Question

Compare the natural chemistry that takes place in the enviroment with the chemistry that takes place due to the manmade factors like pollution. Discuss the efffect of pollution at the local, regional, national, and global level.

Answer 1

It's exactly the same chemistry, and almost any pollutant you care to name -- NOx, petroleum, CO2, CO, lead, mercury -- has natural sources as well as manmade. What makes something a "pollutant" is generally a sharp and/or large increase in the amount of substance, to such a degree that it overwhelms the local natural reactions that process it.

For example, something like 3,000 barrels of crude oil seeps naturally into the Gulf of Mexico every day,, and is, presumably, disposed of by oil-eating bacteria and whatnot. What made the recent Deepwater Horizon spill a case of pollution is that it was dumping 53,000 barrels of oil a day into the Gulf -- more than a tenfold increase, suddenly, which would overwhelm the capability of the oil-eating bacteria and whatnot to incorporate it into the food chain. Similarly, volcanos and other sources naturally inject NOx into the atmosphere every year, but what makes it a pollutant when it comes to cars is the much larger volumes injected over short periods (and concentrated in small areas, like cities). This overwhelms the ability of the ecosystem to incorporate the substance into its natural cycles.

Ecostasis is not that different than homeostasis: drinking a little red wine after dinner every now and then will make you live longer. Drinking a whole bottle before breakfast will make you quite sick -- as you completely overwhelm your natural ability to process the alcohol.

The dose makes the poison, in other words.