The development of a simple, fast, disposable and low cost method for sensing and differentiating a wide range of
concentration of toxic ammonia vapor by using colorimetric sensor is reported. A large dynamic range from 10 ppm to
1,00,000 ppm is successfully classified at ambient temperature with reproducible results. The CSA strip is consists of
the dots of chemo-responsive materials, which are environmental friendly and react specifically with ammonia at
different thresholds. The pattern of color change of colorimetric sensor array is unique for reported concentration range
of ammonia gas.