Rate your air. (Chart-Reading Skills).

Ground-level ozone is a pollutant caused by car emissions, power plants, and other sources. When the ozone level is too high, it can cause coughing, throat irritation, lung damage, and other problems, particularly in children, the elderly, and people with respiratory diseases. The U.S. Environment, al Protection Agency (EPA) monitors ozone levels regularly and alerts the public to unsafe levels through the Air Quality Index (AQI).

The amount of ozone in the air is measured in parts per million (ppm)--the number of ozone molecules per 1 million molecules of air mixture. To ease public understanding, the EPA translates that number into an AQI value scale between 0 (good) to 500 (hazardous). Note: The AQI almost never exceeds 300 in the U.S. The scale is further divided into color-coded rankings.

Directions: Study the AQI information below. Use complete sentences to answer the questions that follow.

1. At which AQI value should active children and adults begin to limit their outdoor exertion?

2. If the AQI in your city reads 162, what is the color code and the level of health concern?

3. If a TV meteorologist says that the AQI today will be code yellow, who shouldn't plan to play a long soccer game?

4. If a newscaster says that no one should exercise outside at all today, what color is the AQI?

5. If there is 0.127 ppm ozone in the air, should a healthy adult limit his or her outdoor exercise?

              Ozone       Color code and       Who should
 AQI      concentration      level of         limit outdoor
value         (ppm)       health concern        activity?

0-50         0.0-0.064    green: good         no one

51-100     0.065-0.084    yellow:             unusually
                          moderate            sensitive people

101-150    0.085-0.104    orange:             active children and
                          unhealthy for       adulst, and people
                          sensitive groups    with respiratory
                                              diseases like asthma

151-200    0.105-0.124    red: unhealthy      everyone,
                                              especially children

201-300    0.125-0.404    purple: very        everyone,
                          unhealthy           especially children

301-500    above 0.404    maroon: hazardous   everyone

           Who should
 AQI      avoid outdoor
value       activity?

0-50      no one

51-100    no one

101-150   no one

151-200   active children and
          adults, and people
          with respiratory diseases
          like asthma

201-300   active children and
          adults, and people
          with respiratory diseases
          like asthma

301-500   everyone

Don't Stop Now: Log on to www.epa.gov/airnow to look up the ozone level in your area today. How healthy is the air in your neighborhood?

ANSWERS

1. Active children and adults should begin to limit their outdoor exertion when the AQI value is at 101 to 150.

2. If the AQI reads 162, the color code is red and level of health concern is "unhealthy."

3. If the AQI is code yellow, unusually sensitive people shouldn't plan to play a long soccer game.

4. If a newscaster reports that no one should exercise outside today, the AQI color is maroon.

5. Yes, a healthy adult should limit his or her outdoor exercise when there is 0.127 ppm ozone in the air.