Figure 3.5: The percentage of measured 24-hour average PM10 concentrations within air quality categories at Khyber Pass, Auckland

Text description of figure

There is a chart showing 24 hour concentrations of PM₁₀ in Khyber Pass, Auckland, between 1998 and 2001. At the beginning of the period most concentrations (about 65 per cent) were in the 'acceptable' category. Just under 30 per cent of measurements were in the 'alert' category, about 5 per cent were in the 'good' category, and about 5 per cent over the guideline. Over the period there was a slight improvement, until in 2001 about 20 per cent of measurements were 'good', with under 10 per cent in the 'alert' category, and no measurements over the guideline.