Name	Notation	Description	Types	Status
Nil	0		Concept	stable
Light	1		Concept	stable
Moderate	2		Concept	stable
Severe	3		Concept	stable
Nil	4		Concept	stable
Light	5		Concept	stable
Moderate	6		Concept	stable
Severe	7		Concept	stable
Nil	8		Concept	stable
Light	9		Concept	stable
Moderate	10		Concept	stable
Severe	11		Concept	stable
Extreme, in clear air	12		Concept	stable
Extreme, in cloud	13		Concept	stable
Extreme, cloud/clear air not specified	14		Concept	stable
Light, isolated moderate	15		Concept	stable
Light, occasional moderate	16		Concept	stable
Light, frequently moderate	17		Concept	stable
Moderate, isolated severe	18		Concept	stable
Moderate, occasional severe	19		Concept	stable
Moderate, frequently severe	20		Concept	stable
Severe, isolated extreme	21		Concept	stable
Severe, occasional extreme	22		Concept	stable
Severe, frequently extreme	23		Concept	stable
Missing value	63		Concept	stable