Air Pollution, Oxidative Stress, and Alzheimer's Disease

Table 2

National ambient air quility standards (NAAQS) for criteria air pollutants [59].

Criteria air pollutant	Primary standard		Secondary standard
	Level	Averaging Time	Level	Averaging Time
(1) Ozone	0.075 ppm (2008 std)	8 hours	Same as primary
(2) Particulate Matter			Same as primary
PM2.5	15.0 μg/m^3	Annual
	35 μg/m^3	24 hours	Same as primary
PM10	150 μg/m^3	24 hours
(3) Carbon Monoxide	9 ppm (10 mg/m^3)	8 hours	None
	35 ppm (40 mg/m^3)	1 hour
(4) Nitrogen Dioxide*	53 ppb	Annual	Same as primary
	100 ppb	1 hour	None
(5) Sulfur Dioxide	75 ppb	1 hour	0.5 ppm	3 hour
(6) Lead	0.15 μg/m^3	Rolling 3 month average	Same as primary

*Although NAAQS cover the entire group of NO_X, NO₂ is use as indicator for this group.