Our Work On Air Toxics Goes Unfinished
This essay is in response to: What is the most important achievement we've gained through air pollution management? What remains to be done to safeguard public health from air pollution?
The Clean Air
Act (CAA) is one of the most important and effective public health laws ever
declaration might have given a few of you a pause – given that popular
understanding is that the CAA is an environmental law. Let us, however, look at
passage, ambient air concentrations for the most common, dangerous air
pollutants (also known as criteria pollutants) have dropped considerably. Notable reductions achieved through CAA
pollution controls include 75% decreased emissions in primary particulates (PM2.5
and PM10) released directly from utility and industrial smokestacks,
50% reductions of carbon monoxide (CO), primarily through motor vehicle
controls, and 99% reductions of lead emissions from 230,000 tons to 3,000 tons.
Continued emission reductions are
anticipated for all criteria pollutants throughout the 2000 to 2020 period as a
result of the 1990 CAA Amendments. The largest predicted reductions will be in SO2
and NOx emissions, by 70.4% and 68.2% respectively.
exposures to criteria pollutants saves lives and decreases human suffering. The
reduction of PM2.5 (fine particulates) has prevented 160,000
premature deaths and 1,700,000 asthma exacerbations. Lowering ground-level
ozone and PM2.5 has prevented 84,000,000 restricted activity days.
As a former visiting nurse, these numbers mean something to me. I am grateful
that critical pollution prevention efforts will ease the discomfort of my
patients who frequently struggled to breathe on bad air days.
The under-realized potential of the CAA is most clear in the
area of limiting our exposure to hazardous air pollutants (HAPs). To better
protect public health, Congress enacted the 1990 CAA Amendments to establish highly
protective emission standards for all major HAPs sources within ten years. Yet
more than two decades later, EPA is just now issuing emission standards for
some of the largest sources of hazardous air pollution: coal- and oil-fired
electric power plants, cement kilns, and industrial boilers. These sources for
too long have escaped regulation while they emitted mercury, arsenic,
other toxic metals, and acid gases which are known neurotoxins, carcinogens, or
contribute to the production of particulate pollution, and, consequently, to cardiovascular
and respiratory illnesses.
tardiness in rule setting for controlling air toxics aside, a glaring failure
to prioritize reducing HAPs can be witnessed in the inconsistent approach to
monitoring emission levels. This is particularly true for communities that bear
the greatest burden of exposure to air toxics. Communities that abut refineries
or industrial areas, or those communities of color in which industrial areas
and high transportation areas are sited, are exposed to the highest levels of
air toxics. Sadly, too few EPA air monitors are located in these communities. The EPA weaves together the limited available
air toxic monitoring data with modeling studies to evaluate trends in hazardous
air pollutants. One modeling study is the National-Scale Air Toxic Assessment
(NATA) that combines ambient HAPs concentrations to model inhalation exposures
and associated health risks for 180 of the 187 HAPs listed under the CAA.
air toxics data collected at industrial sites that feeds into the EPA NATA is part of a largely voluntary reporting program under the
Toxics Release Inventory (TRI). Emissions
reported to the TRI are notoriously underestimated. One CAA exemption that has
enabled this under reporting is the “start-up and shut-down” clause for
industry, in which emissions that are released during plant start-up and
shut-down activities do not need to be reported. Start-ups and shut-downs happen
whenever there are repairs to equipment at industrial sites, refineries, or
power plants. They also occur when the equipment is malfunctioning. Both
situations are frequent and can be responsible for greater-than-average
releases of toxic emissions into local communities. It is precisely these types
of peak exposures to carcinogens or neurotoxins that we want to capture to
identify high-risk communities in need of air pollution interventions.
In its report, Our Nation’s Air, EPA estimates that
nearly 285 million people in the US have a cancer risk greater than 10 in 1
million attributable to air toxics exposures. The national average cancer risk
for 2002 was 36 in 1 million for all known causes. Thus, nearly 30% or 1 in
every 28,000 cases of cancer is a result of breathing air toxics from outdoor
sources over a lifetime of exposure. Reflecting on the 2010 President’s Cancer
Panel report, which asserted that "the true burden of environmentally
induced cancer has been grossly underestimated,” it is clear that the most
important work left incomplete under the CAA is addressing the dramatic health
damages caused by hazardous air pollutants.
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