CO₂ Concentration

2 Day CO₂ Concentration

2 Day Wind Speed and Direction

7 Day CO₂ Concentration

7 Day Wind Speed and Direction

The measurement of atmospheric carbon dioxide (CO2) is a unique indicator of the metabolic rate of the USU campus and surrounding area. CO2 is measured as parts per million (ppm), which is numerically equivalent to micromoles of CO2 per mole of air. The SI unit for CO2 concentration is µmol per mol.

In the summer months, CO2 typically decreases during sunny, warm days as photosynthesis removes CO2 from the air.  At night, CO2 increases because plants are giving off CO2 in respiration. Local CO2 levels also change with wind direction. During the day at the USU campus, the wind is often from the west (180 to 270 degrees) and the CO2 reflects photosynthesis from vegetation or anthropogenic activity upwind of the sensor. At night, in the summer months, the prevailing wind is out of the canyon (east = 90 degrees), and CO2 levels reflect respiration upwind of the sensor. In the winter months, this daily CO2 cycle does not occur because the plants are dormant. CO2 increases to more than 450 ppm because of cars and home heating.

During inversions, the CO2 is trapped in the valley and can increase to over 500 ppm. Although CO2 is not directly harmful to people at these levels, elevated levels indicate the build-up of other air pollutants, such as PM 2.5 and ozone. Current air quality measurements for ozone and PM 2.5 are provided on the Utah Department of Environmental Quality website.

A record of the long-term, steady increase in the CO2 concentration of our atmosphere is available from NOAA.