In Los Angeles, on days when air pollution levels are high, smog alerts are issued. Officials recommend that people avoid strenuous activity and remain indoors with the windows and doors closed. Determine how much protection is afforded against ozone, a key pollutant, by remaining indoors. Consider the case of a typical residence, which can be modeled as a CSTR. Assume that the volume is 250 m3 and that, even with the doors and windows closed, air leaks into the house from outdoors through cracks at a rate of 2.5 m3/min. Ozone reacts with indoor surfaces and this reaction can be represented as a first- order reaction that consumes ozone with a rate constant of 2.6 hr-1.
(a) Write a mass balance for the rate of change of indoor ozone concentration with time.
(b) Calculate the indoor/outdoor ratio of ozone under steady-state conditions.
(c) Comment on the effectiveness of remaining indoors as a means of protecting oneself against outdoor ozone exposure.