The U.S. Environmental Protection Agency (EPA) announced its revisions to the national ambient air quality standards (NAAQS) for ozone in November and proposed changes were published in the Federal Register December 17. These changes were of particular interest to League members because if an area exceeds air quality limits--and is consequently designated as being in "nonattainment"--then the federal air law can reduce federal transportation funding for local governments.
NAAQS Background
The Clean Air Act (CAA) requires EPA to set NAAQS for ozone (the main component in urban smog) and five other pollutants considered harmful to public health and the environment. In addition, it requires EPA to periodically review the standards to ensure that they provide adequate health and environmental protection. 联邦法律还要求环保局在必要时更新这些标准, a process which led to the latest proposed changes. The NAAQS are used to determine what areas are in nonattainment这意味着它们不符合联邦臭氧空气质量标准. Then, EPA sets nonattainment boundaries based on recommendations from the states. The designation can have important implications for growth and development because it gives EPA the authority to review proposed highway projects and long-range transportation plans.
Effect on Transportation Funding
如前所述,达到NAAQS会影响运输资金. 同时要求所有地区达到空气质素标准, the CAA also contains a transportation conformity requirement for these areas. With this second requirement, the CAA promotes a goal of ensuring that federal funding and project approval decisions go to transportation activities that are consistent with the law's air quality goals. The conformity process applies to metropolitan transportation plans, transportation improvement programs (TIPs), and projects funded or approved by the Federal Highway Administration (FHWA) or the Federal Transit Administration (FTA) in areas that do not meet or previously have not met air quality standards for ozone or the five other pollutants.
As required by the CAA, the N.C. Division of Air Quality (DAQ) develops a State Implementation Plan (SIP), which describes how North Carolina will keep the air clean enough so that the state does not violate the NAAQS. In the SIP, the State estimates emissions from factories, power plants, dry cleaners, bakeries, construction equipment, lawn equipment, biogenics, vehicles and other sources. 确保来源不违反标准, the law limits how much certain sources can pollute. 如果一个地区的排放超过了SIP规定的限制, 然后根据运输符合性要求, 联邦资金不能用于资助该地区的交通项目. In North Carolina, the State and municipalities share responsibilities for building and maintaining transportation infrastructure such as roads and bridges.
Ozone Standard: Current and Proposed
NAAQS include both primary and secondary standards. 初级标准规定了保护公众健康的限度, including the health of at-risk populations such as people with pre-existing heart or lung disease, children, and older adults. 二级标准设定了保护公共福利的限制, including protection against visibility impairment, damage to animals, crops, vegetation, and buildings.
In the recently-noticed standard, EPA proposed creating tougher limits by reducing both the primary and secondary standard within a range of 65-70 parts per billion (ppb) over an 8-hour average. The current standard is 75 ppb.
EPA last updated ozone standards in 2008, 将8小时测量的允许水平从80 PPB降低到75 PPB. North Carolina created air quality plans for controlling ozone in nonattainment areas and achieved the desired result; DAQ staff indicated that the whole state is currently in attainment based on the 2008 standard of 75 ppb and 2012-2014 data.
However, some North Carolina counties' current ozone levels (indicated in the map below) could exceed EPA's proposed standard, 取决于标准在建议范围内的位置. For example, if EPA chose to set the ozone standard at 65 ppb, 该州的许多地区将被拖入不达标的境地. However, only Mecklenburg County would be considered in nonattainment if the new standard was set at 70 ppb. 环保署最早要到10月份才会公布实际的标准.
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EPA projects that the vast majority of U.S. counties will meet the proposed standards by 2025 with rules and programs that are currently in place or under way. EPA will make attainment or nonattainment designations for any revised standards by October 2017. 这些指定将基于2014-2016年的空气质量数据, which DAQ staff indicated bodes well for North Carolina because the state's ozone levels will continually improve with the passage of time.
The 90-day comment period ends March 17, 2015, and EPA projects that the final standards will be signed by October 1.