The coefficient of haze (also known as smoke shade) is a measurement of visibility interference in the

atmosphere An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

. One way to measure this is to draw about 1000 cubic feet of air sample through an air filter and obtain the radiation intensity through the filter. The coefficient is then calculated based on the

absorbance Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". Alternatively, for samples which scatter light, absorbance may be defined as "the negative log ...

formula :

COH = -100 \log_ \left ( \frac \right )

where

I_1

is the radiation (400 nm light) intensity transmitted through the sampled filter, and

I_0

is the radiation intensity transmitted through a clean (control) filter.

References

Further reading