Statement of Melody Flowers, March 13, 2003

Statement for the Senate Environment and Public Works
Committee on Clean Air Conformity and the Congestion
Mitigation and Air Quality Program

Wednesday, March 12 2003
Melody Flowers
Sierra Club Washington Representative

Thank you for this opportunity to comment on the implementation of Clean Air Conformity and the CMAQ program. The Sierra Club, the nation's largest and oldest grassroots environmental organization with over 700,000 members in 65 chapters and over 400 local groups nationwide, is committed to protecting and strengthening Clean Air Conformity and the CMAQ program as one of our top priorities in the reauthorization of TEA-21.

These important programs are aimed at achieving clean air in order to protect public health and safety. While the improvements in air quality over the past thirty years have been impressive, we still have a long way to go. One-half, or more than 142 million, Americans breathe air that is not healthy, according to the U.S. Environmental Protection Agency. It is essential that we maintain conformity between clean air and transportation rules since transportation is one of the largest sources of air pollution in many areas. The Sierra Club endorses the testimony and recommendations put forward today by Michael Replogle.

We would like to take this opportunity to specifically draw your attention to the mounting number of studies that examine health and safety questions surrounding the expansion of highways near schools, hospitals, and other places where children, the elderly and vulnerable populations spend large amounts of time. These studies link air pollution near high-traffic areas to cancer, asthma, heart attacks, and low birth weight babies for people who live in nearby communities.

We have attached 17 peer-reviewed, published studies making this link between traffic-related air pollution and increased health risks. We have raised these issues on numerous highway projects from Washington, D.C. to Los Angeles to Las Vegas and Wisconsin.

With highway expansions and constructions proposed in many populated urban areas across the country, the Sierra Club and public health professionals are calling on the Federal Highway Administration of the U.S. Department of Transportation to study the health impacts of increased air pollution and air toxics on children and neighbors where these expansions and constructions are planned.

According to Dr. Ronald Rosen, a pediatric oncologist from Las Vegas, demographic and environmental risk factors are linked to increasing incidence and trends for certain malignancies. Highway air pollution and particulate matter aggravate respiratory and cardiopulmonary disease, asthma, bronchitis, and preliminary data suggest a relationship to childhood leukemia. Historically and more recent studies call attention to urban industrialization contributing to serious public health problems.

Furthermore, Dr. Seth Foldy, City of Milwaukee Medical Commissioner, states there is mounting evidence that people who live near highways and other high-traffic areas may be at higher risk for asthma attacks, lung cancer and other health problems because of motor vehicle pollution, and that in general, expanding highways will draw more cars and trucks to neighboring communities and exacerbate these problems.

The USA Today story printed on March 7, 2003, Lawsuits pits risks and roads,\1\ focused in particular on the health impacts of the proposed expansion of US-95 in Las Vegas to ten lanes. Sierra Club is suing the Federal Highway Administration on the grounds that the agency failed to adequately consider the health risk associated with increased air pollution and air toxics from the expansion.

Studies conducted in Las Vegas confirm what similar studies across the country have shown: that people who live adjacent to large highways are at a much higher risk for cancer and lung disease because of the pollution from cars.

More recently, scientists have begun to look at the problem on a neighborhood scale to estimate how particular sources of air pollution - including highways - affect nearby communities. These studies have found that certain pollutants can be 25 times more concentrated near busy highways, and people who live near high-traffic areas are more likely to suffer a variety of health problems, like more asthma, cancer, and low birth weights. People who spend many hours driving in traffic are at high risk as well.

The good news is that the California Air Resources Board is considering mapping neighborhoods to warn residents of the pollution risk. See the Los Angeles Times story attached below.\2\

We ask you to require detailed studies to investigate how much of the health risk could be eliminated if cleaner transportation services - such as clean buses, rail systems, and improved pedestrian and bicycling infrastructure - are built in high traffic corridors.

As Congress proceeds to chart the spending of billions of dollars in federal transportation funding in the reauthorization of TEA-21, we need to look at the impact of transportation investments on densely populated, high-traffic areas, where highway expansions cause the greatest health problems. These locations are precisely the kinds of places where public transportation is most practical.

By law, the Federal Highway Administration is supposed to evaluate public health risks and explore alternatives for transportation projects. When the agency ignores that part of its responsibility, neighborhoods get more pollution and communities get stuck with bad projects and never know what they are missing-clean air.

KEY STUDIES ON AIR POLLUTION AND HEALTH EFFECTS
NEAR HIGH-TRAFFIC AREAS

Compiled by the Environmental Law and Policy Center and the Sierra Club For more information, contact Brett.Hulsey@sierraclub.org. 608-257-4994

Air Pollution from Busy Roads Linked to Shorter Life Spans for Nearby Residents

Dutch researchers looked at the effects of long-term exposure to traffic-related air pollutants on 5,000 adults. They found that people who lived near a main road were almost twice as likely to die from heart or lung disease and 1.4 times as likely to die from any cause compared with those who lived in less-trafficked areas. Researchers say these results are similar to those seen in previous U.S. studies on the effects of long-term exposure to traffic-related air pollution. The authors say traffic emissions contain many pollutants that might be responsible for the health risks, such as ultrafine particles, diesel soot, and nitrogen oxides, which have been linked to cardiovascular and respiratory problems.

Hoek, Brunekreef, Goldbohn, Fischer, van den Brandt. (2002). Association between mortality and indicators of traffic-related air pollution in the Netherlands: a cohort study. Lancet, 360 (9341): 1203-9.

Truck Traffic Linked to Childhood Asthma Hospitalizations

A study in Erie County, New York (excluding the city of Buffalo) found that children living in neighborhoods with heavy truck traffic within 200 meters of their homes had increased risks of asthma hospitalization. The study examined hospital admission for asthma amongst children ages 0-14, and residential proximity to roads with heavy traffic.

Lin, Munsie, Hwang, Fitzgerald, and Cayo. (2002). Childhood Asthma Hospitalization and Residential Exposure to State Route Traffic. Environmental Research, Section A, Vol. 88, pp. 73-81.

Pregnant Women Who Live Near High Traffic Areas More Likely to Have Premature and Low Birth Weight Babies.

Researchers observed an approximately 10-20% increase in the risk of premature birth and low birth weight for infants born to women living near high traffic areas in Los Angeles County. In particular, the researchers found that for each one part per million increase in annual average carbon monoxide concentrations where the women lived, there was a 19% and 11 % increase in risk for low birth weight and premature births, respectively.

Wilhelm, Ritz. (2002). Residential Proximity to Traffic and Adverse Birth Outcomes in Los Angeles County, California, 1994-1996. Environmental Health Perspectives. doi: 10.1289/ehp.5688.

Traffic-Related Air Pollution Associated with Respiratory Symptoms in Two Year Old Children.

This cohort study found that two year old children who are exposed to higher levels of trafficrelated air pollution are more likely to have self-reported respiratory illnesses, including wheezing, ear/nose/throat infections, and reporting of physician-diagnosed asthma, flu or serious cold.

Brauer et al. (2002). Air Pollution from Traffic and the Development of Respiratory Infections and Asthmatic and Allergic Symptoms in Children. Am J Respiratory and Critical Care Medicine. Vol. 166 pp 1092-1098.

People Who Live Near Freeways Exposed to 25 Times More Particle Pollution

Studies conducted in the vicinity of Interstates 405 and 710 in southern California found that the number of ultrafine particles in the air was approximately 25 times more concentrated near the freeways and that pollution levels gradually decrease to near normal (background) levels around 300 meters, or 990 feet, downwind from the freeway. The researchers note that motor vehicles are the most significant source of ultrafine particles, which have been linked to increases in mortality and morbidity. Recent research concludes that ultrafine particles are more toxic than larger particles with the same chemical composition. Moreover, the researchers found considerably higher concentrations of carbon monoxide pollution near the freeways.

Zhu, Hinds, Kim, Sioutas. Concentration and size distribution of ultrafine particles near a major highway. Journal of the Air and Waste Management Association.. September 2002.

Zhu, Hinds, Kim, Shen, Sioutas. Study of ultrafine particles near a major highway with heavy-duty diesel traffic. Atmospheric Environment. 36(2002),4323-4335.

Asthma More Common for Children Living Near Freeways.

A study of nearly 10,000 children in England found that wheezing illness, including asthma, was more likely with increasing proximity of a child's home to main roads. The risk was greatest for children living within 90 meters of the road.

Venn et al. (2001). Living Near A Main Road and the Risk of Wheezing Illness in Children. American Journal of Respiratory and Critical Care Medicine. Vol. 164, pp 2177-2180.

A study of 1,068 Dutch children found that asthma, wheeze, cough, and runny nose were significantly more common in children living within 100 meters of freeways. Increasing density of truck traffic was also associated with significantly higher asthma levels - particularly in girls.

van Vliet et al. (1997). Motor exhaust and chronic respiratory symptoms in children living near freeways. Environmental Research. 74:12-132.

Children Living Near Busy Roads More Likely to Develop Cancer

A 2000 Denver study showed that children living within 250 yards of streets or highways with 20,000 vehicles per day are six times more likely to develop all types of cancer and eight times more likely to get leukemia. The study looked at associations between traffic density, power lines, and all childhood cancers with measurements obtained in 1979 and 1990. It found a weak association from power lines, but a strong association with highways. It suggested that benzene pollution might be the cancer promoter causing the problem.

Pearson et al. (2000). Distance-weighted traffic density in proximity to a home is a risk factor for leukemia and other childhood cancers. Journal of Air and Waste Management Association 50:175-180.

Most Traffic-Related Deaths Due to Air Pollution, Not Traffic Accidents

Another study analyzed the affect of traffic-related air pollution and traffic accidents on life expectancy in the area of Baden-Wurttemberg, Germany. It estimated that 4325 deaths in this region would result from motor vehicle emissions compared to 891 from traffic accidents (over a lifetime).

Szagun and Seidel. (2000). Mortality due to road traffic in Baden-Aurttemberg - air pollution, accidents, noise. Gesundheitswesen. 62(4): 225-33.

Emissions from Motor Vehicles Dominate Cancer Risk

The most comprehensive study of urban toxic air pollution ever undertaken shows that motor vehicles and other mobile sources of air pollution are the predominant source of cancer-causing air pollutants in Southern California. Overall, the study showed that motor vehicles and other mobile sources accounted for about 90% of the cancer risk from toxic air pollution, most of which is from diesel soot (70% of the cancer risk). Industries and other stationary sources accounted for the remaining 10%. The study showed that the highest risk is in urban areas where there is heavy traffic and high concentrations of population and industry.

South Coast Air Quality Management District. Multiple Air Toxics Exposure Study-II. March 2000.

Cancer Risk Higher Near Major Sources of Air Pollution, Including Highways

A 1997 English study found a cancer corridor within three miles of highways, airports, power plants, and other major polluters. The study examined children who died of leukemia or other cancers from the years 1953-1980, where they were born and where they died. It found that the greatest danger lies a few hundred yards from the highway or pollution facility and decreases as you get away from the facility.

Knox and Gilman (1997). Hazard proximities of childhood cancers in Great Britain from 1953-1980. Journal of Epidemiology and Community Health. 51: 151-159.

A School's Proximity to Freeways Associated with Asthma Prevalence

A study of 1498 children in 13 schools in the Province of South Holland found a positive relationship between school proximity to freeways and asthma occurrence. Truck traffic intensity and the concentration of emissions measured in schools were found to be significantly associated with chronic respiratory symptoms.

Speizer, F. E. and B. G. Ferris, Jr. (1973). Exposure to automobile exhaust. I. Prevalence of respiratory symptoms and disease. Archives of Environmental Health. 26(6): 313-8. van Vliet, P., M. Knape, et al. (1997). Motor vehicle exhaust and chronic respiratory symptoms in children living near freeways. Environmental Research.. 74(2): 122-32.

Lung Function Reduction Among Children More Likely if Living Near Truck Traffic

A European study determined that exposure to traffic-related air pollution, `in particular diesel exhaust particles,' may lead to reduced lung function in children living near major motorways.

Brunekreef B; Janssen NA; de Hartog J; Harssema H; Knape M; van Vliet P. (1997). "Air pollution from truck traffic and lung function in children living near motorways." Epidemiology. 8(3):298-303.

Asthma Symptoms Caused by Truck Exhaust

A study was conducted in Munster, Germany to determine the relationship between truck traffic and asthma symptoms. In total, 3,703 German students, between the ages of 12-15 years, completed a written and video questionnaire in 1994-1995. Positive associations between both wheezing and allergic rhinitis and truck traffic were found during a 12-month period. Potentially confounding variables, including indicators of socio-economic status, smoking, etc., did not alter the associations substantially.

Duhme, H., S. K. Weiland, et al. (1996). The association between self-reported symptoms of asthma and allergic rhinitis and self-reported traffic density on street of residence in adolescents. Epidemiology7(6):

578-82.

Proximity of a Child's Residence to Major Roads Linked to Hospital Admissions for Asthma

A study in Birmingham, United Kingdom, determined that living near major roads was associated with the risk of hospital admission for asthma in children younger than 5 yrs of age. The area of residence and traffic flow patterns were compared for children admitted to the hospital for asthma, children admitted for nonrespiratory reasons, and a random sample of children from the community. Children admitted with an asthma diagnosis were significantly more likely to live in an area with high traffic flow (> 24,000 vehicles/ 24 hrs) located along the nearest segment of main road than were children admitted for nonrespiratory reasons or children form the community.

Edwards, J., S. Walters, et al. (1994). Hospital admissions for asthma in preschool children: relationship to major roads in Birmingham, United Kingdom. Archives of Environmental Health. 49(4): 223-7.

Exposure to Carcinogenic Benzene Higher for Children Living Near High Traffic Areas

German researchers compared forty-eight children who lived in a central urban area with high traffic density with seventy-two children who lived in a small city with low traffic density. They found that the blood levels of benzene in children who lived in the high-traffic-density area were 71% higher than those of children who lived in the low-traffic-density area. Blood levels of toluene and carboxyhemoglobin (formed after breathing carbon monoxide) were also significantly elevated (56% and 33% higher, respectively) among children regularly exposed to vehicle emissions. Aplastic anemia and leukemia are associated with excessive exposure to benzene.

Jermann E, Hajimiragha H, Brockhaus A, Freier I, Ewers U, Roscovanu A: Exposure of children to benzene and other motor vehicle emissions. Zentralblatt fur Hygiene and Umweltmedizin 189:50-61, 1989.

Lawsuit pits risks and roads

By John Ritter, USA TODAY

LAS VEGAS - Tens of thousands of workers commute from suburbs to resort and casino jobs on the glimmering Strip, the economic soul of this booming entertainment mecca. Many of them creep tediously along U.S. 95, the most congested road in the nation's fastest growing urban area.

With the six-lane freeway morphing twice daily into a rush-hour parking lot, policymakers from the governor on down ardently support a plan to widen 95 to 10 lanes.

Bucking the popular project are environmentalists and health experts worried about pollution from the more than 300,000 vehicles a day that already troll up and down 95. They cite studies linking higher levels of foul air along busy urban highways to heightened cancer risks among people who live and work nearby.

Urban highway "hot spots" such as 95 are battlegrounds in many cities, but here the issue has come to a head. The Sierra Club sued in January to stop the project. It says the federal government failed to consider health consequences and alternatives to highway construction as required by law.

Highway projects have been challenged before on environmental and health grounds, but this is the first such lawsuit based on scientific research into traffic-generated pollution.

U.S. 95 is a test case with broad implications for urban highway expansion and population growth in metro areas across the USA. The outcome not only could send Nevada transportation officials back to the drawing board but also could delay relief measures for other snarled roads. It could force planners to give greater weight to solving congestion with mass transit and even alter the patterns of where people choose to live.

"We're spending the most money on the most polluting source, highways, and we're saying we need to balance that out," says Brett Hulsey, national coordinator of the Sierra Club's anti-sprawl campaign.

Besides 95, environmentalists want the Federal Highway Administration to study the health risks of widening Interstate 75 from Dayton, Ohio, to Cincinnati; building a beltway segment around Denver called the Northwest Parkway; widening 1-94 in downtown Detroit; widening 1-94 and U.S. 45 around

Milwaukee; expanding 1-10 and U.S. 290 out of Houston; and widening Virginia's portion of the Capital Beltway around Washington, D.C.

Highways can't keep up

Beyond health issues, the Las Vegas case spotlights a problem facing many thriving cities, particularly in the West. Las Vegas has grown so fast that its highway system hasn't kept up. Congestion worsens monthly. Yet in the last decade, population spilled over such a wide area that developing mass transit will be costly.

"We have 6,000 people a month moving here, bringing 4,000 automobiles with them," says Jacob Snow, general manager of the Regional Transportation Commission of Southern Nevada. "The worst thing we could do from an air quality standpoint is stop building roadways."

Last month, federal Judge Philip Pro denied the highway administration's motion to dismiss the Las Vegas case.

Opponents say the widening will funnel even more traffic onto U.S. 95. "I'll leave if this project goes in," says Barbara Roth, 70, who moved near what was then a two-lane street 38 years ago. "The pollution is going to be terrific because the traffic will back up immediately, just like it is now. Crazy is the word."

The judge could stop work on the project and order the highway agency to reassess health risks. He could order it to consider alternatives to widening, such as mass transit, as required under the National Environmental Policy Act.

Highway administration officials won't comment on the case. But in a sign that the highway pollution issue is gaining traction, a Transportation Department research panel held a forum in January called "Air Toxics: The Next Poison Pill for Transportation?"

Delaying or killing the 95 expansion would anger many who believe growth will choke southern Nevada unless its road system expands rapidly. The 6 miles to be widened have more aggressive drivers than any other road in the region, a study in January found. An irate Gov. Kenny Guinn threatened to erect billboards on 95 that say, "Traffic congestion brought to you by the Sierra Club."

At the lawsuit's core is whether high concentrations of auto emissions such as benzene and 1,3 butadiene, which are known carcinogens, raise health risks. Opponents of the expansion say they do:

A Denver study in 2000 found that children living within 250 yards of highways used daily by more than 20,000 vehicles were eight times more likely to get leukemia.

A study the same year of Interstates 405 and 710 in Los Angeles showed that vehicles accounted for 90% of the cancer risk from air pollution, and that the highest risk was in congested, heavily populated urban zones.

A study in suburban Buffalo last year found that children living in neighborhoods close to heavy truck traffic had increased asthma risks. A Sierra Club-financed study of three pollutants concluded that widening 95 would cause up to 1,400 more cancers per 1 million people over 70 years, more than 10 times greater than what the Environmental Protection Agency considers a serious risk. "It's obvious there's some correlation," says Ronald Rosen, a pediatric oncologist in Las Vegas. He says he has no evidence of more cancers along 95. The study only predicted higher rates. "But to dismiss an environmental group that wants to look at this critically is really a big mistake."

Transit's limited reach

Environmentalists want more buses, trains and light rail, but relying on mass transit as much as denser Eastern cities do is unrealistic in the greater Las Vegas sprawl, experts say. Even in the most optimistic scenario, transit could handle no more than 15% of trips, says Shashi Nambisan, director of the Transportation Research Center at the University of Nevada-Las Vegas.

"People are choosing to live farther and farther out. Commute times and distances are going up," Nambisan says. Low gasoline prices, the comfort and convenience of personal vehicles, and abundant, cheap parking also work against mass transit in Las Vegas.

But efforts are underway. Nevada voters in November endorsed a $2.7 billion transportation initiative that includes $1 billion for transit. The first leg of a 3.6-mile monorail serving the Strip will open next year. A rapid transit bus line will begin serving northern suburbs next winter.

Environmentalists complain that bus service was the budget ax's first victim in the recession. Transit officials say they had no choice because fewer riders meant declines in operating revenue. Transit's supporters point to Salt Lake City's two light-rail lines as proof Las Vegas could do more. Ridership on both lines is nearly double initial estimates. Still, that system carries only about 1% of peak-hour trips.

Work is progressing despite the lawsuit. Bulldozers are moving earth, overpasses are being built and new sound walls are going up. More than 200 homeowners were forced to sell and leave.

Three schools, two community centers, a day care facility, 27 apartment buildings and nearly 400 houses abut this stretch. But many residents are unaware of health concerns. Rick Winget, principal of Ruth Fyfe

Elementary School, says he's eager to use more of his playground once a wall replaces a chain-link fence between the school and the highway. He says no parents have complained about pollution.

"People are really insensitive to the health risks," says Jane Feldman of the Sierra Club's Las Vegas chapter. "They think cancer won't happen to them, that it happens long-term. But this is hard scientific data and it's scary."

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Find this article at:

http://www.usatoday.com/news/nation/2003-03-06-vegas-highway-usat_x.htm

http://www.latimes.com/classified/realestatella-re-freeway 15dec 15.story

Too freeway close?

Homes along the Southland's busy highways may be more affordable, but new studies show possible health risks linked to increased pollution.

By William J. Kelly Special to The Times

December 15, 2002

At sunset, Regina Kennard's house stands in the shadow of an elevated stretch of Interstate 15. Attracted by the home's affordability and its proximity to, the onramp for her daily commute to work at a mortgage company in Orange County, Kennard moved from Ontario to Fontana more than a year ago and joined countless other Southern Californians who live along a freeway.

The mother of two chose the 4,729-square-foot lot next to the freeway because it was bigger than those farther up the street. She purchased the 1,977-square-foot home new last year for $189,900.

“I wanted a big yard," said Kennard, who keeps the windows shut at night because of the din. "I should have been more concerned. I didn't realize the noise."

Even further from her thoughts were the long-term health effects of freeway pollution. Like most buyers, Kennard was unaware of emerging scientific research that shows air pollution immediately downwind of freeways can be more than 4 to 10 times higher than average levels throughout much of Southern California.

"There's a building body of data that living next to a freeway has adverse health effects, particularly among children," said Ira Tager, a UC Berkeley epidemiologist who is studying how air pollution affects asthmatic children for the California Air Resources Board. Work by a variety of health researchers and environmental agencies is finding that the highly concentrated pollution from autos and trucks increases the incidence of asthma, respiratory infections and cancer in people residing along freeways and other heavily traveled thoroughfares.

The studies, some of which have come out in California during the last year and others that are ongoing, are attracting attention as new homes and condominiums have become more common along freeways because of the shrinking availability of land suitable for building and the increasing demand for housing.

If buyers are unaware of the health dangers, so are builders. "It's new information to me," said Tim Piasky, director of environmental affairs for the Building Industry Assn. of Southern California, who noted that individual builders cannot track every study.

"We count on our regulatory agencies to set the requirements," he said. "Unless there are requirements, builders will use the maximum area."

There are no current requirements or recommendations for buffers between homes and freeways, but the Governor's Office of Planning and Research has drafted new planning guidelines for cities and counties, which are responsible for regulating local land use. The guidelines, according to associate planner Brian Grattidge, ask cities to consider whether it is appropriate to zone housing right next to freeways, given the emerging studies on air pollution.

The California Air Resources Board will issue its first official warning in the spring and advise, but not require, that builders create buffer zones between future residential developments and freeways.

"People who construct new homes should consider having at least 100 meters [less than a tenth of a mile] between them and the freeway," said Shankar Prasad, health advisor for the board.

Buyers have long been aware of home health risks ranging from ground water contamination -- think Erin Brockovich -- to the interior culprits of leaded paint, mold and asbestos. But most haven't considered air pollution levels along freeways, according to real estate broker Remy Agaton, who is selling the home of Lydia Fabres, just one house north of Interstate 10 in West Covina. Like Kennard, Fabres did not know about the studies showing higher pollution levels.

"Out of 100, maybe 10 are concerned about the noise, and they never ask about the pollution," said Agaton of Jasrel Real Estate Brokers Inc. in the City of Industry. Buyers are more concerned about amenities, such as good schools and proximity to shopping and transportation routes, said Agaton, who has sold many homes near freeways in her 17-year career.

Fabres, a single mother of four teenagers, said that the location is what attracted her to the West Covina home. She worked in the health-care field near downtown Los Angeles when she purchased the house three years ago after a divorce, and freeway proximity saved the busy mother time.

"It was an advantage," she said. "When you came home it was close." It also was close enough for her children to walk to school, a nearby park and the West Covina Plaza.

The noise bothered the family at first, and Fabres said she was fleetingly concerned about pollution. However, she found that the location and features of the three-bedroom, two-bath home with a den and large backyard outweighed those concerns. Fabres is taking time off from work to sell her home and move to Walnut for its schools and proximity to Mt. San Antonio College, where her children, who have no respiratory disease, plan to continue their education after completing high school.

In addition to saving time, buyers are often attracted to freeway-close homes because of lower prices, according to real estate industry executives. Fabres, for instance, is asking $275,000 for her home.A couple blocks farther north of Interstate 10, a comparable three-bedroom home in the same neighborhood sold for $289,900 in mid-November.

"Home prices near freeways generally are less expensive," said John Burns, president of John Burns Real Estate Consulting in Irvine. A rule of thumb, he said, is that these homes cost the buyer about $5 less per square foot than a comparable home in the same area far enough away that buyers do not perceive the freeway as a negative.

But researchers are beginning to document the drawbacks. Large doses of pollutants emitted by motor vehicles can irritate the respiratory system and exacerbate asthma and chronic bronchitis, from which 10% to 20% of the population suffers, according to Dr. John Balmes of UC San Francisco. Published studies examining the respiratory health of people along freeways show a 75% to 100% increase in asthma because of the higher concentration of air pollutants, said Balmes, former president of the California Thoracic Society, the medical section of the American Lung Assn. of California. Some of the pollutants, including benzene and diesel soot, are known carcinogens.

One study published earlier this fall in the Journal of the Air & Waste Management Assn. shows that the level of so-called ultra-fine particles, which are emitted from automotive tailpipes but are too small to be visible, was four times higher just downwind and east of the 405 Freeway in Westwood. About a fifth of a mile downwind, the level of the particles gradually fell to the same level as upwind of the busy freeway, wrote the research team, headed by William C. Hinds, a professor in the Department of Environmental Health Sciences at UCLA. Carbon monoxide, a good indicator for a range of other automotive emissions, also fell sharply a fifth of a mile downwind of the freeway.

Environmental health scientists are particularly worried about ultra-fine particles because they can penetrate deep into the respiratory system.

In another study in the Los Angeles area, the South Coast Air Quality Management District found that the risk of contracting cancer from air pollution, particularly lung cancer, was up to twice or more as high right along the freeway than in other areas of the region, except for those with both dense traffic and heavy concentrations of industry.

Like many Southern Californians, Kennard, who grew up in Altadena, is used to air pollution. "As you drive into the inland area, you see the smog haze," she said. "However, I can't say that I paid too much attention. My children do not have any respiratory issues."

Yet, Kennard said she is concerned about what the studies reveal. "I would move, if I could, to a cleaner area."

Until environmental and zoning regulators complete ongoing studies and develop guidelines or regulations, home buyers must carefully weigh the benefits and health risks of being near a freeway. Said epidemiologist Tager: "If I were a parent with young children and had a choice between a nice home near a freeway and one not so nice but away from a freeway, I'd buy the one away from the freeway."

William J. Kelly is a freelance writer and the editor of California Environment Report. He can be reached at southlandreports@earthlink.net