Sierra Club Cites Two Dozen Peer Reviewed Studies Showing Pollution Health Hazards From Freeways and Heavily Used Roads

Key Findings from Scientific Studies:

A Johns Hopkins study shows association between traffic and curbside concentrations of cancer causing pollutants.

The Journal of the American Medical Association study links soot in diesel exhaust to lung cancer, cardiopulmonary disease and other causes of death.

A Denver study shows children living near busy roads are six to eight times more likely to develop leukemia and other forms of cancer.

A Journal of the American Medical Association study finds that increasing public transportation along with other traffic control measures during the 1996 Atlanta Olympics reduced acute asthma.

The California South Coast Air Quality Management District did a Multiple Air Toxics Exposure Study-II, the most comprehensive study of urban toxic air pollution, showing that vehicle exhaust is the source of cancer-causing air pollutants in Southern California.

A significant body of scientific evidence is emerging that links pollution from motor vehicles to a range of human health problems including asthma, lung cancer and premature death...

Health Effects From Highway Pollution [footnotes omitted here, full text in pdf below]

Air pollution is a major risk to our health and safety and is the contributing cause of nearly 100,000 premature deaths each year, more than twice the number of deaths from car crashes. In 2002, almost half of all Americans - or 137 million people - lived in counties with unhealthy air laden with one or more criteria air pollutants, according to the American Lung Association.

A major source of this air pollution is the exhaust from the tailpipes of trucks and cars. A variety of dangerous pollutants are released daily from the extensive networks of busy highways that border countless neighborhoods and businesses. These pollutants cause numerous adverse health effects including cancer, asthma, and heart attacks. In addition, asthma, which is exacerbated by pollution from trucks and cars, is the leading serious chronic illness among children and the number one reason children miss school.

The main cancer-causing pollutants from trucks and cars are diesel particulate matter and Volatile Organic Compounds (VOCs) such as benzene, 1,3-butadiene, formaldehyde, and polycyclic aromatic hydrocarbons (PAHs).

In recent years the relationship between vehicle pollution and increased cancer risk has received considerable scientific attention. A Denver study shows that children who live within 250 yards of a road with 20,000 or more vehicles per day are eight times more likely to get leukemia and six times more likely to get other cancers. The authors of the study attribute most of this risk to the VOCs in motor vehicle exhaust...

Children Living Near Busy Roads More Likely to Develop Leukemia, 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 Volatile Organic Compound pollution from traffic may be the cancer promoter causing the problem...

Road Traffic Contributes to the Origin of Childhood Leukemia

A 2004 Italian study found that Childhood Leukemia is partially caused by roadside emissions in the Province of Varese. The authors conducted a population-based, case-controlled study in the Province of Varese, northern Italy, which was covered by a population-based cancer registry. Their study found that the risk of childhood leukemia was almost four times higher for heavily exposed children compared to children whose homes were not exposed to road traffic emissions of benzene. Children either inhale Benzene as a gas or particulate matter which has absorbed benzene. Their model included traffic density divided into two groups -- one greater and one less than 10,000 vehicles per day, distance, and weather conditions to estimate benzene concentration. The researcher’s data suggests that motor vehicle traffic emissions are involved in the origin of childhood leukemia...

Soot Particulate Matter Linked to Lung Cancer, Cardiopulmonary Mortality

A recent study appearing in the Journal of the American Medical Association showed that day-today exposure to soot or fine particulate matter, a major component of tailpipe pollution increased the risk of various adverse health effects. More specifically the study shows that each 10 microgram/meter3 elevation in fine particulate air pollution leads to an 8 percent increased risk of lung cancer deaths, a 6 percent increased risk of cardiopulmonary mortality (heart attacks) and 4 percent increased risk of death from general causes...

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 220 yards 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...

People Who Live Near Freeways Exposed to 25 Times More Soot Particulate Pollution

Studies conducted in the vicinity of Interstates 405 and 710 in Southern California found that the number of ultra-fine soot particles in the air was approximately 25 times more concentrated near the highways and that pollution levels gradually decrease back to normal (background) levels around 300 meters, or nearly 330 yards, downwind from the highway. The researchers note that motor vehicles are the most significant source of ultra-fine particles,which have been linked to increases in mortality and morbidity. Recent research concludes that ultra-fine soot 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 highways...

Motor Vehicle Pollution 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 percent of the cancer risk from toxic air pollution, most of which is from diesel soot (70 percent of the cancer risk). Industries and other stationary sources accounted for the remaining 10 percent. The study showed that the highest risk is in urban areas where there is heavy traffic and high concentrations of population and industry...[Cites SCAQMD Multiple Air Toxics Exposure Study-II.March 2000]

Lung Function Reduced Among Children 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...

Exposure to Cancer-Causing Benzene Higher for Children Living Near High Traffic Areas

German researchers compared 48 children who lived in a central urban area with high traffic density with 72 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 percent 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 percent and 33 percent higher, respectively) among children regularly exposed to vehicle pollution. Aplastic anemia, a serious condition in which bone marrow stops producing blood cells, and leukemia were associated with excessive exposure to benzene...

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 premature cause compared with those who lived in less-trafficked areas. The authors say traffic emissions contain many pollutants that might be responsible for the health risks, such as ultra-fine particles, diesel soot, and nitrogen oxides, which have been linked to cardiovascular and respiratory problems...

Five Times More Deaths Due to Air Pollution than Traffic Accidents

This 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 almost five times more deaths in this region resulted from motor vehicle pollution than from traffic accidents...

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 a highway or polluting facility and decreases as you get further away from the facility...

Motor Vehicle Air Toxins Cause High Pollution Levels Inside Homes

An air pollution study was done as a part of the West Oakland Diesel Truck Emissions Reduction Initiative. Researchers measured diesel particulates near mobile and idling trucks at the West Oakland Port. An aethalometer was used to measure indoor toxins and a high level of diesel particulates was found. The people who lived in these homes were exposed indoors to five times the level of diesel particulates that people were exposed to outdoors in other areas of Oakland...