Clark County Department of Air Quality Ozone Advance Program Progress Report June 2015 Clark County: Ozone Advance Program Progress Report ii Clark County: Ozone Advance Program Progress Report Table of Contents 1. Introduction ........................................................................................................................................... 1-1 2. Ozone Health Effect and Sources ...................................................................................................... 2-4 3. Program Update .................................................................................................................................... 3-1 4. Emission Reductions ............................................................................................................................ 4-1 5. Conclusion ............................................................................................................................................. 5-1 iii Clark County: Ozone Advance Program Progress Report List of Figures Figure 1-2. Ozone design value history. ..................................................................................................... 1-1 Figure 1-3. Average wind speeds at McCarran (1989-2012). ................................................................... 1-2 Figure 1-4. Airflow in Clark County. .......................................................................................................... 1-3 Figure 3-1. Energy reductions in state-owned buildings. ......................................................................... 3-2 Figure 3-2. Renewable capacity. ................................................................................................................... 3-2 Figure 3-3. Renewable generation. .............................................................................................................. 3-3 Figure 3-4. DAQ outreach booth. ............................................................................................................... 3-5 Figure 4-1. Monthly SO2 reductions. .......................................................................................................... 4-2 Figure 4-2. Monthly NOx reductions. ........................................................................................................ 4-2 Figure 4-3. Monthly CO2 reductions. .......................................................................................................... 4-2 List of Tables Table 3-1. 2013 - 2014 RE Projects ............................................................................................................ 3-3 Table 3-2. Electric Vehicle Emission Reductions ..................................................................................... 3-4 Table 3-3. Emission Reduction Comparison ............................................................................................. 3-4 Table 4-1. RE Projects .................................................................................................................................. 4-1 Table 4-2. Inputs for AVERT Model ......................................................................................................... 4-1 Table 4-3. Model Outputs ............................................................................................................................ 4-2 iv Clark County: Ozone Advance Program Progress Report List of Acronyms and Abbreviations Acronyms AQR Clark County Air Quality Regulation AVERT Avoided Emissions and Generation Tool CARB California Air Resources Board CEA Consumer Electronics Association CEP Clean Energy Project, Inc. DAQ Clark County Department of Air Quality EE energy efficiency EV electric vehicle EPA U.S. Environmental Protection Agency HA hydrographic area IRTA Institute for Research and Technical Assistance NAAQS National Ambient Air Quality Standards PV photovoltaic RE renewable energy RTC Regional Transportation Commission of Southern Nevada Abbreviations CO carbon monoxide CO2 carbon dioxide kWh kilowatt-hour GWh gigawatt-hour MW megawatt MWh megawatt-hour NOx nitrogen oxides ppb parts per billion ppm parts per million VOC volatile organic compounds v Clark County: Ozone Advance Program Path Forward 1. Introduction The Clark County Department of Air Quality (DAQ) enrolled in U.S. Environmental Protection Agency (EPA) Ozone Advance program on June 12, 2013. The program’s goal is to help maintenance and attainment areas ensure continued health protection, to better position those areas to remain in attainment, and to efficiently direct available resources toward actions to address ozone and its precursors. Current Attainment Status Clark County was a maintenance area for the 1997 8-hour ozone National Ambient Air Quality Standard (NAAQS), and the 1997 NAAQS was revoked on April 6, 2015, by the 2008 ozone NAAQS implementation rule. Clark County is currently in attainment/unclassifiable for the 2008 8-hour ozone standard. By law, the state of Nevada uses hydrographic areas (HAs) to define airsheds. The Clark County ozone design value history in Figure 1-2 shows a downward trend from 2007 through 2011; however, the design values increased in 2012, 2013, and 2014. Figure 1-1. Ozone design value history. 1-1 Clark County: Ozone Advance Program Progress Report DAQ is in the process of completing exceptional event packages for wildfires that occurred in 2013. If the Region 9 office of the EPA will concur with DAQ’s findings, the design values will lower to near or under the NAAQS. Impacts of Meteorological Conditions on Ozone Concentrations High ozone events in Clark County generally occur during weather patterns characterized by high pressure. Regional wind fields are also influenced by the local terrain, which channels winds through passes, slopes, and valleys. Such slope-and-valley wind systems are local, thermally driven flow circulations created in complex terrain areas like the Las Vegas Valley. These systems directly affect the transport and dispersion of pollutants. According to historical data collected at McCarran International Airport1, the highest average wind speeds in Clark County occur in the early spring (April–May), the same months that ozone concentrations increase rapidly. Figure 1-3 shows average wind speeds during the year. Figure 1-2. Average wind speeds at McCarran (1989-2012). The northwest quadrant of the Las Vegas Valley typically experiences the highest ozone levels when Clark County experiences elevated ozone concentrations. Often stagnant flow conditions in the populated urban areas of California increase ozone concentrations, which can transport to southern Nevada and contribute to widespread exceedances throughout the Clark County network. Figure 1-4 shows the predominant airflow in Clark County; the general airflow enters from the south (following I-15) and exits to the northwest (following U.S. Highway 95). 1 http://weatherspark.com/averages/30697/Las-Vegas-Nevada-United-States. 1-2 Clark County: Ozone Advance Program Progress Report Figure 1-3. Airflow in Clark County. Several studies directed by DAQ confirmed that there is transport from Southern California into Clark County; however, the contribution from local versus transported ozone is difficult to quantify without extensive regional modeling analyses. 1-3 Clark County: Ozone Advance Program Progress Report 2. Ozone Health Effect and Sources2 Overview of Ozone Ozone (O3) is a tri-atomic ion of oxygen. In the stratosphere or upper atmosphere, ozone occurs naturally and protects the Earth’s surface from ultraviolet radiation. Ozone in the lower atmosphere is often called ground-level ozone, tropospheric ozone, or ozone pollution to distinguish it from upper-atmospheric or stratospheric ozone. Ozone occurs naturally in the lower atmosphere (troposphere) and in most locations background ozone is relatively low, well below the NAAQS. However, at higher locations in the west, background ozone can be modeled at levels approaching the NAAQS. The term “smog” is also commonly used to refer to ozone pollution. Although ozone is a component of smog, smog is a combination of ozone and airborne particles having a brownish or dirty appearance. It is possible for ozone levels to be elevated even on clear days with no obvious “smog.” In the lower atmosphere, ozone is formed when airborne chemicals, primarily nitrogen oxides (NOx) and volatile organic compounds (VOCs), combine in a chemical reaction driven by heat and sunlight. These ozone-forming chemicals are called precursors to ozone. Manmade NOx and VOC precursors contribute to ozone concentrations above natural background levels. Since ozone formation is greatest on hot, sunny days with little wind, elevated ozone concentrations occur during the warm weather months, generally April through September. In agreement with EPA’s guidance, Clark County operates certain ozone monitors year-round. Ozone Health Effects When people breathe ozone, it acts as an irritant to the lungs. Short-term, infrequent exposure to ozone can result in throat and eye irritation, difficulty drawing a deep breath, and coughing. Long-term and repeated exposure to ozone concentrations above the NAAQS can result in reduction of lung function as the cells lining the lungs are damaged. Repeated cycles of damage and healing may result in scarring of lung tissue and permanently reduced lung function. Health studies indicate that high ambient ozone concentrations may impair lung function growth in children and result in reduced lung