Arizona PM2_5 Nonattainment Areas

This data set contains the PM-2.5 Nonattainment Areas in Arizona and its classification. It is intended to help provide the public with information to determine whether or not air quality within a given area is healthy. Data and geography were obtained by the United States of Environmental Protection Agency (EPA). This data layer identifies areas in the U.S. where air pollution levels have not met the National Ambient Air Quality Standards (NAAQS) for 2006 PM-2.5 and have been designated "nonattainment". The EPA Office of Air Quality Planning and Standards (OAQPS) has set National Ambient Air Quality Standards for six principal pollutants, which are called "criteria" pollutants. Under provisions of the Clean Air Act, which is intended to improve the quality of the air we breathe, EPA sets limits on how much of a pollutant can be in the air anywhere in the United States. This ensures that all Americans have the same basic health and environmental protections. The law allows individual states to have stronger pollution controls, but states are not allowed to have weaker pollution controls than those set for the whole country. EPA calls these pollutants "criteria air pollutants" because the agency has regulated them by first developing health-based criteria (science-based guidelines) as the basis for setting permissible levels. One set of limits (primary standard) protects health; another set of limits (secondary standard) is intended to prevent environmental and property damage. A geographic area that meets or does better than the primary standard is called an attainment area; areas that don't meet the primary standard are called nonattainment areas. Last Updated: July 2023 Update Frequency: When Readily Available本数据集包含亚利桑那州的细颗粒物（PM2.5）未达标区域及其分类信息，旨在为公众提供相关参考，以便其判断指定区域内的空气质量是否符合健康标准。本数据集的数据与地理信息均由美国环境保护署（Environmental Protection Agency, EPA）提供。 本数据图层可识别美国境内2006年细颗粒物（PM2.5）浓度未达到国家环境空气质量标准（National Ambient Air Quality Standards, NAAQS），且被划定为“未达标区域”的范围。美国环境保护署空气规划与标准办公室（Office of Air Quality Planning and Standards, OAQPS）针对六种主要污染物制定了国家环境空气质量标准，此类污染物被称为“标准污染物”。 依据旨在改善人类呼吸空气质量的《清洁空气法案》相关条款，美国环境保护署为全美范围内的空气污染物浓度设定了限值，此举可确保所有美国民众均能获得同等的基本健康与环境保护权益。该法案允许各州实施更为严格的污染管控措施，但严禁各州制定宽于全国统一标准的污染管控要求。美国环境保护署将此类污染物称为“标准空气污染物”，原因在于该机构在对其进行管控时，首先制定了基于健康的标准（即基于科学研究制定的指导准则），以此作为设定污染物允许浓度限值的依据。 标准分为两类：一类为“一级标准”，用于保护人体健康；另一类为“二级标准”，旨在防范环境破坏与财产损失。达到或优于一级标准的地理区域被称为“达标区域”，未达到一级标准的区域则被称为“未达标区域”。 最后更新时间：2023年7月；更新频率：可随时获取时更新