In June 2007, the Environmental Protection Agency (EPA) proposed
a more stringent revision of the National Ambient Air Quality
Standards (NAAQS) for ground-level ozone, the primary component of
smog. Currently, the eight-hour ozone standard set by the EPA is 84
parts per billion (ppb). The new proposal would lower this to 75ppb
The signature on the final ruling is expected in March, and the
rule would go into effect 60 days after publication in the
Federal Register. The EPA would require each state to
designate attainment and non-attainment areas and to have a
detailed State Implementation Plan outlining how to reduce air
The revisions purportedly aim to strengthen public health safety
for asthmatics, children, and the elderly and to limit
environmental damage to vegetation and ecosystems. However, studies
have proven that the current standard is stringent enough and that
implementing a tighter standard would be extremely costly and could
actually increase some health risks. Many counties would be forced
to comply with new requirements that offer only marginal health
benefits at best. The EPA should withdraw its proposal.
Standard Is Already Stringent
Although it was contested as too stringent by the Departments of
Commerce, Energy, and Transportation and the Small Business
Administration, the eight-hour standard of 84ppb was adopted by the
EPA in 1997. The new standard was implemented despite the fact
that, at the time, EPA estimated that the social costs of
attaining 84ppb would be twice as much as the social benefits. Out of
639 monitored counties, 104 currently violate the standard, most of
them in Southern California and the coastal Northeast. If nearly
one-sixth of monitored counties cannot meet today's standard, it is
unlikely that a harsher standard will increase compliance.
The existing standard is more than sufficient to protect
public health. The laboratory studies used by the EPA to justify a
tougher standard fail to take into account the substantial
difference between ambient concentrations and personal exposure.
Federal, state, and local authorities use fixed ambient monitoring
stations to measure ozone concentrations but this does not measure
the amount of ozone people actually inhale. In other words, the EPA
sets policy based upon ambient concentration but then uses
laboratory studies based on personal exposure to validate the need
for a more stringent ozone standard.
Since ambient monitors do not consider the time that people
spend indoors, ambient concentration is 1.67 times to 2.5
times higher than personal exposure. When laboratory studies assess
the health effects of a 60ppb to 80ppb personal exposure, the
ambient concentration needed to have those effects is actually
100ppb to 134ppb. Thus, the ambient-based standards set by
the EPA are automatically stricter than the levels recommended by
There are no compelling data to warrant a stricter
standard. In laboratory tests, only two out of 30 healthy
college students experienced a temporary reduction of 10 percent in
lung function at a personal exposure of 60ppb.
Personal exposure of 51ppb, which most resembles the current
standard of 84ppb, had no negative effects on those tested.
These findings suggest that the current standard is actually too
stringent. Even the EPA recognizes that "using ambient
concentrations to determine exposure generally overestimates true
personal O3 exposures by approximately 2- to 4-fold in available
studies, resulting in attenuated risk estimates."
Ambiguous Health Effects
Lowering ground-level ozone standards is not entirely beneficial
for quality of health. The EPA distinguishes between "good" ozone
and "bad" ozone: It maintains that ground-level (or
"tropospheric") ozone is a pollutant and a health risk, while
stratospheric ozone protects the public and the environment by
shielding Earth from the Sun.
However, ground-level ozone also reduces exposure to ultraviolet
rays. In fact, Randall Lutter and Christopher Wolz suggest in
Environmental Science and Technology News that a decrease
in tropospheric ozone of 10ppb would result in increases in
cataracts and non-melanoma skin cancer. Subsequently,
tightening the ground-level ozone standard could actually
have detrimental health effects.
The EPA identifies a number of health risks associated with
breathing ozone, most of which involve harmful respiratory
effects. Still, the correlation and severity of these risks,
especially for asthma, are unclear. From 1980 to 2005, when levels
of ozone and other pollutants fell in the United States, the
number of asthmatics increased by 75 percent. In fact, some of the
lowest asthma rates in the world are found in highly polluted
developing countries in the former Soviet Union, while countries in
Western Europe have considerably higher asthma rates and relatively
lower levels of air pollution.
The lack of justified causality between smog and asthma casts
further doubt on the need for states to spend billions of dollars
to meet an EPA standard. College participants in a laboratory study
exposed to ozone levels 50 percent greater than the 84ppb standards
experienced minimal changes in lung function; moreover, these
changes were only short-term.
Economic Costs vs. Benefits
The Clean Air Act forbids the EPA from considering economic
costs when setting ozone standards; however, the EPA must still
provide a detailed cost-benefit analysis when amending NAAQS. A
reduction in ozone-level standards would make sense if the economic
benefits of better health (fewer doctor visits, fewer
inhalers, higher work and school attendance) convincingly
outweighed the costs of implementing the standard. In the Ozone
NAAQS Regulatory Impact Analysis, the EPA projects that the annual
cost of implementing an ozone standard of 70 ppb would range from
$10 billion-$22 billion while the benefits would range from a low
spectrum of $2.5 billion-$24 billion to a high spectrum of $9.7
The EPA's methodology for arriving at these estimates is
questionable. As noted above, it is extremely difficult to
determine the direct causality between lower ozone standards and
improved health benefits. If ozone does not contribute to premature
deaths, adverse health effects and missed days of work and school
as much as the EPA asserts, then the agency's estimates
of the monetary benefits of a lower ozone standard are grossly
overestimated. More study is needed in this area.
A revised standard could also increase illnesses or premature
deaths by reducing household income. By displacing expenditures for
housing, food, and other factors that are highly correlated with
improved health, the new standard could result in an estimated 833
to 2,933 premature deaths.
The EPA's cost-benefit analysis should be subjected
to more serious scrutiny on both sides of the equation.
If the EPA decides on a stricter standard, many counties will
face compliance problems. A standard of 75ppb would increase the
number of non-attainment counties (those violating the standard)
from 104 to 398; under a standard of 70ppb, the number would
increase to 533, or approximately 83 percent of all monitored
The new standards would impose a severe economic burden on the
vast majority of the nation's counties. Businesses would have less
incentive to build new plants or develop in non-attainment
counties. The U.S. Chamber of Commerce recognizes these risks,
citing a study conducted by the Force on Hemispheric Transport of
Air Pollution concluding that emissions from foreign nations
contribute significantly to ozone levels. The Chamber also says the
[N]on-attainment counties can lose federal highway and transit
funding; restrictive permit requirements deter companies from
building new plants or modifying existing ones; and mandated
federal pollution control measures inhibit business expansion as
local plans for economic development are put on hold.
A new ozone standard would affect counties all across the United
States, including counties already classified as non-attainment
areas and new regions that would be required to develop regulations
in order to comply. The counties already struggling to meet the
current standard would have the most trouble.
Furthermore, a study prepared for the National
Association of Manufacturers analyzed five specific regions
and estimated that annual attainment costs would range from $1.4
million in Salt Lake City to $9.8 billion in Atlanta, Georgia.
Complying with a lower target of 65ppb would significantly
exacerbate the financial burden, resulting in lower regional gross
domestic product, thousands of lost jobs, a drop in population, and
millions of dollars in lost state tax revenue.
It is appropriate for the EPA to consider the public health
risks associated with ground-level ozone. However, the EPA
should consider the tradeoffs involved in making the
current standard stricter. Like reducing the speed limit to 15
miles per hour, it might save more lives but would come with
extremely high economic costs.
The EPA should retract its proposal to lower the NAAQS
ground-level ozone standard from 84ppb to 75ppb or 70ppb. The
current ozone standard set by EPA is already more stringent than it
needs to be and provides more than enough leg room to protect
citizens' health. The costs of tightening the standard have
outweighed the benefits in the past, and the new proposal would
experience diminishing marginal returns: Every additional dollar
spent would yield inconsequential or even adverse health benefits.
Before the EPA forces states to adopt onerous air pollution
reduction plans, it should take this proposal off the table.
Nicolas Loris is a Research Assistant and Ben
Lieberman is Senior Policy Analyst in the Thomas A. Roe Institute for
Economic Policy Studies at The Heritage Foundation.