~ Air Quality ~

3.2.4-1 INTRODUCTION
This section of the EIR evaluates the potential impacts on air quality resulting from Township construction and operation. This section also discusses the Specific Plan project in relationship to existing plans and planning policies. Where appropriate, mitigation measures are suggested that would minimize or eliminate potentially significant air quality impacts.

3.2.4-2 SETTING
Climate
The proposed project site is located in Mendocino County, a mountainous area where most ridges, including the Willits Creek canyon, run parallel to the coast. This orientation minimizes the climatic effect of the ocean on inland valleys. Plentiful sunshine prevails in the summer and fall, and inland valleys experience hot and dry conditions. Mountainous areas experience increased precipitation with elevation and temperature fluctuations from drainage of air from the valleys. A strong diurnal pattern is typical of valley and mountain winds, with winds along the axis of the valley blowing uphill/up-valley during the day and downhill/down-valley at night. This pattern is most prevalent during calm and clear weather. The up-valley wind, or "valley wind," is the predominant wind during the day and may reach wind speeds of up to 15 miles per hour (mph) on southerly slopes; northerly slopes winds are less discernable. The down-valley wind, or "mountain wind," is dominant at night and typically reaches wind speeds of 9 mph at the surface.

Regulatory Background
Pursuant to the federal Clean Air Act (CAA) of 1970 and subsequent revisions, the U.S. Environmental Protection Agency (EPA) established federal ambient air quality standards and set emission limits for many sources of air pollutants. The federal standards were to be achieved through a scheduled extension of emission controls to all pollutant sources which came under the CAA's mandates. While major stationary sources receive individual scrutiny from local regulatory agencies and operate under conditions specified in permits issued by those agencies, mobile sources (e.g., motor vehicles, by far the largest sub-category) are regulated at the federal and state level. The State of California began to set California ambient air quality standards in 1969 under the mandate of the Mulford-Carrell Act.

The five criteria pollutants which have attracted the greatest regulatory concern nationwide are: ozone, carbon monoxide (CO), suspended particulate matter less than 10 microns in diameter (PM10), nitrogen dioxide (NO2) and sulfur dioxide (SO2). The federal and state standards for these pollutants are shown in Table 3.2.4-1.

Data collected at permanent monitoring stations are used by the EPA and the state agencies to classify regions as "attainment" or "non-attainment" for each criteria air pollutant. The 1977 CAA Amendments required each state to identify areas within its borders that did not meet the federal standards and to develop a EPA-approved State Implementation Plan (SIP), which would demonstrate attainment.

The 1990 CAA Amendments represent a major revision of the original statute. They specify new strategies for attaining federal air quality standards, including mandatory 3% annual reductions of air pollutant emissions in areas exceeding federal standards, new offset requirements for new stationary sources of air pollutants, the scheduled introduction of low-emitting cars and trucks into the motor vehicle fleet, and the development of alternatives to the private automobile as the primary means of transportation.

The California Clean Air Act (CCAA), which became effective on January 1, 1989, provided a planning framework for attainment of the state standards. Non-attainment areas in the State were required to prepare attainment plans. Such plans are required to demonstrate a 5% per year reduction (or a 15% reduction over a three-year period) in the emissions of non-attainment pollutants or their precursors, unless all feasible measures are being employed. Among the required actions by air districts for attainment plans are:

• Implement a permitting program for new stationary sources with the potential to emit 25 tons per year, designed to assure no net increase in emissions.
•  Require stringent control technology for existing sources
• Adopt control programs for area-wide and indirect sources.
• Develop a sophisticated emission inventory and analytical capabilities.
• Develop public education programs to reduce emissions from transportation and area- wide sources.

In addition, the State may impose programs independent of local air district actions, such as mandatory biennial smog checks for non-attainment air districts where such a program is not already in place.

The California Air Resources Board (CARB) coordinates and oversees both State and federal air pollution control programs in California. The CARB has divided the State into air basins. Authority for air quality management within them has been given to local Air Pollution Control Districts (APCD) which regulate stationary source emissions and develop local non-attainment plans within their jurisdiction. The Mendocino County Air Quality Management District (MCAQMD) is the local agency empowered to regulate air quality in Mendocino County, which together with Del Norte, Humbolt, Trinity, and northern Sonoma Counties make up the North Coast Air Basin (NCAB).

Air Quality Problems

Regional Air Quality Problems. The NCAB is a federal standard attainment area for the five major criteria pollutants. But State PM10 standard violations have been recorded. Controls to reduce PM10 emissions in the NCAB have been relatively successful in that major reductions in emissions and exceedances of the State PM10 standards have been observed. Fugitive dust emissions from paved and unpaved roads, farming, construction and demolition is estimated to account for 66 percent of all the particulate emissions in the NCAB. MCAQMD particulate control efforts have focused on reducing emissions from industrial sources, including lumbering and agricultural operations. Residential wood combustion has also been identified as a major contributor to PM10 emissions. Exceedances of the State PM10 standard have typically occurred in the winter months of December and January when residential wood combustion is particularly high.

Local Air Pollutant Concentrations. The air quality monitoring stations nearest the Township are in Willits. A six-year summary of the data collected at Willits are shown in Table 3.2.4-2. Violations of the State PM10 standards are evident.

Air Quality Management. The following MCAQMD rules would apply to project construction include:

1) Rule 400 (General Limitations) prohibits the discharge of air contaminants in quantities described to cause a public nuisance;

2) Rule 410 (Visible Emissions) restricts the discharge of air contaminants that result in a significant reduction in visibility; and

3) Rule 430 (Fugitive Dust Emissions) defines the proper handling, transportation, or open storage of materials to reduce the potential of airborne particulate emissions.

3.2.4-3 IMPACTS AND MITIGATION MEASURES

Brooktrails Township Specific Plan Policies

The Plan goal specifically related to air quality in the Plan area appears in the Environmental Resources Chapter of the Plan as GOAL ER-6.6-1. The Policies for implementing the Goal are central to the issue of maintaining air quality and are reiterated here to allow the reader easy reference to the actual language in the Plan.

AIR QUALITY GOAL ER-6.6-1: Ensure the continuance of good air quality conditions within the Township.

POLICY ER-6.6-1A: Establish a project approval process with the City of Willits and Airport Land Use Commission to avoid potential air polluting commercial uses at the Ells Field airport.

POLICY ER-6.6-1B:d Encourage non-motorized travel within the Township and the use of regional transit for commuting.

Standards of Significance

According to CEQA, a project would have a significant effect if it would expose sensitive receptors to substantial pollutant concentrations. For the purposes of this EIR, pollutant concentrations that would exceed federal or State ambient air quality standards would be considered significant adverse impacts.

Impact 3.2.4-1

Construction activities would generate PM10 emissions which could exceed federal and/or State ambient air quality standards, and would also result in increased emissions of ozone precursors. (PS) EPA measurements of dust emissions during construction activities provide a means of projecting worst-case impacts. About 1.2 tons of dust are emitted per acre of construction per month. About 35 percent of the dust is made up of large-diameter particulate matter, which is a soiling nuisance rather than a health threat.

The remaining fraction, PM10, produced at a rate of about 0.77 tons per acre worked per month, could aggravate respiratory problems of a sensitive population (i.e., the existing residential population) living near the construction activity. PM10 emissions would result from the travel of workers and construction materials to and from the site and from the operation of construction equipment on the site's unpaved surfaces.

The resultant ambient concentrations near construction sites, would be very dependent upon local meteorology and topography, variations in soil silt and moisture content, and the intensity of construction equipment use. But violation of the federal or State PM10 standards could result unless dust suppression measures were implemented. Furthermore, emissions of ozone precursors and other pollutants from the exhaust of mobile and stationary equipment and during the application of architectural coatings would contribute to regional ozone formation. Temporary local traffic congestion associated with construction activities could also lead to increased emissions of ozone precursors and other pollutants from vehicle exhaust.

Mitigation Measure 3.2.4-1

All construction contracts should include the following requirements:

• Water all active construction areas at least twice a day, or as needed to prevent visible dust plumes from blowing off-site.
• Use tarpaulins or other effective covers for on-site storage piles and for haul trucks that travel on public streets.
• Pave, apply water three times daily, or apply (non-toxic) soil stabilizers on all unpaved access roads, parking areas and staging areas at construction sites.
• Sweep all paved access routes, parking areas and staging areas daily (preferably with water sweepers).
• Sweep streets daily (preferably with water sweepers) if visible amounts of soil material are carried onto public streets.
• Wash trucks leaving construction site.
• Select architectural coatings with low ROG emission rates.
• Properly tune and maintain construction equipment.
• Develop a trip reduction plan to achieve a minimum average vehicle ridership (AVR) of 1.5 for construction employees.
• Utilize existing power sources (e.g., power poles) or clean fuel generators rather than temporary power generators.
• Minimize obstruction of through traffic lanes.
• Schedule operations affecting traffic for off-peak hours to the extent possible.
• Develop a traffic plan to minimize traffic flow interference from construction activities.
• If the working area of any construction site exceeds four acres at any one time, implement the following measures in addition to those above: (I)
• Apply (non-toxic) soil stabilizers to inactive construction areas.
• Enclose, cover, water twice daily, or apply (non-toxic) soil binders to exposed stockpiles.
• Limit construction site vehicle speed to 15 miles per hour (mph) on unpaved areas.
• Replant vegetation in disturbed areas as quickly as possible.

Impact 3.2.4-2

New vehicle trips, wood-burning stoves and other household-related sources in Township residences would generate CO, reactive organic compounds (ROG), NOx, PM10, and toxic air contaminants, which could worsen ambient CO, ozone and PM10, levels and marginally increase toxic-related health risks. (S)

Calculations of motor vehicle pollutant emissions were done using URBEMIS5, developed by the CARB, and peak hour project trip generation rates published in Fehr & Peers Associates' Brooktrails Township Specific Plan Draft Traffic Analysis (February 1996). While estimates of total daily vehicle miles traveled (VMT) related to trip generation were included in the Draft Traffic Analysis, detailed information on the method used to develop these estimates was not available. Therefore, the present analysis applies standard scaling factors to the PM peak trip generation estimates to derive daily trip generation estimates and uses a tally sheet summarizing the results of a Brooktrails travel data survey (referenced in TJKM's Brooktrail Access Study) to estimate trip length distributions.

Estimates of household-related emissions were based on EPA factors for wood burning emissions, Bay Area Air Quality management District factors for general "on-site" household sources (obtained from their Air Quality and Urban Development guidelines), and South Coast Air Quality Management District factors for electricity generation (obtained from their CEQA Air Quality Handbook).

As shown in Table 3.2.4-3, relative to existing air pollutant emissions from Brooktrails at the current time, daily emission increases of 3760 lb (95%) for CO, 760 lb (155%) for ROG, 610 lb (226%) for NOx and 1590 lb (261%) for PM10 would be expected by the year 2020 because the number of units would increase from 1,550 to 4,000. Relative to year 2020 air pollutant emissions from Brooktrails at current buildout (when the average emission rates from the vehicle fleet would be much lower than they are now), daily emission increases of 5620 lb for CO, 920 lb for ROG, 710 lb for NOx and 1590 lb for PM10 would be expected. All of these increases would exceed the AQMD's applicable significance criteria for a single project.

Residential wood combustion is also known to result in emissions of toxic air contaminants (TACs) such as polycyclic aromatic hydrocarbons (PACs). TACs include carcinogens and other compounds which are assessed on a continuous scale of relative health risk rather than in comparison to a single set of criteria. Research on and regulation of toxic air contaminants on both the federal and State levels have focused on emissions from major stationary sources such as industrial facilities rather than residential sources. Although TAC emission factors have been developed for residential wood burning, estimation of Toxic Risk Scores resulting from project wood stove emissions would require computer modeling of TAC dispersion from the thousands of existing and proposed project residences. The complexity of such a modeling exercise would far exceed the level of analysis common for projects of this type. Considering the widespread use of wood-burning stoves and the stagnant winter dispersion conditions common in the Willits-Brooktrails area, it would be advisable for the Mendocino County Air Pollution Control District to develop a regional model to track pollutant concentrations resulting from all wood-burning sources and to determine the additional contribution of each new residential project, similar to what other Air Districts do to set ozone standard attainment goals. What can be stated with some assurance at this time is that the use of noncatalytic wood stoves as the primary heating source for project residences, would increase project TAC emissions to the degree that project TAC impacts would have to be considered significant as a cautionary measure.

Mitigation Measures 3.2.4-2

Mobile-Source Emissions

Implement the following Transportation Demand Management measures:

Provide on-site transit stops to link the development to major in-County destinations.

• Provide ride-matching services to facilitate car pool formation among residents.
• Provide space for banking and postal services in the project commercial uses.
• Install 220V electrical outlets in each garage in anticipation of the potential future use of electrical vehicles.

• Provide heating systems powered by propane, heating oil or electricity to serve as the primary heating source of the proposed new homes, with EPA Phase II woodburning stoves available only as a back-up source.
  
• Retrofit existing residential units with clean burning Phase II catalytic wood-burning stoves.
• Install exterior electrical outlets at the front and back of each new home for electrical yard equipment.
• Incorporate passive solar design and solar heaters.

Table 3.2.4-4, below, summarizes the approximate emissions benefits from various mitigation options related to home heating. The results in the third column correspond to the total CO and PM10 emission estimates shown in Table 3.2.4-3 for Specific Plan Buildout conditions.

Note that total project-related emissions of CO and PM10 would continue to exceed the significance thresholds shown in Table 3.2.4-3 even after full implementation of heating-related mitigation measures. While implementation of other recommended measures would result in additional emissions reductions, the air quality impact would remain significant. (S)

Impact 3.2.4-3
Vehicle trips associated with Township buildout would generate CO emissions. But these CO emissions, when added to the CO background and the CO due to other future cumulative growth, would not cause violations of the federal or State CO standards at curbside. (I)

Carbon monoxide levels were modeled, using the CALINE4 computer model, at the intersections of US 101 with Sherwood Road, Commercial Street and State Route 20 (SR 20). These are the busiest intersections in the site vicinity (and, consequently, the locations where CO levels would be highest). Carbon monoxide levels were estimated for the year 1996, and the year 2020 with 4000 residential units at Brooktrails. For the intersection at Sherwood Road, future traffic volume estimates were obtained from Fehr & Peers' Brooktrails Township Specific Plan Draft Traffic Analysis. Future traffic volume estimates for the remaining two modeled intersections and existing traffic data for all three intersections were obtained from TJKM's General Plan Update Traffic Analysis. This latter document assumes somewhat greater trip generation for the future Brooktrails development than the Draft Traffic Analysis does. One-hour and eight-hour average carbon monoxide concentrations were modeled at curbside and near-curbside locations following guidelines presented in Appendix B of Caltrans' Transportation Project-Level Carbon Monoxide Protocol. As shown in Table 3.2.4-5, traffic from project development would not cause or contribute to violations of the federal or State CO standards.

Mitigation Measure 3.2.4-3
None required.