5.1 Air Quality Sensor Intro


Microscopic particles suspended in the air are an important form of air pollution. Some suspended particles arise from natural processes and are relatively harmless. Other particles, such as dust from exposed soil and smoke from wildfires, arise from natural processes but may be greatly aggravated by human impacts, and are potentially more hazardous. In many areas, especially urban environments, large numbers of human-made particles are also present in air. Sources for these particles include vehicles, fires for cooking or heat, and industrial activities.

Materials Needed:

Materials needed for Basic Air Quality Sensor Construction and Application Activities:

Introduction to Air Quality Sensors:

Particulate sensors measure particulate matter (PM) in the air. This is done using the difference in how light scatters when encountering particles of different sizes.

Inside of the chamber, a laser emits a beam of light and the detector measures the light scattered by the particles in the air. Based on the amount of light scattered, the sensor can estimate the size of the particles that are present and produce a total count of particles within certain size classes. These size classes are typically 1 µm, 2.5 µm, and 10 µm, which is where the names PM1, PM2.5, and PM10 originate.