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  • Allison Stalker

Stricter Particle Pollution Standards

Updated: Aug 29, 2023

The Environmental Protection Agency (EPA) is proposing stricter standards for particle pollutants. The announcement was made on June 14, 2012 and addresses the National Ambient Air Quality Standards (NAAQS). The changes will affect fine particulate matter (PM2.5). The proposal also includes retaining the existing standards for coarse particle matter (PM10).

There are two main changes to the standards. The first one involves the range level for the standard. The current standard sets an annual health standard of 15 micrograms per cubic meter (μg/m3). The proposal would decrease this to a range of 12 μg/m3 to 13 μg/m3. This standard is used to protect the public from heath effects associated with fine particle matter exposure. In order to determine an area’s compliance with the annual health standard, the three year average of PM2.5 concentration is calculated. This value must be less than or within the proposed range. Additionally, the EPA is accepting comments on the proposed range as well as an even stricter level of 11 μg/m3. There also exists a 24-hour standard for PM2.5 concentration; however the proposed rule change seeks to maintain the current 24-hour level of 35 μg/m3.

The second proposed change deals with visibility. Currently, the secondary standard that exists for visibility is the same for both PM2.5 and PM10. The new rule proposes a separate 24-hour standard on visibility for PM2.5. Two levels are being considered for the new rule, 30 deciviews and 28 deciviews. A deciview is a yardstick for measuring visibility, the higher the level, the hazier the air. According to the EPA’s summary on the proposed rule, an area “would meet the visibility standard if the 90th percentile of 24-hour visibility index values in one year, averaged over three years, is less than or equal to the level of the standard”.

In addition to these two changes to the NAAQS, the EPA is also proposing a change to the Air Quality Index (AQI) for fine particle pollution. The proposal involves changes to the breakpoints used in determining the AQI color code. The changes are summarized in the table found on page 4 of the document found here.

The EPA states that exposure to particle pollution can lead to premature death as well as increased hospital admissions for cardiovascular and respiratory problems. It is also linked to developing chronic respiratory disease. Particle pollution also causes haze to form in the air.

Numerous sources create fine particle pollution including vehicles, smokestacks, fires, power plants and industrial processes. There are a few EPA rules that already exist which should help states meet the proposed revisions including clean diesel rules for vehicles, pollution reduction rules for power plants, and pollution reduction rules for stationary diesel engines.

It is expected that the new rule will go into effect in early 2015 and states would have until 2020 to meet the revisions. The EPA is currently taking comments on the proposed rules.

To learn more about the proposal and how to make comments, please click here.



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