U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION 9
FACT SHEET
DETERMINATION OF ATTAINMENT OF THE
CARBON MONOXIDE STANDARD FOR
THE LAS VEGAS METROPOLITAN
NONATTAINMENT AREA
May 2005
Today's Announcement
• EPA is today announcing that it is making a finding that the Las Vegas Valley nonattainment
area within Clark County, Nevada has attained the Carbon Monoxide National
Ambient Air Quality Standard by the applicable attainment date (2000) and has continued to
attain the standard since that time. Based on this final notice of attainment, EPA is finding that
the contingency measures requirement under the Clean Air Act no longer applies to the area.
Background
• There are two federal ambient health-based standards for CO: an 8-hour standard of 9 ppm
and a 1-hour standard of 35 ppm. Las Vegas Valley is currently classified as a serious
nonattainment area based on monitored violations of the 8-hour CO standard. The area has
not exceeded the 1-hour CO standard of 35 ppm since the 1970's. The 8-hour standard has
not been violated since 1998. The Las Vegas area's deadline for attaining the CO standard
was December 31, 2000.
• By means of notice-and-comment rulemaking, EPA issues attainment findings when
appropriate. These findings are based on a review of the air quality data and a verification that
the monitoring network is adequate.
-------
Las Vegas Air Quality
• There are presently no monitored exceedances of the CO health-based standard, which is 9
ppm averaged over 8 hours. Las Vegas Valley has experienced no exceedances from 1999 to
the present. The number of exceedances of the CO NAAQS has decreased from over 40 per
year in the 1980's to less than 3 per year in late 1990's. The severity of violations has also
decreased, from a high value of21 ppm in 1981 to a high value of7.3 ppmin2000. The last
exceedances of the 8-hour CO NAAQS, 10.3 ppm and 10.1 ppm, occurred in 1998 at the
Sunrise Avenue site in Las Vegas.
• The improved air quality is the direct result of Nevada's implementation of controls to reduce
CO levels, as well as tighter federal motor vehicle emission standards. The key controls
adopted by Nevada to improve air quality in the Las Vegas area include cleaner burning
gasoline regulations, an enhanced vehicle inspection and maintenance program, an alternative
iuel vehicle program, and voluntary rideshare programs. Numerous pollution reduction
measures are also in place for industrial and commercial sources. Nevada will need to continue
to implement these controls in order to maintain clean air.
Impact of CO on Public Health
• CO is a pollutant generated primarily by mobile sources, cars and trucks. Major sources of
combustion, Kke power plants, can also generate CO. CO affects people's health by entering
the bloodstream and reducing oxygen delivery to the body's organs and tissues. Exposure to
elevated levels of CO may cause loss of visual perception and manual dexterity, as well as
fatigue, chest pains, and breathing difficulties. Extreme exposures can cause loss of
consciousness and even death.
• Young children, senior citizens, pregnant women and people with asthma or heart and lung
problems are especially susceptible to the eifects of CO pollution.
What Happens Next?
• While meeting the CO standard is a notable achievement and illustrates that Clark County has
made progress toward cleaning up the air, there is still more work to be done. The state and
local air quality agencies must ensure that the area continues to meet the CO standard.
• A finding of attainment does not redesignate the area to attainment. Before an area can be
redesignated, the State must submit and EPA must approve a maintenance plan showing,
Page 2
-------
among other things, that the area will continue to maintain the standard for a 10-year period.
Additional Information
• A copy of the proposed attainment finding is available in the Air Programs section of the EPA
Region IX's website: www.epa.gov/region09/air/vegasco/
• EPA will soon publish it's final finding of attainment in the Federal Register.
• For more information, please call Amy Zimpfer, Associate Director, Air Division, U.S. EPA
Region 9 at (415) 947-4146 or Karina O'Connor, Air Quality Planner, Air Division, U.S. EPA
Region 9 at (775) 833-1276. Correspondence sent by U.S. mail should be addressed to:
Karina O'Connor
U.S. EPA, Region9, AIR-2
75 Hawthorne Street
San Francisco, CA 94105
PageS
------- |