Growing up in polluted towns and cities increases risk of lung health issues

Children who grow up in towns and cities with high pollution levels are at increased risk of lung health issues or low functioning lungs. New research suggests that pollutants from vehicle emissions and fossil fuels have an adverse effect on a child's lung development and can also lower childrens lifetime breathing capacity.

In California, 90% of the children under the age of 14, live in areas that fail to meet state and federal air quality standards. 127 Million Americans ­ half of the nation's population live in regions with air quality that does not meet federal standards for certain air pollutants.

The results of this new study, conducted by researchers at the University of Southern California Keck School of Medicine, are published in this week's issue of the New England Journal of Medicine.

"This is the longest study ever conducted on air pollution and children's health," said Dr. Kenneth Olden, director of NIEHS. "It shows that current levels of air pollution have adverse effects on lung development in children between the ages of 10 and 18."

Each year, pulmonary function data were collected from 1,759 children as they progressed from 4th grade to 12th grade. The researchers also tracked levels of air pollutants like nitrogen dioxide, acid vapor, elemental carbon, and particulate matter in the 12 Southern California communities where the children lived. The study encompassed some of the most polluted areas in the greater Los Angeles basin, as well as several less-polluted communities outside the Los Angeles area.

Over the eight year period, researchers found that children living in the most polluted communities had significant reductions in their "forced expiratory volume" — the volume of air that can be exhaled after taking a deep breath — as compared to children living in communities with cleaner air.

In healthy people, lungs grow to full capacity during the teenage years, but typically stop growing at age 18. Then, lung capacity gradually declines. Adults begin to lose lung function by 1 percent each year after age 20.

"Lung development in teenagers determines their breathing capacity and health for the rest of their lives," said John Peters, M.D., Hastings Professor of Preventive Medicine at the Keck School of Medicine. "The potential long-term effects of reduced lung function are alarming. It's second only to smoking as a risk factor for mortality. As lung function decreases, the risk of respiratory disease and heart attacks increases."

Deficits in lung function are associated with other short- and long-term effects. "If children or young adults with low lung function were to have a cold, they might have more severe lung symptoms, or wheezing," says W. James Gauderman, Ph.D., associate professor of preventive medicine at the Keck School and lead author on the study. "They may have a longer disease course, while children with better lung function may weather it much better."

Researchers are unsure how air pollution may retard lung development. Gauderman believes chronic inflammation may play a role, with air pollutants irritating small airways on a daily basis. Scientists also suspect that air pollutants might dampen the growth of alveoli, tiny air sacs in the lungs.

The research team will continue to follow the study participants into their early 20s, when their lungs will be fully mature. They want to find out whether the participants will experience respiratory symptoms, and if those who moved away from a polluted environment will show some improvement in lung function.

This research is part of the larger Children's Health Study, an ongoing study that was started in 1993. The study is the longest ever undertaken on the association between air pollution and children's health.

Some simple facts from the Coalition for Clean Air


  • Nitrogen Oxides + Hydrocarbons + Sunlight = Smog / Ozone
  • In 1995, 3,518 tons of NOx, 2,214 tons of particulate matter, and 3,495 tons of reactive organic gases were emitted into California's atmosphere every day.
  • In California, 90% of the children under the age of 14, live in areas that fail to meet state and federal air quality standards.
  • 127 Million Americans ­ half of the nation's population live in regions with air quality that does not meet federal standards for certain air pollutants.
  • The lung damage caused by ozone exposure may be likened to the lung damage caused by cigarette smoking.
  • People who live in cities with dirty air have blacker lungs than people who live in rural areas with less air pollution.
  • Asthma is the most chronic disease of children, and the most common cause of childhood hospitalizations in California.
  • The South Coast Air Basin had 40 days above the federal standard for ozone in 2000
  • Gasoline and diesel powered vehicles produce 60% of the smog-forming pollutants in California.
  • Pollutant levels inside vehicles may be 10 times higher than ambient air.
  • Breathing air in Southern California can reduce one's life expectancy by 1 to 2 years.


  • Diesel exhaust has been listed as a known carcinogen under California's Safe Drinking Water and Toxic Enforcement Act (Prop 65) since 1990.
  • Exhaust from heavy-duty diesel engines contains between 100-200 times more small particles than gasoline engine exhaust.
  • Diesel exhaust is a mixture of over 450 different components, including vapors and fine particles coated with organic substances. Over 40 chemicals contained in diesel exhaust are considered toxic air contaminants (TAC's) by the State of California.
  • California's Scientific Review Panel estimates that 16,010 Californians will develop lung cancer over a lifetime of diesel exhaust exposure.
  • Only 2 percent of the vehicles on California's roads are diesel-powered and yet, diesel vehicles account for 31% of the total smog forming oxides of nitrogen (NOx) and 79% of the total particulate matter (PM) emissions produced by on-road vehicles.

School Buses:

  • Children respire at a rate twice that of adults, and are thus more susceptible to the toxicity of airborne diesel particles, vapors and gases.
  • The average diesel school bus is 223.5 times more toxic than a new compressed natural gas (CNG) school bus.
  • Over 69% of the 24,372 school buses in California's fleet run on diesel fuel and approximately 4% of the fleet predates 1977.
  • Compressed natural gas school buses cost approximately $30,000 dollars more than a comparable diesel school bus.
  • Over 40 school districts in California currently operate compressed natural gas school buses to carry school children.

Alternative Fuel Vehicles:

  • Electric vehicles or EV's are the only true zero-emissions vehicles on the road.
  • Electric vehicles run on electricity provided by on-board batteries, and can be recharged at any of the many recharging stations around the state.
  • The only emissions related to electric vehicles are from upstream power plants providing electricity.
  • As of September 1999, there were more than 3,000 electric vehicles (EV's) on the road in the U.S. that were produced by major car companies, most of them in California.
  • Hybrid vehicles offer 2-3 times the energy efficiency of a comparable gasoline-only car, and have ranges of about 600 miles on a tank of gas.
  • The only hybrid vehicles currently available are the Honda Insight and the Toyota Prius, which have retail prices of just over $20,000.
  • Upstream emissions for gasoline vehicles are more than 14 times higher than for electric vehicles.

Light Trucks and SUV's:

  • Light trucks and SUV's do NOT have to meet the strict emission standards placed on passenger cars.
  • SUV's now account for roughly half of all auto sales in the United States.
  • Light-trucks and Sport Utility Vehicles emit approximately 3 times more pollution than the average new car, and are much less fuel efficient.
  • It would cost approximately $200 per vehicle to make SUV's and light-trucks meet the same emission standards as cars.


  • Los Angeles International Airport is the second largest industrial smog source in the Los Angeles area.
  • In 1993, aircraft at U.S. airports emitted 350 million pounds of nitrogen oxides and volatile organic compounds during landing and take-off cycles.
  • One 747 arriving and departing from JFK airport in New York City produces as much smog-forming volatile organic compounds as a car driven 5,600 miles, and as much nitrogen oxides as a car driven 26,500 miles.
  • The U.S. is one of only 3 countries opposing a worldwide standard that would reduce the impact of aircraft emissions in the atmosphere.,


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
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