White Paper: National Ambient Air Quality Standards: Proposed Standards and Potential Impacts

EXECUTIVE SUMMARY

Issue

There are two issues: proposed standard changes for ground-level ozone and for particulate matter. The American Lung Association sued EPA to force a review of the standards. EPA has completed a round of meetings and hearings to gather input and on November 27, 1996 issued the proposed standards. Hearings are now underway. EPA is scheduled to announce a final decision on whether to change the standards in late June 1997.

NAAQ for Ozone

Ozone is a gas found throughout the atmosphere. Ozone pollution occurs when unnaturally high concentrations of ozone accumulate near the ground which results from the reaction of sunlight with a combination of ozone precursor chemicals, including Nox and VOCs.

Current:

.12 parts per million averaged over a one hour period with one exceedance allowed per yr.

Proposed Standard:

.08 parts per million measured over eight hours, possibly allowing more than one exceedance per yr.

EPA is also seeking comment on several other options, including ozone concentrations of .09 parts per million measured over eight hours, as well as a range of ozone concentrations from .07 to .12 parts per million measured over one hour, which is the current standard.

NAAQ for PM

Particulate matter is comprised of primary particles which include fugitive dust, fuel combustion products, biogenic emissions and industrial process emissions and the secondary particles which are transformed chemically in the atmosphere from gases emitted by both stationary and mobile sources.

Current

The current standard is based on particulate matter whose diameter is 10 microns or smaller (PM-10) in concentrations of 50 micrograms per cubic meter annually and 150 micrograms per cubic meter daily.

Proposed Standard

2.5 microns or smaller (PM 2.5) in concentrations of 15 micrograms per cubic meter annually and 50 micrograms per cubic meter daily.

EPA also proposed as an option to tighten the current standards for PM-10 and establishing a new standard for PM-2.5.

OVERVIEW

If either the ozone or the particulate matter standard is made more stringent, the number of non-attainment areas nationwide would increase to possibly three or more times the current number. A map of the potential for new areas in New York to record violations and be designated non-attainment is attached along with a map of those areas currently in non-attainment.

Strict new regulatory programs will be required in these non-attainment areas to control Nox and VOCs (for ozone) and Nox, VOCs and SO2 (precursors that form particulate matter 2.5 through chemical reactions in the atmosphere). Further changes may be required in the composition of motor fuels, such as reduction of sulfur in gasoline and diesel, as well as measures to reduce vehicle miles traveled.

Why the Debate Over the Changes Which Are Being Proposed

The EPA standards are in place to protect public health. The agency established a Clean Air Scientific Advisory Committee (CASAC), a panel of independent scientists, to assure that sound science was the basis for setting standards necessary to protect public health. It is accurate, though a gross oversimplification, to summarize their findings about the standards and the data to support changing the standards this way:

  1. Ozone - On the key aspect of the level for the revised NAAQS, CASAC did not reach consensus and there remain uncertainty and gaps in knowledge with regard to the analysis which is being used. CASAC emphasized the need for EPA's risk assessment to play a central role in identifying an appropriate level for the standard.

  2. Particulate Matter - CASAC urged the agency to undertake a targeted research effort to address the unanswered questions and uncertainties in the scientific questions about the potential health effects of particulate matter. Congress has allocated $18 million to EPA for this research.

Also refer to the white paper entitled Self-Regulation, Market Forces, Drive IAQ Industry.

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