‐cloud interactions (ACI) simulated by climate models using observations is crucial for advancing model development. Here, we use Moderate Resolution Imaging Spectroradiometer (MODIS) data to evaluate aerosol and cloud properties obtained from Community Atmosphere Model 5 (CAM5) over northern Bay of Bengal during...

Black carbon (BC) aerosol is a short-lived climate forcer. BC aerosols are known to perturb the earth’s energy balance by interacting with radiation, modifying the cloud properties, and thereby changing the atmospheric heating pattern associated with various phenomena including the South Asian Summer Monsoon (SASM) system. However, many facets of B...

We investigated the influence of biomass burning (BURN), Diwali fireworks, and fog events on the ambient fine particulate matter (PM2.5) oxidative potential (OP) during the postmonsoon (PMON) and winter season in Delhi, India. The real-time hourly averaged OP (based on a dithiothreitol assay) and PM2.5 chemical composition were measured intermitten...

This work analyzes the PM2.5 bound highly time-resolved non-refractory and elemental compositions to observe the lag effects of the COVID-19 lockdown in the capital city of India. To the best of our knowledge, this is the first study that focuses on PM2.5 bound highly time-resolved chemical species and source apportionment to assess the contributio...

The World Meteorological Organizations' International Cloud Atlas recognizes 10 basic cloud genera for classifying clouds. Many of these have been used for over 200 years and are based on cloud appearance and base altitude as seen from surface. Over the satellite era, several missions and programs provide public products that classify clouds into t...

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 po...

Simultaneous measurements of volatile organic compounds (VOCs) using two PTR‐TOF‐MS instruments were conducted at urban and suburban sites of New Delhi during the winter of 2018. The time series of VOC mixing ratios show substantial variations mainly influenced by local emissions and meteorological conditions. Mixing ratios of methanol (∼28 ppbv),...

India has set a target of 100 GW solar installation capacity by the year 2022. However, the loss of solar energy due to environmental factors like air pollution is not properly considered in renewable energy resource assessment. Here we show that India lost 29% of its utilizable global horizontal irradiance potential due to air pollution between 20...

Volatile organic compounds (VOCs) are ubiquitous atmospheric constituents and play important roles in tropospheric photochemistry. The real-time chemical characterization of VOCs was carried out in this study using the proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) at an urban site of Delhi for the complete year of 2019. The...

Delhi metropolitan area suffers from extreme haze during the post‐monsoon and winter season, impacting climate, public health, and economy. We used a high‐resolution time‐of‐flight aerosol mass spectrometer (HR‐ToF‐AMS) and aethalometer at two urban locations in Delhi to capture non‐refractory PM2.5 (NR‐PM2.5) and black carbon (BC) during the post‐...

In recent years, the Indian capital city of Delhi has been impacted by very high levels of air pollution, especially during winters. 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 p...

Delhi is one of the most polluted cities globally, with frequent severe air pollution episodes and haze events occurring in recent years, thereby compelling us to understand the sources to develop effective mitigation plans. Complete chemical characterization of fine particulate matter (PM2.5) components (non-refractory, refractory and elements) wi...

It is well established that light-absorbing organic aerosols (commonly known as brown carbon, BrC) impact climate. However, uncertainties remain as their contributions to absorption at different wavelengths are often ignored in climate models. Further, BrC exhibits differences in absorption at different wavelengths due to the variable composition i...

National Capital Region (NCR) encompassing New Delhi is one of the most polluted urban metropolitan areas in the world. Real-time chemical characterization of fine particulate matter (PM1 and PM2.5) was carried out using three aerosol mass spectrometers, two aethalometers, and one single particle soot photometer (SP2) at two sites in Delhi (urban)...

This study examines the light absorption characteristics of fine atmospheric particulates using the co-located real-time measurements of chemical and optical aerosol characteristics at a site located in Delhi during winter. The contribution of absorption by black carbon and brown carbon (BC and BrC) to the total absorption (babs) is computed using...

The Government of India (GOI) announced a nationwide lockdown starting 25th March 2020 to contain the spread of COVID-19, leading to an unprecedented decline in anthropogenic activities and, in turn, improvements in ambient air quality. This is the first study to focus on highly time-resolved chemical speciation and source apportionment of PM2.5 to...

We present highly time-resolved (30 to 120 min) measurements of size-fractionated (PM10 and PM2.5) elements in two cities in Asia (Delhi and Beijing) and Europe (Krakow and London). For most elements, the mean concentrations in PM10 and PM2.5 are higher in the Asian cities (up to 24 and 28 times, respectively) than in Krakow and often higher in Del...

Modelling of ambient PM2.5 exposure has improved in recent years with the application of satellite data, but in India, where the ground-based measurements are still inadequate, satellite-based assessment cannot provide temporal continuity. In this work, we analyze MERRA-2 (Modern-Era Retrospective analysis for Research and Applications) reanalysis...

The Government of India (GOI) announced a nationwide lockdown starting 25th March 2020 to contain the spread of COVID-19, leading to an unprecedented decline in anthropogenic activities and in turn improvements in ambient air quality. This is the first study to focus on highly time-resolved chemical speciation and source apportionment of PM$_{2.5}$...

Characteristics and sources of volatile organic compounds (VOCs) were investigated with highly time-resolved simultaneous measurements by two proton-transfer-reaction time-of-flight mass spectrometers (PTR-ToF-MS) at an urban and a suburban site in New Delhi, India, from January to March 2018. During the measurement period, high mixing ratios of VO...

We present highly time-resolved (30 to 120 min) measurements of size-fractionated (PM10 and PM2.5) elements in two cities in Asia (Delhi and Beijing) and Europe (Krakow and London). For most elements, the mean concentrations in PM10 and PM2.5 are higher in Asian cities (up to 24 and 28 times, respectively) than in Krakow, and often higher in Delhi...

Delhi, the capital of India, suffers from heavy local emissions as well as regional transport of air pollutants, resulting in severe aerosol loadings. To determine the sources of these pollutants, we have quantified the mass concentrations of 26 elements in airborne particles, measured by an online X-ray fluorescence spectrometer with time resoluti...

Abstract. Characteristics and sources of volatile organic compounds (VOCs) were investigated with highly time-resolved simultaneous measurements by two proton-transfer-reaction time-of-flight mass spectrometers (PTR-ToF-MS) at an urban and a suburban site in New Delhi, India from January to March 2018. During the measurement period, high mixing rat...

In this study, we categorized detailed mass-based emission factors (EFs) by age, calculated new estimates of fuel use, and developed spatially resolved emission inventories of constituents (PM 2.5 , black carbon [BC], and organic carbon [OC]) in the fine aerosol generated by the on-road transport sector in India. On a national level, this sector re...

Climate change and air pollution have important societal consequences, especially in emerging economies, wherein transitions from polluting technologies to cleaner alternatives coincide with high population vulnerability to environmental threats. India is home to a fifth of the world’s population and a gamut of human activities, employing a far ran...

Abstract The new Energy Exascale Earth System Model Version 1 (E3SMv1) developed for the U.S. Department of Energy has significant new treatments of aerosols and light‐absorbing snow impurities as well as their interactions with clouds and radiation. This study describes seven sets of new aerosol‐related treatments (involving emissions, new particl...

In the present study, we examine the responses of South Asian Monsoon (SAM) rainfall at intra-seasonal scale to remote dust emissions from west Asia, Tibetan Plateau and local dust emissions from within south Asia using a state of the art coupled atmosphere-slab ocean model CESM1-SOM. A series of systematically designed idealized simulations are ca...

Abstract. Estimating ambient PM_2.5 (fine particulate matter) concentrations in India over many years is challenging because spatial coverage of ground-based monitoring, while better recently, is still inadequate and satellite-based assessment lacks temporal continuity. Here we analyze MERRA-2 reanalysis aerosol products to estimate PM<su...

The equilibrium climate response of the south Asian monsoon (SAM) system to West Asia (WA), Tibetan Plateau (TP) and local dust emissions is investigated through a series of systematically designed idealized numerical experiments using CESM1-SOM, an atmospheric general circulation model coupled with a slab ocean model. Our results show that while a...

Accurately measuring emission factors (EFs) are prerequisite for the correct emission estimates. The radiative forcing of carbonaceous constituents of aerosol (Elemental and Organic Carbon) are agreed to have significant climate implications over South Asia including India and China, where the abundance is high. However, a large discrepancy between...

This study is aimed at examining the consistency of the relationship between load of dust and rainfall simulated by different climate models and its implication for the Indian summer monsoon system. Monthly mean outputs of 12 climate models, obtained from the archive of the Coupled Model Intercomparison Project phase 5 (CMIP5) for the period 1951–2...

Using all forcing simulations of fully coupled climate model GFDL-CM3, an attempt has been made to represent the role of natural aerosols (such as dust) in modulating the summer monsoon rainfall over the Central Indian region. For this purpose, long-term data set of dust, winds and rainfall have been obtained from CMIP5 data portal for the past 54...

Present study investigates the similarities and differences in the pattern of dust load and rainfall and their relationship over the South Asian monsoon region under various future warming scenarios with respect to the historical period using multiple coupled climate model runs that participated in CMIP5. Based on statistically robust significance...

Emission estimates are very important inputs for the assessment of burden of disease and climate change at local, regional, and global scale (Lacey and Henze, 2015; Pandey and Venkataraman, 2014; IHME, 2013). The large discrepancy between model simulated and satellite retrieved absorbing aerosol optical depth was estimated in recent work by Bond et...

Motivated by the current leadership for a Clean India, we, a self-organized task force, have developed a set of ten scalable solutions to clean the air. We synthesized available data on sources of air pollution, its transport over long distances, its impact on public health, food production, regional climate, to arrive at the solutions that can sig...

Subtropical North Africa has been subject to extensive droughts in the late 20th century, linked to changes in the sea surface temperature (SST). However, climate models forced by observed SSTs cannot reproduce the magnitude of the observed rainfall reduction. Here, we propose aerosol indirect effects (AIE) as an important positive feedback mechani...

Impact of aerosols on the Indian summer monsoon (ISM) variability is well documented; however there are limited studies which have quantified the role of aerosols in modifying the amount of rainfall. To address this research problem, we make use of the remotely sensed data set of precipitation and aerosols from different observations. In the presen...

We have examined the Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 5.1 Level 2 Aerosol Optical Depth (AOD) from Deep Blue algorithm and Dark Target approach over Ahmedabad, India for 2002 to 2005. Deep Blue algorithm is observed to be able to retrieve AOD over the Rann of Kuchchh, a region of high surface reflectance which poses...

1] Using a global climate model with fully predictive aerosol life cycle, we investigate the fast and slow responses of the South Asian monsoon system to anthropogenic aero-sol forcing. Our results show that the feedbacks associated with sea surface temperature (SST) change caused by aero-sols play a more important role than the aerosol's direct im...

The equilibrium climate response to the total effects (direct, indirect and semi-direct effects) of aerosols arising from anthropogenic and biomass burning emissions on the South Asian summer monsoon system is studied using a coupled atmosphere-slab ocean model. Our results suggest that anthropogenic and biomass burning aerosols generally induce a...

Investigating the climate response to the total effects of anthropogenic and biomass burning aerosols on the South Asian monsoon system is essential to understand and predict climate change not just in Asia but also globally. This study investigates the thermal, radiative, dynamical, and hydrological responses to the combination of direct, semi-dir...

Carbonaceous aerosols enhance scattering and absorption of solar radiation (i.e., direct radiative effect) in the atmosphere and also affect clouds and precipitation through indirect effects, thus heating the atmosphere but reducing the amount of solar radiation that reaches the earth's surface. These effects through dynamic feedbacks can also have...

We present results on detecting and isolating the forcing and response processes in the climate system by applying multiple pseudo-random perturbations of sea surface temperature (SST) patterns across various ocean regions using CAM5 and Hadley Center GCM. As a reasonable first step, we have simplified the original idea of forcing the climate syste...

We present a method to derive the concentration of aerosol components using the spectral measurements of AOD (aerosol optical depth) and single scattering albedo along with their size distribution and extinction profile available from AERONET (Aerosol Robotic Network) and MPLNET (Micro-pulse Lidar Network) stations as well as the space borne CALIOP...

In this work we demonstrate a method to derive the concentration of aerosol components from the spectral measurements of AOD (aerosol optical depth) and single scattering albedo along with their size distribution and extinction profile available from AERONET (Aerosol Robotic Network) and MPLNET (Micro-pulse Lidar Network) stations. The technique in...

Most GCMs (General Circulation Models) fail to reproduce the AOD (aerosol optical depth) peak over the Indo-Gangetic basin (IGB) as noticed through satellite observations. Insufficient data on aerosol composition makes it difficult to improve GCM results over this source region. In this work, we retrieve the composition and concentration of aerosol...