Concern Over Invisible Air Pollutants

Photo by Stephen Rees/Flickr (Creative Commons license BY-NC-ND 2.0)

By Frances Bernards, Utah Recycling Alliance

It’s that time of year when Salt Lake City residents are confronted with episodes of poor air quality.  When temperature inversions hover over Salt Lake City, trapping automotive and other emissions, residents are stuck with a brown, thick haze that cause particulate pollution to double some days.

But some air pollutants aren’t visible.

Some air pollution comes from the food and yard waste that we send to landfills.  The waste decomposes and generates greenhouse gases, in particular methane and carbon dioxide.  Unlike the particulate pollution that contributes to the winter haze, these gases are not visible to the human eye.   

Methane is produced due to the anaerobic decomposition – lack of oxygen – that takes place in a landfill.  Some of the larger, newer municipal solid waste landfills are required to capture and dispose of the gases by either burning the gas or by converting the gas into energy.  

Not all of the landfill gases are captured, though.

The US EPA Landfill Methane Outreach Program estimates that 60%-90% of the methane emitted from landfills can be captured.  Sound good?  Not necessarily.  Methane can hold 28 to 36 times more heat in the atmosphere than carbon dioxide, according to the 2014 Intergovernmental Panel on Climate Change assessment report.  So you need to collect about 95% of the landfill gas to get ahead.

Is there a better alternative to landfilling food and yard waste?

A new University of Washington (UW) study shows that composting is a better choice.

“Putting your food waste in the compost bin can really help reduce methane emissions from landfills, so it’s an easy thing to do that can have a big impact,” said paper author Sally Brown, a UW research associate professor of environmental and forest sciences.

The paper’s author recommends composting food scraps and woody yard materials together since the dryer, high-carbon, yard trimmings mixed with wet food scraps create ideal conditions for the compost process.

Remember that methane is produced when anaerobic decomposition – lack of oxygen –takes place.  Utah State Extension’s website provides tips on how to ensure that your compost pile is aerated properly.

Look for other small challenges you can take on.

In this example, with a little bit of effort, you can help reduce methane emissions, keep resources from filling up our Nation’s landfills and create soil amendments to use in your garden or plants in your yard.