Patent ID: 7323343

Claim:
An instrument for quantifying the concentration of nitrogen dioxide, nitrogen monoxide and ozone in an air sample, the instrument comprising: a conduit equipped with an inlet and an outlet and adapted to permit a flow of gas from said inlet to said outlet; an equilibrium altering means for changing the kinetic equilibrium within the conduit between nitrogen monoxide and nitrogen dioxide in the presence of ozone and oxygen; a control means for modulating the equilibrium altering means; and a first gas sensor for quantifying the concentration of a first gas selected from the group consisting of nitrogen dioxide, nitrogen monoxide and ozone; wherein the first gas sensor is positioned within the conduit and downstream from the equilibrium altering means, wherein the instrument is adapted to take readings of the concentration of the first gas with the first gas sensor and at a plurality of time points and to use those readings to calculate the concentration of nitrogen dioxide, nitrogen monoxide and ozone in the air sample, and wherein some of said plurality of time points occur during the alteration of the kinetics between nitrogen monoxide and nitrogen dioxide in the presence of ozone and oxygen.