Analysis of ground-level ozone formation and its correlation with concentration of other pollutants and weather elements

PUI2016 - Extra Credit Project

<Avikal Somvanshi, as10724, as10724>

Abstract: Ground-level ozone is a deadly pollutant and even short term exposure is know to cause health impact. But unlike other aerosols, ozone is not emitted directly into the air from any one source, but is created by photo-chemical reactions among oxides of nitrogen (NOx) in the presence of sunlight. Therefore, to control ozone pollution it is critical to understand the process of its formation in real world and what role weather and various pollutants play in this process. This study analysed hourly pollution and weather data from the Delhi, India from April 2015 to November 2016 to answer these questions. The results show that ozone concentration in Delhi is correlated with solar radiation, temperature, relative humidity and NOx concentration. No correlation was found with wind speed and PM2.5 concentration. Study also found that instances of high ozone pollution are distributed throughout the year (only exception being rainy days during the monsoon season) in Delhi and it is not only a summer season phenomena as generally believed. 
Figure 1: Ozone concentration at ground level is positively correlates to solar radiation and ambient temperature conditions, while NOx and relative humidity exhibit negatively correlation. No correlation was found with wind speed and PM2.5 concentration.        
Introduction: Ground level Ozone is one of the primary constituents of photo-chemical smog and breathing air laced with high ozone concentration has a marked effect on human health according to the World Health Organisation (WHO). According to the Ambient (outdoor) air quality and health factsheet of WHO "it can cause breathing problems, trigger asthma, reduce lung function and cause lung diseases". Several European studies have reported that the daily mortality rises by 0.3% and that for heart diseases by 0.4%, per 10 µg/m3 increase in ozone exposure. 

This study analyses ozone concentrations monitored in Delhi, India, which is consistently recognized as home to the most polluted air among the megacities in the world by WHO. Delhi is known to have sever ozone pollution problem but it is perceived to be a summer phenomena. This study explores the seasonal variation in ozone concentration in Delhi's air and relative impact of other chemical and weather elements on it.