this invention is directed to a method and apparatus using polymerase chain reaction technology for collecting air samples and identifying biological agents in the air sample . the apparatus 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 ; and pcr biological identifier apparatus for detecting a bio - agent in a piece of mail following manual transport of the cartridge to the identifier apparatus ; retesting of the liquid sample upon various error conditions ; confirmation testing upon preliminary positive results ; fluid transfer to archive containers at the completion of analysis ; and , notification / reporting system to alert designated personnel / organizations upon the occurrence of selected events such as the presence of bacillus anthracis .