Calculate the total mass concentration of respirable dust for the below condition. Mr. X conducted the monitoring of respirable dust at the sand blasting process. The monitoring used two slots of monitoring which was 08:00 am - 12:00 pm and 02:00 pm to 04:00 pm. A 1.7 L/min flowrate of air was sampled for respirable dust using a high flow air sampling pump connected to a two stage plastic cassette and cylone with a pre - weighed 37 - mm, 5.0 micrometer PVC filter and support pad. Laboratory analysis of the filter using gravimetry indicated that the pre - sampling weight for first slot and second slot were 15.212 mg and 16.212 mg, respectively. Meanwhile, the post - sampling weight for first slot was 17.717 mg and second slots was 18.414 mg. The blank weight for first and second slots were 0.04mg and 0.58mg. What was the total concentration of respirable dust in the air during the sampling period? - 0.5724 mg/m3 2.404 mg/m3 O 0.2404 mg/m3 5.724 mama