Some air pollution is easy to see. When a truck roars down my urban street, I can see the coarse particles in soot as a black puff from the tailpipe. Those particles visibly settle on my potted porch plants, drift in my door, and get inhaled by my kids. It’s not pretty, and I’m not happy about it.
But some air pollution is not so obvious. Such is the case with fine particles, a dangerous form of air pollution that comes out of truck tailpipes and power plant smokestacks. Fine particles don’t make obvious soot clouds, though they can form blankets of visible haze. But at times they are invisible, and enter my lungs, and the lungs of my kids without me even knowing it.
And that, my friends, is a serious health problem. Fine particles are so small that the individual liquid droplets and solids it’s comprised are invisible to the naked eye. Also called “PM 2.5,” fine particles are less than 2.5 microns in diameter – 1/30th the width of a human hair. Scientists are increasingly concerned about the dangers of such tiny particles because they can lodge deeply into the lungs.
Many, many people are at risk. Currently, 70 million Americans live in areas that are in violation of the health standards set by EPA. That’s 70 million people routinely exposed to fine particles at levels that the EPA deems unsafe.
What are the resulting health effects?
According to the EPA, PM 2.5 causes irritation of the airways, coughing, and difficulty breathing, decreased lung function, aggravated asthma, chronic bronchitis, irregular heartbeat, nonfatal heart attacks, and premature death in people with heart or lung disease.
Now we can add lung cancer to that terrible list of environmental effects of air pollution.
A study published last month in the American Journal of Respiratory and Critical Care Medicine examined the relationship between long-term fine particle pollution and deaths from lung cancer in 188,000 Americans.
The researchers, led by Michelle Turner of the University of Ottawa, followed their study subjects for 26 years, from 1982 to 2008. They found that PM 2.5 exposure, as measured by air monitoring systems, was significantly correlated with deaths from lung cancer. Turner and her colleagues are fairly certain that these lung cancers were not caused by cigarette smoking, a potent carcinogen and a common confounder in cancer studies, because they studied only those people who had never smoked.
One interesting thing about the study is that it looked at fine particle exposure at levels currently seen in American cities. These are not necessarily places where the pollution is through the roof, or even places where fine particles exceed the EPA standards. Lung cancer risk was increasing with the kinds of exposures that we see in many parts of the country, even places deemed “in attainment” of EPA standards.
Is there something wrong with the PM 2.5 standard? The American Lung Association thinks so. It stands to reason that if the standard can be met while giving people lung cancer, the standard might not be strong enough.
Granted, the lung cancer risk from chronic exposure to fine particle pollution is far less than that from cigarette smoking. But about one in ten people who develop lung cancer have never smoked. When dealing with the leading cause of cancer deaths in both men and women, a cancer that takes over 150,000 lives every year, it’s important to remember that if we can reduce this risk even in small ways, many lives could be saved.
Well, here’s some good news. The EPA has proposed fuel efficiency standards for cars and light trucks that will lower fine particle pollution by reducing the amount of oil we burn. Public hearings on these standards, which will affect cars made through 2025, ended this week. But the comment period is open through February 13th, 2012. You can submit a comment to EPA’s public docket supporting improved fuel efficiency for our cars and light trucks.
Unfortunately, the fine particle pollution coming from power plants is not on track for similar reductions. EPA said this week that it needed more time to finish drafting new standards for fine particles from power plants. The agency is required by the Clean Air Act to set science-based standards every five years. It missed its October 2011 deadline and indicated in a court filing last week that the new standards would not be finalized until June, 2013. It’s a disappointing delay.
Here’s what you can do to help reduce your family’s exposure to fine particle pollution:
Know your air. Find out whether the air you breathe is persistently polluted with fine particles here. Also, you can find out what is the quality of the air you are breathing right now at AirNow, a government website that provides real time air quality mapping.
Avoid exercising outdoors in air that is high in fine particle pollution. Don’t let your kids exercise outside on such days either. Vigorous exercise brings more of the fine particles deep into the lungs.
Use less electricity. Power plants are one of the largest pollution sources in the US.
Drive less. Cars increase air pollution, including fine particle pollution.
Don’t burn wood or trash. Such fires are a large source of fine particle pollution.
Clean up your school system’s school buses. Old diesel buses can be a significant source of particle pollution. Make sure your school system is retrofitting old buses and has a strong anti-idling policy.