INTRODUCTION

As of today, 195 countries have signed The Paris Agreement, which is long-term temperature goal is to keep the increase in global average temperature to well below 2°C above pre-industrial levels. It has been made clear that this can be achieved by reducing emissions as soon as possible. In order to achieve this, the government and industrialist need to have a clear understanding about emissions, its source and the possible methods to reduce them. Emissions of many air pollutants have many negative effects on public health and the natural environment. Emissions from transportation, which are primarily generated by internal combustion engines, contribute to 15% of global emission. Different than the major contributor (power generation sector at 31%), transportation vehicles are scattered and have outstandingly many individual owners. Hence, a special attention is required in order to understand the nature of emissions from vehicles.