ppmort

ppmort, short for "parts per million per year," is a unit used to express the rate of change of a concentration of a substance over time. It is commonly encountered in fields such as environmental science, atmospheric chemistry, and industrial hygiene. The "ppm" part refers to parts per million, a dimensionless quantity representing a ratio of a substance's concentration to the total concentration of the mixture. Multiplying this by "per year" indicates how much that concentration increases or decreases annually.

For example, if a pollutant in the air is increasing at a rate of 0.5 ppmort, it means that for every million parts of air, the concentration of that pollutant is increasing by 0.5 parts each year. This unit helps in quantifying slow but significant changes in chemical concentrations within a given environment. Understanding ppmort is crucial for tracking trends, predicting future concentrations, and assessing the long-term impact of various factors, such as emissions or industrial processes, on environmental quality or workplace safety. It allows for a standardized way to communicate and compare rates of change across different studies and contexts.