The concentration of particulate matter in parts per million t hours after a factory ceases operation for the day is given by the following formula C t Find the average concentration for the period from t 0 to t 4 C t 8In t 9 t 9 The average concentration of particulate matter for the time period from t 0 to t 4 is approximately million Do not round until the final answer Then round to four decimal places as needed parts per