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The Arkansas Department of Energy and Environment – Division of Environmental Quality (“DEQ”) issued a draft report titled:
Ozone Season Summary 2019 (“Report”)
The Report provides the results of DEQ sampling during Arkansas’s ozone season (May 1 – September 30).
Ozone is an irritant gas that is not emitted by any particular source. It is therefore a secondary air pollutant.
The pollutant is formed in the atmosphere in the presence of sunlight and heat from other precursor air pollutants including nitrogen oxide and hydrocarbons. Other precursor pollutants include volatile organic compounds. The photochemical reactions can vary because they are initiated by natural conditions such as sunlight and temperature which can obviously change. As a result, the rate of ground level formation can differ on an hourly, daily, or seasonal basis.
Ground level ozone is the primary component of the phenomena known as smog. It can adversely affect both human health and vegetation. The individuals most likely to be adversely affected by ozone are children and those with compromised respiratory systems. At sufficient concentration, it has been associated with harmful effects due to its oxidative properties and presence in the ambient air.
Ozone has been designated a criteria air pollutant pursuant to Section 108 and 109 of the Clean Air Act for which a National Ambient Air Quality Standard (“NAAQS”) has been established.
The states are primarily responsible for ensuring attainment and maintenance of an NAAQS once the United States Environmental Protection Agency has established them. Each state is required to formulate, subject to federal approval, an implementation plan (“SIP”) designed to achieve each NAAQS. Clean Air Act obligations include a requirement for the state to periodically sample and determine the compliance status of the ambient air in its various air quality control regions.
DEQ’s 2019 Report states that Arkansas currently operates eight ozone monitors.
Arkansas’s previous ozone season is stated to have experienced predominantly “healthy concentrations.” The Executive Summary summarizes the results:
The Little Rock‒North Little Rock‒Conway Metropolitan Statistical Areas (MSA) experienced 135 days within the Air Quality Index’s (AQI) green or “good” category, 18 days in the yellow or “moderate” category, and no days in the orange or “unhealthy for sensitive groups” category. Similarly, the Fayetteville-Springdale-Rogers MSA experienced 140 days in the green or “good” category, 13 days in the yellow or “moderate” category, and no days in the orange or “unhealthy for sensitive groups” category. The Memphis MSA, which includes Crittenden County, Arkansas, experienced 98 days in the green or “good” category, 51 days in the yellow or “moderate” category, and 4 days in the orange or “unhealthy for sensitive groups” category.
Equally important, the Report states that the entire State of Arkansas was in attainment for all NAAQS (including ozone).
A copy of the Report can be downloaded here.
