Environmental Engineering

7

AIR POLLUTION: SOURCES AND EFFECTS

7.1 INTRODUCTION

Breathing is involuntary activity of human life. A healthy person never thinks about the breathing action although air is one of the most important five essentials (air, water, food, heat and light) for human survival. A healthy human being breaths nearly 22,000 times a day inhaling approximately 15 kg (12.4 m³—at 20°C, 1 atm) of air. One estimate says a healthy human being can survive 5 weeks without any food and 5 days without any water. Without an air, it is anyone’s guess. It may not be possible to survive even for 5 minutes without air. Air, a natural resource, is abundantly available over the surface of the Earth, free of cost. Although a must for human survival, it has long been an ...