Putting Houston's Air Quality in Context
The Federal Government has established six National Ambient Air Quality Standards. Houston's air meets
five of the six NAAQS. The one standard that Houston is still working to attain is
ground-level ozone. For more information about
the NAAQS, visit the EPA's website:
http://www.epa.gov/air/criteria.html
Houston’s air quality
compares favorably with many other large cities, with the area attaining
five of the six standards. For comparison, Los Angeles, Washington D.C.,
Chicago, New York, Philadelphia, Phoenix, Sacramento, and Salt Lake City
only meet four or fewer of the six air quality standards.
Through concerted effort and investment, Houston has achieved an
87 percent reduction in the
ambient concentrations of
key Volatile Organic Compounds
(Benzene, Toluene, Ethylbenzene and Xylenes)
in the past 25 years. While great strides have been made, industry have
invested between $4 and 6 billion by 2012 to make further improvements in air quality. This investment is in addition to the substantial investment made in the 1990s.
The 2012 ozone design
values for all Houston area regulatory ozone monitors except for one were below the
1997 8-hour ozone standard of 0.08ppm.
Air Monitoring Comparison Values
TCEQ implemented use of the
term “air monitoring comparison values” (AMCVs) to evaluate air
monitoring data. AMCVs are chemical-specific air concentrations set to
protect human health and welfare. Exposure to an air concentration at or
below the AMCV is not likely to cause adverse health effects. AMCVs are
a collective term that refers to all values used by TCEQ to review
ambient air monitoring data. The short-term AMCV, based on acute
exposure health and welfare data, is compared to monitored
concentrations ranging from instantaneous to up to one hour. The
long-term AMCV, based on chronic health and welfare data, is used to
evaluate annual averaged monitored concentrations or annual
concentrations averaged over multiple years (if available).
In 2012, all
monitored ambient VOC concentrations that were measured in the Houston
Regional Monitoring (HRM) network were less than their respective TCEQ
AMCVs in the Houston Ship Channel area. While historical concentrations
of benzene above the annual benzene AMCV have been monitored at the
Lynchburg Ferry site in recent years, TCEQ actions (working in
cooperation with facilities that emit benzene) have resulted in
significant reductions in the annual average benzene concentrations at
this monitoring site. Since 2006, benzene levels at the Lynchburg Ferry
have declined by over 70%. In 2012, all Houston area monitoring sites
measured annual averages that were less than the long-term benzene AMCV.
Another pollutant of interest in the Houston area is 1,3-butadiene. Like
benzene, there has been a steady decline in the annual ambient
concentration of 1,3-butadiene in the Houston area. The annual ambient
concentration of 1,3-butadiene is below the TCEQ annual AMCV at all
Houston area monitors. To date the greatest reduction in ambient
1,3-butadiene levels has occurred at the Milby Park monitor. These
improved trends are the result of voluntary efforts to reduce the
emissions from nearby industrial sources closest to the Milby Park
monitor.
Our Mission Going Forward:
Maintaining and Improving Air Quality
Our on-going mission is to provide data to member companies to enable them to meet state and federal air standards. By using HRM data, our member companies can identify air control improvement projects.
Our member companies are working with the Texas Commission for Environmental Quality to take advantage of HRM member companies working with TCEQ
to develop and implement the Environmental Monitoring and Response System (EMRS)
at the Lynchburg Ferry monitor. The program in concert with the Monument
Area Air Quality Focus Group (MAAQFG) has resulted in a 70% reduction of
ambient benzene levels at the Lynchburg Ferry since 2006. This has
prompted the TCEQ to remove the Lynchburg Ferry monitoring site from the
benzene air pollutant watch list in 2009.
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