Air pollution modelling for Indian cities: change point analysis of air pollution in Delhi

Abstract

There has been considerable concern with respect to the increasing pollution levels in Delhi. The pollution levels and the resulting fog and effects on health has been alarming and has worried different stakeholders. This paper examines to analyze the monthly pollution data of Delhi from 1990 to 2015 and tries to find out the change point with respect to the pollution levels in Delhi. The change point is essentially the year after which there has been significant increase or decrease in the pollution level. The paper analyses the pollution data componentwise and finds out the overall change point of various components. Further, an analysis of the industrial area and residential is carried out separately to find out whether there are any major differences and the reasons behind that. The change point analyses are done in such a way that no dimensional reduction is required unlike the functional Principal Component analyses. The results suggest that most of the pollutants have change points between 2001 and 2004. The concentrations of the pollutants have generally increased on an average basis after the change point except SO2 which has decreased considerably. The analysis shows that the concentrations of pollution is low in the monsoon months and is highest during the winter months with pollution peaking around November.