What is the equivalent ppm of a 1% drop in oxygen in the air?

To determine the equivalent parts per million (ppm) of a 1% drop in oxygen, it's essential to first understand the relationship between percentage and ppm.

1% can be expressed as a fraction of 100, which means that 1% of any substance in a mixture corresponds to 10,000 ppm. This is because 1% equates to 1 part out of 100 parts, and when converting percent to parts per million, you multiply by 10,000 (since there are 1,000,000 parts in a whole).

When you consider a 1% decrease in oxygen levels, you're essentially looking for how many parts per million that equates to. Thus, a 1% decrease in oxygen represents a drop of 10,000 ppm.

However, in the context of oxygen in the atmosphere, which is roughly 21% by volume under normal conditions, a 1% drop would be equivalent to a decrease from 21% to 20%, hence representing a change of 10,000 ppm.

Now, if we examine the question, it consistently leads to an understanding that every 1% drop corresponds to an equivalent ppm drop, and calculating correctly reveals that dropping from 21%