Smog, climate change and leftover dinner


Smog, climate change and leftover dinner

The EPA wants to lower limits on the allowable amount of smog-causing ozone, reports Juliet Eilperin in The Washington Post. Smog exposure is linked to heart and respiratory illnesses in humans. Because it also stunts the growth of trees and crops, EPA also will set a secondary limit to protect them during the growing season.

Beyond the diminished yields of crops, there's another link to the food on our plates. A major contributor to ozone is methane, which, in the U.S., comes from the decomposition of wastes in landfills, ruminant digestion and manure management associated with domestic livestock, natural gas and oil systems, and coal mining, the EPA says.

Landfills produce 34 percent of all methane emissions in the U.S. The EPA calculates that 12.7 percent of municipal solid waste landfill material is methane-belching food waste, and that we discard about 25 percent of the food we prepare - about 96 billion pounds - at an annual cost of $1 billion. An editorial in The Guardian reports that halving the amount of food waste in the UK could have the same effect as taking one in four cars off the road.

Now, back to ozone: In 2002, it was reported that a reduction of manmade methane by 50 percent would have a greater impact on global surface-level ozone than a comparable reduction in emissions of nitrogen oxides (a component of ozone that comes from power plants, motor vehicles and the use of nitrogen-based fertilizer, among other sources).

Because ozone and methane are also greenhouse gases, a reduction of methane emissions reduces smog - and will cool the planet, say Robert Watson and Mohamed El-Ashry in an opinion piece in The Wall Street Journal. They suggest collecting methane in various ways, including

depositing manure into "biogas" digesting tanks where pipes collect methane produced from decomposition; and covering and lining open landfills, shunting methane into a collection pipe...

and using it to run a village or city-scale power plant.

Nice, but you and I can't capture methane. We can, however, reduce our personal contributions to the methane stream with three lifestyle changes:

Eat less meat and fewer dairy products.
Waste less food.
Compost food waste.


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