Ozone photometer

An apparatus for detecting ozone in an air sample, said apparatus comprising:

• an absorption cell comprising a bounded chamber configured to contain the air sample, wherein the absorption cell comprises a first window positioned on a first end of the chamber and a second window positioned on a second end of the chamber, wherein the absorption cell comprises an inlet port for the air sample to enter the chamber and an outlet port for the air sample to exit the chamber;
• a light source positioned on the first end of the chamber to transmit light through the chamber, wherein a wavelength of the transmitted light substantially overlaps absorption wavelength of the ozone in the air sample;
• a detector positioned on the second end of the chamber to measure attenuation of the light transmitted through the chamber, wherein the detector comprises an optical sensor for generating an electrical signal in response to the attenuation of the light;
• a scrubber positioned downstream from the outlet port of the absorption cell to remove the ozone from the air sample exiting the chamber, wherein the scrubber removing the ozone from the air sample exiting the chamber generates ozone-free air into an exhaust line;
• a first fan positioned to draw the air sample into a main line, wherein the main line connects to an inlet line to the absorption cell and the exhaust line from the scrubber, wherein the exhaust line connected to the main line is positioned downstream from the inlet line, wherein the first fan is positioned downstream from the inlet line and the exhaust line;
• a bidirectional pump comprising a second fan and a third fan for transporting the air sample and the ozone-free air into the chamber, wherein the second fan and the third fan are positioned opposing each other to operate as a reversible pump, wherein the bidirectional pump transporting the air sample into the chamber operates in a forward direction, wherein the bidirectional pump transporting the ozone-free air into the chamber operates in a reverse direction;
• a relative humidity equalizer for adjusting relative humidity of the ozone-free air transported into the chamber, wherein the adjusted relative humidity of the ozone-free air transported into the chamber is substantially equal to relatively humidity of the air sample;
• and
• a data system comprising an analog-to-digital converter for converting the electrical signal generated by the optical sensor to a digital signal and a microcontroller comprising a pump controller, pressure sensor, temperature sensor and relative humidity sensor, wherein the data system processes the digital signal to determine a density of the ozone in the air sample.

An apparatus for detecting ozone in an air sample, said apparatus comprising:

• an absorption cell comprising a bounded chamber configured to contain the air sample, wherein the absorption cell comprises a first window positioned on a first end of the chamber and a second window positioned on a second end of the chamber, wherein the absorption cell comprises an inlet port for the air sample to enter the chamber and an outlet port for the air sample to exit the chamber;
• a light source positioned on the first end of the chamber to transmit light through the chamber, wherein a wavelength of the transmitted light substantially overlaps absorption wavelength of the ozone in the air sample;
• a detector positioned on the second end of the chamber to measure attenuation of the light transmitted through the chamber, wherein the detector comprises an optical sensor for generating an electrical signal in response to the attenuation of the light;
• a scrubber positioned downstream from the outlet port of the absorption cell to remove the ozone from the air sample exiting the chamber, wherein the removing the ozone from the air sample generates ozone-free air;
• a bidirectional pump for transporting the air sample and the ozone-free air into the chamber, wherein the bidirectional pump transporting the air sample into the chamber operates in a forward direction, wherein the bidirectional pump transporting the ozone-free air into the chamber operates in a reverse direction;
• a plurality of check valves for controlling the air sample flow and the ozone-free air flow into the chamber;
• a relative humidity equalizer for adjusting relative humidity of the ozone-free air transported into the chamber, wherein the adjusted relative humidity of the ozone-free air transported into the chamber is substantially equal to relatively humidity of the air sample;
• and
• a data system comprising an analog-to-digital converter for converting the electrical signal generated by the optical sensor to a digital signal and a microcontroller comprising a pump controller, pressure sensor, temperature sensor and relative humidity sensor, wherein the data system determines from the digital signal a density of the ozone in the air sample.