2006 Almanac (page 18) Table 1-3 State PM10 Standards: 50 ug/m3 for 24 hours not to be exceeded and "20 ug/m3 annual arithmetic mean," not to be exceeded. State PM2.5 Standard: "12 ug/m3 annual arithmetic mean," not to be exceeded. National PM10 Standards: "150 ug/m3 for 24 hours, not to be exceeded," more than once per year and 50 ug/m3 annual arithmetic mean "averaged over 3 years, not to be exceeded." National PM2.5 Standards: 65 ug/m3 for 24 hours based on the 98th percentile concentration averaged "over three years, not to be exceeded and" 15 ug/m3 annual arithmetic mean "averaged over 3 years, not to be exceeded."