What does the ug/g (PPM) paint chip equation calculate?

The ug/g (PPM) paint chip equation is utilized to determine the concentration of lead in paint samples. It specifically calculates the amount of lead in micrograms (ug) relative to the weight of the subsample in grams (g). This results in a measurement in parts per million (PPM), which is a common way to express very low concentrations of substances.

Using the weight of lead in micrograms allows for a clearer understanding of even small amounts of lead, which is critical when assessing lead hazards in paint, especially in environments like homes or schools where lead poisoning risks exist. The denominator, subsample weight in grams, normalizes the lead amount to provide a clear ratio of lead to the overall sample weight.

Other potential answers may refer to different measurements or units that do not accurately reflect the specifics of the PPM calculation, which focuses on micrograms of lead to grams of the subsample specifically for assessing contamination levels in paint. Hence, the choice that indicates weight in micrograms of lead divided by the subsample weight in grams correctly embodies this calculation.