One part per million is ·1 inch in 16 miles 。1 minute in two years 。1 cent in10,000 1 ounce of salt in 31 tons of potato chips 1 bad apple in 2,000 barrels of apples Mistretta USFS R-8One part per million is • 1 inch in 16 miles • 1 minute in two years • 1 cent in $10,000 • 1 ounce of salt in 31 tons of potato chips • 1 bad apple in 2,000 barrels of apples Mistretta USFS R-8