Ultraviolet measurement of NOx emissions nixes converter needs
By Bruce Herman and Robb Vanskike Environmental awareness for
clean air becomes more important each passing year, especially
when measuring nitric oxide (NO) and nitrogen dioxide (NO2) in
stack emissions. Regulations require reporting stack NOx as a
combination of all oxides of nitrogen. NO and NO2 are distinct
measurements that can add up to report total NOx. And with
environmental awareness comes more stringent demands on NOx
measurement for lower ranges. Several methods of measuring NOx
have proven effective over the years, but a more effective way
to measure stack emissions is to use a single photometric
analyzer for simultaneous measurements of NO and NO2. The
emissions found in exhaust gases from combustion processes
contain parts-per-million (ppm) levels of NO and other oxides of
nitrogen, primarily NO2. The Clean Air Act of 1970 and its 1990
amendments emphasized the measurement of NOx. It is typical to
analyze only the NO component direct