Ground ozone levels spur officials to issue warning

Southern Nevada residents might experience unhealthful levels of ground ozone this afternoon and evening.

The Department of Air Quality and Environmental Management said people should limit outdoor activity, especially those with asthma and respiratory problems.

Ozone is a gas that naturally occurs in the upper atmosphere and protects the earth from ultraviolet rays caused by the sun. Ground ozone occurs when heat and sunlight mix with pollutants from cars and other sources.

Officials said there are steps that can be taken in order to reduce the risks of unhealthy levels of ground ozone.

• Fill up gas in vehicles after sunset, and be careful not to spill gas.

• Don't leave vehicle engines running.

• Mow lawns after sunset.