May 06, 2025

AQS Reference Table

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To sort on a column, click the column header. That column will be (subtly) highlighted. Particularly useful is the search box at the top of the table on the right. Separate mulitiple search terms with a space. Search looks across all columns in the table.

Downoad a csv version: units.csv

Unit Code	Units
001	Micrograms/cubic meter (25 C)
002	Micrograms/cubic meter (0 C)
003	Nanograms/cubic meter (25 C)
004	Nanograms/cubic meter (0 C)
005	Milligrams/cubic meter (25 C)
006	Milligrams/cubic meter (0 C)
007	Parts per million
008	Parts per billion
009	COHS/1,000 linear feet
010	RUDS/10,000 linear feet
011	Meters/second
012	Miles/hour
013	Knots
014	Degrees Compass
015	Degrees Fahrenheit
016	Millibars
017	Degrees Centigrade
018	Langleys
019	Percent relative humidity
020	Microns
021	Inches (rainfall)
022	Inches (mercury)
023	Mcal/sq cm/min
024	Miles (visibility)
025	Langleys/minute
026	Degrees Rankine
027	Beta Scatter
028	Degrees Centigrade/100m
029	Millimeters (rainfall)
030	Picocuries/cubic meter
031	Microcuries/cubic meter
032	Picocuries/square meter
033	Microcuries/square meter
034	Picocuries/cubic centimeter
035	Picocuries/gram
036	Calories/square centimeter/hour
037	Degrees Kelvin
038	10,000 Fibers/cubic meter
039	Tenths of sky cover
040	Parts per 100 million
041	Mg S03/100 sq cm/month
042	RUDS/1,000 linear ft
043	Micrograms/cubic meter (21.1C)
044	Ug/sq mile/month
045	Tons/sq mile/day
046	Grams/sq meter/day
047	Ug/sq meter/day
048	1000 Particles/sq inch
049	100 Particles/sq inch
050	Number threshold levels
051	% Loss in reflectance/ month
052	Microns/week
053	# Defects/7.7 sq inches/month
054	Particles/sq millimeter/week
055	NBS color difference units
056	Microns/year
057	Condensation nuclei/cu centimeter
058	Meters
059	Millimeters (mercury)
060	Kilometers/hour
061	pH Units
062	Milligrams/liter
063	Micrograms/liter
064	Micrograms/milliliter
065	Cubic meter
066	Millisiemens/meter
067	Microequivalence/liter
068	Millisiemens/centimeter
069	Microsiemens/centimeter
070	Mg F/100 sq cm/day
071	Ug F/100 sq cm/day
072	Cubic feet/minute STP
073	Liters/minute STP
074	Pg/cubic meter(25 C)
075	Micromoles/liter
076	Liters
077	Micrograms
078	Parts per billion Carbon
079	Watts/sq meter
080	Mg S03/100 sq cm/day
081	Ug S02/sq cm/day
082	Ug S02/sq meter/day
083	Cubic meters/minute STP
084	Micrograms/gram
085	Pasquill-Gifford stability class
086	Kilometers (visibility)
087	Parts per ten million
088	Ccal/sq cm/minute
089	Mg/sq meter/hour
090	Tons/sq mile/month
091	Mg/sq cm/month
092	Ug/sq meter/month
093	Grams/sq meter/month
094	Pounds/sq mile/month
095	Mg/sq meter/week
096	Ug/sq meter/hour
097	Ug/sq cm/30 days
098	Mg S04/sq cm/30 days
099	Mg/sq cm/30 days
100	Percent hours with precip
101	Parts per million Carbon
102	Parts per billion - Mole
103	Parts per ten million Carbon
104	Parts per 100 million Carbon
105	Micrograms/cubic meter (LC)
106	Minutes
107	Percent
108	Nanograms/cubic meter (LC)
109	Milligrams/cubic meter (LC)
110	Milligrams as Nitrogen
111	Mg as CACO3
112	Milligrams/liter as CACO3
113	Milligrams/liter as Nitrogen
114	Inches (H2O)
115	Nanograms/liter
116	Temp Difference, Centigrade
117	Temp Difference, Fahrenheit
118	Liters/minute LC
119	Cubic meters/minute LC
120	Structures/Cu Cm
121	Parts per Trillion
122	Inverse 100 Megameters
123	No Units
124	Inverse Megameters
125	Nanograms
126	Cubic feet/minute LC
127	Pg/cubic meter(0 C)
128	Cubic meters/hour LC
129	Kilopascal
130	Picocuries/Liter
131	Milligrams
132	Count per cm^3
133	Cubic Feet
134	Picograms
201	Micrograms/cubic meter (20 C)
202	Centimeters of Water