California Code of Regulations › Title 17 - Public Health › Division 3 - Air Resources › Chapter 1 - Air Resources Board › Subchapter 1.5 - Air Basins and Air Quality Standards › Article 2 - Ambient Air Quality Standards › Section 70100 - Definitions

Current through Register 2024 Notice Reg. No. 28, July 12, 2024
(a) Ambient Air
					 Quality Standards. Ambient air quality standards are specified concentrations
					 and durations of air pollutants which reflect the relationship between the
					 intensity and composition of pollution to undesirable effects.
(b) Most Relevant Effects. "Most Relevant
					 Effects," shown in the Table of Ambient Air Quality Standards, are the effects
					 which the standards are intended to prevent or abate.
(c) Parts Per Million (ppm). Parts per
					 million is a volumetric unit of gas concentration, which is numerically equal
					 to the volume of a gaseous contaminant present in one million volumes of
					 air.
(d) Micrograms Per Cubic Meter
					 ([MICRO]g/m3). Micrograms per cubic meter is a unit
					 of concentration which is numerically equal to the mass of a contaminant (in
					 micrograms) present in a one cubic meter sample of air, measured at EPA
					 reference conditions (corrected to 25 degrees Celsius, 760 torr). (40 CFR Part
					 50.3, November 25, 1971).
(e)
					 Equivalent Method. "Equivalent Method" is any procedure for measuring the
					 concentration of a contaminant, other than that specified in the air quality
					 standard for the contaminant, which can be shown to the satisfaction of the Air
					 Resources Board to give equivalent results at or near the level of the air
					 quality standard.
(f) Visual Range.
					 "Visual Range" is the distance at which a black object on the horizon has a 2
					 percent contrast with the horizon sky. This distance can be calculated from a
					 measured light extinction coefficient, Bext., by the formula:
					 Vr = 3.912 divided by Bext.
(g) Carbon Monoxide (CO). Carbon Monoxide is
					 a colorless gas, odorless under atmospheric conditions, having the molecular
					 form CO.
(h) Sulfur Dioxide
					 (SO2). Sulfur dioxide is a colorless, irritating gas
					 under atmospheric conditions, having the molecular form
					 SO2.
(i)
					 Suspended Particulate Matter (PM10). Suspended particulate matter (PM10) refers
					 to atmospheric particles, solid and liquid, except uncombined water as measured
					 by a (PM10) sampler which collects 50 percent of all particles of 10 [MICRO]m
					 aerodynamic diameter and which collects a declining fraction of particles as
					 their diameter increases and an increasing fraction of particles as their
					 diameter decreases, reflecting the characteristics of lung
					 deposition.
(j) Fine Suspended
					 Particulate Matter (PM2.5). Fine suspended particulate matter (PM2.5) refers to
					 suspended atmospheric particles solid and liquid, except uncombined water as
					 measured by a PM2.5 sampler which collects 50 percent of all particles of 2.5
					 [MICRO]m aerodynamic diameter and which collects a declining fraction of
					 particles as their diameter increases and an increasing fraction of particles
					 as their diameter decreases, reflecting the characteristics of lung
					 deposition.
(k) Visibility Reducing
					 Particles. Visibility reducing particles are atmospheric particles which
					 significantly scatter or absorb light. The effect of these particles on light
					 extinction is to be determined by instrumental monitoring of light scattering
					 and absorption by ARB Method V, as adopted August 18, 1989, or by an equivalent
					 method.
(l) Hydrogen Sulfide
					 (H2S). Hydrogen sulfide is a colorless gas having the
					 molecular form H2S.
(m) Nitrogen Dioxide
					 (NO2). Nitrogen dioxide is a red-brown gas, odorless
					 under atmospheric conditions, having the molecular form
					 NO2.
(n)
					 Lead (particulate). Lead (particulate) is suspended particulate matter
					 containing lead (Pb).
(o) Sulfates.
					 Sulfates are the water soluble fraction of suspended particulate matter (PM10)
					 containing the sulfate ion
					 (SO42-) including but not
					 limited to strong acids and sulfate salts, as measured by MLD Method 007 (based
					 on high-volume size-selective inlet (SSI) sampling and ion chromatography),
					 dated January 19, 1988.
(p) Vinyl
					 Chloride. Vinyl chloride is a colorless gas with the molecular form
					 CH2-CHCl; chloroethene.
(q) Ozone. Ozone is a colorless gas with a
					 pungent odor, having the molecular form O3.
(r) Extinction Coefficient. The "Extinction
					 Coefficient" of a homogenous air mass is the natural logarithm of the
					 fractional transmission of a beam of light per kilometer along the beam's
					 path.
1. New
						section filed 12-22-69; effective thirtieth day thereafter (Register 69, No.
						52).
2. Repealer and new section filed 1-27-71; effective thirtieth
						day thereafter (Register 71, No. 5).
3. Amendment of NOTE filed
						3-18-77; effective thirtieth day thereafter (Register 77, No.
						12).
4. Amendment of subsection (j) filed 7-20-83; effective
						thirtieth day thereafter (Register 83, No. 30).
5. Amendment of
						subsection (i) filed 9-5-84; effective thirtieth day thereafter (Register 84,
						No. 36).
6. Amendment filed 11-27-85; effective thirtieth day
						thereafter (Register 85, No. 48).
7. Amendment filed 3-28-86;
						effective thirtieth day thereafter (Register 86, No. 13).
8. New
						subsection (r) filed 6-28-88; effective 7-28-88 (Register 88, No.
						27).
9. Amendment of subsections (f) and (l) and new subsection (s)
						filed 9-18-89; operative 10-18-89 (Register 89, No. 39).
10.
						Amendment of subsection (k) filed 6-29-92; operative 7-29-92 (Register 92, No.
						27).
11. Amendment of subsections (d), (j), (k), (p) and (q) and
						amendment of NOTE filed 6-5-2003; operative 7-5-2003 (Register 2003, No.
						23).
12. Repealer of subsection (g), subsection relettering and
						amendment of newly designated subsections (i) and (j) filed 4-17-2006;
						operative 5-17-2006 (Register 2006, No. 16).
Note: Authority cited: Sections
						  39600,
						  39601
						  and
						  39606,
						  Health and Safety Code. Reference: Sections
						  39602
						  and
						  39606,
						  Health and Safety Code.