KRC has reviewed the May 2006 Request to Redesignate Bullitt, Oldham and Jefferson Counties, Kentucky Located Within The Louisville, Kentucky-Indiana, MSA 8-Hour Ozone Nonattainment Area, and offers these comments. Based on the ambient monitoring data for the 7 monitoring stations over the 2002-2005 period, the calculated values for each monitor are below the National Ambient Air Quality Standard of .085 ppm, demonstrating attainment of the 8-hour regulatory standard.
KRC acknowledges that the attainment of the standard is in part due to local and regional reductions in emission of ozone precursors, although the District is correct in stating that the overall favorable pattern of weather conditions also contributed to lower levels of ozone formation during the 2002-2005 period. Attainment of the current regulatory standard is a step towards protection of public health, but is not an appropriate endpoint, since there is a substantial body of evidence indicating that adverse health effects occur from exposure to ozone at concentrations and for the durations at and below those allowed by the current standard.
The potential health impacts of exposure to ozone air pollution are significant and include reduced pulmonary function, increased respiratory symptoms, airway hyperreactivity and airway inflammation, premature mortality, increased hospital admissions for cardiopulmonary causes, and exacerbation of bronchitis, asthma, and respiratory symptoms. The groups most at risk of experiencing adverse responses include children and adults who are active outdoors, and outdoor workers. The health benefits of reducing ambient ozone levels are substantial, including reductions in premature deaths; reduced hospitalizations related to chronic obstructive pulmonary disease, cardiovascular disease, and other respiratory diseases, including bronchitis, and asthma; and reduction in school absenteeism.
Controlled human exposure studies demonstrating decrements in pulmonary function, increased respiratory symptoms, increased airway reactivity and induction of airways inflammation in healthy and asthmatic adults exposed for 6.6 to 8 hours to 0.08 ppm ozone, suggest that peak and average exposure values below the current 8-hour standard should be achieved and not be exceeded. The regulatory approach in the current NAAQS allows the District and Commonwealth to use the 4th highest value in demonstrating attainment of the standard, so that exceedances of the standard that may have occurred (and which in fact did occur during the 2002-2005 period at several of the monitors) are ignored. The significant body of literature that has been developed regarding adverse health effects at the exposure values of the 8-hour standard spurred California to adopt a more rigorous standard.
The Health Effects Committee of the Louisville Metro Air Quality Task Force likewise acknowledged that additional reductions below the current regulatory standard are both necessary and advisable to provide the required margin of safety that allows for and compensates for scientific uncertainty, as well as the lack of precise predictions regarding the health impacts of air pollutants on a multiplicity of potentially susceptible subpopulations.
The Task Force recommended that the District Board establish an ongoing and continuous process of review of sources of ozone precursor emissions from all sectors of the economy, and develop and implement policies, practices and standards in order to continue progress towards reduction in ambient concentrations of ozone and precursor pollutants in order to protect public health with an adequate margin of safety. In the development of such policies, practices and standards, the Task Force recommended that strategies that would lower ozone concentrations and achieve lower emissions of particulate or hazardous air pollutants, should be prioritized.
KRC encourages the Louisville Metro Air Pollution Control District to move forward with the effort to achieve additional reductions below the current regulatory standard, and applauds the recognition by the District Board that attainment of the 8-hour standard is a step towards clean air in Louisville, but is not an appropriate endpoint in protection of public health from ozone exposure.