Clean Air is Possible, Practical and Affordable! Highlights from recent medical research on health effects

And it is what people will want when they learn about the risks to their health, their cognition, their children’s and parents’ brains, cancer & lives. Who among us can afford cognitive damage, life threatening inflammation or degenerative diseases from air pollution? Below are highlights from recent research (email to request more detailed compendium of research with references – marie (at)

  • 1-yr exposure to polluted air led to 7.5% increase in mortality for each 10 µg/m3 increase in PM2.5.
  • Mere 2-day exposure led to a 2.14% rise in mortality per 10 μg/m3 increase in PM2.5 concentration.
  • “Particulate air pollution is like lead pollution; there is no evidence of a safe threshold even at levels far below (a third of) current standards.” Even in less polluted (rural) areas “we do not see any signs of safe level”.
  • Long ago exposure to air pollution still increases risk of death. Exposure to air pollution 30 years ago is associated with increased risk of death today, especially via bronchitis, emphysema & pneumonia.

Traffic is typically biggest source of urban air pollution, worldwide, even in places where other sources are large factors. We’ve known air pollution is a global killer for decades, but now we know more.

About increased heart and cardiovascular disease associated with polluted air, now researchers know:

  • Blood sugar & cholesterol levels worsen with exposure to air pollution, raising heart disease risk.
  • Exposure to fine particulate matter over a few hours or weeks can trigger cardiovascular deaths, heart attacks, strokes, heart failure and irregular heartbeats.
  • Difference in air quality between a city like LA and one like St. Louis, Missouri raises a woman’s risk of cardiovascular disease by 44 percent if she has type 2 diabetes and even more in some cases.
  • Pollution levels are linked to narrowing of arteries, often a precursor to stroke. PM2.5 is linked to faster thickening of the carotid artery and indications of atherosclerosis among people with no obvious symptoms of heart disease. And those in higher pollution areas near roads or city centers, controlling for other factors, are twice as likely to suffer from coronary artery calcification (CAC) than people who lived in less polluted urban and rural areas. Increasing accumulations of coronary artery calcium makes patients 6x more likely to suffer from a heart attack or die from heart disease.
  • Narrowing of carotid artery is linked to problems in learning, memory, thinking & decision-making.
  • Air pollution — even at levels below regulatory standards — accelerates the progression of atherosclerosis and can cause heart attacks. For every 5 µg/m3 higher concentration of PM2.5, or 35 parts per billion higher concentration of oxides of nitrogen people had a 20% acceleration in the rate of calcium deposits. Arrhythmias, atrial fibrillation or acute coronary syndromes increase with levels of air pollution: 3% increase in admissions for every 10 microgram increase in PM10.
  • Irregular heartbeat, lung blood clots, atrial fibrillation, & pulmonary embolism are clearly linked to air pollution. For every increase in particulate matter of 10 micrograms per square meter the previous year, the risk of deep vein thrombosis (blood clots in thigh or legs) increased 70 percent.

Doctors say “Reducing air pollution is an incredibly efficient way to improve public health”

  • More than 5.5 million people die prematurely each year due to air pollution. Air pollution is the 4th highest risk factor for death globally and by far the leading environmental risk factor for disease.
  • Lifetime exposure and even miniscule increases in small particles increase deaths. Pollutants and risks spread further than previously thought. A study of over half a million people found that even miniscule increase in small air pollution particles cause overall increase in death from all causes and in heart & respiratory diseases. Risks can increase sharply as traffic increases or rush hour or delay grows longer. Those living or walking near exhaust sources (often lower income) suffer more.
  • Lifetime exposure matters. Every additional unit (10 mg/m3 air) of exposure to air pollution 30 years ago increased risk of mortality increased by 2% in 2002-2009 (vs. 24% increase in such risk for each additional unit of pollution exposure half that long ago, in 2001)

For most of human evolution and modern history, CO2 levels in the air were in a fairly narrow and low range of 180 to 280 ppm. We may not be adapted for higher levels. Should CO2 be a criteria pollutant?

  • CO2 is not a trivial problem for people and cognition too. Inside levels can be 3-4x those outside. Studies have found cognitive scores 2x higher on days with high outdoor air/ventilation (p< 0.0001).
  • Harvard researchers found significant negative impact on human cognition and decision making at 930 ppm of CO2. “The exposure-response between CO2 and cognitive function is approximately linear across the concentrations used in this study,” so the impact threshold may be much lower researchers estimated, and the threshold could be near (or possibly below) levels the world could experience outdoors over the next hundred years, essentially irreversible for centuries.
  • Higher level cognition and decision-making capacity (crisis, response, strategy, information usage) goes down at higher CO2 levels.
  • For 7 of the 9 nine cognitive function domains, average cognitive scores decreased at each higher level of CO2. Cognitive function scores were 15% lower for the moderate CO2 day (~ 945 ppm) and 50% lower on the day with CO2 concentrations of ~1,400 pp. An in-depth analysis reveals that occupant satisfaction with overall air quality is strongly linked to CO2 levels, with significant shifts to satisfaction when CO2 is less than 600 ppm. All of this new research is consistent with  and helps explain  dozens of studies in the past two decades that find low to moderate levels of CO2 have a negative impact on productivity, learning, and test scores.
  • Health and well-being is a multi-billion dollar industry and something people want more of. Air pollution impacts more areas of our health, mental well-being, and quality of life than we realize, and pollution can be addressed and prevented by policy action.

Air pollution worsens allergen severity in multiple ways

  • Air pollution worsens allergens in plants/plants produce higher concentrations of allergen (e.g., in ragweed pollen when plant is exposed to traffic pollution).
  • Traffic pollution also chemically alters and worsens allergens in other ways too: ozone oxidizes an amino acid, setting off a chain of chemical reactions, binding proteins together, making stronger allergens. Other auto exhaust pollutants alter polarity, binding capabilities of allergenic proteins.
  • Risk of developing all allergies rises with exposure to traffic pollution in first year of life.

Lung and asthma development (Do we want to be causing lifelong damage to children?)

  • US researchers/doctors commented: “The traditional approach to estimating the burden of air pollution-related disease has markedly underestimated the true effect
  • Death rates from emphysema, asthma and pneumonia decline with cleaner air. Now we also know:
    • In utero exposure to traffic air pollution is associated with developing asthma by age 6.
    • The effect from exposure to traffic pollution matters more than passive smoking.
    • Even low levels of air pollution affect a child’s lungs, cause permanent damage.

Recent findings in impacts of traffic pollution on maternal and child health

  • Reduced Fertility: For example, breathing ozone levels common in urban areas on day of ovulation decreases progesterone to 25% of that in clean air and reduced ovulated eggs by 30%.
  • Preterm Birth: Traffic-related air pollutants are associated with pre-term births. The time before conception, in early pregnancy, and last 6 weeks are especially important periods for inflammation.
  • Higher air pollution makes intrauterine inflammation twice as likely; linked to lifelong neurological and respiratory disorders for the child.
  • Even small amounts of air pollution have biological effects at the cellular level in pregnant women; women exposed to the highest levels of air pollution were twice as likely to have intrauterine inflammation.
  • Stillbirth: 4 ug/m3 increase in exposure to PM2.5 associated with 2% increased risk of stillbirth. Heightened risk also with exposure to NO2, carbon monoxide, PM10 and ozone.

Air pollution damages neural circuits, brain and cognitive function

  • High levels of traffic-related air pollution lead to slower cognitive development among 7-10 yr. olds. Elevated levels of PM2.5 are associated with smaller cerebral brain volume even in low pollution areas and among otherwise relatively healthy adults. A study of men and women age 50+ found that every 10% (a couple microgram) increase between 4.1 and 20.7 of PM 2.5 led to a .36 point drop in cognitive function score equivalent to 3 years of aging. Medical university studies suggest that long-term exposure can cause damage to brain structures and directly and negatively affects cognitive function in older and even in middle-aged adults.
  • Traffic pollution produces cognition and brain MRI alterations akin to Alzheimer’s. Air pollution is estimated to cause 21% of vascular dementia and Alzheimer’s disease. Higher levels of long-term exposure to PM 2.5 & 10 produce significantly faster cognitive decline and physical changes.
  • An increase of only 2µg per cubic meter in PM2.5 was equivalent to one year of brain aging and a 46% greater risk of silent strokes. Systemic inflammation is the likely cause. Silent strokes increase the risk of overt strokes and developing dementia, walking problems and depression.
  • Air pollution threatens brain development and harms young brains, increasing brain inflammation and neurodegenerative changes, like Alzheimer’s or Parkinson’s disease. These pathologies have been observed in brain biopsies of young urban children in polluted areas. Air pollution produced brain autoantibodies similar to those found in the brains of people who have neuroinflammatory diseases like multiple sclerosis. Long-term exposure to air pollution can cause inflammation and physical changes to the hippocampus associated with depression, memory, and learning difficulties.

Should polluted air be placing your child at risk of autism? Early exposure to PM 2.5, 10, or NOx

  • Researchers find that autism begins in pregnancy: with autism, cortical layers are disrupted during brain development.
  • Exposure to traffic-related air pollution, nitrogen dioxide, and particulate matter during pregnancy and during a child’s first year of life is linked to a higher risk of autism. NOx exposure during the first year doubles the risk of autism. There is greater risk of autism based on the child’s exposure to PM2.5 concentrations during the mother’s pregnancy and first two years of life.
  • Exposure to high levels of traffic-related air pollution during first year increases autism risk by 300%.

We want our children to have the best chances they can in school. They deserve not to be mentally impaired by the air they breathe!

Pollution exposure and lower IQ, social competence, self-regulation, and academic performance after controlling for other factors

  • ADHD, anxiety, depression, inattention & behavioral disorders increase with prenatal exposure to PAHs from motor vehicles, oil & coal, combustion. Research doctors are seeing physical changes to hippocampus (shorter dendrites, reduced cell complexity) with exposure to traffic pollution (PM 2.5); i.e., they are seeing impacts related to learning, memory, and depression.
  • Damage to neural circuits, life-long mental health and social competence are effects of early exposure to vehicle pollution. Prenatal exposure to PAHs raises the odds of behavior problems associated with attention deficit hyperactivity disorder, or ADHD, at age 9.
  • Children exposed to higher levels of PAHs did not improve in self-regulatory function as they grew.
  • Air toxics are associated with significantly lower GPAs and IQ tests at age 5.

Do we have the right to cause these lifelong problems in/to our kids or others?

Psychiatric risk increases with pollution

  • Air pollution is associated with anxiety, the most common psychiatric disorder
  • Prenatal exposure to airborne PAH during gestation associated with developmental delay at age 3, reduced verbal and full-scale IQ at age 5, and symptoms of anxiety and depression at age 7
  • Psychiatric diagnosis and medical treatment thereof correlates with air pollution concentrations: risk increases 9% per 10 mg/cubic meter increased concentration of nitrogen dioxide
  • Salt Lake City residents were more likely to commit suicide within 3 days of exposure to increased levels of nitrogen oxide or high concentrations of fine particulate matter.
  • Short-term air pollution exposure ‘increased suicide risk by up to 25%’. Depression is serious – it’s the leading cause of disability worldwide and results in major economic and life impacts.

Air pollution causes inflammation

Inflammation is a process by which the body’s white blood cells and substances they produce protect us from infection with foreign organisms, such as bacteria and viruses. Air pollution triggers this process, which factors into pain, obesity, ADD/ADHD, peripheral neuropathy, diabetes, heart disease, stroke, migraines, thyroid issues, dental issues, and cancer.

Chronic Inflammatory Diseases & Exposure to Diesel Exhaust

  • Air pollution induces oxidative stress & inflammation in organs & circulatory system. Higher levels of leptin, an “inflammatory cytokine,” have been linked to increased rates of heart disease, obesity, and diabetes. Increased insulin resistance and altered fat tissue linked with air pollution growing up raises risk of insulin resistance (prescursor to diabetes) in children.
  • Chronic inflammatory disease risk, asthma severity rises with exposure to traffic exhaust. Those living in higher traffic areas have markedly increased c-reactive protein, a marker of inflammation.

Rising Cardio-Respiratory, Metabolic Dysfunctions, and Obesity Air Pollution Exposure in Study

  • Outdoor air pollution is a leading cause of deaths from all cancers. Cancer link with air pollution is so pronounced it is now considered a Group 1 human carcinogen along with radiation, dioxins, inhaled asbestos. For every 10 microgram per cubic meter (µg/m³) of increased exposure to PM2.5 the risk of dying from any cancer rose by 22%. PM2.5 was associated with increased risk of mortality for all causes of cancer and for specific cause of cancer in upper digestive tract, digestive accessory organs in all subjects; breast cancer in females; and lung cancer in males. Breast cancer risk increased by about 25% with every increase of NO2 of 5 pp billion (used as an air pollution marker): women exposed to higher pollution levels were almost twice as likely to develop breast cancer.
  • Breast cancer, 2nd leading cause of death in women, has been linked to traffic pollution: an 80% increase in risk of mortality from breast cancer with every 10 µg/m³ increase in exposure to PM2.5
  • Digestive tract, liver, and pancreatic cancer: Every additional 10 µg/m³ of PM2.5 increased mortality from cancer in the upper digestive tract by 42% and by 35% in other digestive organs like the liver, bile ducts, gall bladder, and pancreas.
  • Childhood leukemia is associated with residential exposure to traffic exhaust.

Organ inflammation and/or fibrosis with or from air pollution

  • Kidney disease levels rise with PM 2.5 and PM 10 levels, even where those levels are much lower than typically considered unhealthy
  • There are more appendicitis hospitalizations on “high ozone” days. The effect of air pollution is strongest during summer when people are more often outside
  • Now we know air pollution causes liver fibrosis too, in turn associated with metabolic disease and liver cancer. Liver fibrosis is an advanced stage of chronic liver injuries more usually thought to be caused by chronic hepatitis viral infection, obesity, alcoholism or autoimmune diseases, but
  • Air pollution plays significant role in triggering tuberculosis infection:  study shows how carbon monoxide triggers Mycobacterium tuberculosis. Tuberculosis, leading cause of infectious disease in world, killing 1.5 million/year, in US infecting 4.6 per million people. Exposure to diesel exhaust particles makes immune cells less responsive to infection, suppressing their function on a cellular level. “We’re talking about huge socio-economic and public health implications,” said researcher.