Measurement of Air Pollution Fallout

Procedure

1. Obtain three wide mouth containers of 1 to 2 L capacity. Record the mass of each. Clean them thoroughly.

2. Add about 2-3 cm of a 1:1 solution of distilled water and alcohol.

3. Place the jars at different locations where they will not be disturbed for 4 weeks. The test locations should be at least 1 meter from the ground.

4. Leave the containers for 4 weeks, replacing any evaporated solution. If the jars are outdoors and have overflowed from precipitation, discard the contents and begin again.

5. At the end of the collection period, evaporate the solution from each container to dryness. Determine the new mass and calculate the mass of residue.

6. Calculate the mass of fallout per square meter.

7. Observe a sample of the residue under the microscope and record your observations.