What is the result of the light intensity difference measured in opacity monitoring?

The correct answer relates to the light intensity difference measured in opacity monitoring, which is directly indicative of the amount of particulate matter present in a gas stream. Opacity measurements work on the principle that as particulate matter or other pollutants increase in a gas stream, they scatter and absorb light. When a beam of light passes through a stack or duct where this gas is present, the amount of light reaching the detector on the other side will decrease in proportion to the concentration of particulates. Therefore, a higher difference in light intensity corresponds to a higher concentration of particulate matter, allowing for effective monitoring of emissions and ensuring compliance with environmental regulations.

This measurement is essential in applications such as combustion processes in boilers and exhaust systems, where it is critical to control and minimize emissions of harmful particles. Understanding this relationship enhances the ability to manage air quality and design processes that adhere to environmental standards.