Question: AIR POLLUTION The amount of nitrogen dioxide, a brown gas that impairs breathing, present in the atmosphere on a certain May day in the city of Long Beach is approximated by
A(t) = 136/{(1 + 0.25(t - 4.5)2) + 28 (0 ≤ t ≤ 11)
Where A(t) is measured in pollutant standard index (PSI) and t is measured in hours, with t = 0 corresponding to 7 a.m. Determine the time of day when the pollution is at its highest level.