Bringing your lunch to school or work is green: You might prefer to tote...

This environmental buzzword may take you back a few years, and it's true it gets less press today, but the phenomenon is still very real. Acid rain looks and feels like ordinary rain, but it contains high concentrations of sulfuric and nitric acids-pollutants created in large part by human activities, primarily the burning of coal in power plants. It is more generally referred to as "acid deposition" because the chemicals are deposited in various forms: in rainwater, fog, snow, or dry material such as dust or smoke. Acid rain has been shown to reduce fish populations, cause decreased growth and dieback in forests, and to damage buildings and even the coatings of automobiles; for humans, it can mean asthma, bronchitis, and heart trouble.

It is easy to throw caution to the wind when the office is paying for supplies, business travel...