Question

atmospheric ozone concentration (one day period)
0.90
0.80
0.70
0.60
0.50
first stage smog alert (0.50)
0.40
0.30
0.20
0.10
0.00
-1 4 9 14 19 24
hour
ppm ozone
valley
mountain
beach
question: which region would have a smog alert on the day graphed?
mountain
no region would have a smog alert.
beach
valley

Explanation:

The first - stage smog alert is at 0.50 ppm of ozone concentration. The valley region has ozone concentrations above 0.50 ppm at some points during the day as shown in the graph. The mountain and beach regions do not exceed this level.

Answer:

Valley