Rakesh K Hooda

Finnish Meteorological Institute · Climate Research Programme

Atmospheric new particle formation (NPF) is a crucial process driving aerosol number concentrations in the atmosphere; it can significantly impact the evolution of atmospheric aerosol and cloud processes. This study analyses at least 1 year of asynchronous particle number size distributions from six different locations in India. We also analyze the...

Citation: Ningombam, S.S.; Dumka, U.C.; Mugil, S.K.; Kuniyal, J.C.; Hooda, R.K.; Gautam, A.S.; Tiwari, S.

Atmospheric new particle formation (NPF), via gas-to-particle conversion, is the largest source of aerosol numbers to the terrestrial atmosphere. NPF produces about half of the present-day cloud condensation nuclei (CCN), thus significantly influencing cloud properties and Earth's energy budget. But, observations of NPF are scarce globally, particu...

The impact of climate change has severely affected geosphere, biosphere and cryosphere ecosystems in the Hindu Kush Himalayan (HKH) region. The impact has been accelerating further from the last few decades due to the rapid increase in anthropogenic activities such as modernization, industrialization/ urbanization along with energy demands. In view...

The present study analyzes data from total suspended particulate (TSP) samples collected during 3 years (2005-2008) at Nainital, central Himalayas, India and analyzed for carbonaceous aerosols (organic carbon (OC) and elemental carbon (EC)) and inorganic species, focusing on the assessment of primary and secondary organic carbon contributions (POC,...

Long-term aerosol characteristics were assessed over the Indo-Gangetic Basin (IGB) using satellite-derived aerosol properties from January 2007 to December 2017. The study shows steadily high aerosol optical depth (AOD ~0.7) with a decadal increasing trend (~20%) over the IGB. Angstrom exponent (AE) shows a relatively large increasing trend at Luck...

New particle formation (NPF) can influence the Earth's radiative budget when the newly formed particles grow to climate-relevant sizes. Here, we present analysis of 21 months of continuous aerosol size distribution measurements at a background remote site in the western Himalaya and provide observational evidence that newly formed particles grow to...

Currently, only the mass of sub 2.5 μm and sub 10 μm particles (PM2.5, PM10) in ambient air is regulated and monitored closely, but the same increase in PM2.5 can cause different degrees of health effects in different cities (sometimes more harmful effects in less polluted cities) (1). In addition to mass concentration, other measurement metrics ar...

Snow darkening by deposited light-absorbing particles (LAP) has the potential to accelerate snowmelt and shift the snow melt-out date. Here we investigate the sensitivity of the seasonal snow cover duration to changes in LAP at a high altitude valley site in the Central Himalayas, India. First, the variation of the albedo of the seasonal snow was e...

Anthropogenic activities on the Indo-Gangetic Plain emit vast amounts of light-absorbing particles (LAPs) into the atmosphere, modifying the atmospheric radiation state. With transport to the nearby Himalayas and deposition to its surfaces the particles contribute to glacier melt and snowmelt via darkening of the highly reflective snow. The central...

The particulate matters less than 10 μm sizes (PM10) were measured at a highly polluted urban environment of Delhi, and simultaneously at a downwind semi-urban site, Gual Pahari, in the north-west Indo-Gangetic Basin (IGB). The measurements were conducted during January-December 2008 to compare and contrast aerosol emissions, compositions and relat...

Anthropogenic activities on the Indo-Gangetic Plain emit vast amounts of light-absorbing particles (LAP) into the atmosphere, modifying the atmospheric radiation scheme. With transport to the nearby Himalayan mountains and deposition to its surfaces the particles contribute to glacier and snowmelt via darkening of the highly reflective snow. The Ce...

Aerosol particles are essential constituents of the Earth's atmosphere, impacting the earth radiation balance directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. In contrast to most greenhouse gases, aerosol particles have short atmospheric residence times, resulting in a highly heterogeneous...

In order to assess the evolution of aerosol parameters affecting climate change, a long-term trend analysis of aerosol optical properties was performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single scattering albedo, b...

Abstract. Aerosol particles are essential constituents of the Earth’s atmosphere, impacting the earth radiation balance directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. In contrast to most greenhouse gases, aerosol particles have short atmospheric residence time resulting in a highly heter...

Abstract. In order to assess the global evolution of aerosol parameters affecting climate change, a long-term trend analyses of aerosol optical properties were performed on time series from 52 stations situated across five continents. The time series of measured scattering, backscattering and absorption coefficients as well as the derived single sc...

This study presents analysis of in situ measurements conducted over the period 2005–2014 in the Indian Himalayas to give a thorough overview of the factors and causes that drive aerosol properties. Aerosol extensive properties (namely, particle number concentration, scattering coefficient, equivalent black carbon, PM2.5, and PM10) have 1.5–2 times...

Atmospheric new particle formation (NPF) is an important phenomenon in terms of global particle number concentrations. Here we investigated the frequency of NPF, formation rates of 10nm particles, and growth rates in the size range of 10–25nm using at least 1 year of aerosol number size-distribution observations at 36 different locations around the...

High altitude stations are often emphasized as free tropospheric measuring sites but they remain influenced by atmospheric boundary layer (ABL) air masses due to convective transport processes. The local and meso-scale topographical features around the station are involved in the convective boundary layer development and in the formation of thermal...

Light-absorbing impurities (LAIs) deposited in snow have the potential to substantially affect the snow radiation budget, with subsequent implications for snow melt. To more accurately quantify the snow albedo, the contribution from different LAIs needs to be assessed. Here we estimate the main LAI components, elemental carbon (EC) (as a proxy for...

Light-absorbing impurities (LAI) have the potential to substantially affect snow albedo, with subsequent changes on snow melt and impact on climate. To more accurately quantify the snow albedo, the contribution from different LAI needs to be assessed. Here we estimate the main LAI components, elemental carbon (EC) (as a proxy for black carbon) and...

We have measured black carbon properties by using a size-selected single-particle soot photometer (SP2). The measurements were conducted in northern India at two sites: Gual Pahari is located at the Indo-Gangetic Plain (IGP) and Mukteshwar at the Himalayan foothills. Northern India is known as one of the absorbing aerosol hot spots, but detailed in...

A global vertically resolved aerosol data set covering more than 10 years of observations at more than 20 measurement sites distributed from 63° N to 52° S and 72° W to 124° E has been achieved within the Raman and polarization lidar network PollyNET. This network consists of portable, remote-controlled multiwavelength-polarization-Raman lidars (Po...

A global vertically resolved aerosol data set covering more than 10 years of observations at more than 20 measurement sites distributed from 63° N to 52° S and 72° W to 124° E has been achieved within the Raman and polarization lidar network PollyNET. This network consists of portable, remote-controlled multiwavelength-polarization-Raman lidars (Po...

Climate-aerosol interactions in India are studied by employing the global climate-aerosol model ECHAM5-HAM and the GAINS inventory for anthropogenic aerosol emissions. Model validation is done for black carbon surface concentrations in Mukteshwar and for features of the mon-soon circulation. Seasonal cycles and spatial distributions of radiative fo...

Researcher Atmospheric Composition Research Unit FMI Experience, accomplishments, and training My responsibility as a senior-level researcher is varied from project formulation, project execution to peer review. I have been leading several international collaborations and I am expected to build research networks in my area of expertise. I have acco...

Researcher Atmospheric Composition Research Unit FMI Experience, accomplishments, and training My responsibility as a senior-level researcher is varied from project formulation, project execution to peer review. I have been leading several international collaborations and I am expected to build research networks in my area of expertise. I have acco...

The Energy and Resources Institute (TERI), New Delhi Central Road Research Institute (CRRI), New Delhi Fellow Scientist (Fellow) Experience, accomplishme nts through major projects and services Major Projects My responsibility as a senior-level researcher is varied from project formulation, project execution to peer review. I have been leading seve...

The Energy and Resources Institute (TERI), New Delhi Central Road Research Institute (CRRI), New Delhi Fellow Scientist (Fellow) Experience, accomplishme nts through major projects and services Major Projects My responsibility as a senior-level researcher is varied from project formulation, project execution to peer review. I have been leading seve...

Climate-aerosol interactions in India are studied by employing the global climate-aerosol model ECHAM5-HAM and the GAINS inventory for anthropogenic aerosol emissions. Seasonal cycles and spatial distributions of radiative forcing and the temperature and rainfall responses are presented for different model setups. While total aerosol radiative forc...

The Multi-Angle Absorption Photometer (MAAP) is a widely-used instrument for aerosol black carbon observations. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments with high black carbon concentrations. The artifact occurs after a filter spot change - as BC mass is accumulated on a fresh...

Urban areas need to deal with the problem of deteriorating air quality due to the presence of various contributing sources. This paper quantifies the contribution of various sources towards prevailing ambient particulate matter (PM) concentrations at different landuse categories in an urban setting. PM10 and PM2.5 were monitored at seven locations...

The Multi-Angle Absorption Photometer (MAAP) is a widely-used instrument for aerosol black carbon (BC) measurements. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments characterized by high black carbon concentrations. The artifact occurs after a filter spot change – as BC mass is accum...

Continuous aerosol measurements were made at a regional background station (Mukteshwar) located in a rural Himalayan mountain terrain from December 2005 to December 2008 for a period of 3 years. The average concentrations of particulate matter less than or equal to 10 μm (PM(10)), particulate matter less than or equal to 2.5 μm (PM(2.5)) and black...

The mercury-bearing lamps, towards the end-of-life, pose significant hazard potential due to the likely release of mercury. Though, these fluorescent lamps (FLs) release relatively less quantity of mercury when disposed as compared to other mercury-based products, they are still a concern due to the large and further growing number of FLs in servic...

One year of multi-wavelength (3 backscatter + 2 extinction + 1 depolarization) Raman lidar measurements at Gual Pahari, close to New Delhi, were analysed. The data was split into four seasons: spring (March–May), summer (June–August), autumn (September–November) and winter (December–February). The vertical profiles of backscat-ter, extinction, and...

Particulate matter (PM) and black carbon (BC) concentrations were measured at two locations in Northern India during 2006–2010. The first measurement station is a background site in Mukteshwar, about 350 km northeast of New Delhi, in the foothills of the Indian Himalayas. The second measurement site was located in Gual Pahari, about 25 km south of...

Aerosol physical and optical properties were measured at two locations in Northern India during 2006–2010. The first measurement station was a background site in Mukteshwar, about 350 km northeast of New Delhi, in the foothills of the Indian Himalayas. The second measurement site was located in Gual Pahari, about 25 km south of New Delhi. At both s...

Aerosol physical and optical properties were measured at two locations in northern India. The first measurement station was a background site in Mukteshwar, about 350 km northeast of New Delhi, in the foothills of the Indian Himalayas, with data from 2006 to 2009. The second measurement site was located in Gual Pahari, about 25 km south of New Delh...

Gual Pahari is a polluted semi-urban background measurement site at the Indo-Gangetic plains close to New Delhi and Mukteshwar is a relatively clean background measurement site at the foothills of the Himalayas about 270 km NE from Gual Pahari and about 2 km above the nearby plains. Two years long data sets including aerosol and meteorological para...

This article presents the status of water, air quality and noise pollution in the lime stone mining belt (district Gulbarga and Bagalkot) in the state of Karnataka. These two districts store nearly 55% of total estimated limestone reserve of the state. An attempt was made to assess the environmental quality of this region and compare it with the na...

Particulate matter (PM) and black carbon (BC) concentrations were measured at two locations in Northern India during 2006–2010. The first measurement station is a background site in Mukteshwar, about 350 km northeast of New Delhi, in the foothills of the Indian Himalayas. The second measurement site was located in Gual Pahari, about 25 km south of...

One year of multi-wavelength (3+2) Raman lidar measurements at Gual Pahari, close to Delhi, were analysed. The data was split into four seasons: spring (March–May), summer (June–August), autumn (September–November) and winter (December–February). The vertical profiles of backscatter, extinction, and lidar ratio and their variability during each sea...

The Finnish Meteorological Institute (FMI), together with The Energy and Resources Institute of India (TERI), contributed to the European Integrated project on Aerosol Cloud Climate and Air Quality Interactions, EUCAARI, by conducting aerosol measurements in Gual Pahari, India, from December 2007 to January 2010. This paper describes the station se...

The Finnish Meteorogical Institute (FMI), together with The Energy and Resources Institute of India (TERI), contributed to the The European Integrated project on Aerosol Cloud Climate and Air Quality Interactions, EUCAARI, by conducting aerosol measurements in Gual Pahari, India, from December 2007 to January 2010. This paper describes the station...

Dyes are usually present in trace quantities in the treated effluents of many industries. The effectiveness of adsorption for dye removal from wastewaters has made it an ideal alternative to other expensive treatment methods. This study investigates the potential use of Indian Rosewood (Dalbergia sissoo) sawdust, pretreated with formaldehyde and su...

Adsorbents prepared from Prosopis Cineraria sawdust—an agro-industry waste—were successfully used to remove the malachite green from an aqueous solution in a batch reactor. The adsorbents included formaldehyde-treated sawdust (PCSD) and sulphuric acid-treated sawdust (PCSDC). The effects of adsorbent surface change, initial pH, initial dye concentr...

The adsorption of Cr(VI) from aqueous solutions on formaldehyde treated sawdust (SD) and sulphuric acid treated sawdust carbon (SDC) of Indian Rosewood, a timber industry waste, was studied at varying Cr(VI) concentrations, adsorbent dose, pH and agitation time. Similar experiments were conducted with commercially available coconut based activated...

Formaldehyde treated and sulphuric acid treated saw dusts were used to adsorb malachite green at varying dye concentration, adsorbent dose, pH and agitation time. Similar experiments were conducted with laboratory grade activated carbon to compare the results. The adsorption efficiency of sulphuric acid treated sawdust (SD) was higher than formalde...

Generating a vertical profile of aerosols and the elemental concentrations in an un-inhabited environment in the envelope of a high rise building in an unpolluted environment as a part of M Tech dissertation entitled “Vertical Distribution of Atmospheric Particulate Matter and Trace Metals in the Envelope of a High Rise Building”. The results of th...