Sunil Gulia

Urban air quality management-A review

Urban air quality management plan (UAQMP) is an effective and efficient tool employed in managing acceptable urban air quality. However, the UAQM practices are specific to a country’s needs and requirements. Majority of the developed countries have full–fledged UAQMP with a regulatory management framework. However, developing countries are still working in formulating the effective and efficient UAQMPs to manage their deteriorating urban air environment. The first step in the process of formulation of UAQMP is to identify the air quality control regions based on ambient air quality status and second, initiate a time bound program involving all stakeholders to develop UAQMPs. The successful implementation of UAQMPs depends on the strength of its key components, e.g. goal/objective, monitoring network, emission inventory, air quality modeling, control strategies and public participation. This paper presents a comprehensive review on UAQMPs, being implemented worldwide at different scales e.g., national (macro), city (medium), and local (micro).

PERFORMANCE EVALUATION OF ISCST3, ADMS-URBAN AND AERMOD FOR URBAN AIR QUALITY MANAGEMENT IN A MEGA CITY OF INDIA

Urban air quality has deteriorated in last few decades in the mega cities of both developed and developing countries. Many mathematical models have been widely used as prediction tool for urban air quality management in developed countries. However, applications of these models are limited in developing countries including India due to lack of suffi cient validation studies. In this paper, three state-of-the-art air quality models namely AERMOD, ADMS-Urban and ISCST3 have been used to predict the air quality at an intersection in Delhi city, India, followed by their performance evaluation and sensitive analysis under different meteorological conditions. The models have been run for different climatic conditions, i.e. summer and winter season to predict the concentration of carbon monoxide (CO), nitrogen dioxide (NO 2 ) and PM 2.5 (diameter size less than 2.5 µm). The ISCST3 has performed satisfactorily (d = 0.69) for predicting CO concentrations when compared with AERMOD (d = 0.50) and ADMS-Urban (d = 0.45) for winter period. The ADMS-Urban (d = 0.49) has performed satisfactorily for predicting NO 2 concentration when compared with ISCST3 (d = 0.36) and AERMOD (d = 0.32). The AERMOD, ISCST3 and ADMS-Urban have performed satisfactorily for predicting PM 2.5 concentrations having d values as 0.46, 0.45 and 0.43 respectively. All three models have performed satisfactorily for predicting CO concentrations when wind speed was in the range of 0.5–3 m/s and wind direction in the range 90–180 degrees, i.e. downwind direction. The difference in model’s performance may be due to differences in model formulation and the treatment of terrain features. The causal nature of these Gaussian based models may be one of the reasons for difference in performance of the models, because these are sensitive to

Urban local air quality management framework for non-attainment areas in Indian cities

Increasing urban air pollution level in Indian cities is one of the major concerns for policy makers due to its impact on public health. The growth in population and increase in associated motorised road transport demand is one of the major causes of increasing air pollution in most urban areas along with other sources e.g., road dust, construction dust, biomass burning etc. The present study documents the development of an urban local air quality management (ULAQM) framework at urban hotspots (non-attainment area) and a pathway for the flow of information from goal setting to policy making. The ULAQM also includes assessment and management of air pollution episodic conditions at these hotspots, which currently available city/regional-scale air quality management plans do not address. The prediction of extreme pollutant concentrations using a hybrid model differentiates the ULAQM from other existing air quality management plans. The developed ULAQM framework has been applied and validated at one of the busiest traffic intersections in Delhi and Chennai cities. Various scenarios have been tested targeting the effective reductions in elevated levels of NOx and PM2.5 concentrations. The results indicate that a developed ULAQM framework is capable of providing an evidence-based graded action to reduce ambient pollution levels within the specified standard level at pre-identified locations. The ULAQM framework methodology is generalised and therefore can be applied to other non-attainment areas of the country.

Emission Inventorisation and Modelling of Non-Methane Volatile Organic Compounds from Petrol Distribution Centres in an Urban Area

Non-methane volatile organic compounds (NMVOCs) are associated with various respiratory, cardiovascular and cancerous diseases. Emission of NMVOCs from petrol distribution centres in urban areas is one of the major sources. This study focuses on the estimation of emission load of NMVOCs from petrol distribution centre in one of the metropolitan cities of India, i.e., Delhi city. It is estimated that approximately 3190 tone of NMVOCs are emitted every year from petrol pumps in Delhi city. Further, AERMOD has been used to simulate NMVOCs concentrations over Delhi city in three different seasons (winter, summer and post-monsoon). Further, AERMOD’s predicted NMVOC concentration are compared with monitoring data at three different locations in Delhi city for winter period and observed satisfactory performance of AERMOD. It is observed that ambient NMVOCs concentrations exceed the NAAQS in Delhi city .