Question

What is the concentration in ppm assuming that 2 quarts of dichlorobenzene has spilled and evaporated in an unventilated area measuring 4 meters x 6 meters x 13 meters?

Your company has a degreasing process involving methylchloroform.   Your exhaust ventilation system has failed and you have conducted area surveys. The lab reports to you a result of 6.3 grams collected on the sample media. You review your notes and determine that 4.5 liters of air were collected. What is the level of contaminant expressed as: mg/ m³ and expressed as ppm?

Answer 1

1) Volume = 4 m x 6 m x 13 m = 312 m³ = 312000 lts ( 1m³ = 1000 l)

volume of dichlorobenzene = 2 quarts = 1.89271 litres (1 quart = 0.946353 litres)

Density of dichlorobenzene = 1.24 g/ml

   0.001 litre -----> 1.24 g

   1.89271 litre ---> == 2347 g

Concentration in g/l = Mass of dichlorobenzene/volume = 2347 g/312000 litres = 0.0075 g/l

1 g/l ----> 1000 ppm

0.0075 g/l ----> == 0.0075 x 1000 = 7.5 ppm

2) Mass of methyl chloroform = 6.3 g

Volume = 4.5 lts

Concentration = mass/vol = 6.3 g/4.5 lts = 1.4 g/l

1 g/l ----> 1000 ppm

1.4 g/l ----> == 1.4 x 1000 = 1400 ppm

mg/m³ : mass = 6.3 g = 6.3 x 1000 mg = 6300 mg

Volume = 4.5 lts = 0.0045 m³ ( 1 lt = 0.001 cm³)

Concentration in mg/m³ = 6300 mg/0.0045 m³ = 14 x 10⁵ mg/m³