The Clean Air Act created the United States Environmental Protection Agency, and invested it with the power to create a National Ambient Air Quality Standard for anthropogenic, or manmade pollution, that threatens human health. Initial standards were established in 1979 for six “criteria pollutants” including lead, sulpher dioxide, nitrogen dioxide, particulate matter, carbon monoxide, and ozone. Particulate matter is broken into two sub-categories for particles below 10 microns in size, and below 2.5 microns. The standards have been continuously tightened as more has been learned about the health hazards of pollution.
Implementation of monitoring air quality and the steps to reduce air pollution in Delaware has been handled by the Air Quality Division of the Department of Natural Resources & Environmental Control (DNREC). Action was needed. In 1980 there were over 140 days when air quality exceeded the standards with many of those days in the Unhealthy, and Very Unhealthy categories. For 2014, data from the state’s monitoring stations show compliance with the standards for all six of the criteria pollutants for the first time! In fact, pollution levels run between 90% and 20% below the standards for criteria pollutants except ozone.
The last air pollutant to meet the standard was ground level ozone which can cause breathing difficulties, especially for people with asthma or COPD. We don’t actually emit ozone directly. Ozone forms from chemical reactions from emissions from both natural and manmade sources. At this point, the primary manmade source of ozone pollution is from motor vehicles. Federal regulations already in place for improvements in fuel mileage, and tail pipe emissions should significantly reduce ozone formation in the near future.
While ozone forms year round, it only reaches high levels on hot summer days with the confluence of sunlight, heat, and humidity. To meet the standard, air quality at all seven Delaware monitoring stations must be below a maximum level based on a three year average. Most of the country now meets the ozone standard. The EPA has announced potentially tighter ozone standards moving from an 8 hour average of 75 Parts Per Billion (PPB) averaged over three years to between 65 and 70 PPB.
The Lewes air monitoring station has had the highest ambient levels of ozone despite its rural location. This report looks at the Lewes station in detail and exams air monitoring in general to determine why Lewes has high ambient levels of ozone, to suggest avenues of possible investigation to improve the accuracy of the station’s results, and to determine if the station should continue operation.
We have found some serious issues:
• The purpose of the Air Quality Standards is to determine our progress in reducing manmade air pollution based on discrete reduction steps required by regulatory action. It appears the Lewes station, and others stations in Delaware, may be at or near background levels of ambient ozone. The EPA is using data from these stations to declare Delaware a non-attainment zone requiring further expensive corrective actions when no actions can reduce background levels. This can be determined by measuring CO, methane, and Volatile Organic Compounds by species to separate natural and manmade ozone precursors.
• The Lewes station may be un-representative because of its close proximity to ocean breezes that accelerate ozone production, and to the Great Marsh which could be producing excessive methane, an ozone precursor.
• Further analysis is needed of wind speed and direction to look for a possible correlation between wind and ambient ozone levels un-characteristic of Delaware in general.
Click the link below for the full report (total: 8 pages).
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