Air Pollution & Brain Cancer

CURWOOD: California state legislators say it’s their way or the highway when it comes to protecting school children from air pollution. Concerns over childhood asthma and lung cancer have led to the passage of a bill will block the building of new schools near major freeways and busy roads. Tiny particles from passing diesel vehicle pose some of the biggest dangers to health. Now, an emerging study may show that air pollution isnot only linked to respiratory problems, but may also to brain cancer. Dr. Keith Black is heading up this study and directs neurosurgery at CedarSinaiMedicalCenter. He joins me now from his Los Angeles office. Dr. Black, welcome.
BLACK: Thank you.
CURWOOD: Tell me, Doctor, what’s the best evidence to date that there may be a link between specific types of air pollution and brain cancer?
BLACK: Well, we know from animal studies that we’ve done, that when animals are exposed to toxins that we find in air pollution that they’re able to develop brain tumors. These toxins can include things that are released by diesel engines, such as ultra-fine particles that we know can readily cross the blood-brain barrier and get right into the brain. We also know that particular occupational exposure to high concentrations of diesel exhaust may result in a higher incidence of brain tumor development. Firemen, for example, that live in fire stations where the diesel engines for the fire engines are turned on. And this diesel exhaust is able to escape into the fire station, exposing firemen to very high concentrations of diesel exhaust, resulting in a higher development of brain tumors in fireman.
CURWOOD: Why the special interest in particulates?
BLACK: Well, we know that, particularly along freeways, there’s a very high concentration of ultra-fine particles, that(they) are released by diesel engines. And when we inhale these ultra-fine particles, they rapidly cross into our blood, and cross from blood into the brain.
CURWOOD: Now, how small are these ultra-fine particles?
BLACK: They’re extremely small. They’re in the range of what we would consider to be nanoparticles. And they’re so small, in fact, that they can rapidly cross almost any biological barrier, or any other barriers. You know you’re rolling up your windows, or your filtration system on your air conditioning unit will not filter out these particles.
CURWOOD: So what exactly is the mechanism of action here? How may air particulates, these ultra-fine particulates, cause tumors?
BLACK: What we’re speculating, at this point, is that they’re able to disrupt the molecular and genetic machinery in the cells, increasing the expression of bad genes, or cancer genes within these cells.
CURWOOD: To what extent do you think your study could revolutionize the perception of how dangerous particulates might be?
BLACK: I think that it’s easy to make the association between asthma and particulates, between lung cancer and particulates, because we’re breathing those in the lung. What we don’t understand readily is that these particulates are crossing from the lung into the blood system and they’re effecting(affecting) other organs in the body. We’re focused on the development of brain tumors, but getting particulates into the brain may actually extend beyond brain cancer. We don’t know what the contribution of that may be to the development of Alzheimer’s disease, other neurological disorders, including autism and other disabilities.
CURWOOD: Dr. Keith Black is the director of neurosurgery at CedarSinaiMedicalCenter. Thanks for taking this time with me today.
BLACK: Alright, well, thank you. It’s been a pleasure.
[MUSIC: Beastie Boys “Instant Death” HELLO NASTY (Capitol Records-1998)]

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toxin (n) : a poisonous substance that is a specific product of the metabolic activities of a living organism and is usually very unstable, notably toxic when introduced into the tissues, and typically capable of inducing antibody formation

asthma: noun: a condition often of allergic origin that is marked by continuous or paroxysmal labored breathing accompanied by wheezing, by a sense of constriction in the chest, and often by attacks of coughing or gasping

paroxysm 'par-&k-"si-z&m also p&-'räk-: noun 1: a fit, attack, or sudden increase or recurrence of symptoms (as of a disease) 突發性: CONVULSION <a paroxysm of coughing> 2 : a sudden violent emotion or action : OUTBURST <a paroxysm of rage>突發, - paroxysmal"par-&k-'siz-m&l also p&-"räk-/ adjective

Discussion Questions

  1. Normally, we associate air pollution with coughing, i.e., respiratory problems. Are you surprised by the study here that air pollution is linked to brain tumor? Have you known this before? Try to tell us more about either your feelings or prior knowledge.
  2. Do you know that most commercial trucks have diesel engines? Next time if you are in the traffic jam, on a motor cycle, a bus or even in your own car and near diesel trucks, what would you do? (You know the fine particle can get through the car AC filtration.)
  3. Commercial trucks use diesel engines to save fuel. Now, if we can verify that their exhaust fume can cause brain tumor, would you ban the commercial trucks? If you were in the United Nations, how many years would you program to totally phase out the diesel engines?
  4. What do you think of the air quality at Yang-MingUniversity, as compared to downtownTaipeiCity? Do you think air quality is important to life? How important? Have you tried to avoid some places because of air-pollution? Give us some examples.