Pallavi Saxena

University of Delhi | DU · Department of Environmental Sciences Hindu College

In this study, a pre-monsoon dust storm (14 May 2018 ± 2 days), originating from the Thar Desert (Rajasthan state) that spread to north Indian states—Haryana, Delhi, and Uttar Pradesh is selected. We leverage satellite (MODIS, GPM_IMERG), climate model reanalysis (MERRA-2), and ground monitoring station (CPCB, IMD, AERONET) observations to study th...

Open biomass burning has major impacts globally and regionally on atmospheric composition. Fire emissions include particulate matter, tropospheric ozone precursors, greenhouse gases, as well as persistent organic pollutants, mercury 55 and other metals. Fire frequency, intensity, duration, and location are changing as the climate warms, and modelli...

By exploring key research gaps and challenges in climate change and biodiversity, this report offers insights into promoting transformative change through research and innovation. Developed through an open and participatory approach, the report builds on the extensive international network of researchers and innovators at Future Earth and beyond. I...

Objective: The present study focuses on residential areas of Delhi to identify the elevated levels of ambient PM10 and PM2.5 due to biomass burning followed by the coloring activity in the Holi festival celebrated at the end of the winter season. This study also focuses on the health risk assessment and mortality among different age groups due to...

Non-technical summary Greenhouse gas emissions and land use change – from deforestation, forest degradation, and agricultural intensification – are contributing to climate change and biodiversity loss. Important land-based strategies such as planting trees or growing bioenergy crops (with carbon capture and storage) are needed to achieve the goals...

In the present study, a pre-monsoon dust storm event (14 May 2018 ± 2 days), originating from Thar Desert (Rajasthan state), spread to north Indian states- Haryana, Delhi, and Uttar Pradesh is selected. Satellite observations, climate model reanalysis datasets, and ground monitoring station and meteorological parameters were used to study the dust...

Climate change is a global concern of the current century. Its rapid escalation and ever-increasing intensity have been felt worldwide, leading to dramatic impacts globally. The aftermath of climate change in India has brought about a profound transformation in India’s environmental, socio-economic, and urban landscapes. In 2019, India ranked seven...

We honor here Dinesh Chandra Uprety (1945-2023), one of the most remarkable plant scientists of India, who devoted most of his life in solving the question of how best to tune the crop plants so that they can serve the growing human population in this world. We have provided here a glimpse of his personal life as well as his remarkable scientific c...

Forests are complex ecosystems comprising various trophic levels responsible for carrying out various biogeochemical processes and providing ecosystem services. However, forests in Asia are doubly challenged by climate change and air pollution. The rapidly changing air quality, with increasing concentration of greenhouse gases (GHGs), trace gases,...

The variability of organic carbon (OC), elemental carbon (EC), and secondary organic aerosol (SOA) and their relationship with meteorological parameters have been studied during foggy and non-foggy days in the peak winter months (December–January) from 2015 to 2016 in Delhi, India. Different sectoral locations were chosen based on predominant indus...

Air pollution and its impact on human health is a very mysterical problem in Indian sub-continent (Badarinath et al., 2006; Pradhan, 2001; Sonwani and Kulshrestha, 2016). Past air pollution related Indian studies have reported peak concentrations of aerosols (Escuin et al., 2008; Murphy et al., 2008; Singh et al., 2009, 2015; Sandhu et al., 2018),...

Atmospheric pollution is one of the vital issues since last 10 decades due to rapid industrialization and urbanization. Among all the air pollutants, particulate matter (PM) is one of the major hazardous pollutants to both human and plant health. The significant variation noted in the ambient atmosphere because of particulate matter load in urban r...

This collaborative article discusses the opportunities and challenges of adopting integrated, coordinated, open, and networked (ICON) principles in atmospheric sciences. From the global nature of the atmosphere, there has always been a need for atmospheric science to be an ICON science. With the help of evolving technology, it is possible to go fur...

Objective: This study focuses on the profile of ambient particulate polycyclic aromatic hydrocarbons (PAHs), their seasonal distribution, source identification and human health risk assessment due to inhalation exposure of ambient PAHs in Delhi, India. Materials and Methods: Two sampling sites were chosen, one at roadway (MH) and other at urban bac...

Greenhouse gases (GHG) occur naturally in our atmosphere and are essential to the survival of most of the organisms on the planet earth. GHG such as carbon dioxide, methane, nitrous oxide, and ozone play a major role in balancing the radiative budget, by absorbing or emitting some of the infrared rays reflecting from the earth’s surface. But unfort...

Greenhouse gases (GHGs) is considered as one of the biggest reasons behind climate change in Anthropocene. The GHGs (carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone (O3), chlorofluorocarbons (CFCs) and carbon tetrachloride (CCl4) play a major role in balancing the radiative budget, by absorbing or emitting some of the infrared rays...

Extremes in atmospheric phenomena and processes can strongly affect ambient air quality that has harmful impacts on human and climate health. High urbanization and industrialization are highly responsible for causing disturbances in different spheres of environment like atmosphere and its processes and phenomena. This will further impact human and...

Recurrent and large forest fires negatively impact ecosystem, air quality, and human health. Moderate Resolution Imaging Spectroradiometer fire product is used to identify forest fires over central India domain, an extremely fire prone region. The study finds that from 2001 to 2020, ∼70% of yearly forest fires over the region occurred during March...

The impacts of dust storms that originated over the north-western parts of India, are therefore very common in the northern part of India, in particular, Delhi. Dust storms affect the daily lives of people and also report severe health impacts. The air quality is badly influenced by dust storms events and ultimately creates a big threat to the surr...

The carbonaceous content of rainwater was investigated in samples collected at an urban background site in northern India. Sampling was performed on an event basis during two seasons: pre-monsoon (PM) and monsoon (MN) season covering May–June and July–August, respectively, in 2016. The concentrations of different fractions of water-insoluble organi...

Present study aims to evaluate the tolerance and sensitivity of some selected common ornamental plants like Dracaena deremensis, Tagetes erecta and Dianthus caryophyllus by the Air Pollution Tolerance Index (APTI) at selected sites in an urban metropolis of Northern India, Delhi city. Air pollutant concentrations were monitored at Site I (nearby tr...

Nanoparticles (NPs) are receiving an increasing attention from many scientific communities due to their strong influence on human health. NPs are an important marker of air pollution caused by a variety of natural and anthropogenic sources. Due to their ultrafine size, they can be suspended in the atmosphere for a long time and can thus travel larg...

Biomass burning occurred during Rabi and Kharif season contributes huge emission of gaseous pollutants and particulate matter in the atmosphere which deteriorate the air quality in almost all regions of the world. Crop residue burning activities emits a number of air pollutants like particulate matter (PM), sulfur dioxide (SO2), nitrogen oxides (NO...

This book provides an overview of the fundamental concept of air pollution, emission sources of air pollutants and their transportation. First, the book presents a brief background on air pollution and its emission sources, then it continues with their impact on agriculture, health, and climate change. Furthermore, it covers the basic concepts of...

Crop residue burning (CRB) over northern India is a major air quality and human health issue. The present study assesses the impact of PM10, PM2.5, NO2 and SO2, emitted during CRB activities in Haryana on the air quality of Delhi. The transition from pre-burning to burning period, in both rabi and kharif seasons, shows considerable increase in poll...

PM10 samples were collected and atmospheric organic carbon (OC) and elemental carbon (EC) were determined during summer monsoon (SM) and winter monsoon (WM) seasons in 2016–17 at an industrial location in New Delhi, India. Owing to high combustion and emission activities in the industrial area, it was imperative to characterize the carbonaceous aer...

The historical changes in temperature of the earth have been the concern of people since time immemorial. The exponential rise in the earth's temperature affects the production of crop plants. Taking the seriousness of such changes in temperature, it was considered important to measure them and their impact on agricultural crop production. Various...

The discovery of methane gas in the atmosphere was first reported by an Italian scientist Alessandro Volta (1778), and its effect on global warming is described in the beginning of this chapter. Methods of methane emission measurements are described on the basis of its flux along with their advantages and disadvantages. Measurement of methane flux...

Climate change significantly affects the water status of the soil and plants. Historical analysis of the soil and plant water status showed that it has been a topic of discussion since time immemorial. It was considered important to collect data on plant and soil water characters to explain the relationship of soil moisture and plant water status c...

Nitrous oxide was first discovered by a British chemist Joseph Priestly in 1772. The historical analysis of its role as GHG in global warming and as a natural regulator of stratospheric ozone is described in this chapter. The quantitative measurement of nitrous oxide has been illustrated on the basis of soil surface flux distribution and using micr...

This chapter starts with the historical aspect of CO2 and its natural and anthropogenic sources. Methodologies for measuring CO2 in the atmosphere, crops and soil are illustrated and explained. Technologies used for studying the responses of crop plants to the increasing concentration of CO2, namely Open Top Chamber (OTC), SPAR system, SACC technol...

Tropospheric ozone is one of the GHGs, which adversely affects the productivity of crop plants and ecosystems, whereas stratospheric ozone protects people from harmful UV radiations. The ozone-generating system to study the effect of O3 on agricultural crops is described in detail. Open-top chambers (OTC) using filtered charcoal and ozone FACE syst...

Covers technologies and methods including the simulation of the future climate changes. Elucidates the response of crop plants to GHGs and characterizes their responses. Includes the latest information on technologies for climate change research on agriculture. Useful literature in decision making to target policies aimed at amplifying agricultural...

Our understanding of the processes that control the burden and budget of tropospheric ozone has changed dramatically over the last 60 years. Models are the key tools used to understand these changes, and these underscore that there are many processes important in controlling the tropospheric ozone budget. In this critical review, we assess our evol...

To control the spread of the coronavirus (COVID-19) pandemic, the Government of India imposed various phases of lockdown starting from the third week of March 2020. Improvement in city air quality has emerged as a benefit of this lockdown in India. The objective of this paper is to quantify the health benefits due to this lockdown. PM2.5 concentrat...

The carbonaceous aerosol is one of the important components of the aerosol and plays a significant role in changing climate, fluctuating air quality and health of the living being. These carbonaceous aerosols emitted by the partial burning of fossil fuels through several processes such as emissions from industries, traffic and biomass burning inclu...

Our understanding of the processes that control the burden and budget of tropospheric ozone has changed dramatically over the last 60 years. Models are the key tools used to understand these changes, and these underscore that there are many processes important in controlling the tropospheric ozone budget. In this critical review, we assess our evol...

Air pollution is an alarming problem, not only in terms of air quality, but also in relation to health issues. Toxic air pollutant concentrations produce harmful impacts on plant health and human health. Further, though there are various sources of air pollution, anthropogenic and biogenic sources are becoming increasingly problematic. A number of...

The present study deals with the impact of firework activities on the variation of carbonaceous aerosols in Foggy days during in and around Diwali period vs. background period at three different sites, segregated on the basis of land-use pattern viz. JNU (dense vegetative), VN (residential) and AN (industrial) in Delhi, India. The average Organic C...

The indoor air quality is much more matter of concern as relative to ambient or outdoor air quality, especially in the context of human health. However, very few studies have been reported for remediation of indoor ozone by plant species. The main objective of this study is to evaluate ozone deposition velocities and ozone removal effectiveness of...

Globally, a number of firework events have been celebrated on a large scale in the names of different festivals. Diwali is one among the popular Indian festival held during October or November every year with huge fireworks. In the present study, various air pollutants like nitrogen oxides (NOx), particulate matter (PM2.5 and PM10) and ozone (O3) w...

Increasing tropospheric ozone concentration is a big threat to food security due to its phytotoxicity. It causes a huge damage to crop production across the globe, especially in the C 3 plants (paddy (Oryza sativa)). The present study focuses on exposure-plant response index over different O 3 concentration. In this study, two metrics viz. the aver...

The air quality in the capital city of India, Delhi has been worsened on regular basis since last 5 years. Most of the air pollutants (PM10, PM2.5, PM1 and black carbon) are alarmingly increasing at the rate of 3-5% particularly at busy traffic intersection sites. In this study, the variations of on-road emission factors of carbon monoxide (CO) and...

Ambient air pollution is the foremost reason for global death and disease. An estimated premature death globally is related to ambient air pollution, mainly from emphysema, obstructive bronchiolitis, lung cancer, heart disease, stroke, and severe respiratory problems in children. The criteria air pollutants include particulate matter (PM), ozone (O...

Air quality has been worsened due to increase in urbanization and industrialization both nationally and internationally. This poor air quality has affected floral and faunal diversity severely. This will affect the whole ecosystem widely. The major factors including biomass burning, high vehicular emissions, increment in industrial emissions and in...

A polluted air is a harmful complex combination of primary and secondary pollutants in the atmosphere. The US Environmental Protection Agency (USEPA) listed the six most common air pollutants as criteria air pollutant under the Clean Air Act. The primary criteria air pollutants (CO, SO2, NO2, PM and Pb) are released into the atmosphere directly fro...

Air quality has become a serious concern in mostly urban areas and covering different parts of the world. Over the last few years, there have been tremendous studies reported so far related to harmful health effects due to bad air quality in urban areas across the globe. Among all air pollutants, criteria air pollutants are specifically highlighted...

Tropospheric ozone (O 3) is a phytotoxic pollutant causing harmful impacts on plant species and their metabolism. Ozone has several potential effects on plants: direct reaction with cell membranes; generation of ROS and H2O2 , negative impact on photosynthetic machinery and up or downregulation of antioxidants, defence reactions and variations in m...

SECONDARY DATA COLLECTION The collected data had a duration of 5 months (January-May, 2019). The data included pollutants viz PM 10, PM 2.5, NH3, NOx, CO, and Ozone. Furthermore, meteorological data such as WS, WD, AT, RH, SR, and BP were also collected. Data collected from the CPCB’s 'Central Control Room For Air Quality Management' website. DATA...

The atmospheric hydrocarbon budget influenced by a vast range of volatile organic compounds (VOCs) is both anthropogenic and biogenic in origin. Evolution of plant VOCs is a complex process affected by interactions of plants with biotic and abiotic factors in constantly changing environment but their functional role is still a matter of speculation...

Air pollution is a global hazard. Majority of the world’s population is affected by air pollution. Contamination of air is no more an only an atmospheric problem but now has become a health concern too. Under the Clean Air Act of 1971, a set of air pollutants are designated as criteria pollutants. These are suspected to be strongly harming the publ...

The different chapters in this book explain about sources of air pollution i.e. both anthropogenic and biogenic, impact studies on human health, environment and economy and control methods and policies to curb air pollution.

This Tropospheric Ozone Assessment Report (TOAR) on the current state of knowledge of ozone metrics of relevance to vegetation ( TOAR-Vegetation ) reports on present-day global distribution of ozone at over 3300 vegetated sites and the long-term trends at nearly 1200 sites. TOAR-Vegetation focusses on three metrics over vegetation-relevant time-per...

The high concentration of ground-level ozone is a serious problem in many areas. Ozone formation is non-linear process and is produced from the photochemical interactions of volatile organic compounds (VOCs) and oxides of nitrogen (NOx) in the troposphere. Generally, MIR (Maximum Incremental Reactivity) scale is one of the popular ones in the asses...

In support of the first Tropospheric Ozone Assessment Report (TOAR) a relational database of global surface ozone observations has been developed and populated with hourly measurement data and enhanced metadata. A comprehensive suite of ozone data products including standard statistics, health and vegetation impact metrics, and trend information, a...

Air pollution is a widely known problem which can have significant effects on plant health. In this regard, pollutants such as air particulates, ozone, nitrogen oxides, sulphur dioxides have a negative impact on plant physiology and morphology. Recently, it has been noticed that most of the plant species are affected by tropospheric ozone and parti...

-Air quality in most of the mega-cities has been resulted from natural as well as anthropogenic environmental conditions. As compared to developed countries, the issue of air pollution is more serious and complicated in developing countries. Air pollution can be governed by two ways such as emission and transboundary movement of air pollutants. Eac...

Plants emit a substantial amount of biogenic volatile organic compounds (BVOCs) into the atmosphere having significant effects on atmospheric chemistry, physics, and the organisms. In this chapter, important facts about BVOCs’ production mechanism, storage, and emissions due to various abiotic and biotic factors have been discussed. The role of BVO...

Urbanization and industrialization processes contribute significant amount of various air pollutants such as SO2, NO2, CO, particulate matter, etc. These pollutants affect plant health and emit various forms of SO2, NOx, and O3 which may act in combination of a variety of ways: additive, synergistic, and antagonistic. These pollutants can have a de...

This review presents the status of knowledge about gasoline exhaust pollution and its impact biochemical and physiological characteristics of plants. Parameters on such as leaf conductance, membrane permeability, ascorbic acid, chlorophyll and relative water content have been used as indicators to assess the impact of gasoline exhaust pollution on...

This book focuses upon air pollution, types of air pollutants and their impact on plant physiological and biochemical systems. The book begins with a brief background on air pollution and continues with a discussion on different types, effects, and solutions to the pollution. The chapters that follow, explore the different effects of pollution on c...

The results based on the analysis of satellite fire counts detected by the Along-Track Scanning Radiometer (ATSR) sensors over different regions of India during 1998–2009 have been presented. Generally, the activities of open biomass burning show large spatial and temporal variations in India. The highest and lowest values of monthly fire counts we...

Emissions from motor vehicle exhausts have been shown to have deleterious effects on the physiology of plant species. Our present study focuses on evaluating the tolerance and sensitivity of selected plant species viz. Dracaena deremensis (good absorber of VOCs) and Dianthus caryophyllus (susceptible to ethylene and formaldehyde (VOCs)) at selected...

Mitigation of urban air pollution is a big challenge, especially for the metropolitan cities of the world. In an Indian metropolis like Delhi, even after the implementation of several control policies, no such remarkable change has been observed in its air quality. Globally, afforestation or greenbelt development is an effective and well-recognized...

Air pollution kills more than 5.9 million people annually, with more than 90 per cent of these deaths in capital city of India, Delhi. For improving the status of air pollution in Delhi, various policies and laws have been implemented. But even after the implementation of CNG, there was no significant change of pollutants (NOx, O3, SPM, RSPM & CO)...