You have used an air monitor to measure the Ammonia exposure of a plant worker who conducts ammonia level testing throughout her 12 hour work shift. You did multiples samples to capture the tasks that were ongoing. You get the following results. What is the average of this workers exposure for her work shift? 8:00-11:00 : 20 ppm 11:00-11:15 : 36 ppm 11:15 - 12:00 :15 ppm 12:00-13:00 : 0 ppm 13:00 - 20:00 :13 ppm What is the solution (with units)