ozone formation. Ozone and its precursors can remain in the atmosphere for 

 long periods of time and consequently are subject to long-distance transport. 



Ozone and its transport into the State from large metropolitan areas to the 

 southwest is a significant problem in Maine. The entire coastal 

 characterization area has nonattainment status with regard to ozone. Ozone 

 transport into Maine is particularly severe in the warmer months of the year, 

 when the prevailing winds are from the southwest. Automobile travel in Maine, 

 particularly in the tourist seasons, contributes to the ozone problem. The 

 Portland area, with its large number of petroleum bulk stations and terminals, 

 contributes greatly to the ozone problem through the evaporation of volatile 

 organic hydrocarbons. Measurement of ozone concentrations did not begin until 

 1976, when violations in Portland were recorded. Subsequent sampling in 1977 

 demonstrated that (1) Maine's southwestern coastal areas (south of the 

 characterization area) frequently exceeded the NAAQS , (2) local sources of 

 ozone were at least partly responsible for the violations, and (3) standard 

 violations existed quite far inland and north of the Portland area (Maine 

 Department of Environmental Protection 1979). 



Ozone is principally a public health concern. A growing concern exists that 

 ozone may be responsible for "tip burn" disease in eastern white pine. This 

 condition, which can lead to tree death, occurs at relatively low ozone 

 concentrations (i.e., lower than NAAQS requirements; personal communication 

 from R. Campana , Department of Plant and Soil Sciences, University of Maine, 

 Orono, ME; January, 1980). 



By studying data on Maine in close detail and in conjunction with data from 

 nearby States and by analyzing wind and other meteorologic factors, it was 

 determined that southern Maine is affected by transport of ozone from other 

 areas, most noticeably the metropolitan Boston area "urban plume" (Maine 

 Department of Environmental Protection 1979). 



In 1978, sampling stations for ozone were set up throughout Maine at five 

 sites in five areas. Data gathered at three stations within the 

 characterization area indicated numerous exceedances of the new ozone standard 

 (0.12 ppm) in regions 1 to 4 but none in region 5. However, since more data 

 must be collected to ensure that regions 5 and 6 have reached attainment 

 levels, the State has requested that these regions be declassified. 



In order to reduce ozone concentrations to compliance levels, it is necessary 

 to control the emission of volatile organic compounds (VOCs), the major 

 precursor of ozone. The major sources of VOC and amounts released per year in 

 Maine are listed in table 3-7. Information on methods of reducing VOCs have 

 been prepared by the Maine DEP (1979) for the Portland area (region 1). 



Effects of atmospheric deposition on coastal ecosystems . Elevated levels 

 of air pollution can reduce the quality of life in the coastal zone. The 

 systems most affected by all forms of air pollution are terrestrial 

 (especially developed areas), lacustrine, riverine, and palustrine. The 

 lacustrine system is particularly sensitive to acid rain. The marine and 

 estuarine systems may be affected directly by heavy metals that enter them via 

 precipitation. Because of the high buffering capacity of salt water, the 

 marine and estuarine systems are not generally affected by the low pH of acid 

 rain. 



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