How does ozone relate to air pollution and how bad is our air?

SEATTLE — As an Air Stagnation Advisory has been extended to Thursday afternoon, we looked to the National Oceanic and Atmospheric Administration's maps for a view of what our air stagnation looks like across our state.

>> Visit this link for a real-time air quality map monitoring Puget Sound.

The map below shows the air quality index for ozone in a color coded format. Scroll to the bottom of the page for a key to the map.

What is ozone?
According to the Environmental Protection agency, "ozone is a gas that occurs both in the earth's upper atmosphere and at ground level. Ozone can be "good" or "bad" for your health and the environment, depending on its location in the atmosphere."

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How Can Ozone Be Both Good and Bad?
The EPA says "ozone occurs in two layers of the atmosphere. The layer closest to the Earth's surface is the troposphere. Here, ground-level or "bad" ozone is an air pollutant that is harmful to breathe and it damages crops, trees and other vegetation. It is a main ingredient of urban smog. The troposphere generally extends to a level about 6 miles up, where it meets the second layer, the stratosphere. The stratosphere or "good" ozone layer extends upward from about 6 to 30 miles and protects life on Earth from the sun's harmful ultraviolet (UV) rays."

This map shows NOAA's National Weather Service Air Quality Forecast Guidance.

Click image or this link for a larger version.