The Scosche AFP2-SP Fresch Air is a portable HEPA air purifier and deodorizer that you can use in your vehicle or small office. It features two modes: automatic, which turns on when you start your car, and manual, with two fan speeds to control the on/off feature. The 3-stage H13 HEPA filter captures 99.5% of small particles and dust, making it ideal for people with allergies or sensitivity to pet dander, dust, or odors. It can purify an average-size vehicle in 15-20 minutes and up to 100 sq. ft of space in about an hour. It is also small and compact enough to fit in your cup holder or on any flat surface. To maintain the best performance, replace the HEPA filter every 3 to 6 months, depending on use. Note that PM2.5 are fine inhalable particles with diameters of generally 2.5 micrometers or smaller.