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Contaminated "Tule Fog" is Making a Mess of California's Central Valley

3p is proud to partner with the Presidio Graduate School’s MPA Curriculum on a blogging series about “Sustainable Development.” This post is part of that series. To follow along, please click here.

By Pauline Hamilton

Five months out of the year, from November thru March, the California Central Valley experiences a mix of airborne toxins that exacerbate an otherwise natural phenomenon known as Tule Fog: This breathable toxic soup contains the product of ‘development’, such as diesel emission particles (DEP), ammonia, methane, pesticides, herbicides, and other particulate matter trapped in fog. DEP comes from traffic on Highway 99 and Interstate 5; ammonia and methane are contributed by California's largest feed lots of cows, numerous landfills housing most of California's waste, incinerators and waste disposal services; and pesticides, herbicides and other particulate matter are a generous contribution from the way we grow and harvest our agricultural products. Are these residues and the air this population breathe what we intend to create with our ‘progress’? Is this sustainable? How much can we pollute before all our bees die or our food becomes toxic to us and the communities where they grow?

Tule Fog forms when condensation happens as temperatures reach below dew point.  Although it is a natural phenomenon that has been happening regularly since long before the valley was developed, these tiny water particles have the capacity to absorb high concentrations of pollutants, creating something like the air quality of Industrial-era London in its density.  Yet the most imminent threat comes from smaller particles as they enter the lungs and get sent to the bloodstream. This cause acute irritation and inflammation of the lungs and have the capacity for long term consequences of asthma, and diseases like “emphysema, bronchitis, lung cancer, heart disease, and strokes. James N. Siebert, an environmental toxicologist, identified sixteen different pesticides in modern Tule Fog.”

I care because the Central Valley is the most productive agricultural land in America producing enormous amounts of produce and nuts that feed this nation and the world thru exports. The fact that we are growing the food we eat adjacent to waste sites and feedlots, and that it is sprayed with pesticides and fungicides far exceeds my comprehension. Imagine if God had designed your body to have the beginning and end of your digestive system in the same place, I wonder. Yet what’s most appalling to me is how on earth we expect people who live in this valley and harvest our food to survive the toxic soup they breathe in and out with every breath, day in and day out during autumn and winter months without repercussions on their health.

How can we justify this in the name of health, feeding the people in the planet or progress? If you have any words of advice please share them with this despaired soul!


Pauline Hamilton is a vibrant entrepreneurial woman pursuing a Master in Public Administration at Presidio Graduate School of Management in San Francisco, California. She is dedicated to the attainment of environmental and social justice by designing alternative models of trade and cooperation among sustainable farmers that brings them self reliance and promotes equity in local communities.

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