Learning Center

Plain-language explanations of the measurements, sensors and numbers behind environmental monitoring.

ABC assumes the room reaches outdoor air each week. Some rooms never do, and the baseline drifts.

CO₂ for how much fresh air a room gets; PM2.5 for what is in that air. Sometimes they conflict.

CO₂ measures ventilation. VOC indicates chemicals. Neither substitutes for the other.

Ventilation has clearly fallen behind. Not dangerous, but the room needs fresh air now.

One extra molecule per thousand, and the threshold most ventilation guidance is built around.

Outdoor air is a free 420 ppm reference. Fifteen minutes in the shade tells you if the baseline is right.

A fan only helps if it pushes air in or out of the room. In a closed room it changes nothing.

Only if it brings in outdoor air. Most home units recirculate, and CO₂ keeps rising.

No. HEPA and carbon filters catch particles and some gases, but CO₂ passes straight through.

A room of houseplants absorbs a small fraction of what one person exhales. The numbers.

Sensor response time, sampling interval and room mixing each add their own delay.

Stated accuracy, placement, baseline drift and sensor type explain almost every gap.