Climate in cities

Attach a piece of adhesive tape to a plastic pot so that the adhesive surface is upwards.
Place several prepared pots in different places around where you live - perhaps in your school car park, close to a road, in your garden or near your playground.  To prevent measuring dust which is simply kicked up from the ground, place the cups 1m above the ground. Expose the pots to the air for the same length of time.  After a few rain free days collect all the pots and examine the dust on the adhesive tape and note down its quantity and the size of the dust grains.