Local air pollution begins at home
Activity 1
Testing for particulates in the air
Particulates are very small solid or liquid particles found in the atmosphere, either as the result of natural processes (such as salt spray by the sea or smoke from bushfires) or of human activities (such as soot, or asbestos from vehicle brake linings).
Materials (for the class)
- cylinder vacuum cleaner
- tin with lid (eg, treacle tin)
- hammer
- small nail
- pieces of filter paper (to fit over the lid of the tin)
- an old pair of scissors
- electrical tape
- extension cords (to reach from a power point to the testing sites)
Procedure
- Make a series of small holes in the lid of the tin with the hammer and nail.
- Use the old scissors to make a hole in the side of the tin, large enough for the vacuum cleaner hose.
- Insert the vacuum cleaner hose into the hole and tape into position.
- Place a piece of filter paper over the lid of the tin. When you switch on the vacuum cleaner, the suction will draw air through the filter paper and particulates will collect on the paper.
- Test for the amount of particulates in the air in various places and conditions (eg, beside a busy road, in a side street, on an unsealed road and on windy and still days).
Teachers notes
Comparisons can be based on the amount of time needed to produce a visible film on the filter paper, the colour of the deposit or the amount of deposit observed over a fixed time.
The biggest limitation to sample collection is the length of the extension cords!
A more elaborate version of this experiment, including calculations to determine the concentration of black carbon in the air, can be found at How to sample black carbon air pollution.
Posted August 1997.