**Appendix D Natural Sources** **ARB Almanac 2013 – Appendix D: Natural Sources D-2** **Appendix D Appendix D:** Natural SourcesIntroduction .........................................................................................................................................................................................................D-4Biogenic Sources ..................................................................................................................................................................................................D-5Geogenic Sources .................................................................................................................................................................................................D-9Wildfires ............................................................................................................................................................................................................ D-13**ARB Almanac 2013 – Appendix D: Natural Sources D-3** **Appendix D**D-1 Statewide Natural Source Emissions ..............................................................................................................................................D-4D-2 Natural Source Emissions - Biogenic Sources .................................................................................................................................D-6D-3 Natural Source Emissions - Geogenic Sources..............................................................................................................................D-10D-4 Natural Source Emissions - Wildfires ...........................................................................................................................................D-14List of TablesD-1 Statewide Biogenic Emissions .........................................................................................................................................................D-5D-2 Wildfires 2001-2010 .....................................................................................................................................................................D-13List of Figures**ARB Almanac 2013 – Appendix D: Natural Sources D-4** **Appendix D**IntroductionAppendix D contains estimates of emissions from natural processesoccurring in terrestrial, marine, or aquatic ecosystems. Natural sourceair emissions include a variety of compounds and occur as a resultof geologic or meteorological activity (such as petroleum seeps, orwildfires), or living processes by flora and fauna(such as emissionsfrom vegetation foliage, or from soil microbes). Emissions resultingfrom anthropogenic activities, such as soil ammonia(NH3) emissionsresulting from fertilizer application, burning of agricultural crop residues, prescribed burning of natural areas, wildfires that are managedfor resources benefit, and windblown dust from cropfields and pastures are provided in Chapter 2. Windblown dust emissions from drylake beds have not been included.For this edition of the Almanac, categories of natural sources includegeogenic (petroleum seeps) and biogenic (vegetation) sources, andwildfires. Other categories may be added in futureeditions. Naturalemissions are strongly affected by seasonal influences on factors suchas temperature and moisture conditions, or wind regimes. Emissionsduring “peak season” are often orders of magnitudegreater thanemissions during dormant periods. Emissions for some categories (forexample see Figure D-1) are therefore reported withrespect to time ofyear, in addition to annual averages. Emissions canfluctuate greatlyfrom year-to-year due to variation in meteorology or land cover/landuse. Methods for forecasting future natural emissions due to changesin climate or land cover/land use remain in the realm of on-goingscientific research, and have not been applied in this edition of theAlmanac.Category VOC NOXSOXPM10PM2.5NH3Biogenic Sources2067 0 0 0 0 0Geogenic Sources31 0 0 0 0 62Wildfires335 27 24 445 377 48Natural Sources Total2433 27 24 445 377 110Statewide**Natural Source Emissions (tons/day, annual average)***** Biogenic and geogenic emissions are not year-specific.****** Wildfire emissions reflect 10-year averages. Table D-1** **ARB Almanac 2013 – Appendix D: Natural Sources D-5** **Appendix D**Biogenic volatile organic compounds (BVOCs) are emitted into theatmosphere from terrestrial ecosystems such as vegetation. BVOCsinclude isoprene, monoterpenes, methylbutenol (MBO), and otherbiogenic VOCs (OVOCs). These compounds are of interest becauseof their roles in atmospheric chemistry and climate. In the presenceof anthropogenic NOxcompounds, isoprene has been found to playa significant role in ozone chemistry. Monoterpenesand MBO aremoderately reactive. OVOCs are a general category comprised of lessreactive compounds, such as methanol and acetone. Isoprene, monoterpenes, MBO, and a fraction of the OVOCs are considered as reactive organic gas (ROG).Plant BVOC emissions vary by compound and by ordersof magnitudeamong various plant species. BVOCs play roles in plant physiologyand chemical defense from pests and plant diseases.BVOC emissionsare strongly influenced by environmental factors such as temperatureand sunlight. Biophysical and environmental mechanisms controllingthe synthesis and emission of isoprene, monoterpenes, and MBO havebeen studied across a variety of plant species andlandscapes. Less isknown about OVOCs. As a result, the BVOC research community hasdeveloped BVOC emission models, which have been routinely appliedby the climate research, air quality, and emissionsmodeling community. A statewide model was developed to estimate BVOC emissionsfrom vegetation over the course of a calendar year.The model runsat a 4 km x 4 km spatial resolution and generates hourly emissions ofisoprene, monoterpenes, MBO, and OVOCs. Emissions from vegetation were estimated from plant species leaf mass and emission factors, and environmental adjustment algorithms representing light andtemperature dependence of BVOC emissions. Leaf massdensity estimates, used to scale emissions from leaf to landscapes, were based ongeographic information system (GIS) land use/land cover databases,species leaf weight factors, and monthly satelliteleaf area index (LAI)Biogenic Sourcesdata. Temporal and spatial variation in the model was driven bymonthly estimates of leaf mass densities and hourlylight and temperature. The annual statewide emission of BVOC (reported here asROG) is estimated to be over 750,000 tons, composedof 37 percentisoprene, 30 percent MBO, 24 percent monoterpenes,and 9 percentOVOC. As shown in Figure D-1, the majority of biogenic emissions areproduced during the ozone season (May through October).Statewide Biogenic Emissions0100020003000400050006000JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

tons ROG/day**Figure D-1 ARB Almanac 2013 – Appendix D: Natural Sources** **D-6 Appendix D** Natural Source Emissions - Biogenic Sources**(tons/day, annual average) Table D-2** COUNTY AIR BASIN DISTRICTVOC**Alameda San Francisco Bay Area Bay Area AQMD 11** **Alpine Great Basin Valleys Great Basin Unifi ed APCD 9 Amador Mountain Counties Amador County APCD 15** **Butte Sacramento Valley Butte County AQMD 41 Calaveras Mountain Counties Calaveras County APCD 38** **Colusa Sacramento Valley Colusa County APCD 22 Contra Costa San Francisco Bay Area Bay Area AQMD** **11 Del Norte North Coast North Coast Unifi ed AQMD 24** **El Dorado Lake Tahoe El Dorado County APCD 2 El Dorado Mountain Counties El Dorado County APCD 49** **Fresno San Joaquin Valley San Joaquin Valley Unifi ed APCD 63 Glenn Sacramento Valley Glenn County APCD 17** **Humboldt North Coast North Coast Unifi ed AQMD 81 Imperial Salton Sea Imperial County APCD 3** **Inyo Great Basin Valleys Great Basin Unifi ed APCD 7 Kern Mojave Desert Kern County APCD 23** **Kern San Joaquin Valley San Joaquin Valley Unifi ed APCD 18 Kings San Joaquin Valley San Joaquin Valley Unifi ed APCD 4** **Lake Lake County Lake County AQMD 55 Lassen Northeast Plateau Lassen County APCD 56** **Los Angeles Mojave Desert Antelope Valley AQMD 6 Los Angeles South Coast South Coast AQMD 30** **Madera San Joaquin Valley San Joaquin Valley Unifi ed APCD 38 Marin San Francisco Bay Area Bay Area AQMD** **7 Mariposa Mountain Counties Mariposa County APCD 35** **Mendocino North Coast Mendocino County AQMD 117 Merced San Joaquin Valley San Joaquin Valley Unifi ed APCD 6** **Modoc Northeast Plateau Modoc County APCD 54 Mono Great Basin Valleys Great Basin Unifi ed APCD 21** **Monterey North Central Coast Monterey Bay Unifi ed APCD 50 ARB Almanac 2013 – Appendix D: Natural Sources** **D-7 Appendix D** COUNTY AIR BASIN DISTRICTVOC**Napa San Francisco Bay Area Bay Area AQMD 26** **Nevada Mountain Counties Northern Sierra AQMD 36 Orange South Coast South Coast AQMD 9** **Placer Lake Tahoe Placer County APCD 1 Placer Mountain Counties Placer County APCD 26** **Placer Sacramento Valley Placer County APCD 7 Plumas Mountain Counties Northern Sierra AQMD 43** **Riverside Mojave Desert Mojave Desert AQMD 0 Riverside Mojave Desert South Coast AQMD 0** **Riverside Salton Sea South Coast AQMD 7 Riverside South Coast South Coast AQMD 22** **Sacramento Sacramento Valley Sacramento Metropolitan AQMD 10 San Benito North Central Coast Monterey Bay Unifi ed APCD 17** **San Bernardino Mojave Desert Mojave Desert AQMD 6 San Bernardino South Coast South Coast AQMD 15** **San Diego San Diego San Diego County APCD 67 San Francisco San Francisco Bay Area Bay Area AQMD** **1 San Joaquin San Joaquin Valley San Joaquin Valley Unifi ed APCD 8** **San Luis Obispo South Central Coast San Luis Obispo County APCD 32 San Mateo San Francisco Bay Area Bay Area AQMD** **7 Santa Barbara South Central Coast Santa Barbara County APCD 35** **Santa Clara San Francisco Bay Area Bay Area AQMD 29** **Santa Cruz North Central Coast Monterey Bay Unifi ed APCD 5 Shasta Sacramento Valley Shasta County AQMD 166** **Sierra Mountain Counties Northern Sierra AQMD 17 Siskiyou Northeast Plateau Siskiyou County APCD 159** **Solano Sacramento Valley Yolo/Solano AQMD 4 Solano San Francisco Bay Area Bay Area AQMD** **3 Sonoma North Coast Northern Sonoma County APCD 23** **Sonoma San Francisco Bay Area Bay Area AQMD 10** Natural Source Emissions - Biogenic Sources**(tons/day, annual average)**(Cont)**Table D-2 (Cont) ARB Almanac 2013 – Appendix D: Natural Sources** **D-8 Appendix D** COUNTY AIR BASIN DISTRICTVOC**Stanislaus San Joaquin Valley San Joaquin Valley Unifi ed APCD 12 Sutter Sacramento Valley Feather River AQMD 3** **Tehama Sacramento Valley Tehama County APCD 66 Trinity North Coast North Coast Unifi ed AQMD 118** **Tulare San Joaquin Valley San Joaquin Valley Unifi ed APCD 61 Tuolumne Mountain Counties Tuolumne County APCD 46** **Ventura South Central Coast Ventura County APCD 26 Yolo Sacramento Valley Yolo/Solano AQMD 15** **Yuba Sacramento Valley Feather River AQMD 15**Natural Source Emissions - Biogenic Sources**(tons/day, annual average)**(Cont)**Table D-2 (Cont)***** Biogenic emissions are not year-specific. ARB Almanac 2013 – Appendix D: Natural Sources** **D-9 Appendix D** Petroleum gas and oil seeps occur naturally in California and havebeen active for millennia. Oil and gas seeps form where oil or naturalgas emerge from subsurface sources to the ground orwater surface.Seeps are associated with water springs in which oil floats to thesurface of the water, and gas bubbles out into theatmosphere. Largeseeps may be comprised of nearly pure oil, asphaltum, or semisolidbitumen. Most seeps are mixed with varying amountsof sand, clay,and biomass debris. Terrestrial seep flows vary with the seasons, withelevated flows occurring during warm weather. Seismic activity cancreate new seeps or cause increased flows from existing seeps. Majormarine seeps are located off the coast of Santa Barbara County. Otherseeps occur in regions of oil and gas production throughout the state.Geogenic Sources**ARB Almanac 2013 – Appendix D: Natural Sources D-10** **Appendix D**Natural Source Emissions - Geogenic Sources**(tons/day, annual average) Table D-3** COUNTY AIR BASIN DISTRICTVOC NH3**Alameda San Francisco Bay Area Bay Area AQMD 0 0** **Alpine Great Basin Valleys Great Basin Unifi ed APCD 0 0 Amador Mountain Counties Amador County APCD 0 0** **Butte Sacramento Valley Butte County AQMD 0 1 Calaveras Mountain Counties Calaveras County APCD 0 1** **Colusa Sacramento Valley Colusa County APCD 0 0 Contra Costa San Francisco Bay Area Bay Area AQMD** **0 0 Del Norte North Coast North Coast Unifi ed AQMD 0 1** **El Dorado Lake Tahoe El Dorado County APCD 0 0 El Dorado Mountain Counties El Dorado County APCD 0 1** **Fresno San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 2 Glenn Sacramento Valley Glenn County APCD 0 0** **Humboldt North Coast North Coast Unifi ed AQMD 0 3 Imperial Salton Sea Imperial County APCD 0 1** **Inyo Great Basin Valleys Great Basin Unifi ed APCD 0 3 Kern Mojave Desert Kern County APCD 0 1** **Kern San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 1 Kings San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0** **Lake Lake County Lake County AQMD 0 1 Lassen Northeast Plateau Lassen County APCD 0 2** **Los Angeles Mojave Desert Antelope Valley AQMD 0 0 Los Angeles South Coast South Coast AQMD 0 1** **Madera San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 1 Marin San Francisco Bay Area Bay Area AQMD** **0 0 Mariposa Mountain Counties Mariposa County APCD 0 1** **Mendocino North Coast Mendocino County AQMD 0 2 Merced San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0** **Modoc Northeast Plateau Modoc County APCD 0 2 Mono Great Basin Valleys Great Basin Unifi ed APCD 0 1** **Monterey North Central Coast Monterey Bay Unifi ed APCD 0 1 ARB Almanac 2013 – Appendix D: Natural Sources** **D-11 Appendix D** COUNTY AIR BASIN DISTRICTVOC NH3**Napa San Francisco Bay Area Bay Area AQMD 0 0** **Nevada Mountain Counties Northern Sierra AQMD 0 1 Orange South Coast South Coast AQMD 0 0** **Placer Lake Tahoe Placer County APCD 0 0 Placer Mountain Counties Placer County APCD 0 1** **Placer Sacramento Valley Placer County APCD 0 0 Plumas Mountain Counties Northern Sierra AQMD 0 2** **Riverside Mojave Desert Mojave Desert AQMD 0 0 Riverside Mojave Desert South Coast AQMD 0 1** **Riverside Salton Sea South Coast AQMD 0 1 Riverside South Coast South Coast AQMD 0 1** **Sacramento Sacramento Valley Sacramento Metropolitan AQMD 0 0 San Benito North Central Coast Monterey Bay Unifi ed APCD 0 0** **San Bernardino Mojave Desert Mojave Desert AQMD 0 5 San Bernardino South Coast South Coast AQMD 0 0** **San Diego San Diego San Diego County APCD 0 1 San Francisco San Francisco Bay Area Bay Area AQMD** **0 0 San Joaquin San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0** **San Luis Obispo South Central Coast San Luis Obispo County APCD 0 1 San Mateo San Francisco Bay Area Bay Area AQMD** **0 0 Santa Barbara Outer Continental Shelf Santa Barbara County APCD 9 0** **Santa Barbara South Central Coast Santa Barbara County APCD 18 1 Santa Clara San Francisco Bay Area Bay Area AQMD** **0 1 Santa Cruz North Central Coast Monterey Bay Unifi ed APCD 0 0** **Shasta Sacramento Valley Shasta County AQMD 0 2 Sierra Mountain Counties Northern Sierra AQMD 0 1** **Siskiyou Northeast Plateau Siskiyou County APCD 0 4 Solano Sacramento Valley Yolo/Solano AQMD 0 0** **Solano San Francisco Bay Area Bay Area AQMD 0 0** **Sonoma North Coast Northern Sonoma County APCD 0 1**Natural Source Emissions - Geogenic Sources**(tons/day, annual average)**(Cont)**Table D-3 (Cont) ARB Almanac 2013 – Appendix D: Natural Sources** **D-12 Appendix D** COUNTY AIR BASIN DISTRICTVOC NH3**Sonoma San Francisco Bay Area Bay Area AQMD 0 0** **Stanislaus San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0 Sutter Sacramento Valley Feather River AQMD 0 0** **Tehama Sacramento Valley Tehama County APCD 0 1 Trinity North Coast North Coast Unifi ed AQMD 0 2** **Tulare San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 2 Tuolumne Mountain Counties Tuolumne County APCD 0 1** **Ventura South Central Coast Ventura County APCD 4 1 Yolo Sacramento Valley Yolo/Solano AQMD 0 0** **Yuba Sacramento Valley Feather River AQMD 0 0**Natural Source Emissions - Geogenic Sources**(tons/day, annual average)**(Cont)*** Geogenic emissions are not year-specific. Table D-3 (Cont)** **ARB Almanac 2013 – Appendix D: Natural Sources D-13** **Appendix D**A wildfire is a natural event that burns a varietyof vegetation typesranging in timing, scale and severity. This wildfire category does notinclude prescribed fires such as agriculture burning, forest management fires, or Wildland Fire Use (WFU). A prescribed burn is a fireignited by a planned management action whereas a WFU is a naturally ignited lightning fire that is managed for resources benefit.Wildfires can vary significantly from year to year;an area may haveextreme wildfire behavior one year and none the following year.Emissions for PM10, PM2.5, NOx, SOx, NH3, and VOC (Total NonMethane Hydrocarbon, reported here as VOC) are estimated by airbasin and county. About 90 percent of wildfires occur between Mayand October, with July as the highest month. The wildfire emissionestimates presented in this Almanac are based on a10-year average that was calculated from actual 2001 - 2010 wildfire activity.Figure D-2 is a map showing all of the wildfires that burned between2001 and 2010 in California. The tables that followshow the 10-yearaverage emissions per county and air basin.Wildfires2001-2010Wildfires**Figure D-2 ARB Almanac 2013 – Appendix D: Natural Sources** **D-14 Appendix D** Natural Source Emissions - Wildfires**(tons/day, annual average) Table D-4** COUNTY AIR BASIN DISTRICTVOC NOxSOxPM10PM2.5NH3**Alameda San Francisco Bay Area Bay Area AQMD 0 0 0 0 0 0** **Alpine Great Basin Valleys Great Basin Unifi ed APCD 0 0 0 0 0 0 Amador Mountain Counties Amador County APCD 2 0 0 3 2 0** **Butte Sacramento Valley Butte County AQMD 9 0 1 11 10 1 Calaveras Mountain Counties Calaveras County APCD 1 0 0 2 1 0** **Colusa Sacramento Valley Colusa County APCD 1 0 0 2 2 0 Contra Costa San Francisco Bay Area Bay Area AQMD** **0 0 0 0 0 0 Del Norte North Coast North Coast Unifi ed AQMD 11 0 1 14 12 2** **El Dorado Lake Tahoe El Dorado County APCD 1 0 0 1 1 0 El Dorado Mountain Counties El Dorado County APCD 1 0 0 2 2 0** **Fresno San Joaquin Valley San Joaquin Valley Unifi ed APCD 1 0 0 1 1 0 Glenn Sacramento Valley Glenn County APCD 3 0 0 4 4 0** **Humboldt North Coast North Coast Unifi ed AQMD 5 0 0 6 5 1 Imperial Salton Sea Imperial County APCD 0 0 0 0 0 0** **Inyo Great Basin Valleys Great Basin Unifi ed APCD 1 0 0 1 1 0 Kern Mojave Desert Kern County APCD 8 0 0 11 9 1** **Kern San Joaquin Valley San Joaquin Valley Unifi ed APCD 1 0 0 1 1 0 Kings San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0 0 0 0 0** **Lake Lake County Lake County AQMD 2 0 0 3 3 0 Lassen Northeast Plateau Lassen County APCD 6 0 0 8 7 1** **Los Angeles Mojave Desert Antelope Valley AQMD 1 0 0 2 2 0 Los Angeles South Coast South Coast AQMD 12 2 1 17 14 2** **Madera San Joaquin Valley San Joaquin Valley Unifi ed APCD 1 0 0 1 1 0 Marin San Francisco Bay Area Bay Area AQMD** **0 0 0 0 0 0 Mariposa Mountain Counties Mariposa County APCD 5 0 0 6 5 1** **Mendocino North Coast Mendocino County AQMD 18 0 1 23 19 3 Merced San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0 0 0 0 0** **Modoc Northeast Plateau Modoc County APCD 3 0 0 4 4 0 Mono Great Basin Valleys Great Basin Unifi ed APCD 2 0 0 3 3 0** **Monterey North Central Coast Monterey Bay Unifi ed APCD 24 1 1 31 26 3 ARB Almanac 2013 – Appendix D: Natural Sources** **D-15 Appendix D** Natural Source Emissions - Wildfires**(tons/day, annual average)**(Cont)**Table D-4 (Cont)**COUNTY AIR BASIN DISTRICTVOC NOxSOxPM10PM2.5NH3**Napa San Francisco Bay Area Bay Area AQMD 1 0 0 1 1 0** **Nevada Mountain Counties Northern Sierra AQMD 1 0 0 2 1 0 Orange South Coast South Coast AQMD 1 0 0 1 1 0** **Placer Lake Tahoe Placer County APCD 0 0 0 0 0 0 Placer Mountain Counties Placer County APCD 7 0 0 9 8 1** **Placer Sacramento Valley Placer County APCD 0 0 0 0 0 0 Plumas Mountain Counties Northern Sierra AQMD 22 1 1 28 24 3** **Riverside Mojave Desert Mojave Desert AQMD 0 0 0 0 0 0 Riverside Mojave Desert South Coast AQMD 0 0 0 0 0 0** **Riverside Salton Sea South Coast AQMD 0 0 0 0 0 0 Riverside South Coast South Coast AQMD 2 1 0 3 2 0** **Sacramento Sacramento Valley Sacramento Metropolitan AQMD 0 0 0 0 0 0 San Benito North Central Coast Monterey Bay Unifi ed APCD 0 0 0 0 0 0** **San Bernardino Mojave Desert Mojave Desert AQMD 2 0 0 3 3 0 San Bernardino South Coast South Coast AQMD 7 1 1 10 8 1** **San Diego San Diego San Diego County APCD 17 5 2 25 21 2 San Francisco San Francisco Bay Area Bay Area AQMD** **0 0 0 0 0 0 San Joaquin San Joaquin Valley San Joaquin Valley Unifi ed APCD 0 0 0 0 0 0** **San Luis Obispo South Central Coast San Luis Obispo County APCD 0 0 0 0 0 0 San Mateo San Francisco Bay Area Bay Area AQMD** **0 0 0 0 0 0 Santa Barbara South Central Coast Santa Barbara County APCD 11 2 1 15 13 2** **Santa Clara San Francisco Bay Area Bay Area AQMD 2 0 0 2 2 0** **Santa Cruz North Central Coast Monterey Bay Unifi ed APCD 2 0 0 3 3 0 Shasta Sacramento Valley Shasta County AQMD 13 1 1 17 15 2** **Sierra Mountain Counties Northern Sierra AQMD 1 0 0 1 1 0 Siskiyou Northeast Plateau Siskiyou County APCD 37 2 2 48 41 5** **Solano Sacramento Valley Yolo/Solano AQMD 0 0 0 0 0 0 Solano San Francisco Bay Area Bay Area AQMD** **0 0 0 0 0 0 Sonoma North Coast Northern Sonoma County APCD 1 0 0 1 1 0** **Sonoma San Francisco Bay Area Bay Area AQMD 0 0 0 0 0 0** **ARB Almanac 2013 – Appendix D: Natural Sources D-16** **Appendix D**COUNTY AIR BASIN DISTRICTVOC NOxSOxPM10PM2.5NH3**Stanislaus San Joaquin Valley San Joaquin Valley Unifi ed APCD 2 0 0 3 2 0 Sutter Sacramento Valley Feather River AQMD 0 0 0 0 0 0** **Tehama Sacramento Valley Tehama County APCD 10 0 1 13 11 1 Trinity North Coast North Coast Unifi ed AQMD 34 2 2 44 38 5** **Tulare San Joaquin Valley San Joaquin Valley Unifi ed APCD 27 1 2 35 29 4 Tuolumne Mountain Counties Tuolumne County APCD 5 0 0 6 5 1** **Ventura South Central Coast Ventura County APCD 11 2 1 15 13 2 Yolo Sacramento Valley Yolo/Solano AQMD 0 0 0 1 0 0** **Yuba Sacramento Valley Feather River AQMD 0 0 0 1 0 0**Natural Source Emissions - Wildfires**(tons/day, annual average)**(Cont)**Table D-4 (Cont)***** Wildfire emissions reflect 10-year averages.**