Saurabh Sonwani | Jawaharlal Nehru University,New Delhi,India (original) (raw)

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Papers by Saurabh Sonwani

41st COSPAR Scientific Assembly, Jul 1, 2016

Frontiers in sustainable cities, Aug 31, 2022

Disaster Resilience and Green Growth, 2022

43rd COSPAR Scientific Assembly. Held 28 January - 4 February, 2021

<p>As part of the Ozone and Precursors in the Tropics (OPT) working group of the Tr... more <p>As part of the Ozone and Precursors in the Tropics (OPT) working group of the Tropospheric Ozone Assessment Report Phase 2 (TOAR-II), we present the first results on the distribution of tropospheric ozone (O3) and its precursors (carbon monoxide, CO; formaldehyde, HCHO; nitrogen dioxide, NO2) in the tropics over the past 20-25 years. The goal is to give an overview of the seasonal, geographical and vertical variabilities of tropical tropospheric O3 and its precursors. To do so, we use in situ measurements of O3 and its precursors from surface sites, sounding balloons (SHADOZ) and instrumented aircraft (IAGOS and ATOM), as well as ground-based (FTIR) and spatial (IASI, OMI, GOME-2) remote-sensed observations. The observations are averaged monthly over the longest available time-period as well as over the first five years of the time period. The results for these two time periods give the context to interpret distributions and variabilities of O3 and its precursors over the most recent five years as we call it “Present-day”.  Special emphasis is given to the differences of O3 and its precursors’ distributions between remote and polluted regions and to the relationships between the gaseous species. Model output will be included to fill gaps in space and time when necessary to help the interpretation of the analysis based on observations.</p><p>From IAGOS measurements, the highest O3 and CO maxima occur in the lower troposphere of Northern Hemisphere Africa, which remains the most influenced by biomass burning. CO maxima are attributed using SOFT-IO model to anthropogenic emissions by 60%. Second maxima are observed in the lower troposphere of Asia, mostly due to anthropogenic emissions. The highest amount of transported CO in the tropics originates from Africa.</p>

Airborne Particulate Matter

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

43rd COSPAR Scientific Assembly. Held 28 January - 4 February, 2021

Ecosystem Health and Sustainability

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous persistence organic pollutants (POPs). Sev... more Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous persistence organic pollutants (POPs). Several PAHs are known toxic, mutagenic and carcinogenic compounds. Understanding the contributions of the various emission sources is critical to appropriately managing PAH levels in the environment. In the present study, PM 10 samples were collected at two sampling sites (UA and CR) in Delhi during the period of monsoon and winter season from July 2013 to January 2014. The concentrations of 10 selected PAHs in aerosols were quantified for source apportionment analysis. Their total amount at CR ranged from 18 to 161 ngm-3 whereas at UA it varies from 15 to 116 ngm-3. The sources of PAHs in Delhi were determined by using source apportionment methods (molecular diagnostic ratios). At CR, vehicular emissions in the form of diesel and gasoline exhaust were major emission sources. On the contrary, mixed type of sources (coal combustion, wood combustion and gasoline and diesel engine emissions) ...

Inhalation Toxicology

Abstract Objective: This study focuses on the profile of ambient particulate polycyclic aromatic ... more Abstract 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 background (JNU) site in Delhi. Determination of PAHs was carried with the help of HPLC with UV detector. Principal component analysis and Molecular diagnostic ratios were used for the source apportionment of PAHs. Health risks associated with inhalation of particulate PAHs were assessed using benzo(a)pyrene equivalent concentration and incremental lifetime cancer risk (ILCR) approach. Results: The results showed that the average mass concentration of Σ16 PAHs near roadway (67.8 ± 40.2 ng m−3) is significantly higher than urban background site (56 ± 30 ng m−3). Moreover, source apportionment study indicated that major PAH-emission sources in Delhi NCR are traffic and coal combustion. ILCR values at both the sites fall in the range of 10−2–10−4 that corresponds to the priority risk level (10−3) and higher than the acceptable risk level (10−6). conclusions: The high PAHs concentration at MH site was due to it’s nearness to busy traffic area. Thus, the spatial variations in PAHs were influenced by local emission sources. The high PAHs level during the winter season can be due to their higher emissions from local heating sources, shift of gas/particle partitioning toward the particulate phase at low temperature and reduced photochemical degradation of some PAHs in winter. The low level of PAHs in monsoon season can be attributed to their wet scavenging and higher percentage in vapor phase. PCA showed that the emissions from vehicles predominate at MH site; whereas, coal combustion and traffic both are the significant PAHs sources at JNU site. Health risk assessment revealed that the highest exposure risks occur at busy traffic site, thereby indicating a significantly higher health risk to the population of Delhi.

Greenhouse Gases: Sources, Sinks and Mitigation

Criteria Air Pollutants and their Impact on Environmental Health

A polluted air is a harmful complex combination of primary and secondary pollutants in the atmosp... more 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 from their emission source. Due to their highly reactive nature, they get easily participated in a variety of reactions during atmospheric chemical transformation reactions. Due to the dry and wet deposition process, they may easily settle down onto ground/vegetation/ecosystems/water surfaces/building materials and show negative impact on their health/life/durability/beauty. The primary criteria air pollutants also produce adverse health effects to human being after their short-term/long-term exposure. Asthma, bronchitis, lung cancer and cardiopulmonary problems are the major noticed due to inhalation exposure of these pollutants. Mental disorder, kidney disorder and abortion are other harmful impacts. The WHO reported the level distribution and harmful effects of air pollutants several times in the past few decades. The direct and indirect effects of criteria air pollutants in changing climate are also discussed.

Journal of Atmospheric Chemistry

Real-time simultaneous measurements of rainwater and PM10 chemistry were carried out at Delhi dur... more Real-time simultaneous measurements of rainwater and PM10 chemistry were carried out at Delhi during the year 2016–17 in order to assess the levels of carbonaceous species and their wet scavenging during monsoon and non-monsoon seasons at Delhi. The PM10 samples were collected Before Rain (BR), During Rain (DR) and After Rain (AR) events, while rainwater samples collected on an event basis. The ambient OC levels were always higher than the levels of EC during both monsoon and non-monsoon seasons in ambient aerosol as well as in rainwater. On an average, during rain (DR) 30% of OC aerosols and 28.2% of EC aerosols removed via wet scavenging process. In after rain (AR), 26.2% OC and 1.8% EC aerosols further decreased in comparison to DR samples due to the presence of OC and EC free air parcel. Overall it observed that the OC concentration significantly lowered from BR to DR and AR. However, EC concentrations in AR were found to be higher than DR samples indicating their build-up after the rains. The Scavenging Ratios (SRs) of OC and rain intensity had a significant positive correlation, whereas the SRs of EC showed a weak correlation with rain intensity. The SRs of EC were significantly higher during non-monsoon as compared to monsoon season. Such characteristics can be explained based on the particles size, source and the hygroscopicity of both types of carbonaceous aerosol.

41st COSPAR Scientific Assembly, Jul 1, 2016

Frontiers in sustainable cities, Aug 31, 2022

Disaster Resilience and Green Growth, 2022

43rd COSPAR Scientific Assembly. Held 28 January - 4 February, 2021

<p>As part of the Ozone and Precursors in the Tropics (OPT) working group of the Tr... more <p>As part of the Ozone and Precursors in the Tropics (OPT) working group of the Tropospheric Ozone Assessment Report Phase 2 (TOAR-II), we present the first results on the distribution of tropospheric ozone (O3) and its precursors (carbon monoxide, CO; formaldehyde, HCHO; nitrogen dioxide, NO2) in the tropics over the past 20-25 years. The goal is to give an overview of the seasonal, geographical and vertical variabilities of tropical tropospheric O3 and its precursors. To do so, we use in situ measurements of O3 and its precursors from surface sites, sounding balloons (SHADOZ) and instrumented aircraft (IAGOS and ATOM), as well as ground-based (FTIR) and spatial (IASI, OMI, GOME-2) remote-sensed observations. The observations are averaged monthly over the longest available time-period as well as over the first five years of the time period. The results for these two time periods give the context to interpret distributions and variabilities of O3 and its precursors over the most recent five years as we call it “Present-day”.  Special emphasis is given to the differences of O3 and its precursors’ distributions between remote and polluted regions and to the relationships between the gaseous species. Model output will be included to fill gaps in space and time when necessary to help the interpretation of the analysis based on observations.</p><p>From IAGOS measurements, the highest O3 and CO maxima occur in the lower troposphere of Northern Hemisphere Africa, which remains the most influenced by biomass burning. CO maxima are attributed using SOFT-IO model to anthropogenic emissions by 60%. Second maxima are observed in the lower troposphere of Asia, mostly due to anthropogenic emissions. The highest amount of transported CO in the tropics originates from Africa.</p>

Airborne Particulate Matter

The use of general descriptive names, registered names, trademarks, service marks, etc. in this p... more The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

43rd COSPAR Scientific Assembly. Held 28 January - 4 February, 2021

Ecosystem Health and Sustainability

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous persistence organic pollutants (POPs). Sev... more Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous persistence organic pollutants (POPs). Several PAHs are known toxic, mutagenic and carcinogenic compounds. Understanding the contributions of the various emission sources is critical to appropriately managing PAH levels in the environment. In the present study, PM 10 samples were collected at two sampling sites (UA and CR) in Delhi during the period of monsoon and winter season from July 2013 to January 2014. The concentrations of 10 selected PAHs in aerosols were quantified for source apportionment analysis. Their total amount at CR ranged from 18 to 161 ngm-3 whereas at UA it varies from 15 to 116 ngm-3. The sources of PAHs in Delhi were determined by using source apportionment methods (molecular diagnostic ratios). At CR, vehicular emissions in the form of diesel and gasoline exhaust were major emission sources. On the contrary, mixed type of sources (coal combustion, wood combustion and gasoline and diesel engine emissions) ...

Inhalation Toxicology

Abstract Objective: This study focuses on the profile of ambient particulate polycyclic aromatic ... more Abstract 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 background (JNU) site in Delhi. Determination of PAHs was carried with the help of HPLC with UV detector. Principal component analysis and Molecular diagnostic ratios were used for the source apportionment of PAHs. Health risks associated with inhalation of particulate PAHs were assessed using benzo(a)pyrene equivalent concentration and incremental lifetime cancer risk (ILCR) approach. Results: The results showed that the average mass concentration of Σ16 PAHs near roadway (67.8 ± 40.2 ng m−3) is significantly higher than urban background site (56 ± 30 ng m−3). Moreover, source apportionment study indicated that major PAH-emission sources in Delhi NCR are traffic and coal combustion. ILCR values at both the sites fall in the range of 10−2–10−4 that corresponds to the priority risk level (10−3) and higher than the acceptable risk level (10−6). conclusions: The high PAHs concentration at MH site was due to it’s nearness to busy traffic area. Thus, the spatial variations in PAHs were influenced by local emission sources. The high PAHs level during the winter season can be due to their higher emissions from local heating sources, shift of gas/particle partitioning toward the particulate phase at low temperature and reduced photochemical degradation of some PAHs in winter. The low level of PAHs in monsoon season can be attributed to their wet scavenging and higher percentage in vapor phase. PCA showed that the emissions from vehicles predominate at MH site; whereas, coal combustion and traffic both are the significant PAHs sources at JNU site. Health risk assessment revealed that the highest exposure risks occur at busy traffic site, thereby indicating a significantly higher health risk to the population of Delhi.

Greenhouse Gases: Sources, Sinks and Mitigation

Criteria Air Pollutants and their Impact on Environmental Health

A polluted air is a harmful complex combination of primary and secondary pollutants in the atmosp... more 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 from their emission source. Due to their highly reactive nature, they get easily participated in a variety of reactions during atmospheric chemical transformation reactions. Due to the dry and wet deposition process, they may easily settle down onto ground/vegetation/ecosystems/water surfaces/building materials and show negative impact on their health/life/durability/beauty. The primary criteria air pollutants also produce adverse health effects to human being after their short-term/long-term exposure. Asthma, bronchitis, lung cancer and cardiopulmonary problems are the major noticed due to inhalation exposure of these pollutants. Mental disorder, kidney disorder and abortion are other harmful impacts. The WHO reported the level distribution and harmful effects of air pollutants several times in the past few decades. The direct and indirect effects of criteria air pollutants in changing climate are also discussed.

Journal of Atmospheric Chemistry

Real-time simultaneous measurements of rainwater and PM10 chemistry were carried out at Delhi dur... more Real-time simultaneous measurements of rainwater and PM10 chemistry were carried out at Delhi during the year 2016–17 in order to assess the levels of carbonaceous species and their wet scavenging during monsoon and non-monsoon seasons at Delhi. The PM10 samples were collected Before Rain (BR), During Rain (DR) and After Rain (AR) events, while rainwater samples collected on an event basis. The ambient OC levels were always higher than the levels of EC during both monsoon and non-monsoon seasons in ambient aerosol as well as in rainwater. On an average, during rain (DR) 30% of OC aerosols and 28.2% of EC aerosols removed via wet scavenging process. In after rain (AR), 26.2% OC and 1.8% EC aerosols further decreased in comparison to DR samples due to the presence of OC and EC free air parcel. Overall it observed that the OC concentration significantly lowered from BR to DR and AR. However, EC concentrations in AR were found to be higher than DR samples indicating their build-up after the rains. The Scavenging Ratios (SRs) of OC and rain intensity had a significant positive correlation, whereas the SRs of EC showed a weak correlation with rain intensity. The SRs of EC were significantly higher during non-monsoon as compared to monsoon season. Such characteristics can be explained based on the particles size, source and the hygroscopicity of both types of carbonaceous aerosol.