Respiratory disease has been the top concern for people exposed to air pollution in Houston and other large cities, and most studies have examined the association of air pollution with lung cancer and asthma. However, recent studies have found that air pollution is related to more deaths from heart disease than lung cancer and other respiratory illnesses.

Studies show strong link between air pollution and death from heart disease
C. Arden Pope III, a Brigham Young University epidemiologist, analyzing data from more than half a million adults participating in an American Cancer Society’s Cancer Prevention Study decided to compare incidence of heart attacks and other cardiovascular diseases and respiratory diseases with the Environmental Protection Agency’s air pollution data for more that 150 cities. He was surprised to find that more than two-thirds of the deaths due to air pollution were deaths from heart disease.

The American Heart Association has voiced its concern as more studies reveal the effects of air pollution on health and its link to heart disease and stroke.

How does air pollution affect the functioning of the cardiovascular system?
More study is needed, but researchers agree that several mechanisms may be involved. Lung inflammation that results from breathing polluted air makes it harder to breathe and reduces the blood’s capacity to carry oxygen to the heart. Exposure to particulate matter can cause the blood to thicken damaging arteries and causing clotting that can result in a heart attack. These pollutants also can disturb the heart’s rhythm. Air pollution from petrochemical plants, refineries and automobile emissions can increase blood pressure, narrow blood vessels, decrease blood flow to the heart and interfere with regulation of vital involuntary functions.

Carbon monoxide takes oxygen away from the heart and other vital organs
At the American Heart Association’s 2003 Scientific Sessions, researchers from the First Cardiology Clinic at The University of Athens School of Medicine in Athens, Greece reported on their five-year study examining air pollution and heart disease and stroke in Athens. Among other links to air pollution and heart disease, they found that a 10 unit increase in carbon monoxide was associated with a 46 percent increase in cardiovascular deaths.

Carbon monoxide (CO) is a colorless, odorless and highly poisonous gas produced by combustion reactions in cars and other vehicles. When the CO level increases in the blood, the amount of oxygen the blood can carry decreases. At 20 parts per million (ppm) of CO, loss of oxygen to vital organs begins. The amount of CO in the air during an urban “air pollution emergency” alert is 50 ppm. A short peak in CO is enough to cause a stroke in a person who has blood vessel disease. The increased CO from air pollution may be especially dangerous for smokers who already have a higher level of CO binding with the oxygen in their system from cigarette smoke. In addition, nicotine causes blood pressure to rise and arteries to narrow.

Exposure to polluted air affects regulation of blood pressure and heart rate
Another study by scientists at Pennsylvania State University College of Medicine looked at the connection between air pollution and cardiac autonomic control – regulation of involuntary bodily functions such as blood pressure and acceleration of the heart. Using data from the population-based Atherosclerosis Risk in Communities Study, they found that higher concentrations of air pollution are associated with lower cardiac autonomic control especially among people who have cardiovascular disease.

Ozone and particulate matter exposure increases risks several ways Narrowing of the blood vessels is another mechanism linked to heart attacks and strokes. A study led by Dr. Robert Brooks, a specialist in the biology of blood vessels at the University of Michigan, studied what happened to 25 healthy volunteers when they breathe air containing levels of ozone and fine particulate air pollution that can be found in large cities like Houston on bad air days. After two hours of breathing polluted air, the volunteers’ blood vessels constricted between 2 percent and 4 percent. Their vessels did not constrict when they breathed clean, filtered air.

Exposure to particulate matter and ozone also may increase the risk of ischemia – decreased blood flow to the heart – another serious symptom of heart disease. Researchers at the National Public Health Institute in Kuoplo, Finland, studied 45 heart disease patients exposed to pollution in Helsinki from factory smokestacks and diesel-powered buses and trucks. The researchers used electrocardiograms to measure the changes in patients’ oxygen supply. They found that patients exposed to the dirty air were about three times more likely to have ischemia while exercising than when they exercised after breathing cleaner air.

Scientists at Health Canada found that exposure to ultrafine particles (PM 0.1 – 0.1 micrometers) that have accumulated metals and/or hydrocarbons doubles the amount of endothelin in the blood. Endothelin, a small protein, increases blood pressure. While healthy people may be able to tolerate this spike in blood pressure, it may kill someone who has heart or blood vessel disease.

Take care of yourself and your family
Heart disease is a leading cause of death for men and women in the United States.

To reduce your risk of heart disease:

Call 9-1-1 if you or someone you are with has symptoms of a heart attack. Symptoms include:

• Chest discomfort. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes, or that goes away and comes back. It can feel like uncomfortable pressure, squeezing, fullness or pain.
• Discomfort in other areas of the upper body. Symptoms can include pain or discomfort in one or both arms, the back,neck, jaw or stomach.
• Shortness of breath... This feeling often comes along with chest discomfort. But it can occur before the chest discomfort.
• Other signs: These may include breaking out in a cold sweat, nausea or lightheadedness.

If you or someone you're with has chest discomfort, especially with one or more of the other signs, get to a hospital right away. A few minutes can make a big difference in recovering from a heart attack. Calling 9-1-1 is almost always the fastest way to get lifesaving treatment. Emergency medical services staff can begin treatment when they arrive -- up to an hour sooner than if someone gets to the hospital by car. If you can't access the emergency medical services (EMS), have someone drive you to the hospital right away. If you're the one having symptoms, don't drive yourself, unless you have absolutely no other option.

Do your part to reduce air pollution:

• Limit driving. Share rides, carpool. Combine errands.
• Take public transportation.
• Avoid excessive idling of your automobile.
• Keep your car well-tuned.
• Refuel your vehicle carefully and in the evening when it is cooler.
• Contact your local, state and national representatives and let them know you want a responsible energy policy and proper monitoring and control of emissions from petrochemical refineries and power plants.
• Be informed about the platforms and records of political candidates and vote for candidates who have a track record for protecting the environment.