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Table 4.12-1 (continued) California and National Ambient Air Quality Standards Pollutant Averaging Cafdomia National Standards 2 - Time Standards 64 Attainment Prima oa Seconds oA Attainment Status e Primary ry Status s 0.01 ppm Unclassified/ - Vinyl Chloride 24-Hour (26 pg/m) Attainment Extinction coefficient of - 0.23 per kilometer— visibility of 10 _ miles or more Visibility- (0.07-30 Reducing Particle 8-hour miles or more Unclassified No Federal Standards Matter for Lake _ Tahoe) because of particles when the relative humidity is less than 70%. On June 20,2002,ARB approved staff recommendation to revise the PM10 annual average standard to 20 Pg/M3 and to establish an ` annual average standard for PM2.5 of 12 pg/m3. These standards took effect on July 5,2003. Information regarding these revisions can be found at<http://www.arb.ca.gov/research/aaqs/std-rs.htm>. California standards for 03,CO(except Lake Tahoe),sulfur dioxide(1-and 24-hour),nitrogen dioxide,PM(PM10 and PM2.5).and visibility-reducing particles are values that are not to be exceeded. All others are not to be equaled or exceeded. California ambient air quality standards are listed in the Table of Standards in Section 70200 of Title 17 of the California Code of Regulations. ° National standards(other than 03,PM,and those based on annual averages or annual arithmetic means)are not to be exceeded more than once a year. The 03 standard is attained when the fourth highest 8-hour concentration in a year,averaged over 3 years,is equal to or less than the standard. The PK,24-hour standard is attained when 99%of the daily concentrations,averaged over 3 years,are equal to or less than the standard. The PM2 s 24-hour standard is attained when 98%of the daily concentrations,averaged over 3 years, are equal to or less than the standard. Contact the EPA for further clarification and current federal policies. Concentration expressed first in units in which it was promulgated. Equivalent units given in parentheses are based on a reference temperature of 25"C and a reference pressure of 760 tort. Most measurements of air quality are to be corrected to a reference temperature of 25'C and a referencE!pressure of 760 torr;ppm in this table refers to ppm by volume,or micromoles of pollutant per mole of gas. National Primary Standards:The levels of air quality necessary to protect the public health. National Secondary Standards:The levels of air quality necessary to protect the public welfare from any known or anticipated adverse effects of a pollutant. ' New federal 8-hour 03 and fine PM standards were promulgated by the EPA on July 18, 1997. Contact the EPA for further clarification and current federal policies. e ARB has identified lead and vinyl chloride as toxic air contaminants with no threshold of exposure for adverse health effects determined. These actions allow for the implementation of control measures at levels below the ambient concentrations specified for these pollutants. " Unclassified(U)=a pollutant is designated unclassified if the data are incomplete and do not support a designation of attainment or nonattainment. Attainment:a pollutant is designated attainment if the state standard for that pollutant was not violated at any site in the area during a 3-year period. Nonattainment:a pollutant is designated nonattainment if there was a least one violation of a state standard for that pollutant in the area. Nonattainment/Tmnsitonal:a subcategory of the nonattainment designation. An area is designated _. nonattainment/transitional to signify that the area is close to attaining the standard for that pollutant. Sources:ARB 2004c,EPA 2004a Pursuant to the California Clean Air Act(CCAA),ARB is required to designate areas of the state as attainment, nonattainment, or unclassified with respect to applicable standards. An"Attainment"designation signifies that pollutant concentrations did not violate the applicable standard in that area. A"Nonattainment"designation indicates that a pollutant concentration violated the applicable standard at least once, excluding those occasions when a violation was caused by an exceptional event,as defined in the criteria. An"Unclassified"designation signifies that the data do not support either an attainment or nonattainment status. The CCAA divides districts EDAW College Park at Mountain House Specific Plan III Draft EIR - Air Quality 4.12-6 San Joaquin County