Study: Las Vegas’ leafy areas add to air pollution

By Mary Manning

Thursday, June 18, 2009 | 5:37 p.m.

Las Vegas growth has attracted more people and plants, but it has also increased the ingredients that make up ozone, an air pollutant considered a health hazard, according to a recently published study.

Until researchers conducted the study, not much was known about what contributions pines, juniper trees and rosemary bushes made to the pollutant.

Suburban Las Vegas areas, particularly in the southwest and northwest, had the highest levels of compounds emitted by these plants, chemicals known as terpenes. Terpenes help the plants fend off insects and protect them from withering in high temperatures.

It's when terpenes mix with other pollutants -- such as nitrogen oxide formed from traffic exhaust in Las Vegas, then cook under Southern Nevada's sunlight -- that ozone forms. This pollutant can affect people with chronic breathing conditions, the elderly and children.

Mark Potosnak of DePaul University in Chicago conducted the study at five sites around the Las Vegas Valley and measured terpenes from March to August 2006, he said. Potosnak at the time worked at the Desert Research Institute with student Maria Papiez, he said.

The study found that plant-emitted terpenes increase ozone production 50 times higher than normal.

In every case ozone levels exceeded the federal Environmental Protection Agency safe standard of 75 parts per billion over an eight-hour period. The worst reading reached 107 ppb.

Lower levels of terpenes were found near industrial and commercial areas.

The article urges urban planners to continue updating the research as more buildings, asphalt, automobiles and different plant species are introduced to the Las Vegas Valley.

The study was accepted for publication in the journal Atmospheric Environmental on May 31.