I agree somewhat........but how about the unhealthy habits caused by all of us?...........like carbon monoxide, like the toxins caused from run offs, and other sources that contaminate water supplies, there are as many sources surrounding these issues as any............what causes cancer?.....who knows which agent is the worst?.......illegal dumping often goes unchecked..............what has destroyed our ozone layer that made holes in it?........what about oil spills and mercury entering our food sources?, our ocean is polluted, and can you imagine how difficult it is to pollute an ocean, or for that matter fish it out?.....mining run offs contanminate.......The point I'm trying to make is that all of these things can be attributable to health problems...........and no doubt are..........A library can be constructed to house the books written on pollution.........we don't know what we are breathing, eating, drinking unless we get it analysed before hand.