A stack was sampled for 8 minutes.  The gas velocity (at stack conditions) through the sampler was 15.0 m/s and the area of the sample probe was 5.07 cm ² .  The net mass of particulates collected was 0.43 grams. 

a) Calculate the concentration of particulates in the stack in micrograms per cubic meter. 

b) The temperature in the stack is 300 F and the pressure is 725 mm Hg. If the total flow rate of gas out of the stack is 190 standard cubic meters per second, calculate the total mass emissions of particulates out of the stack in kg/day.