What are the National Ambient Air Quality Standards for the six criteria pollutants?

Keep in mind, the standards are periodically reviewed and sometimes may be revised, establishing new standards. The most recently established standards are as follows:

• Carbon monoxide is 9 parts per million (ppm) measured over 8 hours and 35 ppm measured over 1 hour.
• Lead is 0.15 micrograms per cubic meter of air (µg/m³) measured over a rolling 3-month average.
• Nitrogen dioxide is 100 parts per billion (ppb) measured over 1 hour and 53 ppb measured over 1 year.
• Ozone is 0.070 ppm measured over 8 hours.
• Particle pollution (PM2.5) is 12.0 µg/m³ for primary measured over 1 year and 15.0 µg/m³ for secondary measured over 1 year.
• Particle pollution (PM10) is 150 µg/m³ measured over 24 hours.
• Sulfur dioxide is 75 ppb for primary measured over 1 hour and 0.5 ppm for secondary measured over 3 hours .