The present invention provides a gas purification system with improved efficiency, simpler construction, cost reduction, form factor improvements, and increased durability. The controller processes temperature signals from the sensor, diagnoses the pump and heater by turning on the pump in response to a received enabling signal, calculates an absolute value of a temperature gradient of the fluid while the pump remains on, and records a passing pump diagnostic code if the absolute value of the temperature gradient exceeds a calibrated rate. The silver layer includes a first silver layer, which is arranged on the carbon layer, covers the ridges and valleys, and mainly contains spherical silver particles, and a second silver layer, which is arranged on the first silver layer and mainly contains silver flakes. The recognition of the freehand drawn lines and shapes is accomplished by comparing source segments of a source freehand drawn line to a straight line and substituting a straight line segment for a source segment if the deviation between the source segment and the straight line is below a predetermined value.