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HomeMy WebLinkAboutEIR 91-01; RANCHO SANTA FE RD REALIGNMENT AND MASS GRADING; EIR; 1998-12-01Giroux & Associates Environmental Consultants DRAFT AXR QtrA.3L.ITY XME>ACT AISTALYS X S RANCHO SANTA FE ROAD BRIDGE JTOLACEMENT CITY OF CARLSBAD, CALIFORNIA Prepared for: City of Carlsbad 2075 Las Palmas Drive Carlsbad, CA 92009 Date: December 1, 1998 17744 Sky Paric Circle, Suite 210, Irvine, California 92614 - Phone (949) 851-8609 - Fax (949) 851-8612 TABLE OF COISTTEISTTS Page No. 1.0 PROJECT DESCRIPTION 1 1.1 Proposed Project 1 1.1.1 Roadway Realignment 1 1.1.2 Bridge Improvements 1 1.1.3 Project Conservation Design Elements 2 1.2 Air Quality Implications 2 2.0 ENVIRONMENTAL SETTING 4 2.1 Meteorology/Climate 4 2.2 Ambient Air Quality 5 2.2.1 Ambient Air Quality Standards (AAQS) 5 2.2.2 Baseline Air Quality ; 6 2.2.3 Sources of Pollution 8 2.2.4 Air Quality Management Planning 8 3.0 AIR QUALITY IMPACTS 12 3.1 Impact Significance Criteria 12 3.2 Constiruction Impacts 14 3.2.1 Fugitive Dust 14 3.2.2 Equipment Combustion Emissions 15 3.3 Microscale Impact Analysis 18 4.0 MITIGATION 20 5.0 REFERENCES 21 6.0 REPORT PREPARERS 22 List of Tables Table 1 - Ambient Air Quality Standards Table 2 - Oceanside Air Quality Monitoring Summary Table 3 - Emissions Factors for Construction Equipment and Vehicles Used in Grading/Compaction Table 4 - Grading/Compaction Activity Emissions Table 5 - Microscale Air Quality Impact Analysis 1-0 PROJECT DESCRIPTION 1.1 Proposed Project The City of Carlsbad's proposed Rancho Santa Fe Road improvement and bridge replacement project would realign and widen approximately 3,500 linear feet of Rancho Santa Fe Road (S-10) from two lanes to an ultimate six-lane Prime Arterial Roadway from just south of Questhaven Road to just north of Melrose Drive (Figures 1 and 2). 1.1.1 Roadway Realignment The proposed widening and realignment project is part of the City of Carlsbad's General Plan to upgrade Rancho Santa Fe Road to meet its designation as a Prime Arterial Roadway. A Prime Arterial Roadway has a 126-foot right of way containing six travel lanes, a bike lane, an 18-foot raised median, sidewalks, curb, and gutter. The new bridge over San Marcos Creek is planned to accommodate the Prime Arterial Roadway. The bridge replacement project would involve construction of a new bridge in a location west of the existing bridge. The existing bridge will be demolished. The northerly roadway approach for the new bridge(s) will be approximately 2,200 feet long and includes the reconstruction of the La Costa Meadows Drive/Rancho Santa Fe Road intersection, and reconstruction of approximately 300 feet of La Costa Meadows Drive east of the intersection. The realigned Rancho Santa Fe Road will be constructed to the full width on the east side of the median, with sidewalks, curb and gutter, and street lights from the bridge to north of Melrose Drive. The west side of the roadway will be constructed with 32 feet of paving adjacent to the median curb. The current alignment of Melrose Drive would be altered to accommodate the proposed widening of Rancho Santa Fe Road. The Melrose Drive/Rancho Santa Fe Road intersection would be moved approximately 400 feet to the north of the present intersection. Melrose Drive Would be realigned from the Cornita Drive/Melrose Drive intersection where Melrose Drive would extend to the northwest to the realigned Melrose Drive/Rancho Santa Fe Road intersection. Cornita Drive would be extended east to connect with the realigned Melrose Drive. 1.1.2 Bridge Improvements The bridge would consist of six lanes and an overall 126-foot right of way. The span over San Marcos Creek would extend for approximately 375 feet and would range in height frora 15 to 20 feet from the creek bottom to the bottom of the bridge. The bridge Orange County Mexico 1" - 8 Miles Tijuana FIGURE Regional Map BASE MAP SOURCE: USGS 7.5 Minute Series, Rancho Santa Fe Quadrangle 1" - 2000" FIGURE Vicinity Map would be supported by manufactured fill slopes at the northern and southerTi termini of the bridge. A total of twelve piers would support the bridge span. Each pier would be constructed by excavating a pit and using driven iron piers to form and cast each individual concrete pier. Following construction of the piers the excavation area would be refilled and returned to original grade. Each pier would include 4' X 6' columns and 12' X 12' footings. 1.1.3 Project Conservation Oesign Elements A number of measures have been incorporated into the project to minimize impacts to biological resources. These include: o The new bridge and abutments have been designed to avoid and minimize impacts to jurisdictional wetlands and waters of the United States wherever possible. o The project will include dedication of habitat credits in conformance with the applicable Habitat Conservation Plan (HCP). o Vegetation removal will be conducted between 15 September and 15 February immediately prior to construction to avoid avian breeding activities. o All work will be conducted during the daytime hours. 1.2 Air Quality Implications The proposed bridge improvements will modify travel patterns in the project vicinity that may have corresponding effects on air quality. Roadway realignment and bridge widening will reduce vehicular congestion that shifts travel to slower, more polluting speeds. Within the range of arterial roadway travel speeds, vehicular emissions of carbon monoxide (CO) and reactive organic gases (ROG) are inversely proportional to travel speed. If mean speeds decrease by 50 percent due to congestion, emissions per mile of travel are almost doubled. Conversely, doubling travel speeds by congestion elimination cuts the emissions of CO and ROG in half. Roadway improvements may attract additional travel that would have avoided a given area because of congestion. However, the proposed improvements would not promote more travel on Rancho Santa Fe Road than is currently planned in the City of Carlsbad Circulation Element of the General Plan. There is therefore no growth inducement that would lead to higher air emissions. Construction activities will generate temporary air pollution emissions during demolition of the existing pavement/bridge and for new construction. Because of the proximity of pollution-sensitive avian habitats, a variety of design measures, including reduced impact construction practices, will be used to minimize impacts to the extent feasible. 2.0 ENVIRONMENTAL SETTING 2.1 Meteorology/Climate The climate of Carlsbad, as with much of Southern California, is largely controlled by the semi-permanent, high pressure system near Hawaii and the moderating effects of the nearby oceanic thermal reservoir. The San Diego North County climate is characterized by cool summers, mild winters, infrequent rainfall, abundant sunshine, and comfortable humidities. Winds are generally light until mid- afternoon, when the daily sea breeze reaches maximum strength. Unfortunately, the same factors that create a highly desirable living climate combine to limit the ability of the air to disperse the air pollution generated by the population attracted, in part by the climate. Temperatures average 62 degrees Fahrenheit annually. Summer afternoons reach the upper 70s, while winter mornings drop down into the lower 40s. Because of the moderating influence of the ocean, temperature extremes over 100 degrees or much below freezing rarely, if ever, occur. Rainfall in the local area averages 11 inches per year, but moderate spatial variation may occur as a function of site exposure. Most of the rain falls from late November to early April, when the fringes of mid-latitude storms pass through Southern California. A shift in the storm track from year to year can mean the difference between a drought year with half the annual average rainfall versus a year with twice the normal total. Winds across the Carlsbad area result mainly from temperature differences between the ocean to the west and the mountains and desert to the east. These winds are steered by local topography, but they are primarily onshore by day, especially in summer, and primarily offshore at night especially in winter. The daytime sea breeze typically has its origin over open waters and thus .brings clean air across North County, and locally generated emissions have little time to undergo photochemical reactions and form smog. Similarly, the winter drainage winds blow down from nearby open higher terrain and thus arrive relatively "clean" in the local area. While daytime winds are typically strong enough to rapidly ventilate the local area, nocturnal winds often are nearly calm and thus do allow for the possible localized stagnation of air pollutants near traffic intensive sources such as Highway 78 or Interstate 5. With low background pollution levels and a relatively low overall emissions density in inland areas upwind of Carlsbad during nocturnal offshore flow, the potential for any air pollution "hot spots" under stagnation conditions is, however, minimal in the Carlsbad area. One wind pattern that does lead to occasional unhealthful air quality is when offshore winds at night in the South Coast Air Basin (SCAB) blow onshore across North County the next day, containing day-old air pollutants that already contain high levels of ozone and other irritants. This pollution recycling which sometimes occurs in late summer and early fall, may create some of the most unhealthful air quality that is observed in the otherwise typically healthful North County air quality environment. This weather pattern has not been prevalent in the last few years, and air quality has also improved dramatically in the SCAB. The Carlsbad area thus has not experienced any recent first-stage smog (ozone) alerts as sometimes occurred 10-15 years ago. In addition to the winds that control horizontal transport processes important in characterizing regional air pollution dispersion, San Diego County also has numerous temperature inversions that control the vertical extent through which pollutants can be mixed. When the onshore flow of cool, marine air undercuts a large dome of warm, sinking air with the oceanic high pressure area, it forms a marine/subsidence inversion. These inversions allow for good local mixing, but they act like a giant lid over the area. As air moves inland, sources add pollution from below without any dilution from above. The boundary between the cool air near the surface and the warm air aloft is a zone where air pollutants become concentrated. As the air moves inland and meets elevated terrain of inland foothill communities, these communities are exposed to many of the trapped pollutants within this most polluted part of the inversion layer. A second inversion type forms when cool air drifts into lower valleys at night and pools on the valley floor. These radiation inversions are strongest in winter when nights are longest and air is coldest. They may lead to stagnation of ground-level pollution sources such as automobile exhaust near freeways or major parking facilities. While these radiation inversions are prevalent in the Carlsbad area in winter, low background pollutant levels and a limited development density, as noted above, minimize the impact of these inversions on air quality. Any local air pollution problems are therefore more related to the summer marine inversions and the transport of polluted air into the local area rather than any winter microscale stagnation. 2.2 Amhif^nt Air Quality 2.2.1 Ambient Air Quality Standards (AAQS) In order to assess the air quality impact of the proposed bridge reconstruction and roadway realignment, that impact, together with baseline air quality levels, must be compared to the applicable AAQS. These standards are the levels of air quality considered safe, with an adequate margin of safety, to protect the public health and welfare. They are designed to protect that segment of the public most susceptible to respiratory distress or infection such as asthmatics, the very young, the elderly, people weak from other illness or disease, or persons in heavy work or exercise called sensitive receptors. Healthy adults can tolerate occasional exposure to air pollution levels somewhat above these standards before adverse health effects are observed. The Clean Air Act amendments of 1970 established national AAQS with states retaining the option to adopt more stringent standards or to include other pollution species. Because California already had standards in existence before federal AAQS were established, and because of unique meteorological problems in California, there is considerable diversity between state and federal standards currently in effect in California, as shown in Table 1. Further amendments to the Act promulgated in 1977 specified that all areas of the country must attain all national AAQS by 1982, with a possible extension to 1987 for some species if reasonable further progress had been demonstrated by the 1982 interim deadline. By the end of 1987, national air quality standards for ozone (O3) and carbon monoxide (CO) were still being violated in San Diego County. State standards for nitrogen dioxide (NO2) and for respirable particulate matter (PM-10) also exceeded their allowable maxima within the airshed. A new air quality planning cycle was initiated to develop an air quality plan for the San Diego Air Basin (SDAB) in response to an EPA call for a revision to the State Implementation Plan (SIP). Preparation of an air quality plan was also mandated by the California Clean Air Act (CCAA - AB- 2595) which required completion of a plan to also meet State AAQS. The Clean Air Act Amendments of 1990 ordered EPA to periodically review all AAQS in light of the most current health effects information. After extensive review, two additional national clean air standards were adopted in 1997 not included in Table 1. These standards included an 8-hour ozone exposure, and a new particulate standard for ultra-small diameter particulates of 2.5 microns or less called "PM-2.5." Attainment planning for the 8-hour ozone standard will be included in the next SIP update. For PM-2.5, it will take a number of years of monitoring data to determine the basin compliance status and any possible future PM-2.5 mitigation needed to meet the federal AAQS. 2.2.2 Baseline Air Quality Air quality in Carlsbad is best documented from measurements made at a monitoring station in Oceanside operated by the San Diego Air Pollution Control District (APCD) at 1701 Mission Avenue. Table 2 TABLE 1 Ambient Air Quality Standards STATE STANDARD FEDERAL PRIMARY STANDARD MOST RELEVANT EFFECTS AIR CONCENTRATION/ CONCENTRATION/ POLLUTANT AVERAGING TIME AVERAGING TIME Ozone 0.09 ppm, I-hr. avg. > 0.12 ppm, l-hravg.> (a) Short-temi exposures: (1) Pulmonary function decrements and localized lung edema in humans and animals. (2) Risk to public health implied by alterations in pulmonary morphology and host defense in animals; (b) Long-term exposures: Risk to public health implied by altered connective tissue metabolism and altered pulmonary morphology in animals afier long-term exposures and pulmonary function decrements in chronically exposed humans; (c) Vegetation damage; (d) Property damage Carbon Monoxide 9.0 ppm, 8-hr avg. > 20 ppm, 1-hr avg. > 9 ppm, 8-hr avg.> 35 ppm, l-hravg.> (a) Aggravation of angina pectoris and other aspects of coronary heart disease; (b) ' Decreased exercise tolerance in persons with peripheral vascular disease and lung disease; (c) impairment of central nervous system functions; (d) Possible increased risk to fetuses Nitrogen Dioxide 0.25 ppm, I-hr avg. > 0.053 ppm, ann. avg.> (a) Potential to aggravate chronic respiratory disease and respiratory symptoms in sensitive groups; (b) Risk to public health implied by pulmonary and extra-pulmonary biochemical and cellular changes and pulmonary structural changes; (c) Contribution to atmospheric discoloration Sulfur Dioxide 0.04 ppm, 24-hr avg.> 0.25 ppm, 1-hr. avg. > 0.03 ppm, ann. avg.> 0.14 ppm, 24-hr avg.> (a) Bronchoconstriction accompanied by symptoms which may include wheezing, shortness of breath and chest tightness, during exercise or physical activity in persons with asthma Suspended Particulate Matter (PMio) 30 ng/m-^, ann. geometric mean > 50 (tg/m^, 24-hr average> 50 ng/m^, annual arithmetic mean > 150^g/m^, 24-hr avg.> (a) Excess deaths firom short-term exposures and exacerbation of symptoms in sensitive patients with respiratory disease; (b) Excess seasonal declines in pulmonary function, especially in children Sulfates 25 (ig/m-^, 24-hr avg. >= (a) Decrease in ventilatory fiinction; (b) Aggravation of asthmatic symptoms; (c) Aggravation of cardio-pulmonary disease; (d) Vegetation damage; (e) Degradation of visibility; (f) Property damage Lead 1.5 ng/m^, 30-day avg. >= 1.5 ng/m^, calendar quarter> (a) Increased body burden; (b) Impairment of blood formation and nerve conduction Visibility- Reducing Particles In sufficient amount to reduce the visual range to less than 10 miles at relative humidity less than 70 percent, 8-hour average (10am - 6pm) Visibility impairment on days when relative humidity is less than 70 percent summarizes the monitoring data from the last six years, as published by the California Air Resources Board. These data show that the State standard for 10-micron diameter or less particulate matter is the most frequently exceeded (about 10 days per year, on average). The State standard for ozone is exceeded on around 6 days per year. The only federal standard exceeded in Oceanside in the last six years was an average of one (1) day with ozone levels above the national clean air standard. Standards for carbon monoxide (CO), sulfur dioxide (SO^) and nitrogen dioxide (NO2) are not exceeded. Ozone trends in coastal North County have been steadily downward from their occasionally very high maxima in the late 1970s. The last first-stage smog alert (ozone > 0.20 ppm for one hour) was in 1988. In 1994, the federal one hour ozone standard was met for the first time near Carlsbad. It continued to be met through 1997. Peak annual ozone levels from 1994-97 were within 0.02 ppm of meeting the State standard. Ultimate attainment of the more stringent State ozone standard is considered feasible in the not- too-distant future. With relatively low background levels of certain species, such as CO, directly related to automobile traffic, the data in Table 2 suggests that the Carlsbad area can accommodate considerable additional vehicular growth without significantly impacting local air quality. 2.2.3 Sources of Pollution Nitrogen oxides (NO^) and reactive organic gases (ROG) are the two precursors to photochemical smog formation. In 1995 in San Diego County, 63% of the 267 tons per day of ROG emitted come from mobile (cars, ships, planes, heavy equipment, etc.) sources. For NO^, 92% of the 233 tons emitted daily are from mobile sources. Computer modeling of smog formation has shown that a reduction of around 25% each of NO^ and ROG would allow the San Diego Air Basin to meet the federal ozone standard on days when there is no substantial transport of pollution from the South Coast Air Basin. 2.2.4 Air Quality Management Planning The continvied violations of national AAQS in the SDAB, particularly those for ozone in inland foothill areas, requires that a plan be developed outlining the pollution controls that will be undertaken to improve air quality. In San Diego County, this attainment planning process is embodied in a regional air quality management plan developed jointly by the APCD and SANDAG. Several plans had been adopted in the late 1970s and early 1980s under the title Regional Air Quality Strategies (RAQS). Until recently, the 1982 RAQS was the last federally-approved (EPA) air quality plan for attainment of the federal ozone standard. More recent planning efforts have been modifications, improvements and updates of the earlier RAQS efforts. TABLE 2 OCEANSIDE AIR (yjALITY MONITORIBG SUMMARY (days exceeding standards and aaxiaui observed concentrations) Pollutant/Standard 1992 1993 1994 1995 1996 1997 Ozone: 1-Hour > 0.09 ppa (*) 1-Hour > 0.12 ppm (**) Max 1-Hour Cone, (ppm) 12 2 ' 0.15 7 4 0.16 2 0 0.11 5 0 0.11 4 0 0.11 6 0 0.11 Carbon Monoxide: 1-Hour > 20. ppm (*) 8-Hour > 9. ppm (*/**) Max. 1-Hour Cone, (ppn) Max. 8-Hour Cone, (ppn) 0 0 7. 3.9 0 0 5. 3.3 0 0 5. 4.0 0 0 4. 3.3 0 0 4. 2.8 0 0 6. 3.0 Nitroaen Dioxide: 1-Hour > 0.25 ppn (*) Max. 1-Hour Cone, (ppi) 0 0.19 0 0.12 0 0.12 0 0.14 0 0.11 0 0.11 Sulfur Dioxide: 1-Hour >0.25 ppn (*) 24-Hour >0.04 ppn (*) Max. 1-Hour Cone, (ppm) Max. 24-Hour Cone.(ppm) 0 0 0.02 0.010 0 0 0.02 0.012'^' 0 0 0.07 0.03 0 0 0.06 0.07 0 0 0.05 0.03 0 0 0.05 Respirable Partieulates (PM-10): 24-Hour > 50 (iq/m^ (*) 24-Hour > 150 )ig/m^ ( ) Max. 24-Hr. Cone, (/ig/m^) 0/57 0/57 47. 2/61 0/61 68. 3/63 0/63 75. 4/59 0/59 80. 1/60 0/60 63. 0/60 0/60 50. Key: (a) (*) (**) (*/**) Monitoring for SO^ diseontinued in mid-1993, data from 1994-96 from downtown San Diego. Califomia state standard, not to be exceeded. National air quality standard, not to be exceeded more than once per year. State and Federal standard. Source: Califomia Air Resources Board, "California Air Quality Data" San Diego APCD (sdaped.eo.san-diego.ca.us), 1997 Vols. XXIV-XXVIII, 1992-96. The California Clean Air Act (AB-2595) required that a state clean air plan be developed to address meeting State standards as well as the often less stringent federal criteria. A basin plan was developed and adopted in 1991 that predicted attainment of all national standards by the end of 1997 due to pollution sources within the air basin, but that little can be done for the problem of interbasin transport. Since the South Coast Air Basin is predicted to exceed the national ozone standard until the year 2010, the San Diego Air Basin, will also not experience completely healthful air for the next several decades. A plan to meet the federal standard for ozone was developed in 1994 during the process of updating the 1991 state plan. This local plan was combined with those from all other California non- attainment areas with serious ozone problems to create the California State Implementation Plan (SIP). The SIP was adopted by the Air Resources Board (ARB) after public hearings on November 9- 10, 1994, and forwarded to the U. S. EPA for their approval. During the planning process and smog formation modeling, it was discovered that the SDAB can meet the federal ozone standard by the year 1999 without the creation of any new control programs. Airsheds demonstrating an ability to meet standards by 1999 (in the absence of transport from one basin to another) are classified as having a "serious" ozone problem instead of "severe". The SDAPCD requested that EPA reclassify the air basin from severe to serious. This request was subsequently approved. All progress towards attainment, including offsetting the effects of growth, is expected to derive from existing local, state and federal rules and regulations. Controversial rules previously judged by some people as overly intrusive into personal lifestyles (mandatory trip reduction programs or minimum average vehicle occupancy goals) are not needed to predict attainment. Any violations of ozone standards in the year 2000 or beyond are forecast to occur only on days when transport from the Los Angeles Basin creates substantially elevated baseline levels upon which any local basin impacts would be superimposed. A project such as the proposed bridge replacement and roadway realignment does not directly relate to the RAQS/SIP process because the project itself creates no emissions except possibly during construction. The project's long-term indirect air quality consequence lies with the volumes of traffic using the new bridge/ roadway, and how efficiently they drive through the project area. Mobile source emissions are incorporated into the air quality planning process through the growth and mobility forecasts prepared by the metropolitan planning organization (MPO). SANDAG is the MPO for San Diego County. To the extent that the proposed project is 10 consistent with SANDAG's growth and mobility forecasts, the project will be consistent with the RAQS/SIP process. Because the project improves mobility and decreases congestion, and because congestion- relief is an important component of any basinwide mobile source emissions reduction program, there is an intrinsic project consistency with RAQS/SIP by its very nature. 11 3.0 AIR OUALITY IMPACTS Project-related air quality impacts may derive . from short-term construction activities and from long-term roadway operations. Short-term impacts will result from dust generated by surface disturbance to construct bridge and realigned roadway. Such dust will create potential soiling nuisance to parked cars, landscaping/ vegetation or other surfaces. Heavy equipment (mainly diesel- powered) will generate exhaust emissions from on-site activity and on-road hauling of dirt, concrete and other construction materials. Project operations will create changes in the location of automotive pollution sources, in the number of vehicles using the roadway, and in the degree of congestion that will occur. Roadway improvements may also affect patterns of growth that were previously constrained by access limitations. Localized changes in air pollution patterns may create elevated levels of primary (unreacted) air pollutants such as carbon monoxide (CO). Localized violations of GO standards are often called "hot spots." With low background CO levels in the project vicinity, and with continuing reductions in CO emissions from the average vehicle, hot spot formation is highly unlikely. A screening level analysis was conducted to confirm this finding. Regional air quality effects from pollutants related to patterns of growth or transportation system congestion can not be analyzed on a single project basis. Such secondary pollutants require atmospheric chemical transformations that occur hours later and many miles away from the source. The impact from any single project is immeasurably small. It is the cumulative impact of the entire regional transportation system that determines the relationship between mobility and air quality. As long as any individual roadway project is consistent with the regional mobility plan and/ or transportation improvement plan/program, regional air quality impacts are presumed to be less than significant. 3.1 Impact Significance Criteria Air quality impacts are considered possibly significant under CEQA for the following reasons: 1. If they cause violations of clean air standards, 2. If they measurably increase existing violations, or, 3. If they constitute exposure of air contaminants for which there is no known safe level. 12 Criterion 2 is the most difficult to address because many pollutants require additional chemical transformation to reach their most unhealthful level. It may require many hours to complete this transformation. By the time the conversion is completed, individual project emissions will have been diluted to immeasurably small levels. It is, however, the combined effects of thousands of such infinitesimal contributions that lead to regionally degraded air quality. A number of air quality management agencies have recognized that impacts from secondary (converted) pollutants can not be individually evaluated. They have assigned significance to some specified quantity of emissions that are a surrogate for the diluted impact that will occur. In San Diego County, however, the SDAPCD has not established such an emissions-based significance threshold. The City of San Diego, in its CEQA implementation guidelines, has identified emission levels that should be considered as potentially significant. These generally apply to operational, long-term impacts and not to temporary construction activities. These criteria are: o In congested traffic areas - 550 pounds/day of CO In other areas - 100 pounds/day of ROG Federal guidelines relative to implementation of the 1990 Clean Air Act Amendments contain "de minimis" emissions thresholds at levels that are presumed not to interfere with the attainment process for national clean air standards. They are applicable to both construction and operational activity emissions. On an average daily basis, the federal thresholds are: ROG - 275 pounds/day NOx ~ 275 pounds/day CO - 550 pounds/day PM-10 - 550 pounds/day Given that there is federal involvement through resource agency permits in the proposed project that would trigger a comparison of project-related emissions to these guidelines, their use in 13 evaluating impact significance for project environmental clearance would appear well justified. The above "de minimis" criteria are thus the thresholds that have been applied to the proposed project for construction activities. For operations, the microscale air quality impact has been explicitly calculated in the project vicinity. Any regional consequence, either through growth or congestion effects, are already accommodated through project consistency with an adopted transportation improvement plan. No further regional evaluation beyond the microscale impact analysis was conducted. 3.2 Construction Impacts 3.2.1 Fugitive Dust Dust emissions were calculated based on the California ARB estimate that each acre under construction disturbance generates about 100 pounds of dust per day, if no dust control measures are implemented. Dust control measures, such- as frequent watering, paving of access roadways, and periodic street washing near construction access, as required by San Diego APCD rules, can reduce the dust generation rate by approximately 50 percent. This emission rate is for total suspended particulates (TSP). The respirable fraction of the TSP, called 10-micron diameter particulate matter, or PM-10, typically is less than one-half of "fresh" TSP dominated by larger particles. For purposes of analysis, a one-acre disturbance site was presumed to generate 25 pounds of PM-10 when the site is under active disturbance when "standard" dust control measures are utilized. If the entire construction corridor were under simultaneous disturbance to the full width of the entire corridor, the total disturbance area would be 9.2 acres. Daily regional PM-10 emissions would be approximately 230 pounds per day. Even if every square foot of the site were under simultaneous disturbance, the PM-10 emissions would still be less than the identified significance threshold. On a regional scale, daily PM-10 emissions would be considered less than significant. Given, however, the elevated PM-10 levels above the state standard in the San Diego Air Basin, these PM-10 emissions, while localized, temporary and incrementally small on a regional basis, nevertheless should be minimized to the extent feasible. With respect to regional impact significance of PM-10, current research shows that PM-10 is not a good indicator of any possibly adverse health impact from airborne particulate exp9sure. New 14 national standards for the 2.5 micron or less fraction of PM-10 called "PM-2.5" were adopted in 1997. Construction activities generate negligible levels of PM-2.5. Independent of emissions magnitude, regional dust impacts are therefore less than significant because earth disturbance creates less than one percent of the PM-2.5 found in the San Diego Air Basin atmosphere. Noticeable impacts due to construction occur in very close proximity to the disturbance. Dust deposition on parked cars, outdoor furniture or other exposed surfaces may create a soiling nuisance. Similarly, large diameter dust deposition on sensitive biotic habitats near the bridge crossing could retard plant growth. EPA studies have shown, however, that the zone of impact for heavy soiling nuisance extends 50 feet or less from the activity (EPA, AP-42, 1995). The amount of dirt-sensitive uses within such a small impact corridor is small. Except in unusual circumstances where construction occurs within only a few feet of very sensitive uses, soiling nuisance impacts will be adverse, but less than significant. 3.2.2 Equipment Combustion Emissions Equipment exhaust emissions will vary from day to day as a function of activity level. Emissions will also vary from one contractor to another as a function of equipment used for a given task. The maximum equipment activity level was assumed to occur during clearing, grading, delivery and dumping of base rock and compaction of the roadway subgrade. Table 3 lists the type of equipment likely to be in use during such activity. Table 4 combines the equipment inventory with representative load factors during typical grading/compaction activities. PM-10 emissions of 130 pounds per day and NO^ emissions of 123 pounds per day are closest to the established threshold. Each is at slightly under 50 percent of the threshold. Total daily construction activity impacts, from equipment exhaust and from fugitive dust, would not create a significant air quality impact. Indirect emissions increases could result during construction in public roadways if lane closures, detours or other interference with local traffic measurably worsened congestion on already heavily traveled roadways. A fifty percent reduction in mean travel speed may double the localized emissions of ROG and CO from impacted traffic. Limited lane closures during the a.m. and p.m. peak travel periods, and use of temporary steel plates on any excavated roadway links, is recommended to reduce any indirect congestion effects for any in-roadway construction within the existing roadway travel lanes. 15 TABLE 3 EMISSIONS FACTORS POR CONSTRDCTION EQDIPMENT AND VEHICLES DSED IN (3(ADING/C0HPACTIOH Ouan. CO ROG NOx SOX PM-10 Source Dozer Ib/hr. 1,79 0.19 4.17 0.35 0.02 AP-42, II-7.1 Backhoe Ib/hr. 0.43 0.16 2.01 0.13 0.14 AP-42, 3.3-1 Loader Ib/hr. 0.57 0.25 1.89 0.18 0.17 AP-42, II-7.1 Compactors Ib/hr. 1.01 0.08 0.06 <0.01 0.02 AP-42, II-7.2 Haul Truck lb/1000 mi. 19.84 3.42 28.04 Negl. 4.50 EMFAC7G Employee Commute lb/1000 mi. 31.81 3.35 4.54 Negl. 0.06 EMFAC7G Water Truck lb/1000 li 56.99 11.57 38.71 Negl. 4.98 EHFAC7G Key: AP-42 = EPA compilation of Air Pollutant Emission Factors (5th Ed., 1995). EHFAC7G = ARB Vehicular Emissions Computer Model (1997). TABLE 4 GRADING/COMPACTION ACTIVITY MISSIONS (Pounds/Day) Source Daily Load s CO Eaissions (poun(te/8-Hr. day) ROC NOx SOX PM-10 Dozer 501 7.2 0.8 16.7 1.4 0.1 Backhoe 501 1.7 0.6 8.0 0.5 0.6 Loader 501 2.3 1.0 • 7.6 0.7 0.7 Compactors 1001 8.1 0.6 0.5 <0.1 0.2 Haul Truck (150 trips § 20 mi/trip) 3000 mi. 59.5 10.3 8 4.1 Negl. 13.5 Employee Commute (25 empl.) § 40 liles/empl./day) 1000 mi. 31.8 3.4 4.5 Negl. 0.1 Water Truck 50 mi. 2.8 0.6 1.9 0.2 Fugitive Dust* 4.6 ae. rm _™. 115.0 Daily Total (pounds) 113.4 17.3 123.3 2.6 130.4 Significance Threshold 550 275 275 N/A 275 Exceeds Threshold (?) No No No No No = assuming a maximum of 50 percent of the entire project site is under simultaneous disturbance. 3.3 Microscale Impact Analysis In order to assess any microscale air quality implications of project implementation, a roadway air pollution dispersion calculation was performed near three intersections along Rancho Santa Fe Road. Carbon Monoxide (CO) was used to evaluate the potential for any microscale "hot spots." Worst-case meteorology and peak hour traffic conditions were combined in a Caltrans (AQTAN, 1988) roadway air pollution screening model. In 1997, maximum one-hour CO levels in Oceanside, the nearest SDAPCD air monitoring station, were 6 ppm. It would require an additional local contribution of 14 ppm to equal the most stringent California one-hour CO standard of 20 ppm. Table 5 summarizes the results of the microscale air quality impact analysis. Table 5 demonstrates that: 1. Existing maximum local CO increments at the shoulder of any project area roadway are well within acceptable standards, and, 2. Continued vehicular emissions reductions will more than offset any effects of growth or increased congestion. Horizon year CO levels will be comparable to, and generally less, than in 1998. Air quality impacts of project implementation are considered less than significant. 18 TABLE 5 MICROSCALE AIR QUALITY IMPACT ANALYSIS (Peak One-Hour CO Concentration [ppm]) AM: Rancho Santa Fe Rd./Melrose Rancho Santa Fe Rd./La Costa Meadows Rancho Santa Fe Rd./Questhaven Exist. 5.5 2.4 1.9 2015 2015 No Proj. w/Proj, 2.0 0.9 2.2 2.0 0.9 2.3 PM: Rancho Santa Fe Rd./Melrose Rancho Santa Fe Rd./La Costa Meadows Rancho Santa Fe Rd./Questhaven 3.1 2.9 1.9 2.6 1.1 2.7 2.6 1.1 2.7 Source: Caltrans Screening Procedure based upon CALINE4 Model (1988). Note: Peak background level = 6 ppm. Any microscale exposure of 14 ppm or more in the above table would indicate a potential "hot spot." 4.0 MITIGATION No significant air quality impacts were identified. Roadway operation is consistent with transportation improvement plans and microscale air quality patterns near the realigned roadway will be well within acceptable levels. Any measurable changes in air quality will be temporary during project construction. During construction, the incremental addition to pollutants at less than significant levels was considered as an adverse impact. Increased congestion on existing roadways due to construction during peak traffic hours was also a potentially adverse impact. Recommended measures to minimize project-related impact potential include: Using adequate water and/or other dust palliatives on all disturbed areas. Washing down or sweeping streets from which construction access is taken to remove dirt carried from the new alignment to the existing roadway to keep vehicles from pulverizing the dirt into fine particles. Terminating soil excavation, clearing or grading when wind speeds exceed 25 mph for an hourly average. Covering/tarping all vehicles hauling dirt or spoils on public roadways unless additional moisture is added to prevent material blow-off during transport. Requiring low-NO^-emission tune-ups for all on-site construction equipment at a minimum of every ninety (90) days. Providing rideshare or transit incentives for construction personnel. Minimizing obstruction of through traffic lanes from construction equipment or activities. Prohibiting engine idling while waiting to load or unload if the expected wait exceeds ten (10) minutes. Scheduling partial or full street closures to off-peak traffic hours. 20 5.0 REFERENCES Caltrans, 1988 - Air Quality Technical Analysis Notes, Sacramento, CA. Caltrans Materials & Research Dept. - EMFAC7F1.1 Computer model for Mobile Source Emissions (rel. 02/24/95), Sacramento, CA South Coast Air Quality Management District, 1993 - CEQA Air Quality Handbook (SCAQMD-93), El Monte, CA U.S. Environmental Protection Agency, 1995 - Compilation of Air Pollutant Emissions Factors (AP-42), Research Triangle Park, N.C. 21 6.0 REPORT PREPARERS This technical report was prepared by Hans Giroux of Giroux & Associates. Mr. Giroux has 30+ years of experience in atmospheric sciences with the last 21 years focused on air quality studies in support of environmental (CEQA/NEPA) clearance for proposed projects. He has worked extensively throughout northern San Diego County within the last two decades, including a number of projects in the Carlsbad area. Mr. Giroux has interacted with staffs of various air quality planning agencies on numerous projects, including roadway improvement projects with agencies such as SDAPCD, Caltrans, SANDAG, etc. He has been listed on the San Diego County list of qualified consultants in the area of air quality and noise since the inception of the list in 1989. 22