Civil Engineering

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Shiv Nadar University

Nitrogen dioxide (NO2) plays an important role in atmospheric chemistry through formation of secondary particulate nitrate that contributes a major portion to the mass of particulate matter (PM) that has several impacts on the environment in the scales of local, regional and global. NO2 is regulated in most of the countries, because it acts as a precursor for nitrate formation and it shows significant negative effects on human health. The present study was conducted for measurement of NO2 concentration at 204 and 101 sampling locations in two Indian large cities (population more than 4 million), Delhi and Kanpur, respectively by using passive samplers. From the experimental results, an average concentration of 68.6±20.1μg/m3 was observed in Delhi and it was 36.9±12.1μg/m3 in Kanpur. The observed data from all sampling sites were utilized on the platform of Geographic Information System (GIS) to generate spatially distributed pollution maps (using Kriging interpolation method) and maps of probability of exceedences of air quality standards. Based on the survey results on emission activities, meteorology and pollution maps, this study proposed locations of air quality sampling sites for a long-term monitoring network in Delhi and Kanpur. © 2014 Elsevier B.V.

(SoE) School of Engineering

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Urban Climate

Passive measurement of NO2 and application of GIS to generate spatially-distributed air monitoring network in urban environment

An intensive measurement campaign was undertaken to characterize eight fractions of organic carbon (OC) and elemental carbon (EC) in particulate matter (PM) at four urban sites with different pollution characteristics during summer, post-monsoon, and winter at Kanpur, India. Speciation samplers were used to collect particulate samples on quartz filters followed by analysis of OC and EC using Interagency Monitoring of Protected Visual Environments (IMPROVE)-based thermal/optical reflectance (TOR) method. Based on 24-h average results at each site, the highest levels of OC and EC were observed during winter as 96.7 ± 26.9 and 31.8 ± 9.8 μg/m3 at residential site and traffic site, respectively. The levels of OC at residential sites during winter appeared to be more than twice of that during summer. The site close to the road traffic had the least value of OC/EC, as 1.77 ± 0.28 during post-monsoon, and the site influenced by emissions of domestic cooking and heating had the highest value of OC/EC, as 4.05 ± 0.79 during winter. The average abundances of OC1, OC2, OC3, OC4, OP, EC1, EC2, and EC3 in total carbon (TC) at all sites for three seasons were 10.03, 19.04, 20.03, 12.32, 10.53, 33.39, 3.21, and 1.99 %, respectively. A sharp increase in levels of OC1 and EC1-OP during winter at two residential sites revealed that biomass burning could be a significant contributor to carbonaceous aerosols. From the application of EC-tracer method, it was observed that contribution of secondary organic carbon (SOC) to PM mass increased from 5 % during post-monsoon to 16 % during winter at residential sites and from 2 % during post-monsoon to 7 % during winter at traffic sites. Therefore, it could be inferred that increase in primary emissions coupled with unfavorable meteorological conditions could cause particle agglomeration and hygroscopic growth, leading to unpleasant pollution episode during winter. © 2015, Springer-Verlag Berlin Heidelberg.

Environmental Science and Pollution Research

Spatial and seasonal variations of atmospheric particulate carbon fractions and identification of secondary sources at urban sites in North India

Volatile organic compounds (VOCs) prevalent in our atmosphere are of major environmental concerns. Several methods of controlling VOCs exist. Most of them have direct or indirect environmental consequences in terms of materials they use and wastes they produce albeit control VOCs. It has been found that conventional techniques especially of physical and chemical nature pose a number of problems such as high on cost, high material requirement, produce lots of waste and contribute to climate change and environmental degradation. Various biological oxidation methods adopted in various reactors for controlling gaseous VOCs have been reviewed, pros and cons of these technologies have been studied and the sensitive parameters for improving removal efficiency along with their environmental implications have been identified. It has been found that rotating biological contactor (RBC) could be an effective alternative to control gaseous VOCs because of its simple design and operation. Further, it provides higher oxygen transfer, offers better mixing, consumes low energy and has potential of higher removal efficiency as compared to the other biological techniques. There is, moreover, an ample scope in improving its gaseous-control efficiency by optimizing the parameters like rotational speed, hydraulic loading rate, and hydraulic retention time and similarly by the use of different media, biofilm characteristics and dissolved-oxygen levels. With these scopes, RBC can be an eco-friendly, and promising option for controlling gaseous VOCs. © 2014 Elsevier Ltd. All rights reserved.

Journal of Environmental Chemical Engineering

Biological oxidation of gaseous VOCs - Rotating biological contactor a promising and eco-friendly technique

The present study investigated the temporal and diurnal distributions of atmospheric acidic gases (sulphur dioxide (SO2), nitrous acid (HONO), and nitric acid (HNO3)) and those of particulate nitrate (NO3-) and sulfate (SO42-) through a comprehensive field campaign during the largest smoke haze episode in Singapore, a representative country in Southeast Asia (SEA). To identify the atmospheric behavior of these pollutants during the smoke haze period, the data generated from the measurement campaign were divided into three distinct periods: prehaze, during haze, and posthaze periods. The 24 hr average data indicated that ambient SO2, HONO, and HNO3 during the smoke haze episodes increased by a factor ranging from 1.2 to 2.6 compared to those during the prehaze and posthaze periods. Similarly, in the case of particulates SO42- and NO3-, the factor ranged from 2.3 to 4.2. Backward air trajectories were constructed and used to find the sources of biomass burning to the recurring smoke haze in this region. The air trajectory analysis showed that the smoke haze episodes experienced in Singapore were influenced by transboundary air pollution, caused by severe biomass burning events in the islands of Indonesia. © 2014 Sailesh N. Behera and Rajasekhar Balasubramanian.

Fulltext

Advances in Meteorology

Influence of biomass burning on temporal and diurnal variations of acidic gases, particulate nitrate, and sulfate in a tropical urban atmosphere

In the electro-mechanical impedance (EMI) technique, which is based on induced strain actuation through piezoelectric ceramic (PZT) patch, the knowledge of shear stress distribution in the adhesive bond layer between the patch and the host structure is very pertinent for reliable health monitoring of structures. The analytical derivation of continuum based shear lag model covered in this paper aims to provide an improved and more accurate model for shear force interaction between the host structure and the PZT patch (assumed square for simplicity) through the adhesive bond layer, taking care of all the piezo, structural and adhesive effects rigorously and simultaneously. Further, it eliminates the hassle of determining the equivalent impedance of the structure and the actuator separately, as required in the previous models, which was approximate in nature. The results are compared with the previous models to highlight the higher accuracy of the new approach. Based on the new model, a continuum based interaction term has been derived for quantification of the shear lag and inertia effects. © 2013 Elsevier Ltd. All rights reserved.

International Journal of Solids and Structures

A continuum based modelling approach for adhesively bonded piezo-transducers for EMI technique

In this study, an atmospheric dispersion model along with a systematic emission inventory was used to explore the possible control strategy to reduce ambient levels of nitrogen oxides (NOx) in Kanpur city, India. A GIS based emission inventory of NOx was developed for the base, 5th and 10th years. It was observed that the 5th and 10th years will experience increased emissions by factors of 1.7 and 2.5 of the base year if no control policy is implemented. Seventeen control options (i.e. introduction of Euro 6 to vehicles, banning of 15-year old private vehicles etc.) were considered for evaluation through the dispersion modelling. A control scenario comprising the following control options (1) implementation of Euro 6 for vehicles, (2) compressed natural gas (CNG) for commercial and public vehicles, etc. was found to be most effective in reducing the ambient NOx levels and attaining a 24-hour average air quality standard. © 2014 Copyright Taylor and Francis Group, LLC.

Journal of Environmental Planning and Management

An approach for evaluation of proposed air pollution control strategy to reduce levels of nitrogen oxides in an urban environment

Toxic particulate elements present in cigarette smoke pose health threats to the life of smokers due to direct inhalation and at the same time increase health risks to non-smokers present in the vicinity of smokers because of their exposure. This study conducted a series of experiments using a controlled experimental chamber, equipped with simulated smoking conditions for characterization of particulate trace elements in mainstream and sidestream cigarette smoke. Four popular commercial cigarette brands available in Singapore market were used in this study. The target elements for extraction and analysis were Al, As, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, K, Li, Mg, Mn, Na, Ni, Pb, Rb, Se, Sn, Sr, Te, Tl and Zn of both water-soluble and total constituents. The human health risk assessment results showed that the sidestream smoke had higher concentrations of toxic elements than those in the mainstream smoke. However, risk assessment analysis revealed that the sidestream smoke resulted in less human health risks compared to the mainstream smoke due to the influence of dilution of particulate emissions in sidestream smoke prior to inhalation exposure experienced by non-smokers. The cumulative non-cancer and cancer risks of toxic elements varied from 2.0 to 3.1 and from 398.4×10-6 to 626.1×10-6 due to inhalation of cigarette smoke by an active smoker. In the case of non-smokers, the risks were estimated under three possible cases of exposure. The cumulative cancer risks under three different cases were greater than the permissible limits. Therefore, it could be concluded that the toxic particulate elements present in cigarette smoke have significant carcinogenic and non-carcinogenic health effects due to inhalation exposure in the environment. © 2013 Elsevier B.V.

Science of the Total Environment

Human health risk associated with exposure to toxic elements in mainstream and sidestream cigarette smoke

Recurring biomass burning-induced smoke haze is a serious regional air pollution problem in Southeast Asia (SEA). The June 2013 haze episode was one of the worst air pollution events in SEA. Size segregated particulate samples (2.5-1.0 μm; 1.0-0.5 μm; 0.5- 0.2 μm; and &lt;0.2 μm) were collected during the June 2013 haze episode. PM2.5 concentrations were elevated (up to 329 μg/m3) during the haze episode, compared to those during the nonhaze period (11-21 μg/m3). Chemical fractionation of particulate-bound trace elements (B, Ca, K, Fe, Al, Ni, Zn, Mg, Se, Cu, Cr, As, Mn, Pb, Co, and Cd) was done using sequential extraction procedures. There was a 10-fold increase in the concentration of K, an inorganic tracer of biomass burning. A major fraction (&gt;60%) of the elements was present in oxidizable and residual fractions while the bioavailable (exchangeable) fraction accounted for up to 20% for most of the elements except K and Mn. Deposition of inhaled potentially toxic trace elements in various regions of the human respiratory system was estimated using a Multiple-Path Particle Dosimetry model. The particle depositions in the respiratory system tend to be more severe during hazy days than those during nonhazy days. A prolonged exposure to finer particles can thus cause adverse health outcomes during hazy days. Health risk estimates revealed that the excessive lifetime carcinogenic risk to individuals exposed to biomass burning-impacted aerosols (18 ± 1 × 10-6) increased significantly (P &lt; 0.05) compared to those who exposed to urban air (12 ± 2 × 10 -6). © 2014 American Chemical Society.

Environmental Science and Technology

2013 Southeast Asian smoke haze: Fractionation of particulate-bound elements and associated health risk

The spatial distribution of seismic site coefficients at Guwahati is presented in this article. Estimated site coefficients consider different site types in the city and several level of ground shaking consider average of probable seismic event. The evaluation of site coefficients is based on the standard penetration test data at 105 boreholes distributed over the city. Equivalent linear one dimensional site response analyses are performed to predict the site amplification and to determine the spectral acceleration response. Due to the unavailability of recorded ground motion data for the region, synthetic ground motions simulated at the bedrock level for the city corresponding to several combinations of magnitude (Mw) and source-to-site distance (R) are used as input excitation. Simulated synthetic ground motion data with varying levels of excitation have been used to take care of the uncertainties in the input ground motions. The analyses depict the modification of the seismic ground motion due to the presence of soil overlying the bedrock. © 2014, Capital Publishing Company.

Proceedings of the 16th International Association for Mathematical Geosciences - Geostatistical and Geospatial Approaches for the Characterization of Natural Resources in the Environment: Challenges, Processes and Strategies, IAMG 2014

Spatial distribution of seismic site coefficients for Guwahati city

This paper examines the effect of outdoor air pollution on respiratory disease in Kanpur, India, based on data from 2006. Exposure to air pollution is represented by annual emissions of sulfur dioxide (SO2), particulate matter (PM), and nitrogen oxides (NOx) from 11 source categories, established as a geographic information system (GIS)-based emission inventory in 2 km × 2 kmgrid. Respiratory disease is represented by number of patients who visited specialist pulmonary hospital with symptoms of respiratory disease. The results showed that (1) the main sources of air pollution are industries, domestic fuel burning, and vehicles; (2) the emissions of PM per grid are strongly correlated to the emissions of SO2 and NOx; and (3) there is a strong correlation between visits to a hospital due to respiratory disease and emission strength in the area of residence. These results clearly indicate that appropriate health and environmental monitoring, actions to reduce emissions to air, and further studies that would allow assessing the development in health status are necessary. © 2013 Taylor & Francis Group, LLC.