Air pollution is a major aggravation of respiratory symptoms and disease. Effects are decreases in pulmonary function and evidence of inflammation as well as suggestions of increases in chronic respiratory disease. Orozco-Levi et al. (2006) showed strong association between wood smoke exposure and obstructive pulmonary disease. Several studies have shown that especially the small particles, has an effect on airways, and that asthmatic subjects may be the group at greatest risk from air pollutants. The awareness of the impact of airborne particles, particularly fine and ultra fine particles, on health is growing. In recent years, exposure to fine and ultra fine airborne particles has been identified as an important factor affecting human health [Seaton et al., 1995; Schwartz et al., 1996; Oberdörster et al., 1994; Alvin et al., 2000]. Several researchers hypothesize that an increased mortality is associated with the particle levels prevailing in urban air [Jamriska et al., 1999; Dockery et al., 1993]. Mølhave et al (2000; 2005) have suggested that reactive short-lived compounds resulting from reactions between ozone and particulate matter cause indoor air quality complaints and objective health effects such as impaired lung functions.