this invention is directed to a method and apparatus using polymerase chain reaction technology for automatically collecting air samples and identifying biological agents in the air sample . a fully automated system is provided that is capable of detecting transient events such as bacillus anthracis in a piece of mail being processed on high - speed mail processing equipment . the system includes apparatus for implementing the following features : particle collection and pre - separation using a collection hood and dry cyclone passive filtration system ; continuous particle collection into a liquid sample ; automated fluid transfer to a pcr analysis cartridge at pre - scheduled times ; automated cartridge handling and transfer to pcr bio - agent identification apparatus for detecting a bio - agent in a piece of mail ; automatic retesting of the liquid sample upon various error conditions ; automatic confirmation testing upon preliminary positive results ; automated fluid transfer to archive containers at the completion of analysis ; and , automated notification / reporting system to alert designated personnel / organizations upon the occurance of selected events such as the presence of bacillus antracis .