I'll say the same thing again, until the point sinks in...

Jeff Rigby wrote:
Pine trees outgas more hydrocarbons than cars do although they are simple
chains and don't contain lead, sulfur or mercury.

Yep.

That's why hundreds of years ago, before we had automobiles & smokestack
factories & fossil fueled power plants that clean up the atmosphere,
planet Earth was so polluted from all the trees that it could barely
support life.

DSK