Air Pollution

Every day, the air we breathe makes all of the things we enjoy in our lives possible. This week--Air Quality Awareness Week 2016--is a great time to reflect on the atmosphere that we often take for granted. Running from May 2 to 6, Air Quality Awareness Week is being sponsored for the tenth year by the U.S. Environmental Protection Agency (EPA). This year’s theme is “Show How You Care About the Air.”

It’s easy to think of air pollution as a big-city problem. High pollution days are most common in large urban areas, where the concentration of factories, homes, and vehicles leads to high levels of airborne contaminants. Yet poor air quality can result from both natural and human activity, and it makes a difference to the lives of billions of people who live far from urban centers. Across the interior U.S. West, the iconic views in places such as Grand Canyon National Park are often shrouded by ozone and other visibility-reducing pollutants. Wildfires dump ash on thousands of mountain residents each year. In the remote valleys of Appalachia, smoke can build up for days within cold air masses that get trapped by inversions. And in tiny settlements across Africa and Asia, cookstoves pump out soot that affects many who live and work indoors.

In the year 2013, outdoor air pollution was connected to about 2.9 million deaths globally, and about 80,000 deaths in the U.S., according to a 2016 study by the University of British Columbia. The global toll was even larger when considering both indoor and outdoor air pollution: more than 5.5 million premature deaths. The WHO has labeled air pollution “the world’s largest single environmental health risk.”

The good news is that people around the world are recognizing the priceless value of clean air and taking steps to protect it. Overall, U.S. air quality has improved dramatically since the passage of the Clean Air Act in 1970 and its strengthening in 1990. The prevalence of the most serious pollutants has dropped significantly (see graphic below). For example, the use of unleaded gasoline has almost eliminated airborne lead, which was a major threat in the 1970s.

One pollutant that’s been hard to reduce is particulate matter--tiny droplets and particles suspended in the air. Particulates less than 2.5 microns in diameter (about 0.0001 inches) are small enough to pass through the filters of our respiratory systems, which means they can accumulate in the lungs and cause both short- and long-term trouble. This includes a heightened risk of cardiovascular disease as well as asthma, lung cancer and other respiratory ailments. Worldwide, roughly 80% of the deaths related to outdoor air pollution in 2012 were from heart disease or stroke.

Droughts and wildfires are adding to short-term spikes in air pollution that may get worse in a warming climate. This includes low-level ozone, which tends to form on sunny, stagnant days. However, as our planet moves away from fossil fuels and toward renewable energy, we also stand to gain the win-win benefit of reduced air pollution, which can potentially save many thousands of lives. To find out more about the emerging connections between climate change and air quality, check out this WunderBlog post by Dr. Jeff Masters and Bob Henson.

Cutting emissions could prevent nearly 300,000 U.S. air pollution deaths by 2030

A key argument used to oppose reducing emissions to reduce global warming is the high cost. However, this opposition typically neglects the huge direct health benefits that occur due to the large reductions in air pollution that occur when greenhouse gas emissions are reduced. A February 2016 study published in Nature Climate Change, “Climate and health impacts of US emissions reductions consistent with 2 °C,” found that reducing U.S. emissions in the energy and transport sectors could prevent almost 300,000 early deaths caused by air pollution in the U.S. between 2015-2030, or about 20,000 per year. The reductions in pollution would also lead to about 29,000 fewer asthma attacks per year in children under 18 requiring emergency room visits, and save 15 million lost adult work hours per year.

These benefits would require a reduction of air pollution emissions of 2.7% per year between 2015 and 2050, consistent with the U.S. pledge made at the Paris Climate Summit in 2015 to keep global warming less than 2 °C above pre-industrial levels. The researchers estimated that the saved lives and reduced health care costs would benefit the U.S. economy by $250 billion per year, and estimated that “benefits seem to outweigh costs by at least a factor of 5–10.” Once you include the benefits of emissions cuts for reducing global climate change, these economic gains “roughly quintuple”, they said. Air pollution in the U.S. causes more than 200,000 early deaths every year. That’s roughly equal to the number of Americans who die from diabetes, Alzheimer’s or pneumonia every year put together, according to analysis of the new research done by Carbon Brief.

When one adds in the huge health and environmental costs associated with fossil-fuel extraction--such as oil spills, mountaintop removal for coal mining and failures of coal ash ponds--the benefits of switching away from fossil fuel energy sources grows even more stark.

Airborne allergens

There’s something else in the air too, and it’s making many of us sneeze and cough! Airborne allergens such as ragweed are on the increase across the United States. Hay fever now affects close to a third of all Americans, up from 10% in 1970, and a warming climate has lengthened the pollen season in many areas (see graphic). For more on airborne allergens and climate, see the new report on climate change and air quality, released in April by the U.S. Global Climate Research Program.

Air Pollution Safety

How you can avoid a premature death due to air pollution:

Pay attention to forecasts for high air pollution days to know when to take precautions
Avoid exercising near high-traffic areas
Avoid exercising outdoors when pollution levels are high, or substitute an activity that requires less exertion
Eliminate indoor smoking
Reduce the use of fireplaces and wood burning stoves

How you can help others avoid a premature death due to air pollution:

Support national, state and local efforts to clean up sources of pollution. When one hears talk about the high cost of cutting fossil fuels use to reduce global warming, keep in mind that any lessening of fossil fuel use will also reduce air pollution and all of its costs.
Conserve electricity and set your air conditioner at a higher temperature.
Choose a cleaner commute--share a ride to work or use public transportation. Combine errands and reduce trips.
Bicycle or walk to errands when possible.
Refuel cars and trucks after dusk.
Limit engine idling.
Get regular engine tune ups and car maintenance checks (especially for the spark plugs).
Avoid spilling gas and don’t “top off” the tank. Replace gas tank cap tightly.
Properly dispose of household paints, solvents and pesticides. Store these materials in airtight containers.
Paint with a brush, not a sprayer.
Buy low VOC paints for indoor and outdoor painting jobs.
Reduce or eliminate fireplace and wood stove use.
Avoid using gas-powered lawn and garden equipment.
Avoid burning leaves, trash and other materials.
Use household, workshop, and garden chemicals in ways that keep evaporation to a minimum, or try to delay using them when poor air quality is forecast.
Replace your car’s air filter and oil regularly

Nitrogen Dioxide (NO2) is a reddish-brown, highly reactive gas formed when another pollutant (nitric oxide) combines with oxygen in the atmosphere. Once it has formed, NO2 reacts with other pollutants, such as volatile organic compounds. Eventually these reactions result in the formation of ground level ozone. Major sources of NO2 include vehicles, waste disposal systems, and power plants.

The Environmental Protection Agency uses its Air Quality Index to provide general information to the public about air quality and associated health effects. An Air Quality Index (AQI) of 100 for any pollutant corresponds to the level needed to violate the federal health standard for that pollutant. For nitrogen dioxide, an AQI of 100 corresponds .053 parts per million (averaged over 24 hours) -- the current federal standard. Short-term health effects for NO2 do not occur until index values are above 200; therefore, an AQI value is not calculated below 201 for NO2. An index value of 201 for NO2 corresponds to an NO2 level of 0.65 parts per million (averaged over 24 hours).

Nitrogen Dioxide Health Hazards

What are the health effects from Nitrogen Dioxide?

In children and adults with respiratory disease, such as asthma, NO2 can cause respiratory symptoms such as coughing, wheezing, and shortness of breath. Even short exposures to NO2 affects lung function.
In children, short-term exposure can increase the risk of respiratory illness.
Animal studies show that long-term exposure to NO2 may increase susceptibility to respiratory infection and may cause permanent structural changes in the lungs.

Sulfur Dioxide (SO2) is a colorless, reactive gas. It is produced when sulfur-containing fuels such as coal and oil are burned, during the smelting of metal, and by other industrial processes. It can also enter the atmosphere naturally when volcanos erupt, and as sulfate particles from ocean spray. Generally, the highest concentrations of (SO2) are found near large industrial sources. High concentrations of this pollutant are not usually found in the United States. (SO2) causes rain to become acidic, and it reduces visibility by creating haze (smog).

Sulfur Dioxide Health Hazards

What are the health effects from Sulfur Dioxide?

Children and adults with asthma who are active outdoors are most vulnerable to the health effects of (SO2). The primary effect they experience, even with a brief exposure, is a narrowing of the airways, which may cause symptoms such as wheezing, chest tightness, and shortness of breath. Symptoms increase as (SO2) concentrations and/or breathing rates increase. When exposure ceases, lung function typically returns to normal within an hour.
At very high concentrations, (SO2) may cause wheezing, chest tightness, and shortness of breath in people who do not have asthma.
Long-term exposure to both (SO2) and fine particles can cause respiratory illness, alter the lung’s defense mechanisms, and aggravate existing cardiovascular disease. People who may be most susceptible to these effects include individuals with cardiovascular disease or chronic lung disease, as well as children and the elderly.

Carbon Monoxide (CO) is a colorless, odorless gas. It forms during the incomplete combustion of fuels that contain carbon. Vehicle exhaust makes up more than 60% of all CO emissions nationwide, and is one of the most dominant pollutants in cities. CO can also come from forest fires, and its concentrations are the highest during cold weather. This is because cold temperatures make combustion less complete and cause temperature inversions which trap pollutants low to the ground.

Luckily, CO is quickly removed from the atmosphere by microorganisms in the soil. Small amounts of this gas are extremely dangerous. Poorly ventilated areas such as parking garages and highway tunnels are especially vulnerable areas because CO can kill without warning.

Carbon Monoxide Health Hazards

What are the health effects from Carbon Monoxide?

CO enters the bloodstream when you inhale air. Usually your cells get oxygen through your hemoglobin (blood pigment), which carry it from your lungs throughout your body. Unfortunately, human hemoglobin prefer CO to oxygen, so if there is too much CO in the air your brain will become oxygen starved -- thus death may result.

People with cardiovascular disease, such as angina, are most at risk from CO. These individuals may experience chest pain and more cardiovascular symptoms if they are exposed to CO, especially when exercising.
People with marginal or compromised cardiovascular and respiratory symptoms, women that are pregnant, or small children, are most at risk from CO pollution.
In healthy individuals, exposure to higher levels of CO can affect mental alertness and vision.

Ozone is a colorless gas composed of three atoms of oxygen. Ozone forms both in the Earth’s upper atmosphere and at the surface. Where ozone forms determines whether it is helpful or harmful to your well-being.

An Ozone Action Day is declared when weather conditions are likely to combine with pollution emissions to form high concentrations of ground-level ozone that may cause harmful health effects. People and businesses should take action to reduce emissions of ozone-causing pollutants.

The Environmental Protection Agency uses its Air Quality Index to provide general information to the public about air quality and associated health effects. An Air Quality Index (AQI) of 100 for any pollutant corresponds to the level needed to violate the federal health standard for that pollutant. For ozone, an AQI of 100 corresponds to 0.08 parts per million (ppm) over an 8-hour period -- the current federal standard. Over half of the U.S. population lives in areas where the AQI exceeds 100 and violates the federal health standard at least once per year. Some metropolitan cities have severe air pollution problems, and can see ozone AQI values in the 200s or even 300s.

Ozone Health Hazards

Ozone Standards

In 2008, the EPA under the Bush administration chose to set the ozone air quality standard at 0.075 parts per million. The previous standard, set in 1997, was 0.08 ppm. Because ozone is measured out to three decimal places, the standard effectively became 0.084 ppm as a result of rounding. The 2008 standard was done in defiance of the recommendations of the Clean Air Scientific Advisory Committee, which found that the standard should be set between 0.06 and 0.07 ppm, and anything higher could not be scientifically justified. Since a unanimous 2001 Supreme Court decision upheld EPA’s long-standing interpretation that it must set these standards based solely on public health considerations without consideration of the economic costs, the 2008 standards were set not only in defiance of the best science available, but also in defiance of the law. The ozone standard in the European Union is set at 0.06 ppm.

According to the EPA, the 0.075 ppm standard would prevent 420 - 2,300 premature deaths each year, and save $4 - $17 billion per year in health care and other costs. The costs to business would be $7.6 - $8.8 billion. The stricter standard of 0.060 ppm would prevent 4,000 - 12,000 premature deaths, and save $35 - $100 billion per year. The estimated costs to businesses would be $52 - $90 billion pre year.

High ozone levels have been linked to increases in the severity of asthma attacks and other respiratory health problems, especially for children and the elderly.

Even healthy people will experience irritation of the respiratory system. Ozone causes constriction of the bronchial airways such as coughing, sore throat, ear aches, wheezing, chest discomfort, uncomfortable breathing. People who exercise or work outdoors may experience reduced exercise capacity. Those individuals with heart and lung disease react more severely to air pollution. People with asthma have more asthma attacks when ozone levels are high. Ozone makes individuals become more sensitive to allergens and can also be involved in the development of asthma. Ozone weakens the immune system and facilitates the development of lung infections. Thus ozone can inflame and damage the lung tissue.

Children are most at risk from exposure to ozone:

The average adult breathes 13,000 liters of air per day. Children breathe even more air per pound of body weight than adults. Because children’s respiratory systems are still developing, they are more susceptible than adults to environmental threats. Ground-level ozone is a summertime problem, and children are at risk when they are outside playing and exercising during the summer months at summer camps, playgrounds, neighborhood parks and in backyards.

Asthmatics and Asthmatic Children:

Asthma is a growing threat to children and adults. Children make up 25 percent of the population and comprise 40 percent of the asthma cases. Fourteen Americans die every day from asthma, a rate three times greater than just 20 years ago. African-Americans die at a rate six times that of Caucasians. For asthmatics having an attack, the pathways of the lungs become so narrow that breathing becomes akin to sucking a thick milkshake through a straw. Ozone can aggravate asthma, causing more asthma attacks, increased use of medication, more medical treatment and more visits to hospital emergency clinics.

Healthy Adults:

Even moderately exercising healthy adults can experience 15 to over 20 percent reductions in lung function from exposure to low levels of ozone over several hours. Damage to lung tissue may be caused by repeated exposures to ozone -- something like repeated sunburns of the lungs -- and this could result in a reduced quality of life as people age. Results of animal studies indicate that repeated exposure to high levels of ozone for several months or more can produce permanent structural damage in the lungs. Among those most at risk to ozone are people who are outdoors and moderately exercising during the summer months. This includes construction workers and other outdoor workers.

The term Particulate Matter (PM) includes both solid particles and liquid droplets found in air. Many man-made and natural sources emit PM directly or emit other pollutants that react in the atmosphere to form PM. These solid and liquid particles come in a wide range of sizes. Particles less than 10 micrometers in diameter tend to pose the greatest health concern because they can be inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter are referred to as “fine” particles. Sources of fine particles include all types of combustion (motor vehicles, power plants, wood burning, etc.) and some industrial processes. Particles with diameters between 2.5 and 10 micrometers are referred to as “coarse”. Sources of coarse particles include crushing or grinding operations, and dust from paved or unpaved roads.

The Environmental Protection Agency uses its Air Quality Index to provide general information to the public about air quality and associated health effects. An Air Quality Index (AQI) of 100 for any pollutant corresponds to the level needed to violate the federal health standard for that pollutant. For PM2.5, an AQI of 100 corresponds to 40 micrograms per cubic meter (averaged over 24 hours) -- the current federal standard. An AQI of 100 for PM10 corresponds to a PM10 level of 150 micrograms per cubic meter (averaged over 24 hours).

Particulate Matter Health Hazards

PM has two sets of cautionary statements, which correspond to the two sizes of PM that are measured:

Particles up to 2.5 micrometers in diameter (PM2.5)
Particles up to 10 micrometers in diameter (PM10)

On any given day, scientists estimate that about 10 MILLION tons of solid particulate matter are suspended in our atmosphere. In a polluted environment, a volume the size of a sugar cube can contain as many as 200,000 particles!

Particulate Matter Standards

In 1997 the Environmental Protection Agency (EPA) proposed a new standard of ozone and particulate matter levels in the atmosphere. The particulate matter levels of up to 10 microns in diameter(PM10) at each monitor within an area must not exceed 150 μg/m3, in one hour more than once per year, averaged over 3 years. The particulate matter levels of up to 2.5 microns in diameter (PM2.5), must not exceed 15 micrograms per cubic meter (μg/m3) and 65 μg/m3, respectively, each year and 24-hour period.

However, a coalition of business and industry interests sued to have those standards blocked, claiming they were too expensive and ill-conceived. In 1999 a federal court agreed, issuing a ruling blocking implementation of the tougher standards. Changes were made again in February 2001, when the U.S. Supreme Court unanimously upheld the constitutionality of the Clean Air Act as EPA had interpreted it in setting health-protective air quality standards for ground-level ozone and particles. The Supreme Court also reaffirmed EPA’s long-standing interpretation that it must set these standards based solely on public health considerations without consideration of costs.

However, the Supreme Court did find that the EPA’s plans for implementing the rules were unreasonable, and it ordered the agency to develop new implementation policies. Industry opponents immediately promised to use this aspect of the ruling as the basis for new legal challenges to weaken implementation of the new standards. It remains to be seen if the new standards will truly take effect as legislated.

According to the EPA, the new particulate matter and ozone standards will have the following effects:

Reduced risk of significant decreases in children’s lung functions. The new standards should provide approximately 1 million fewer incidences of difficulty of breathing or shortness of breath in children each year. These problems can limit a healthy child’s activities or result in increased medication use, or medical treatment for children with asthma.
Reduced risk of moderate to severe respiratory symptoms in children. The new standards should result in hundreds of thousands of fewer incidences each year of symptoms such as aggravated coughing and difficult or painful breathing.
Reduced risk of hospital admissions and emergency room visits for respiratory causes. The new standards should result in thousands fewer admissions and visits for individuals with asthma.
Reduced risks of more frequent childhood illnesses and more subtle effects such as repeated inflammation of the lung, impairment of the lung’s natural defense mechanisms, increased susceptibility to respiratory infection, and irreversible changes in lung structure. Such risks can lead to chronic respiratory illnesses such emphysema and chronic bronchitis later in life and/or premature aging of the lungs.
Reduce the yield loss of major agricultural crops, such as soybeans and wheat, and commercial forests by almost $500,000,000.

What are the health effects from Particulate Matter?

The Environmental Protection Agency has found that numerous health effects arise from both fine and coarse particles when they accumulate in the respiratory system. Coarse particles can aggravate respiratory conditions such as asthma. Exposure to fine particles is associated with several serious health effects, including premature death. Health effects have been associated with exposures to PM over both short (such as a day) and longer periods (a year or more).

When exposed to even small levels of PM, people with existing heart or lung diseases-such as asthma, chronic obstructive pulmonary disease, congestive heart disease, or ischemic heart disease-are at increased risk of premature death and or admission to hospitals or emergency rooms.
The elderly are very sensitive to PM exposure. They are at increased risk of admission to hospitals or emergency rooms and premature death from heart or lung diseases.
Children and people with existing lung disease may not be able to breathe as deeply or vigorously as they normally would, and they may experience symptoms such as coughing and shortness of breath when exposed to levels of PM.
PM can increase the susceptibility to respiratory infections and can aggravate existing respiratory diseases, such as asthma and chronic bronchitis, causing more use of medication and more doctor visits.

What parents need to know about diesel school buses:

If your kids are riding a diesel bus to school, chances are they’re being exposed to unacceptable levels of particulate matter. Visit the Natural Resource Defense Council website for more information.

The presence of an upper layer of atmospheric ozone shields the earth’s surface from incoming solar ultraviolet radiation and protects us from its effects. Many epidemiological studies have recognized that UV radiation is harmful to animals and plants. The UV rays have been linked to skin cancer, cataracts, and probably macular degeneration an important cause of blindness in America. There are 2 types of UV radiation: A and B, both are dangerous.

The fraction of UV-A and UV-B is constantly changing due to solar elevation, angle, varying hourly and seasonally and also varies with the ozone level. Sunburn is the result of overexposure to the sun’s ultraviolet radiation. Long-term cumulative sun exposure increases the risk of melanoma and non-melanoma skin cancer. Melanoma is a kind of skin cancer, sometimes called malignant melanoma. It arises from the melanocytes, the cells where pigment is synthesized. This is a very serious kind of skin cancer that can cause death. If melanoma is caught early, when still very small, it can be cured. Melanoma can have many different shapes and appearances and can occur any place on the body.

Non-melanoma skin cancers are: Basal cell cancers and squamous cell cancers. Basal cells are usually seen in exposed areas of the body, they are slow growing and rarely spread internally. Squamous cells also appear in sun exposed areas, but is more aggressive than Basal cell. About 3% of them spread to distant parts of the body. Both cancers are more prevalent in men due to greater sun exposure.

Prevention:

Avoid the strongest UV sunlight, between 10AM-3PM
Avoid tanning parlors and sunlamps, which emit UV-A.
Use sunscreens with an SPF of 15 or higher on areas exposed to the sun. Use water resistant sunscreens often when swimming or sweating.
When buying sunglasses, look for a pair that blocks 99-100% of UV-A and UV-B. The safest material for use in sunglasses is polycarbonate since it is the most impact resistant material available.
Make sure that children’s eyes are not overexposed to the sun. They may develop photokeretitis, also known as corneal sunburn. This condition is very painful and may cause temporary vision loss.
Lifeguards and skiers are at increased risk of UV eye damage since UV reflects off water, sand, snow, and other bright surfaces. For this reason it is advised that these individuals should wear UV coated sunglasses. Lifeguards should also wear brimmed hats for maximum protection.
Be aware that there is more exposure to UV radiation in higher elevations. Cloud cover decreases UV radiation, but dangerous amounts of UV radiation can still be present on cloudy days.

Sun Sensitivity:

Some people experience a skin reaction to the sun rays after even a brief sun exposure. The skin will be red, itchy, or swollen or will blister. These individuals are called photosensitive or “sun sensitive”. The skin reaction will last longer than sunburn and be more painful. It is important to check with your physician about medications that can make your skin more sensitive to sun exposure.

The best known products to cause increased sensitivity are:

antibiotics like tetracycline, quinolones, and sulfas
diuretics like thiazide
some cancer drugs
tricyclic antidepressents
oral diabetic medications
some blood pressure controlling drugs
some creams and acne medication
ibuprofen like products

Very Important: Contact your physician for proper diagnosis and treatment of your condition.

Beneficial Effects of UV Radiation:

UV Radiation is beneficial in vitamin D formation. Vitamin D deficiency can be corrected by sunlight exposure. Also, sunlight is beneficial in Seasonal Affective Disorder, known as SAD.

The UV Index

The UV Index is a forecast of the probable intensity of skin damaging ultraviolet radiation reaching the surface during the solar noon hour: 11:30-12:30 Local Standard Time, or 12:30-13:30 Local Daylight Time. The greater the UV Index is the greater the amount of skin damaging UV radiation. How much UV radiation is needed to actually damage one’s skin is dependent on several factors. In general, the darker one’s skin is — that is, the more melanin one has in his/her skin — the longer (or the more UV radiation) it takes to cause erythema (skin reddening).