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Air Pollution


The risks to health from air pollution are largely invisible today in the industrial world yet air pollution is a leading environmental cause of cancer.  In years past, polluted air resulted in shocking episodes of deadly killer smog. EHT’s Dr. Davis documented the Donora Smog in her book When Smoke Ran Like Water of the five days in October, 1948 when  20 persons dropped dead after a lethal smog descended on the small Monongahela Valley steel town of Donora, Pennsylvania.

China and India are experiencing the same sorts of poisonous episodes of air pollution today similar to Donora, Pennsylvania in 1948 and London, England in 1952. The sources of this pollution largely stem from the  burning of fossil fuels, such as coal, oil, natural gas, and gasoline to produce electricity and power our vehicles  and industry emissions. Until stronger standards to reduce toxic emissions industries are implemented, harmful toxic chemicals will continue to pollute the air,  threatening public health.

The impressionist painter Claude Monet painted nearly 100 different canvases depicting London’s famed smogs at the turn of the 20th century, which were fueled largely by coal-burning. These same conditions in 1952 combined with newly released diesel bus exhausts, led to the deaths of 12,000 Londoners, according to important analyses of historical medical records by Yale University Professor, Michelle Bell and Dr. Davis showing elevated mortality in the months after the smog.
A 2015 leak at the California Aliso Canyon natural gas storage facility ejected nearly 90 thousand metric tons of methane into the air and thousands of residents near the leak are suffering from headaches, nosebleeds, coughs and have been forced to relocate to hotels and temporary apartments.
1997: Scientists State That Inaction Will Lead To Preventable Deaths

Evidence developed by Dr. Davis and colleagues and published in the Lancet on the toxic impact of polluted air provided the foundation for the Intergovernmental Panel on Climate Change 1995-2004 to advise that if current patterns of pollution in the 1990s were not changed to burn fewer fossil fuels, then 8 million avoidable deaths would occur by 2020 around the world.

2013: 7 Million Premature Deaths Annually Linked to Air Pollution

In 2014, the World Health Organization reported that  in 2012 around 7 million people died – one in eight of total global deaths – as a result of air pollution exposure. “This finding more than doubles previous estimates and confirms that air pollution is now the world’s largest single environmental health risk. Reducing air pollution could save millions of lives.” Read the World Health Organization press release.

“The air we breathe has become polluted with a mixture of cancer-causing substances,” said Dr Kurt Straif, Head of the IARC Monographs Section. “We now know that outdoor air pollution is not only a major risk to health in general, but also a leading environmental cause of cancer deaths.”


World Health Organization Monograph On Outdoor Air Pollution as A Carcinogen.

Science Blog: Air pollution classified as a human carcinogen in 2013.

CNN WHO: Air pollution caused one in eight deaths


Even healthy people can experience air pollution-related symptoms such as watery eyes, breathing difficulties, coughing, or wheezing. Your actual risk depends on your current health status, the pollutant type and concentration, and the length of your exposure to the polluted air.

People most susceptible to severe health problems from air pollution are those with heart disease, lung disease, outdoor workers, athletes who exercise outdoors, pregnant women and children under age 14, as their lungs are still developing.

Increasing levels of smog are associated with increased hospital admission rates and death for people with respiratory diseases such as asthma, and worsens the health of people suffering from cardiac or pulmonary disease. High pollution adds stress to the heart and lungs, which must work harder to supply the body with oxygen. Damaged cells in the respiratory system

Long-term exposure to polluted air can have permanent health effects:

  • Accelerated aging of the lungs
  • Loss of lung capacity
  • Decreased lung function
  • Development of diseases such as asthma, bronchitis, emphysema, and possibly cancer
  • Shortened life span

Approximately 158 million Americans live in counties where air pollution exceeds national health-based standards.

Particulate Matter (PM)Ground-level OzoneStratospheric Ozone
Particulate Matter is a complex mixture of air pollutants that may contain soot, smoke, metals, nitrates, sulfates, dust, water and tire rubber. It can be directly emitted, as in smoke from a fire, or it can form in the atmosphere from reactions of gases. These small particles (known as PM2.5 or fine particulate matter) pose the greatest problems because they can get deep into your lungs and some get into your bloodstream affecting both your lungs and your heart.

In the presence of sunlight combined with VOCs and oxides of nitrogen (NOx) from vehicles ground-level ozone forms and reaches its highest levels during the afternoon and early evening hours.  Ozone irritates the lungs and causes a host of diseases including emphysema, bronchitis and asthma, lung damage, wheezing, respiratory issues, reduced resistance to infection, fatigue and weakened athletic performance. Long term continuous exposure to ground-level ozone can damage lung tissue and contribute to chronic lung disease and reduce life expectancy.

While ground level ozone is increasing, stratospheric ozone (located several miles above the earth) decreasing. Stratospheric ozone is actually protective, filtering the sun’s ultraviolet rays, insulating the earth from harmful radiation. Scientists are report a thinning of this shield and “holes” have appeared in some areas, such as in the Antarctic. Emissions of Chlorofluorcarbons (CFCs) -being phased out-   have accounted for a large percentage of stratospheric depletion. CFCs can remain in the atmosphere for as long as a century, meaning their impact will persist for a long time.


The Ozone Hole Tour – This tour explores the loss of ozone over Antarctica and what’s being done to avert a growing environmental crisis.

EPA: Stratospheric Ozone Site

The Tribune Democrat: Report on Environment Critical of Power Plants

  • The report, “Dirty Energy’s Assualt on our Health: Mercury,” details the most polluting plants and points to RRI Energy Inc. Keystone Power Plant in Shelocta as the second-most polluting plant for mercury emissions in the country. The report says it emits 2,164 pounds of mercury every year.

The Lancet: Short-term improvements in public health from global-climate policies on fossil-fuel combustion: an interim report Devra Lee Davis, Working Group on Public Health and Fossil-Fuel Combustion