National Ambient Air Quality Standards (NAAQS): Difference between revisions
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The Clean Air Act is the primary federal law governing air pollution in the | The [https://www.epa.gov/laws-regulations/summary-clean-air-act Clean Air Act] is the primary federal law governing air pollution in the U.S.<ref>[https://web.archive.org/web/20250618033034/https://www.epa.gov/clean-air-act-overview/evolution-clean-air-act Evolution of the Clean Air Act.] November 12, 2024.</ref> The Clean Air Act gives the [[U.S. Environmental Protection Agency (EPA)]] authority to set and enforce limits on atmospheric levels of harmful air pollutants, including [[Particulate Matter and Coal Dust|particulate matter]] like [[Particulate Matter and Coal Dust|coal dust]]. | ||
The [[U.S. Environmental Protection Agency (EPA)|EPA]] has identified six "criteria pollutants" that must not exceed concentration thresholds known as the [https://www.epa.gov/criteria-air-pollutants/naaqs-table National Ambient Air Quality Standards (NAAQS)], pronounced as "the nacks". The criteria pollutants are [[Particulate Matter and Coal Dust|fine particulate matter (PM<sub>2.5</sub>)]] and [[Particulate Matter and Coal Dust|coarse particulate matter (PM<sub>10</sub>)]], also known as [[Particulate Matter and Coal Dust|dust]], as well as ozone (O<sub>3</sub>), lead (Pb), carbon monoxide (CO), sulfur dioxide (SO<sub>2</sub>), and nitrogen dioxide (NO<sub>2</sub>). | |||
The [[ | |||
To determine NAAQS compliance, atmospheric concentrations of criteria pollutants must be measured using designated [[General Air Monitoring|regulatory air monitors]] by an agency with the authority to do so, which in Virginia is the [[Virginia Department of Environmental Quality (VA DEQ)]]. When locations exceed the NAAQS for any of the criteria pollutants, regulatory action is triggered, including stricter permitting requirements, emission reductions plans, enforcement measures, and public health advisories. | |||
== | === Particulate Matter === | ||
* | * The [[Particulate Matter and Coal Dust|PM<sub>10</sub>]] NAAQS is a 24-hour average mass concentration of 150 μg/m<sup>3</sup>, not to be exceeded more than three times over three years.<ref name=":0">U.S. EPA, [https://www.epa.gov/criteria-air-pollutants/naaqs-table NAAQS Table].</ref> | ||
* There are two [[Particulate Matter and Coal Dust|PM<sub>2.5</sub>]] NAAQS: a 24-hour average mass concentration of 35 μg/m<sup>3</sup> and a recently revised annual average mass concentration of 9 μg/m<sup>3</sup>.<ref name=":0" /> | |||
The NAAQS are set to protect public health, including the health of more sensitive individuals such those with asthma as well as children and elders. That said, there is no known safe level of exposure to [[Particulate Matter and Coal Dust|PM<sub>2.5</sub>]], with documented health impacts below the NAAQS.<ref>Makar et al., [https://journals.lww.com/epidem/abstract/2017/09000/estimating_the_causal_effect_of_low_levels_of_fine.1.aspx Estimating the Causal Effect of Low Levels of Fine Particulate Matter on Hospitalization], ''Epidemiology'', 28, 5, 627–634, 2017.</ref> | |||
=== Limitations === | |||
== Documents == | |||
== References == | == References == | ||
Latest revision as of 08:01, 28 January 2026
The Clean Air Act is the primary federal law governing air pollution in the U.S.[1] The Clean Air Act gives the U.S. Environmental Protection Agency (EPA) authority to set and enforce limits on atmospheric levels of harmful air pollutants, including particulate matter like coal dust.
The EPA has identified six "criteria pollutants" that must not exceed concentration thresholds known as the National Ambient Air Quality Standards (NAAQS), pronounced as "the nacks". The criteria pollutants are fine particulate matter (PM2.5) and coarse particulate matter (PM10), also known as dust, as well as ozone (O3), lead (Pb), carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2).
To determine NAAQS compliance, atmospheric concentrations of criteria pollutants must be measured using designated regulatory air monitors by an agency with the authority to do so, which in Virginia is the Virginia Department of Environmental Quality (VA DEQ). When locations exceed the NAAQS for any of the criteria pollutants, regulatory action is triggered, including stricter permitting requirements, emission reductions plans, enforcement measures, and public health advisories.
Particulate Matter
- The PM10 NAAQS is a 24-hour average mass concentration of 150 μg/m3, not to be exceeded more than three times over three years.[2]
- There are two PM2.5 NAAQS: a 24-hour average mass concentration of 35 μg/m3 and a recently revised annual average mass concentration of 9 μg/m3.[2]
The NAAQS are set to protect public health, including the health of more sensitive individuals such those with asthma as well as children and elders. That said, there is no known safe level of exposure to PM2.5, with documented health impacts below the NAAQS.[3]
Limitations
Documents
References
- ↑ Evolution of the Clean Air Act. November 12, 2024.
- ↑ 2.0 2.1 U.S. EPA, NAAQS Table.
- ↑ Makar et al., Estimating the Causal Effect of Low Levels of Fine Particulate Matter on Hospitalization, Epidemiology, 28, 5, 627–634, 2017.