Introduction

Carbon dioxide is a colorless and odorless gas. It has many important uses. It is the fizz in soft drinks, beer, and sparkling wines. Carbon dioxide is released by baking powder of yeast to make cake batter rise. It is used in some fire extinguishers. Dry ice is solid carbon dioxide. Carbon dioxide is a product in cellular respiration and a reactant in photosynthesis.

But too much of a good thing, like carbon dioxide, can be bad. Carbon dioxide concentration is a surrogate for indoor pollutants that can cause drowsiness, headaches, and lower activity levels. CO₂ levels less than 600 ppm are desirable, and levels greater than 1000 ppm are generally considered indicative of inadequate ventilation. Levels of 2,500 ppm or greater can cause headaches. Unfortunately, studies indicate that many classrooms have peak CO₂ levels in excess of 2,500 ppm.

Objectives