Aparticulate matter sampler was operated for 24 hours at a flowrate of 1.4 m3 min-1. the starting weight of the filter paper before sampling was 2.05 grams. at the end of the sampling period, the filter's weight was 3.84 grams, and the gain in weight was due completely to the particulate matter that had collected on the surface of the filter paper during air sampling. determine the particulate matter concentration, in micrograms per cubic meter (expressed to one decimal place), for the given sampling time.

887.89 μg/m³

Explanation:

Given:

Duration of mass flow = 24 hours = 24 × 60 = 1440 minutes

Flowrate = 1.4 m³/min

starting weight of the filter paper before sampling = 2.05 grams

Filter's weight = 3.84 grams

Now,

Mass of the particular matter collected

= Mass of filter after 24 hours - Initial weight of the filter

= 3.84 - 2.05

= 1.79

Now,

The total volume passing through filter = Flowerate × Time

= 1.4 × 1440

= 2016 m³

Particulate matter concentration =

or

Particulate matter concentration =

or

Particulate matter concentration = 0.0008878 g/m³

also,

1 gram = 10⁶ micrograms

thus,

Particulate matter concentration = 0.0008878 × 10⁶ μg/m³

= 887.89 μg/m³

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.