## CHAPTER 2 AIR QUALITY AND HEALTH EFFECTS

Introduction Ambient Air Quality Standards Comparison to Other U.S. Areas Current Air Quality SummaryChapter 2 Air Quality and Health Effects

2 - 1 

### INTRODUCTION In this chapter, year 2001 air quality in the South Coast Air Basin (Basin), and in the portion of the Salton Sea Air Basin (SSAB) monitored by the South Coast Air Quality Management District (District), is compar ed to state and federal ambient air quality standards. For those polluta nts for which the Basin is in nonattainment of the federal standards, maps have been included which compare the year 2001 air quality in different areas of the Basin. 1 Nationwide air quality for 2001 is also briefly summarized in this chapter. A comparison of air qua lity in the Basin to other U.S. and California urban areas is presented in the following pages.



### AMBIENT AIR QUALITY STANDARDS Ambient air quality standards for ozone, carbon monoxide, nitroge n dioxide, sulfur dioxide, particulate matter (P M10 and PM2.5), and lead have been set by both the California state and federal governments. The state has also set standards for sulfate and visibility. The ambient air qua lity standards for each of these pollutants and their effects on health are summarized in Table 2-1.
In 2001, the Basin exceeded the federal sta ndards for ozone, PM10 and PM2.5 on a total of 58 days. Despite the substantial improveme nt over historical air quality in the past few decades, some areas in th e Basin still exceed the 1-hour federal standard for ozone more frequently than any other area of the U.S. In 2001, nine out of ten locations in the nation that exceeded the standard most frequen tly were located in th e Basin and the Basin is currently the only area in the nation cla ssified as "extreme" nonattainment for ozone. The Basin is also among the few areas in the nation that still is classified as nonattainment for carbon monoxide. (The Basin has technically met the CO standards in 2002 and the District will request reclassificati on as attainment in the next few years.)



### COMPARISON TO OTHER U.S. AREAS The Basin’s severe air pollution problem is a consequence of the combination of emissions from the nation’s second largest urban area and meteor ological conditions which are adverse to the disp ersion of those emissions. The average wind speed for Los Angeles is the lowest of the nation’s ten larg est urban areas. In addition, the summertime maximum mixing height (an inde x of how well pollutants can be dispersed vertically in the atmosphere) in Southern California averag es the lowest in the U.S. The Southern California area is also an area with abundant sunshine, which drives the photochemical reactions which form pollutants such as ozone.

1 Complete data for the year 2002 is not available at this time.Final 2003 AQMP

2 - 2 TABLE 2-1 Ambient Air Quality Standards*

STATE STANDARD FEDERAL PRIMARY STANDARD MOST RELEVANT EFFECTS
AIR POLLUTANT CONCENTRATION/ AVERAGING TIME CONCENTRATION/ AVERAGING TIME Ozone 0.09 ppm, 1-hr. avg. > 0.12 ppm, 1-hr avg.> 0.08 ppm, 8-hr avg.> (a) Short-term 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 after 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, 1-hr avg.> (a) Aggravation of angi na 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 increasedrisk to fetuses Nitrogen Dioxide 0.25 ppm, 1-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 (PM 10 )** 30 μg/m 3 , ann. geometric mean > 50 μg/m 3 , 24-hr average> 50 μg/m 3 , ann. arithmetic mean > 150μg/m 3 , 24-hr avg.>
Suspended Particulate Matter (PM 2.5 )** 15 μg/m 3 , ann. arithmetic mean > 65 μg/m 3 , 24-hr avg.> (a) Excess deaths from short-term exposures and exacerbation of symptoms in sensitive patients with respiratory disease; (b) Excess seasonal declines in pulmonary function, especially in children; (c) Increased ri sk of premature death from heart or lung diseases in elderly

Sulfates 25 μg/m 3 , 24-hr avg. ≥ (a) Decrease in ventilatory function; (b) Aggravation of asthmatic symptoms; (c) Aggravation of cardio-pulmonary disease; (d) Vegetation damage; (e) Degradation of visibility; (f) Property damage
Lead 1.5 μg/m 3 , 30-day avg. ≥ 1.5 μg/m 3 , calendar quarter> (a) Increased body burden; (b) Impairment of blood formation and nerve conductionVisibilityReducing Particles In sufficient amount such that the extinction coefficient is greater than 0.23 inverse kilometers (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

* For readers' convenience in picking out standards quickly, c oncentration appears first; e.g. "0.12 ppm, 1-hr avg. >" means 1-hr avg. > 0.12 ppm. ** New and stricter state standards for PM are proposed and a dopted by ARB. They include: PM10 annual average of 20 μg/m 3 and new PM2.5 annual average of 12 μg/m 3

.Chapter 2 Air Quality and Health Effects

2 - 3 In the Basin, high concentrations of ozone are normally recorded during the spring and summer months. By contrast, high concentr ations of carbon m onoxide are generally recorded in late fall and winter. High PM10 and PM2.5 concentrations can occur throughout the year, but occur most frequently in fall and winter. Although there are changes in emissions by season, the observed variations in pollutant concentrations are largely a result of seasonal differences in weather conditions. In the year 2001, the federal standard for ozone was exceeded at one or more Basin locations on 10 percent of days (36 days). The federal PM 10 standard was exceeded on 4 percent of the days sampled (2 days) and the federal PM2.5 standard was exceeded on 6 percent of the days sampled (23 days) 2 . For the first time sinc e monitoring began, the federal carbon monoxide standards were not excee ded in the Basin in the year 2001. The Basin is among the few locations in the nation still exceeding car bon monoxide standards in the recent years. Figure 2-1 shows maximum pollutant concen trations in 2001 for the South Coast Air Basin compared to other urban areas inthe U.S. and California. Maximum concentrations in some of th ese other large U.S. urban areas exceeded the federal ozone or PM10 standards. In Califor nia, all of the other large ur ban areas shown in Figure 2-1 exceeded the ozone standard. The PM10 sta ndard was exceeded in one of the areas shown. None of the areas shown in Figure 2-1 exceeded the carbon monoxide standard. In 2001, the Houston metropolitan area record ed the highest maximum 1-hour average ozone concentration in the nation (0.194 ppm). The highest concentration in the Basin was more than one and a half times the fede ral standard (0.190 ppm). Houston, like Los Angeles, is an area with a bundant sunshine which creates favorable conditions for the photochemical reactions that yield ozone and other photochemical pollutants. In California, the San Joaquin Valley, Sa cramento Valley and San Diego Air Basins exceeded the 1-hour ozone standard by smaller margin than the South Coast Air Basin. San Francisco and South Centra l Coast Basins barely exceed ed the standard. San Diego and South Central Coast Air Ba sins, located immediately s outh and north of the South Coast Air Basin, respectively, are subject to ozone transport from the South Coast Air Basin. Maximum annual average PM10 concentrations exceeded the federal annual average PM10 standard in the Basin and Phoenix and in the San Joaquin Valley Air Basin.

2 Particulate matter exceedances may have been higher since PM 10 samples are collected only every 6 days (except for

two sites at which samples are collected every 3 days); PM 2.5 samples are collected every 3 days at most sites except for a few sites which are sampled every day. The gaseous pollutants such as ozone and carbon monoxide are sampled continuously.Final 2003 AQMP

2 - 4 A) South Coast Air Basin Compared to Major U.S. Metropolitan Areas

B) South Coast Air Basin Compared to Other Air Basins in California

FIGURE 2-1 2001 Air Quality Maximum Pollutant Concentrations as Percentages of the Federal Standard 0 50 100 150 200

South Coast Houston Philadelphia New York Washington D.C. Atlanta Chicago Phoenix Denver

Ozone Carbon Monoxide PM10 Nitrogen Dioxide Sulfur Dioxide Percent of Federal Standard

STANDARD

0 20 40 60 80 100 120 140 160

South Coast San Joaquin Valley Sacramento Valley San Diego San Francisco South Central Coast

Ozone Carbon Monoxide PM10 Nitrogen Dioxide Sulfur Dioxide Percent of Federal Standard

STANDARDChapter 2 Air Quality and Health Effects

2 - 5 In the year 2001, no location in the Basin or any other area of th e U.S. exceeded the nitrogen dioxide standards. The Los Angele s county portion of the Basin was the last area of the U.S. to exceed the federal standard for nitrogen dioxide, but has remained in compliance since 1991. Sulfur dioxide concentr ations in the Basin continued to remain well below federal standards. Concentrations of sulfur dioxide in urban areas in the Eastern U.S. have generally been higher than those in the Basin due to the use of fuels such as coal which have relatively high sulfur content.



### CURRENT AIR QUALITY SUMMARY Figure 2-2 shows the maximum pollutant c oncentrations in the Basin for 2001 as percentages of the federal standards compar ed to the years 1990 and 1980. In 2001, the maximum ozone, PM10 and PM2.5 concentrati ons exceeded federal standards by wide margins. Maximum 1-hour a nd 8-hour average ozone concen trations recorded (0.190 ppm in East San Gabriel Va lley and 0.144 ppm in Centra l and East San Bernardino Valley areas) were 152 and 169 pe rcent of the federal standard, respectively. Maximum 24-hour average and annual averag e PM10 concentrations (219 μg/m 3 recorded in Banning Airport area and 63.1 μg/m 3 recorded in the Metropolitan Riverside County area) were 146 and 125 percent of the fede ral 24-hour and annual average standards, respectively. Maximum 24-hour average and annual average PM2.5 concentrations (98.0 μg/m 3 and 31.1 μg/m 3 , both recorded in Metropolitan Riverside County area) were, respectively, 150 and 201 percen t of the federal 24-hour and annual average standards, respectively. Carbon monoxide concentra tion did not exceed the standards in 2001 3

. The highest 8-hour average carbon monoxide c oncentration recorded (7.71 ppm in the South Central Los Angeles County area) was 81 percent of the federal carbon monoxide standard. Concentrations of other pollutants remainedbelow the standards. The maximum annual average nitrogen dioxide concentration (0. 0419 ppm recorded in th e East San Fernando Valley area) was 78 percent of the federal standard, and the maximum annual average sulfur dioxide concentrati on (0.0031 ppm recorded in S outhwest Coastal Los Angeles County area) was 10 percent of the federal st andard. The maximum sulfate concentration recorded (20.6 μg/m 3 in Southwest Coastal Los Angeles County area) was 82 percent of the state sulfate standard. The maximum quart erly average lead c oncentration recorded at any District air monitoring station was 8 percent of the federal standard. However, higher concentration of lead (32 percent of the standard) was recorded at special monitoring sites immediately adjacent to st ationary sources (in Central Los Angeles area).

3 Preliminary data from 2002 indicates one violation of CO, which is allowed under the Clean Air Act for attainment

classification purpose.Final 2003 AQMP

2 - 6 Figure 2-3 shows the percent of days on whic h the federal standards were exceeded in 2001 at the Basin locations which exceeded most frequently compared to previous years. The federal ozone standard was exceeded on a maximum of 26 days (seven percent of days in the Central San Bern ardino Mountains area). Exceed ances of the federal 24-hour PM10 standard were recorded on a maximum of one day (two percent of days sampled at each of the locations in Banning Airport a nd Southwest San Bernar dino Valley area), and the federal 24-hour PM2.5 standard was exce eded on a maximum of 19 days (6 percent of days sampled, in Metropolitan Riverside County area). Detailed analyses of current air quality and statistics for all monitoring areas are contained in Appendix II. The following se ctions present summary information on health effects and how frequently, and by how much of a margin, different areas of the Basin and SSAB exceeded the federal and st ate ambient air quality standards in 2001.Chapter 2 Air Quality and Health Effects

2 - 7 * Carbon monoxide standard was exceeded in 2002. ** There is no federal standard for sulfate. *** Higher lead concentrations were recorded at special monitoring s ites immediately adjacent to sources.

FIGURE 2-2 Maximum Pollutant Concentrations as Percent of Federal Standards

FIGURE 2-3 Percent of Days Exceeding Federal Standards at Most Affected Locations STANDARDNO DATANO DATA Percent of Standard

0 100 200 300 400 500

Ozone (1-Hour) Carbon* Monoxide (8-Hour) Nitrogen Dioxide (Annual) Sulfur Dioxide (Annual) PM2.5 (Annual) PM10 (Annual) Sulfate** (24-Hour) Lead*** (Quarter) 1980

1990

2001

Standard

Percent of Days Exceeding

0% 20% 40% 60% 80% 100%

Any Standard Basin-Day Ozone (1-Hour) Carbon Monoxide (8-Hour) PM10 (24-Hour) PM2.5 (24-Hour) 1985

1990

1995

2001

NO DATAFinal 2003 AQMP

2 - 8 

### Ozone (O 3 

### ) Specific Information

Health Effects Individuals exercising outdoors, children and people with pr eexisting lung disease such as asthma and chronic pulmonary lung disease are considered to be the most susceptible sub-groups for ozone effects. Short-term e xposures (lasting for a few hours) to ozone at levels typically observed in S outhern California can result in breathing pattern changes, reduction of breathing capacity, increased sus ceptibility to infections, inflammation of the lung tissue, and some immunological changes. Elevated ozone levels are associated with increased school absences. In recent years, a correlation between elevated ambient ozone levels and increases in daily hospital admission rates, as well as mortality, has also been reported. An increased risk for asth ma has been found in ch ildren who participate in multiple sports and live in high ozone communities. Ozone exposure under exercising conditions is known to increa se the severity of the above mentioned observed res ponses. Animal studies sugge st that exposures to a combination of pollutants which include oz one may be more toxic than exposure to ozone alone. Although lung vol ume and resistance changes observed after a single exposure diminish with repeated exposures, biochemical and cellular changes appear to persist, which can lead to subse quent lung structural changes.
Air Quality In 2001, the South Coast Air Quality Manage ment District regularly monitored ozone concentrations at 28 locations in the Basin and SSAB. All areas monitored were below the stage 1 episode level (0.20 ppm), but th e maximum concentrations in the Basin exceeded the health advisory level (0.15 ppm ). Maximum ozone concentrations in the SSAB areas monitored by the District were lower than in the Basin and were below the health advisory level. Tables 2-2 and 2-3 show maximum 1- hour and 8-hour ozone concentrations by ai r basin and county.Chapter 2 Air Quality and Health Effects

2 - 9 TABLE 2-2 2001 Maximum 1-Hour Ozone Concentrations by Basin and County

Basin/County Maximum 1-Hr Avg. ppm Percent of Federal Standard Area

South Coast Air Basin Los Angeles 0.190 152 East San Gabriel Valley Orange 0.125 100 Saddleback Valley Riverside 0.152 122 Perris Valley San Bernardino 0.184 147 Central San Bernardino Valley Salton Sea Air Basin Riverside 0.137 110 Coachella Valley

TABLE 2-3 2001 Maximum 8-Hour Ozone Concentrations by Basin and County

Basin/County Maximum 8-Hr Avg. ppm Percent of Federal Standard Area

South Coast Air Basin Los Angeles 0.135 159 East San Gabriel Valley Orange 0.098 115 Saddleback Valley Riverside 0.136 160 Perris Valley San Bernardino 0.144 169 Central San Bernardino Valley, East San Bernardino Valley Salton Sea Air Basin Riverside 0.114 134 Coachella Valley

The number of days exceeding the federal sta ndard varied widely by area. Figure 2-4 shows the number of days exc eeding the 1-hour ozone federal standard in different areas of the Basin. Areas along or nearby the coast did not exceed the federal standard, due in large part to the prevailing sea breeze whic h transports polluted air inland before high ozone concentrations can be reached. The standard was exceeded mo st frequently in the inland valleys extending from East San Ga briel Valley through the Riverside-San Bernardino area, and in the adjacent mountai ns. The Central San Bernardino MountainsFinal 2003 AQMP

2 - 10 area recorded the greatest number of exceedances of the state standard (88 days), federal standard (26 days) and health advisory level (12 days). Figure 2-5 shows the distributi on of the number of days exce eding the federal standard for 8-hour average ozone concentration in th e Basin for the year 2001. The number of exceedances of the 8-hour federal ozone standard was also lowest at the coastal areas, increasing to a peak in the Riverside-San Bern ardino Valley and adjacent mountain areas.Chapter 2 Air Quality and Health Effects

2 - 11 FIGURE 2-4
Ozone -2001 Number of Days Exceeding the Federal Standard (1-hour average ozone > 0.12 ppm)

FIGURE 2-5 Ozone -2001 Number of Days Exceeding the Federal Standard (8-hour average ozone > 0.08 ppm)Final 2003 AQMP

2 - 12 

### Carbon Monoxide (CO) Specific Information

Health Effects

Individuals with a deficient blood supply to the heart are th e most susceptible to the adverse effects of CO exposure. The effect s observed include earlier onset of chest pain with exercise, and electrocardiograph changes indicative of worsening oxygen supply to the heart.

Inhaled CO has no direct toxic effect on th e lungs, but exerts its effect on tissues by interfering with oxygen transport by comp eting with oxygen to combine with hemoglobin present in the bl ood to form carboxyhe moglobin (COHb). Hence, conditions with an increased demand for oxygen supply can be adversely affe cted by exposure to CO. Individuals most at risk include pa tients with diseases involving heart and blood vessels, fetuses (unborn babies), and patients with chronic hypoxemia (oxygen deficiency) as seen in high altitudes. Reduction in birth weight and impaired neurobehavioral de velopment has been observed in animals chronically exposed to CO resulti ng in COHb levels sim ilar to those observed in smokers. Recent studies ha ve found increased risks for adverse birth outcomes with exposure to elevated CO levels. These incl ude pre-term births and heart abnormalities. Additional research is needed to confirm these results.
Air Quality

Carbon monoxide concentrations were measured at 23 locations in the Basin and neighboring SSAB areas in 2001. Table 2-4 shows the 2001 maximum 8-hour average concentrations of carbon monoxi de by air basin and county. Figure 2-6 shows the distribution of th e maximum 8-hour average carbon monoxide concentrations in the Basin in 2001. Higher concentrations were limited to the areas of Los Angeles County where vehicular traffi c is most dense, with the maximum concentration (7.71 ppm) record ed in the South Central Los Angeles County area. The Basin recorded the 6 th highest maximum 8-hour averag e carbon monoxide concentration in the nation in 2001 and is one of the fe w areas in the country still designated as nonattainment for carbon monoxide.Chapter 2 Air Quality and Health Effects

2 - 13 TABLE 2-4 2001 Maximum Carbon Monoxide Concentrations by Basin and County

Basin/County Maximum 8-Hr Avg. ppm Percent of Federal Standard Area

South Coast Air Basin Los Angeles 7.7 81 South Central L.A. County Orange 4.7 49 Central Orange County, North Orange County Riverside 4.5 47 Metropolitan Riverside County San Bernardino 3.3 35 Central San Bernardino Valley Salton Sea Air Basin Riverside 1.5 16 Coachella Valley

FIGURE 2-6 Carbon Monoxide - 2001 Maximum 8-Hour Average Concentration, ppm (Federal Standard = 8-hour average CO > 9 ppm)Final 2003 AQMP

2 - 14 

### Particulate Matter (PM10 and PM2.5) Specific Information

Health Effects

A consistent correlation between elevated ambient fine particulate matter (PM10 and PM2.5) levels and an increase in mortalityrates, respiratory infections, number and severity of asthma attacks and the number of hospital admissions has been observed in different parts of the United States and vari ous areas around the world. In recent years, some studies have reported an association between long-term exposure to air pollution dominated by fine particles and increased mortality, reduction inlife-span, and an increased mortality from lung cancer. Daily fluctuations in fine particulate matter c oncentration levels have also been related to hospital admissions for acute respiratory conditions in children, to school and kindergarten absences, to a d ecrease in respiratory lung volumes in normal children and to increased medication use in children and adults with asthma. Recent studies show lung function growth in children is reduced w ith long-term exposure to particulate matter. The elderly, people with pre-existing resp iratory and/or cardiova scular disease and children appear to be more su sceptible to the effects of PM 10 and PM 2.5

. Air Quality, PM 10 The South Coast Air Quality Management District monitored PM10 c oncentrations at 18 locations in 2001. Maximum 24-hour and annual average conc entrations are shown in Tables 2-5 and 2-6. Higher concentrations associated with high winds in the desert areas were recorded in the Coachella Valley area of Salton Sea Air Basin. The data for samp les collected on these high-wind days were excluded in accordance with U.S. EPA's Natural Event Policy. Figure 2-7 shows the 2001 annual average PM 10 concentrations in different areas of the Basin. The federal annual PM 10 standard was exceeded at only a few locations in the District in the areas of Riverside and San Bernardino Counties in and around the Metropolitan Riverside County ar ea and further inland in San Bernardino Valley areas. The federal 24-hour standard was also exceed ed at two locations in Riverside and San Bernardino counties. The much more stringent state standards were ex ceeded in all areas of the Basin monitored in 2001.Chapter 2 Air Quality and Health Effects

2 - 15 TABLE 2-5 2001 Maximum 24-hour Average PM10 Concentrations by Basin and County

Basin/County Maximum 24-Hr Avg. μ g/m 3 Percent of Federal Standard Area

South Coast Air Basin Los Angeles 106 70 East San Gabriel Valley Orange 93 62 Central Orange County Riverside 219 146 Banning Airport San Bernardino 166 110 Southwest San Bernardino Valley Salton Sea Air Basin Riverside* 149* 99* Coachella Valley *Adjusted for high-wind days in accordance with U.S. EPA's Natural Event Policy.

TABLE 2-6 2001 Maximum Annual Average PM10 Concentrations by Basin and County

Basin/County Annual Average

μ g/m 3 Percent of Federal Standard Area

South Coast Air Basin Los Angeles 45.3 90 East San Gabriel Valley Orange 36.0 79 Central Orange County Riverside 63.1 125 Metropolitan Riverside County San Bernardino 52.4 104 Southwest San Bernardino Valley Salton Sea Air Basin Riverside* 50.2* 99* Coachella Valley *Adjusted for the high-wind days in accordan ce with U.S. EPA's Natural Event Policy.

Air Quality, PM 2.5 The South Coast Air Quality Management District began regul ar monitoring of PM 2.5 in 1999 following the EPA's adoption of the nati onal PM2.5 standards in 1997. In 2001, PM 2.5 concentrations were mon itored at 18 locations throughout the District. Maximum 24-hour and annual average concen trations are shown in Tabl es 2-7 and 2-8. Both 24- hour and annual PM 2.5 standards were exceeded at most locations in the Basin.Final 2003 AQMP

2 - 16 TABLE 2-7 2001 Maximum 24-hour Average PM2.5 Concentrations by Basin and County

Basin/County Maximum 24-Hr Avg. μ g/m 3 Percent of Federal Standard Area

South Coast Air Basin Los Angeles 94.7 145 East San Fernando Valley Orange 70.8 108 Central Orange County Riverside 98.0 150 Metropolitan Riverside County San Bernardino 78.5 120 Central San Bernardino Valley Salton Sea Air Basin Riverside 44.7 68 Coachella Valley

TABLE 2-8 2001 Maximum Annual Average PM2.5 Concentrations by Basin and County

Basin/County Annual Average

μ g/m 3 Percent of Federal Standard Area

South Coast Air Basin Los Angeles 26.1 168 South San Gabriel Valley Orange 22.4 145 Central Orange County Riverside 31.1 201 Metropolitan Riverside County San Bernardino 26.2 169 Southwest San Bernardino Valley, Central San Bernardino Valley Salton Sea Air Basin Riverside 12.2 79 Coachella Valley

Figure 2-8 shows the distribution of annual av erage PM2.5 concentrations in different areas of the Basin. Similar to PM10 concentrations, PM2.5 c oncentrations were higher in the inland valley areas of San Bernardi no and Metropolitan Riverside counties. However, PM2.5 concentrations were also high in Los Angele s county and central Orange county. The high PM2. 5 concentrations in Los Ange les and Orange counties are due to the secondary formation of smalle r particulates resulting from mobile and stationary source activities. In contrast to PM10, PM2.5 concentrations were low in the Coachella Valley area of SSAB. PM10 concentr ations are normally higher in the desert areas due to windblown a nd fugitive dust emissions.Chapter 2 Air Quality and Health Effects

2 - 17 FIGURE 2-7
PM10 - 2001 Annual Average Concentration Compared to Federal Standard (Federal standard = 50 μg/m 3 , annual arithmetic mean)

FIGURE 2-8
PM2.5 - 2001 Annual Average Concentration Compared to Federal Standard (Federal standard = 15 μg/m 3 , annual arithmetic mean)Final 2003 AQMP

2 - 18 

### Nitrogen Dioxide (NO 2 

### ) Specific Information

Health Effects Population-based studies suggest that an incr ease in acute respiratory illness, including infections and respiratory symptoms in children (not infants), is associated with longterm exposures to NO 2 at levels found in homes with gas stoves, which are higher than ambient levels found in Southern California. Increase in resistance to air flow and airway contraction is observed afte r short-term exposure to NO 2 in healthy subjects. Larger decreases in lung functions are observed in individuals with asth ma and/or chronic obstructive pulmonary disease (e.g., chroni c bronchitis, emphysema) than in healthy individuals, indicating a greater susceptibility of these sub-groups. In animals, exposure to levels of NO 2 considerably higher than ambient concentrations results in increased su sceptibility to infections, possibly due to the observed changes in cells involved in maintaining immune functions. The severity of lung tissue damage associated with high levels of ozone exposure increases wh en animals are exposed to a combination of ozone and NO 2 . Air Quality In 2001, nitrogen dioxide concentr ations were monitored at 23 locations. No area of the Basin or SSAB exceeded the federal or stat e standards for nitrogen dioxide. Maximum annual average concentrations for 2001 are s hown in Table 2-9. The Basin has not exceeded the federal standard for nitrogen dioxide since 1991, when the Los Angeles County portion of the Basin recorded the last exceedance of the standard in any U.S. county. The state standard was not exceeded at any District monitoring location in 2001. The highest 1-hour average concentration recorded (0.25 ppm in East San Fernando Valley) was 96 percent of the state standard.Chapter 2 Air Quality and Health Effects

2 - 19 TABLE 2-9 2001 Maximum Nitrogen Dioxide Concentrations by Basin and County

Basin/County Maximum Annual Avg. ppm Percent of Federal Standard Area

South Coast Air Basin Los Angeles 0.0419 78 East San Fernando Valley Orange 0.0293 55 Central Orange County Riverside 0.0247 46 Metropolitan Riverside County San Bernardino 0.0384 72 Northwest San Bernardino Valley Salton Sea Air Basin Riverside 0.0175 33 Coachella Valley



### Sulfur Dioxide (SO 2 

### ) Specific Information

Health Effects Exposure of a few minutes to low levels of SO 2 can result in airway constriction in some asthmatics. All asthmatics are sensitive to the effects of SO 2 . In asthmatics, increase in resistance to air flow, as well as reducti on in breathing capacity leading to severe breathing difficulties, are observe d after acute exposure to SO 2 . In contrast, healthy individuals do not exhibit si milar acute responses even after exposure to higher concentrations of SO 2 . Animal studies suggest that despite SO 2 being a respiratory irritant, it does not cause substantial lung injury at ambient concentra tions. However, very hi gh levels of exposure can cause lung edema (fluid accumulation), lung tissue damage, and sloughing off of cells lining the respiratory tract. Some population-based studies indicate th at the mortality and morbidity effects associated with fine particles show a similar association with ambient SO 2 levels. In these studies, efforts to separate the effects of SO 2 from those of fine particles have not been successful. It is not clear whether th e two pollutants act synergistically or one pollutant alone is the predominant factor.
Air Quality

No exceedances of federal or state standards for sulfur dioxide occurred in 2001 at any of the nine District locations monitored. T hough sulfur dioxide concen trations remain wellFinal 2003 AQMP

2 - 20 below the standards, sulfur dioxi de is a precursor to sulfate, which is a component of fine particulate matter, PM10 and PM 2.5 . Standards for PM10 and PM 2.5 were both exceeded in 2001. Maximum concentrations of sulfur dioxide for 2001 are shown in Table 2-10. Sulfur dioxide was not meas ured at SSAB sites in 2001. Historical measurements showed concen trations to be well below standards and monitoring has been discontinued.

TABLE 2-10 2001 Maximum Sulfur Dioxide Concentrations by Basin and County

Basin/County Maximum 24-hr Avg. ppm Percent of Federal Standard Area

South Coast Air Basin Los Angeles 0.012 8 Southwest Coastal Los Angeles County, South Coastal Los Angeles County Orange 0.007 5 North Coastal Orange County Riverside 0.011 8 Metropolitan Riverside County San Bernardino 0.010 7 Central San Bernardino Valley Salton Sea Air Basin Riverside N.D.

N.D. = No Data. Historical measurements i ndicate concentrations are well below standards.


### Sulfates (SO 4 = 

### ) Specific Information

Health Effects

Most of the health effects a ssociated with fine particles and sulfur dioxide at ambient levels are also associated with sulfates. Thus, both mortality and morbidity effects have been observed with an increase in ambient sulfate concentrations. However, efforts to separate the effects of sulfates from the effect s of other pollutants have generally not been successful. Clinical studies of asthmatics exposed to sulf uric acid suggest that adolescent asthmatics are possibly a subgroup susceptible to acid aeros ol exposure. Animal studies suggest that acidic particles such as sulfuric acid aeroso l and ammonium bisulfate are more toxic than non-acidic particles like ammonium sulfate. Whether the effects are attributable to acidity or to particles remains unresolved.Chapter 2 Air Quality and Health Effects

2 - 21 Air Quality
In 2001, the state sulfate standard was not exceeded anywhere in the Basin. Maximum concentrations by air basin and county are shown in Table 2- 11. No sulfate data were obtained at SSAB stations in 2001. Historical sulfate data showed concentrations in the SSAB areas to be well below the standard, a nd measurements have been discontinued.

TABLE 2-11 2001 Maximum Sulfate Concentrations by Basin and County

Basin/County Maximum 24-hr Avg. μg/m 3 Percent of Federal Standard Area

South Coast Air Basin Los Angeles 20.6 82 Southwest Coastal Los Angeles County Orange N.D. Riverside 10.7 43 Metropolitan Riverside Co. San Bernardino 11.5 46 Central San Bernardino Valley Salton Sea Air Basin Riverside N.D.

N.D. = No Data. Historical measurements i ndicate concentrations are well below standards.


### Lead (Pb) Specific Information

Health Effects
Fetuses, infants, and children ar e more sensitive than others to the adverse effects of lead exposure. Exposure to low le vels of lead can adversely affect the development and function of the central nervous system, lead ing to learning disorders, distractibility, inability to follow simple commands, and lower intelligence quotient. In adults, increased lead levels are associat ed with increased blood pressure. Lead poisoning can cause anemia, lethargy, seizur es and death. It appears that there are no direct effects of lead on the respiratory sy stem. Lead can be stored in the bone from early-age environmental exposure, and elev ated blood lead levels can occur due to breakdown of bone tissue during pregnancy, hyperthyroidism (increased secretion of hormones from the thyroid gla nd) and osteoporosis (breakdow n of bony tissue). Fetuses and breast-fed babies can be exposed to higher levels of lead because of previous environmental lead exposure of their mothers.Final 2003 AQMP

2 - 22 Air Quality The federal and state standards for lead were not exceeded in any area of the District in 2001. There have been no violations of th e standards at the District’s regular air monitoring stations since 1982, as a result of removal of lead from gasoline. However, special monitoring stations immediately adja cent to stationary sources of lead have recorded exceedances of the sta ndards in very localized areas of the Basin as recently as 1991 for the federal standard and 1994 for th e state standard. Table 2-12 shows the maximum concentrations recorded in 2001. The highest quarterly average lead concentration (0.49 μg/m 3 in Central Los Angeles), measured at special monitoring sites immediately adjacent to stationary source s of lead, was 32 percent of the federal standard. The maximum monthly average lead concentr ation at the regular monitoring stations (0.23 μg/m 3 in the South Central Los Angeles C ounty area) was 15 percent of the state standard. The maximum at the special monito ring sites immediately adjacent to sources (0.57 μg/m 3 in Central Los Angeles) was 38 percent of the standard.

TABLE 2-12 2001 Maximum Lead Concentrations by Basin and County

Basin/County Maximum Quarterly Average

μ g/m 3 Percent of Federal Standard Area

South Coast Air Basin Los Angeles 0.12 8 South Central Los Angeles County Orange N.D. Riverside 0.03 2 Metropolitan Riverside County San Bernardino 0.04 3 Northwest San Bernardino Valley, Central San Bernardino Valley Salton Sea Air Basin Riverside N.D.

N.D. = No Data. Historical measurements i ndicate concentrations are well below standards.


### Summary
In 2001, the Basin exceeded federal and stat e standards for ozone, PM10 and PM2.5. The Salton Sea Air Basin areas continued to exceed standards for ozone and PM10.

The Basin exceeded one or more federal standards on 58 days. Maximum concentrations of PM2.5 exceeded the federal standard by the widest margin. Ozone and PM10Chapter 2 Air Quality and Health Effects

2 - 23 concentrations exceeded the federal standards by a smaller margin. In 2001, for the first time since its monitoring, carbon monoxide con centration did not exceed the standards anywhere in the Basin. Maximum concentr ations for nitrogen di oxide, sulfur dioxide sulfate and lead continued to remain be low the state and federal standards.