A pound is a measure of mass (or monetary value). A ppm is a measure of concentration. The two measure different things and, according to basic principles of dimensional analysis, conversion from one to the other is not valid.

ppm

Residential pools: 1.0 - 3.0 ppm; Commercial pools: 3.0 ppm - 5.0 ppm; Bromine levels: 4.0 - 6.0 ppm

Zn < O.6 ppm Fe < 4.5 ppm Mn < 2.0 ppm Cu < 0.2 ppm

Carbon dioxide levels are not decreasing in the atmosphere, in fact, they are increasing.

In 1960 levels were 316 ppm.

In 1970 levels were 325 ppm.

In 1980 levels were 338 ppm.

In 1990 levels were 353 ppm.

In 2000 levels were 369 ppm.

In 2010 levels were 388 ppm.

Jan of 2012 levels were 393.09 ppm.

As of today we are at 393.68 ppm at Manua Loa.