2014-069 - Final Environmental Impact Report No. 2014-01

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HARBOR BLVD. MIXED USE TRANSIT CORRIDOR PLAN FINAL FIR CITY OF SANTA ANA 5. Environmental Analysis AIR QUALITY operating at slow speeds are the primary source of CO in the SoCAB. The highest ambient CO concentrations are generally found near traffic- congested corridors and intersections. The primary adverse health effect associated with CO is interference with normal oxygen transfer to the blood, which may result in tissue oxygen deprivation (SCAQMD 2005). The SoCAB is designated under the California and National AAQS as being in attainment of CO criteria levels (CARB 2013a). Volatile Organic Compounds (VOC) are compounds composed primarily of atoms of hydrogen and carbon. Internal combustion associated with motor vehicle usage is the major source of hydrocarbons. Other sources of VOCs include evaporative emissions associated with the use of paints and solvents, the application of asphalt paving, and the use of household consumer products such as aerosols. There are no ambient air quality standards established for VOCs. However, because they contribute to the formation of 03, the South Coast Air Quality Management District (SCAQMD) has established a significance threshold for this pollutant (SCAQMD 2005). Nitrogen Oxides (NO :) are a by- product of fuel combustion and contribute to the formation of ground level 03, PM30, and PMzs. The two major forms of NOx are nitric oxide (NO) and nitrogen dioxide (NO2). NO is a colorless, odorless gas formed from atmospheric nitrogen and oxygen when combustion takes place under high temperature and /or high pressure. The principal form of NO2 produced by combustion is NO. However, NO reacts with oxygen quickly to form NO2, creating the mixture of NO and NO2 commonly called NO.. NO2 acts as an acute irritant and is more injurious than NO in equal concentrations. At atmospheric concentrations, however, NO2 is only potentially irritating. NO2 absorbs blue light; the result is a brownish red cast to the atmosphere and reduced visibility. NO2 exposure concentrations near roadways are of particular concern for susceptible individuals, including people with asthma asthmatics, children, and the elderly. Current scientific evidence links short -term NO2 exposures, ranging from 30 minutes to 24 hours, with adverse respiratory effects, including airway inflammation in healthy people and increased respiratory symptoms in people with asthma. Also, studies show a connection between breathing elevated short -term NO2 concentrations and increased visits to emergency departments and hospital admissions for respiratory issues, especially asthma (SCAQMD 2005, EPA 2012). The SoCAB is designated an attainment area for NO2 under the National AAQS and nonattamment under the California AAQS (CA" 2013a).3 .Sulfur Dioxide (SO2) is a colorless, pungent, irritating gas formed by the combustion of sulfurous fossil fuels. It enters the atmosphere as a result of burning high - sulfur- content fuel oils and coal and from chemical processes at chemical plants and ref ncries. Gasoline and natural gas have very low sulfur content and do not release significant quantities of S02. When sulfur dioxide forms sulfates (SO4) in the atmosphere, together these pollutants are referred to as sulfur oxides (SOX). Thus, S02 is both a primary and secondary criteria air pollutant. At sufficiently high concentrations, S02 may irritate the upper respiratory tract. Current scientific evidence links short -term exposures to S02, ranging from 5 minutes to 24 hours, with an array of adverse respiratory effects, including bronchoconstriction and increased asthma symptoms. These effects are particularly important for asthmatics at elevated ventilation rates (e.g., while exercising or playing.) At lower concentrations and when combined with particulates, S02 may do greater harm by injuring lung tissue. The SoCAB is designated attainment under the California and National AAQS (CARB 2013a). I CARB has proposed to redesignate the SoCAB as attainment for NOz under the California AAQS (CARB 2013d). October 2014 Page 5.2 -3