8.2.6.3 Air pollutants from forest fires

In some regions, changes in temperature and precipitation are projected to increase the frequency and severity of fire events (see Chapter 5). Forest and bush fires cause burns, damage from smoke inhalation and other injuries. Large fires are also accompanied by an increased number of patients seeking emergency services (Hoyt and Gerhart, 2004). Toxic gaseous and particulate air pollutants are released into the atmosphere, which can significantly contribute to acute and chronic illnesses of the respiratory system, particularly in children, including pneumonia, upper respiratory diseases, asthma and chronic obstructive pulmonary diseases (WHO, 2002a; Bowman and Johnston, 2005; Moore et al., 2006). For example, the 1997 Indonesia fires increased hospital admissions and mortality from cardiovascular and respiratory diseases, and negatively affected activities of daily living in South-East Asia (Sastry, 2002; Frankenberg et al., 2005; Mott et al., 2005). Pollutants from forest fires can affect air quality for thousands of kilometres (Sapkota et al., 2005).

8.2.6.4 Long-range transport of air pollutants

Changes in wind patterns and increased desertification may increase the long-range transport of air pollutants. Under certain atmospheric circulation conditions, the transport of pollutants, including aerosols, carbon monoxide, ozone, desert dust, mould spores and pesticides, may occur over large distances and over time-scales typically of 4-6 days, which can lead to adverse health impacts (Gangoiti et al., 2001; Stohl et al., 2001; Buchanan et al., 2002; Chan et al., 2002; Martin et al., 2002; Ryall et al., 2002; Ansmann et al., 2003; He et al., 2003; Helmis et al., 2003; Moore et al., 2003; Shinn et al., 2003; Unsworth et al., 2003; Kato et al., 2004; Liang et al., 2004; Tu et al., 2004). Sources of such pollutants include biomass burning, as well as industrial and mobile sources (Murano et al., 2000; Koe et al., 2001; Jaffe et al., 2003, 2004; Moore et al., 2003).

Windblown dust originating in desert regions of Africa, Mongolia, Central Asia and China can affect air quality and population health in remote areas. When compared with non-dust weather conditions, dust can carry large concentrations of respirable particles, trace elements that can affect human health, fungal spores and bacteria (Claiborn et al., 2000; Fan et al., 2002; Shinn et al., 2003; Cook et al., 2005; Prospero et al., 2005; Xie et al., 2005; Kellogg and Griffin, 2006). However, recent studies have not found statistically significant associations between Asian dust storms and hospital admissions in Canada and Taiwan (Chen and Tang, 2005; Yang et al., 2005a; Bennett et al., 2006). Evidence suggests that local mortality, particularly from cardiovascular and respiratory diseases, is increased in the days following a dust storm (Kwon et al., 2002; Chen et al., 2004).