Ozone becomes a moderate health risk when it reaches a level of 55 parts per billion (ppb) in the air. Write an inequality that describes a safe ozone level. What inequality symbol would you use and why?
To write an inequality describing a safe ozone level, we need to express that the ozone level should be below the moderate health risk threshold of 55 ppb.
The inequality symbol we would use is < (less than), because the safe ozone level must be below 55 ppb.
Therefore, the inequality that describes a safe ozone level is:
Ozone level < 55 ppb