Typically a counting station, which gathers data on the amount of pollen and mold in the air, will use one of several types of devices to make its assessment. These devices include:

• Sedimentation samplers. Commonly known as a Durham Sampler, this device catches pollen and mold particles on a microscopic slide coated with an adhesive.
  
  
• Rotating-arm impactor samplers. These devices use plastic rods that are mechanically rotated to more efficiently collect particles onto the small collection surface.
  
  
• Suction/cascade impactor samplers. These devices suck air through several stages. Each stage has a trap that is capable of stopping successively smaller particles. This device can be used to estimate the diameter of certain particles, which is useful for accurately determining their type.
  
  
• Liquid impingers. These devices use a vacuum pump to collect airborne particles. Water-based collection liquids are used to trap the particles.
  
  
• Filtration samplers. These devices use filters with specifically defined pores to trap particles of various sizes.