Particulate matter consists of a mixture of particles ranging from large particles such as smoke, dust, and pollen to smaller ones from vehicle exhaust and coal-fired plants. The major contributors of particles to the air you breathe include coal and oil burning power plants, diesel fuel, and wood-burning fireplaces. Natural sources of particulate matter include volcanic ash, pollen and dust. The amount of particulate matter in the air can be measured using various techniques. One technique uses a device that collects particulates on a filter strip and periodically shines light through the strip to record the difference in light transmittance. This difference correlates to the particle mass collected over a period of time. You will use a similar technique.

In this experiment, you will measure the amount of light that passes through a test card that has been allowed to collect particulate matter in the air for a week. You will compare the transmittance of light through the test card to a control card.


In this experiment, you will

  • Collect particulate matter from the air.
  • Use a Light Sensor to determine the amount of light blocked by the particulate matter.
  • Calculate the percent light transmittance for various locations.