In the run up to his first Presidential election, Ronald Regan became the butt of jokes and night time comedies when he said that trees cause more pollution than the cars. But Regan may not have been altogether wrong in his claim. Trees emit a big range of volatile organic compounds (VOCs) in large quantities and these compounds, by reacting with the exhausts from the vehicles and the industries, are the cause of smogs across the continents. The Biogenic Volatile Organic Compounds (BVOCs), to distinguish them from those of anthropogenic origin, are a large number of saturated and unsaturated organic compounds including alkanes, alkenes, carbonyls, alcohols, esters and ethers.