Air Pollution In Delhi Research Articles

Quantifying the influence of agricultural fires in northwest India on urban air pollution in Delhi, India

Since at least the 1980s, many farmers in northwest India have switched to mechanized combine harvesting to boost efficiency. This harvesting technique leaves abundant crop residue on the fields, which farmers typically burn to prepare their fields for subsequent planting. A key question is to what extent the large quantity of smoke emitted by these fires contributes to the already severe pollution in Delhi and across other parts of the heavily populated Indo-Gangetic Plain located downwind of the fires. Using a combination of observed and modeled variables, including surface measurements of PM2.5, we quantify the magnitude of the influence of agricultural fire emissions on surface air pollution in Delhi. With surface measurements, we first derive the signal of regional PM2.5 enhancements (i.e. the pollution above an anthropogenic baseline) during each post-monsoon burning season for 2012–2016. We next use the Stochastic Time-Inverted Lagrangian Transport model (STILT) to simulate surface PM2.5 using five fire emission inventories. We reproduce up to 25% of the weekly variability in total observed PM2.5 using STILT. Depending on year and emission inventory, our method attributes 7.0%–78% of the maximum observed PM2.5 enhancements in Delhi to fires. The large range in these attribution estimates points to the uncertainties in fire emission parameterizations, especially in regions where thick smoke may interfere with hotspots of fire radiative power. Although our model can generally reproduce the largest PM2.5 enhancements in Delhi air quality for 1–3 consecutive days each fire season, it fails to capture many smaller daily enhancements, which we attribute to the challenge of detecting small fires in the satellite retrieval. By quantifying the influence of upwind agricultural fire emissions on Delhi air pollution, our work underscores the potential health benefits of changes in farming practices to reduce fires.

Air pollution and public health: the challenges for Delhi, India.

Mitigating the impact of pollution on human health worldwide is important to limit the morbidity and mortality arising from exposure to its effect. The level and type of pollutants vary in different urban and rural settings. Here, we explored the extent of air pollution and its impacts on human health in the megacity of Delhi (India) through a review of the published literature. The study aims at describing the extent of air pollution in Delhi, the magnitude of health problems due to air pollution and the risk relationship between air pollution and associated health effects. We found 234 published articles in the PubMed search. The search showed that the extent of air pollution in Delhi has been described by various researchers from about 1986 onwards. We synthesized the findings and discuss them at length with respect to reported values, their possible interpretations and any limitations of the methodology. The chemical composition of ambient air pollution is also discussed. Further, we discuss the magnitude of health problem with respect to chronic obstructive pulmonary diseases (COPD), bronchial asthma and other illnesses. The results of the literature search showed that data has been collected in last 28 years on ambient air quality in Delhi, though it lacks a scientific continuity, consistency of locations and variations in parameters chosen for reporting. As a result, it is difficult to construct a spatiotemporal picture of the air pollution status in Delhi over time. The number of sites from where data have been collected varied widely across studies and methods used for data collection is also non-uniform. Even the parameters studied are varied, as some studies focused on particulate matter ≤10 μm in aerodynamic diameter (PM10) and those ≤2.5 μm in aerodynamic diameter (PM2.5), and others on suspended particulate matter (SPM) and respirable suspended particulate matter (RSPM). Similarly, the locations of data collection have varied widely. Some of the sites were at busy traffic intersections, some on the terraces of offices and residential houses and others in university campuses or airports. As a result, the key question of the extent of pollution and its distribution across various parts of the city could be inferred. None of the studies or a combination of them could present a complete picture of the burden of diseases like COPD, bronchial asthma and other allergic conditions attributable to pollution in Delhi. Neither could it be established what fraction of the burden of the above diseases is attributable to ambient air pollution, given that other factors like tobacco smoke and indoor air pollution are also contributors to the causation of such diseases. In our discussion, we highlight the knowledge gaps and in the conclusion, we suggested what research can be undertaken to fill the these research gaps.

Managing future air quality in megacities: A case study for Delhi

Megacities in Asia rank high in air pollution at the global scale. In many cities, ambient concentrations of fine particulate matter (PM2.5) have been exceeding both the WHO interim targets as well as respective national air quality standards. This paper presents a systems analytical perspective on management options that could efficiently improve air quality at the urban scale, having Delhi as a case study. We employ the newly developed GAINS-City policy analysis framework, consisting of a bottom up emission calculation combined with atmospheric chemistry-transport calculation, to derive innovative insights into the current sources of pollution and their impacts on ambient PM2.5, both from emissions of primary PM as well as precursors of secondary inorganic and organic aerosols. We outline the likely future development of these sources, quantify the related ambient PM2.5 concentrations and health impacts, and explore potential policy interventions that could effectively reduce environmental pollution and resulting health impacts in the coming years. The analysis demonstrates that effective improvement of Delhi's air quality requires collaboration with neighboring States and must involve sources that are less relevant in industrialized countries. At the same time, many of the policy interventions will have multiple co-benefits on development targets in Delhi and its neighboring States. Outcomes of this study, as well as the modelling tools used herein, are applicable to other urban areas and fast growing metropolitan zones in the emerging Asian regions.

Using Nonprofit Narratives and News Media Framing to Depict Air Pollution in Delhi, India

ABSTRACTHow is the air pollution issue in Delhi framed by the news media and narrated by nonprofit organizations? To study news media framing, we employed an inductive approach based on automated text coding of news coverage of the issue. To study nonprofit organization narrations, a deductive approach guided by the Narrative Policy Framework was used to focus on the stories told via online documents as found on nonprofit websites. The findings confirm existing theory and empirical research regarding the leading causes and effects of air pollution; however, perceptions are mixed regarding the government’s ability to implement policy. The combined deductive and inductive approaches provide a systematic and multi-method research study for understanding perceptions of air pollution in one of the largest cities in the world. The result is a depiction of the priorities that influence public opinions, political decisions, and eventually public policies.

Air quality in Delhi: status and concerns

Data on the status of air quality are presented for two locations in Delhi, the capital city of India, for 2013. Our study revealed that the levels of oxides of nitrogen (NOx), particulate matter of 10 or <10 μm aerodynamic diameter (PM10) and benzene exceeded the maximum permissible limits laid down in the National Ambient Air Quality Standards (NAAQS). On most of the monitoring days, the concentrations of PM10 also exceeded the limits for 24 h averages stipulated by the NAAQS. This study also demonstrated that the concentration of pollutants varied with the season, peaking in dry season (winter) mainly because of the relatively stable meteorological conditions and recording the lowest values in the wet season (the rainy season) because of turbulence, strong winds, and rains. The post-monsoon season showed the contribution of local sources. The strong correlation among NOx, PM10, and benzene strongly suggests that motor vehicles are the major contributor to this pollution. Intervention by regulatory agencies is essential to improve the air quality of Delhi.

Study of Temporal Variation in Ambient Air Quality during Diwali Festival in Delhi – A Case Study

Fireworks are one of the most unusual sources of pollution potassium nitrate, carbon and sulphur apart from an array of chemicals such as strontium, barium, sodium, titanium, zirconium, magnesium alloys, copper and aluminum powder to create the colorful effects .The boundless in atmosphere containing harmful chemicals such as use of fireworks was found to be related to short-term variation in air quality of Delhi (28.6139°N, 77.2090°E). These variation episodes are responsible for high concentrations of pollutants (especially metals, organic compound and gases). In this paper the ambient concentrations of air pollutants [sulphur dioxide (SO2), oxides of nitrogen (NO2), Suspended Particulate Matter (SPM) and carbon monoxide (CO)] during Diwali have been compared to the data of a typical day in Delhi , November 2015. The data reveals that there is a shift in meteorological parameters which resulted in easy dispersion of air pollutants due to which the concentration of pollutants was observed to be increased ∼23-fold at few sites. The trend also shows that pollutants concentration increased just before Diwali and reached to a maximum concentration on the day of the festival. These results also indicate that fireworks during the Diwali festival affected the ambient air quality adversely due to emission, dispersion and accumulation of air pollutants.

The Effect of Metro Expansions on Air Pollution in Delhi

The Delhi Metro (DM) is a mass rapid transit system serving the National Capital Region of India. It is also the world’s first rail project to earn carbon credits under the Clean Development Mechanism of the United Nations for reductions in CO2 emissions. Did the DM also lead to localized reduction in three transportation source pollutants? Looking at the period 2004–2006, one of the larger rail extensions of the DM led to a 34 percent reduction in localized CO at a major traffic intersection in the city. Results for NO2 are also suggestive of a decline, while those for PM25 are inconclusive due to missing data. These impacts of pollutant reductions are for the short run. A complete accounting of all long run costs and benefits should be done before building capital intensive metro rail projects.

Strategies for reducing poor indoor air quality and adverse temperature exposure in Delhi's households: A multi-objective assessment

High temperatures, an extremely polluted ambient environment, alongside disparities in housing quality and household energy use, indicate overheating risk and poor indoor air quality in Delhi dwellings. In this study, we explore a range of interventions to reduce adverse temperature exposure and improve indoor air quality, focusing on PM2.5, for exemplar base case households developed to cover the range of settlements types found in Delhi. Interventions are modelled using dynamic thermal simulation, and include a range of modifications to dwelling operation and building fabric, as well as additional building components. A weighted multi-objective assessment considering annual energy use, intervention cost, and a health metric encompassing heat, cold and PM2.5 exposure, is employed to score the suitability of strategies for each settlement type. The most effective strategy is found to be a combination of changes in building fabric with evaporative cooling and cooking ventilation in all archetypes. The results demonstrate how a weighted multi-objective assessment is effective in selecting strategies for settlement types with differing priorities. Practical application: Current dwellings in Delhi risk significant energy consumption or provide inadequate indoor environmental quality. This work presents the performance of potential interventions, by considering multiple criteria, which could be deployed in Delhi households to provide low-energy healthy homes.

Analysis of ambient air quality using fuzzy air quality index: a case study of Delhi, India

Ambient air quality is one of the most serious environmental concerns in urban areas around the world, especially in developing countries. In recent years, there has been increasing concern over the adverse effects of air pollution on human health. In the present study, the concentrations of air pollutants and their adverse effect at various locations over Delhi are studied using fuzzy air quality index (FAQI). The 24-hourly average concentrations of main criteria pollutants viz., fine particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3) over the years 2008 to 2012 have been used for the analysis at three different locations in Delhi (residential-Sirifort, industrial-DCE and busiest traffic intersection-ITO junction). Further, the weightages of criteria pollutants have been determined using an analytical hierarchical process to access the air quality index. The developed methodologies also have been compared with the conventional approach and validated with different statistical measures. The results clearly indicate that the air quality of Delhi is degraded and lies in the ranges of 'bad' and 'very bad' categories.

Assessment of outdoor workers’ exposure to air pollution in Delhi (India)

Air quality monitoring (PM2.5, CO, NOx, SO2 and EC/OC) was carried out at highway toll plazas, municipality toll plazas and control sites (n = 23) in the National Capital Region of Delhi, to determine the exposure of toll plaza workers to air pollution and its effect on lung function. Lung function indices (n = 45) were also measured for these workers. The results reveal the high level of air pollution at almost all locations with PM2.5 values exceeding the national permissible limit except at a few control sites. Observed reduction in lung function indices was significant over years of occupational exposure even after adjusting for age, amongst non-smoking outdoor workers. This study found pollutant concentrations were highest at municipality toll plazas with minimum protective work area. The paper suggests measures to reduce the exposure of outdoor workers.

Air quality in Delhi during the Commonwealth Games

Abstract. Air quality during the Commonwealth Games (CWG, held in Delhi in October 2010) is analyzed using a new air quality forecasting system established for the games. The CWG stimulated enhanced efforts to monitor and model air quality in the region. The air quality of Delhi during the CWG had high levels of particles with mean values of PM2.5 and PM10 at the venues of 111 and 238 μg m−3, respectively. Black carbon (BC) accounted for ~ 10% of the PM2.5 mass. It is shown that BC, PM2.5 and PM10 concentrations are well predicted, but with positive biases of ~ 25%. The diurnal variations are also well captured, with both the observations and the modeled values showing nighttime maxima and daytime minima. A new emissions inventory, developed as part of this air quality forecasting initiative, is evaluated by comparing the observed and predicted species-species correlations (i.e., BC : CO; BC : PM2.5; PM2.5 : PM10). Assuming that the observations at these sites are representative and that all the model errors are associated with the emissions, then the modeled concentrations and slopes can be made consistent by scaling the emissions by 0.6 for NOx, 2 for CO, and 0.7 for BC, PM2.5, and PM10. The emission estimates for particles are remarkably good considering the uncertainty in the estimates due to the diverse spread of activities and technologies that take place in Delhi and the rapid rates of change. The contribution of various emission sectors including transportation, power, domestic and industry to surface concentrations are also estimated. Transport, domestic and industrial sectors all make significant contributions to PM levels in Delhi, and the sectoral contributions vary spatially within the city. Ozone levels in Delhi are elevated, with hourly values sometimes exceeding 100 ppb. The continued growth of the transport sector is expected to make ozone pollution a more pressing air pollution problem in Delhi. The sector analysis provides useful inputs into the design of strategies to reduce air pollution levels in Delhi. The contribution for sources outside of Delhi on Delhi air quality range from ~ 25% for BC and PM to ~ 60% for day time ozone. The significant contributions from non-Delhi sources indicates that in Delhi (as has been show elsewhere) these strategies will also need a more regional perspective.

Assessment of traffic-generated gaseous and particulate matter emissions and trends over Delhi (2000–2010)

Development and urbanization over the past decade has led to rapid increase in the population of Delhi, the metropolitan city of India. Consequently, there has been a tremendous increase in the number of vehicles, which are causing very high levels of air pollution. Vehicular emissions are becoming most predominant source of air pollution in Delhi. An annual emission inventory of road transport emissions of pollutants including carbon monoxide (CO), methane (CH4), nitrogen oxides (NOX), sulfur dioxide (SO2), volatile organic compounds (VOCs), particulate matter (PM10), lead (Pb) and hydrocarbon (HC), organic carbon (OC) and black carbon (BC) has been developed (for the period 2000–2010), for the Delhi region. Emissions have been estimated using emission factor and activity–based approach recommended by IPCC. The emissions of CO and NOX have increased nearly 77% and 29% respectively over 2000 to 2010, whereas contribution of SO2 has greatly reduced (~21%) due to phasing out of diesel driven buses and implementation of Bharat Stage–III norms to commercial vehicles. An appreciable increase in NOX emissions has been observed after 2005, which might be due to the use of CNG fuel. Emissions of PM10, OC and BC have decreased in 2001 and 2002, however these are continuously increasing after 2002 due to rapid rise in the annual rate of growth of registered vehicles in Delhi. Two wheelers (2Ws), which constitute 60% of total registered vehicles, have been found to be major contributors towards emissions of the pollutants considered in the present study.

Quantifying the effect of air quality control measures during the 2010 Commonwealth Games at Delhi, India

In 2010, the XIX Commonwealth Games (CWG-2010) were held in India for the first time at Delhi and involved 71 commonwealth nations and dependencies with more than 6000 athletes participating in 272 events. This was the largest international multi-sport event to be staged in India and strict emission controls were imposed during the games in order to ensure improved air quality for the participating athletes as a significant portion of the population in Delhi is regularly exposed to elevated levels of pollution. The air quality control measures ranged from vehicular and traffic controls to relocation of factories and reduction of power plant emissions. In order to understand the effects of these policy induced control measures, a network of air quality and weather monitoring stations was set-up across different areas in Delhi under the Government of India's System of Air quality Forecasting And Research (SAFAR) project. Simultaneous measurements of aerosols, reactive trace gases (e.g. NOx, O3, CO) and meteorological parameters were made before, during and after CWG-2010. Contrary to expectations, the emission controls implemented were not sufficient to reduce the pollutants, instead in some cases, causing an increase. The measured pollutants regularly exceeded the National Ambient Air Quality limits over the games period. The reasons for this increase are attributed to an underestimation of the required control measures, which resulted in inadequate planning. The results indicate that any future air quality control measures need to be well planned and strictly imposed in order to improve the air quality in Delhi, which affects a large population and is deteriorating rapidly. Thus, the presence of systematic high resolution data and realistic emission inventories through networks such as SAFAR will be directly useful for the future.

Vehicular emission inventory of criteria pollutants in Delhi

The rapid urbanization in Delhi has resulted in a tremendous increase in the number of motor vehicles with the increase in population and urban mobilization. The vehicular traffic is now recognized as one of the main sources of air pollution in Delhi and has noticeable impact on air quality. The emission of criteria pollutants namely Carbon Monoxide (CO), Nitrogen Oxide (NOx) and Particulate Matter (PM) due to vehicles is estimated through the International Vehicle Emission (IVE) model, which includes the different driving modes of vehicles and meteorological parameters. The estimated emissions of Carbon Monoxide (CO), Nitrogen Oxides (NOx) and Particulate Matter (PM) due to different types of vehicles in the year 2008–09 are found to be 509, 194 and 15 tons/day respectively. The diurnal variation of emissions of air pollutants shows two peaks, which are fortunately matching with the morning and evening office hours. The emissions of CO and NOx due to personal cars (PCs) are found to be about 34% and 50% respectively, and the emission of CO due to 2 W (2- Wheeler) is about 61%. Similarly, the Heavy Commercial Vehicles (HCVs) are contributing PM about 92%. The analysis of fuel-wise emission of pollutants reveals that CO is mainly contributed by petrol, and NOx and PM are contributed by diesel. It is also noticeable that CO, NOx and PM emissions at ITO, one of the busiest traffic intersections of Delhi, are approximately 15, 6 and 0.5 tons/day respectively, which are found to be the maximum followed by Kashmiri Gate (ISBT), Nizamuddin etc. The present vehicular emissions inventory has been compared quantitatively with previous studies of Delhi. The present vehicular emission inventory has also validated using US environmental protection agency’s (USEPA’s) AERMOD model with observed concentration at different locations in Delhi. However, the present study shows that the air quality of Delhi has been degraded due to high level emissions of criteria pollutants.

"Air pollution in Delhi: Its Magnitude and Effects on Health"

Air pollution is responsible for many health problems in the urban areas. Of late, the air pollution status in Delhi has undergone many changes in terms of the levels of pollutants and the control measures taken to reduce them. This paper provides an evidence-based insight into the status of air pollution in Delhi and its effects on health and control measures instituted. The urban air database released by the World Health Organization in September 2011 reported that Delhi has exceeded the maximum PM10 limit by almost 10-times at 198 μg/m3. Vehicular emissions and industrial activities were found to be associated with indoor as well as outdoor air pollution in Delhi. Studies on air pollution and mortality from Delhi found that all-natural-cause mortality and morbidity increased with increased air pollution. Delhi has taken several steps to reduce the level of air pollution in the city during the last 10 years. However, more still needs to be done to further reduce the levels of air pollution.

Status of Air Pollutants after Implementation of CNG in Delhi

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, O 3 , SPM, RSPM & CO) except SO 2 . The objective of our study is whether CNG conversion has impinged on the primary pollutant and tropospheric ozone pollution profile and for the improvement in the quality of air in post CNG period. To carry out the analysis, daily ambient air quality secondary data (Jan 2002-Dec 2009; Source-CPCB) of all the above discussed pollutants were used. For generating own data, NOX and O3 monitoring were carried out at four different sites viz. Site I (Yamuna Biodiversity Park, away from traffic intersection), Site II (Traffic intersection at outside YBP, outer ring road, Gandhi vihar), Site III (Aravalli Biodiversity Park, away from traffic intersection) and Site IV (traffic intersection at outside ABP, ring road, Vasant vihar) during monsoon season (Aug-Sept, 2009). The concentration of ozone was higher at sites which are at traffic intersection (Site II & IV) than those which are away from traffic intersection (Site I & III). The results however, do not indicate an all round improvement in ambient air quality of Delhi. Hence, our short term study suggests that after the implementation of CNG in Delhi there is no remarkable improvement in the status of the pollutants and moreover, the sites which are near to traffic intersection possess high concentration of pollutants than the sites which are away from traffic intersection.

Forecasting of air quality in Delhi using principal component regression technique

Over the past decade, an increasing interest has evolved by the public in the day–to–day air quality conditions to which they are exposed. Driven by the increasing awareness of the health aspects of air pollution exposure, especially by most sensitive sub–populations such as children and the elderly, short–term air pollution forecasts are being provided more and more by local authorities. The Air Quality Index (AQI) is a number used by governmental agencies to characterize the quality of the air at a given location. AQI is used for local and regional air quality management in many metropolitan cities of the world. The main objective of the present study is to forecast short–term daily AQI through previous day’s AQI and meteorological variables using principal component regression (PCR) technique. This study has been made for four different seasons namely summer, monsoon, post monsoon and winter. AQI was estimated for the period of seven years from 2000–2006 at ITO (a busiest traffic intersection) for criteria pollutants such as respirable suspended particulate matter (RSPM), sulfur dioxide (SO2), nitrogen dioxide (NO2) and suspended particulate matter (SPM) using a method of US Environmental Protection Agency (USEPA), in which sub–index and breakpoint pollutant concentration depends on Indian National Ambient Air Quality Standard (NAAQS). The Principal components have been computed using covariance of input data matrix. Only those components, having eigenvalues ≥1, were used to predict the AQI using principal component regression technique. The performance of PCR model, used for forecasting of AQI, was better in winter than the other seasons as studied through statistical error analysis. The values of normalized mean square error (NMSE) were found as 0.0058, 0.0082, 0.0241 and 0.0418 for winter, summer, post monsoon and monsoon respectively. The other statistical parameters are also supporting the same result.

Changing air quality in Delhi, India: determinants, trends, and policy implications

Air pollution is a major environmental problem in urban areas worldwide. Delhi, the capital city of India, is no exception to the universal pattern of deteriorating urban air quality with concentration of pollutants being well above the recommended WHO levels. The magnitude and urgency of the problem as a global environmental issue needs a systematic understanding of the potential causes of pollution and their contribution to air quality. In the present study, ambient air quality data (1987–2006) of SO2, NO2, SPM, and RSPM were analyzed to asses the changing air quality in the study area and to evaluate the effect of measures taken to control it. The primary data were collected from 1,583 households to examine the relationship between outdoor and indoor pollution level. Based on the data, the current study concludes that despite the implementation of different pollution-controlling measures, the pollutants, especially the particulate pollutants, were well above the standard limits set by CPCB. Integration between technological and social approach of urban planning is required to mitigate and manage urban environmental problems in sustainable manner.

An Analysis of Ambient Air Quality Conditions Over Delhi, India From 2004 to 2009

We analyzed 1-hour, 8-hour and 24-hour averaged criteria pollutants (NO2, SO2, CO, PM22.5, and PM10) during 2004 - 2009 at three observational sites i.e. Income Tax Office (ITO), Sirifort and Delhi College of Engineering (DCE) in Delhi, India. The analysis reveals increased pollutant concentrations at the urban ITO site as compared to the other two sites, suggesting the need to better locate hot spots in designing the monitoring network. There is also significant year to year variation in the design value trends of criteria pollutants at these three sites, which may be attributed to meteorological variations and local-level emission fluctuations. Correlations among criteria pollutants vary annually and spatially from site to site, indicating the heterogeneous nature of air mix. The annual ratios of CO/NOx are considerably higher than SO2/NOx confirming that vehicular source emissions are the primary contributors to air pollution in Delhi. The seasonal analysis of criteria pollutants reveals relatively higher concentrations in winter because of limited pollutant dispersion and lower concentrations during the monsoon period (rainy season). The diurnal averages of criteria pollutants reveal that vehicular emissions strongly influence temporal variations of these pollutants. Weekdays and weekend diurnal averages do not show noticeable differences.

Effects of meteorological conditions on concentration of air pollutants in Delhi

Air pollution in Delhi is a serious environmental problem. In this paper, the effects of meteorological conditions on local air quality are quantitatively assessed by determining the relationships between concentrations of Suspended Particulate Matter (SPM), Respirable Suspended Particulate Matter (RSPM), sulphur dioxide (SO2) and nitrogen dioxide (NO2) with meteorological parameters on monthly basis, from 2000 to 2006. The multi-linear regression approach, used in the study, has facilitated analysis of the air quality-meteorology relationship and predicted the concentrations of SPM and RSPM within a scatter of ±18% and of SO2 and NO2 within a scatter of ±14%.