To determine the PM2.5 concentration in a classroom a researcher sampled the air over 24 hours. She collected all the airborne particles in a total sample of 14.4 m3 of air. Then she measured the total particle mass in different particle size (diameter) ranges. Her results are shown in this table:

(3 point) What was the PM2.5 concentration in the classroom?

(2 point) Would you say this is a low concentration or a high concentration of PM2.5? Why?
 

Particle Diameters (um) 0.0-0.5 0.5 1.0 1.0 1.5 - - 1.5-2.0 2.0 - 2.5 2.5-3.0 3.0-3.5 3.5-4.0 4.0 - 4.5 4.5-5.0 Total Mass of Particles Collected (ug) 350 550 700 950 1050 1150 900 1050 900 950