Researchers surveying the air along the Santa Monica Mountains found some of the highest levels of one pollutant at the eastern, most urban end of the range – where many people like to hike.

See also: Santa Monica Airport Provides Some of L.A.'s Worst Air Pollution.

The pollutant in question here is comprised of oxides of nitrogen. It naturally occurs in our air supply, but in higher levels it can cause “wheezing, coughing, colds, flu and bronchitis,” federal officials say.

And these higher levels of oxides might not bode well for plant life and fire season, either.
Initial results detailing Santa Monica Mountains air quality were released this week. They're from the first year of a three-year, $100,000 study by Irina Irvine, restoration ecologist for Santa Monica Mountains National Recreation Area, UC Riverside's Edith B. Allen, the U.S. Forest Service's Dr. Andrzej Bytnerowicz and Dr. Mark Fenn.

The research is funded by the National Park Service's Air Resources Division.

The results show much higher concentrations of oxides of nitrogen at the eastern end of the area, which includes Franklin Canyon, with cleaner and cleaner air the further west you go.

Researchers say the higher levels of oxides could be feeding non-native grasses that are prone to wildfire. According to a summary:

Higher levels of nitrogen led to a decline in native shrub seedlings and an increase in nonnative grasses. Other studies in Australia and California have demonstrated a link between nonnative grasses, also known as “flashy fuels,” and larger and more frequent wildfires. 

The source of the nitrogen at the 10 testing spots checked out by researchers? It's no mystery. Kate Kuykendall of the National Park Service told us this:

The nitrogen deposits in this area are caused by vehicle emissions. The closer you get to the more urban areas in the eastern part of the mountains, the higher levels you get.

Researchers seem more concerned with the pollutants' affects on plant life than their affect on hikers – at least for now. Ultrafine particles and carbon monoxide seem to have a worse rap for harming our breathing.

But the influence nitrogen has on fire fuels could be alarming. Restoration ecologist Irvine:

What's more intriguing about this study is learning how high nitrogen levels affect native vegetation and what that might mean for fire risk in such a fire-prone region.

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