“…NO x sensors have been investigated by Kato et al (1999) and Orban et al (2005). NO x virtual sensors are presented by Re et al (2005) and Subramaniam et al (2008). Particulate matter sensors are discussed in Allan et al (2003), Warey andHall (2005), Hauser (2006), Diller et al (2008), and Cai and Ma (2009.…”