OAQPS Fact Sheet
July 17, 1997
Health and Environmental Effects of Particulate Matter
Why are We Concerned about Particulate Matter?
Who is Most at Risk from Exposure to Fine Particles?
- Particulate matter is the term used for a mixture of solid
particles and liquid droplets found in the air. Coarse particles
(larger than 2.5 micrometers) come from a variety of sources
including windblown dust and grinding operations. Fine particles
(less than 2.5 micrometers) often come from fuel combustion,
power plants, and diesel buses and trucks.
- These fine particles are so small that several thousand of
them could fit on the period at the end of this sentence.
- They are of health concern because they easily reach the
deepest recesses of the lungs.
- Batteries of scientific studies have linked particulate
matter, especially fine particles (alone or in combination with
other air pollutants), with a series of significant health
- Premature death;
- Respiratory related hospital admissions and
emergency room visits;
- Aggravated asthma;
- Acute respiratory symptoms, including aggravated
coughing and difficult or painful breathing;
- Chronic bronchitis;
- Decreased lung function that can be experienced as
shortness of breath; and
- Work and school absences.
How do Particulate Matter and Fine Particles Effect the
- The Elderly:
- Studies estimate that tens of thousands of elderly people
die prematurely each year from exposure to ambient levels of
- Studies also indicate that exposure to fine particles is
associated with thousands of hospital admissions each year.
Many of these hospital admissions are elderly people suffering
from lung or heart disease.
- Individuals with Preexisting Heart or Lung Disease:
- Breathing fine particles can also adversely affect
individuals with heart disease, emphysema, and chronic
bronchitis by causing additional medical treatment. Inhaling
fine particulate matter has been attributed to increased
hospital admissions, emergency room visits and premature death
among sensitive populations.
- The average adult breathes 13,000 liters of air per day;
children breathe 50 percent more air per pound of body weight
- Because children's respiratory systems are still
developing, they are more susceptible to environmental
threats than healthy adults.
- Exposure to fine particles is associated with increased
frequency of childhood illnesses, which are of concern both
in the short run, and for the future development of healthy
lungs in the affected children.
- Fine particles are also associated with increased
respiratory symptoms and reduced lung function in children,
including symptoms such as aggravated coughing and difficulty
or pain in breathing. These can result in school absences and
limitations in normal childhood activities.
- Asthmatics and Asthmatic Children:
- More and more people are being diagnosed with asthma
every year. Fourteen Americans die every day from asthma, a
rate three times greater than just 20 years ago. Children
make up 25 percent of the population, but comprise 40 percent
of all asthma cases.
- Breathing fine particles, alone or in combination with
other pollutants, can aggravate asthma, causing greater use
of medication and resulting in more medical treatment and
What Improvements Would Result from EPA's New Standards?
- The same fine particles linked to serious health effects are
also a major cause of visibility impairment in many parts of the
- In many parts of the U.S. the visual range has been reduced
70% from natural conditions. In the east, the current range is
only 14-24 miles vs. a natural visibility of 90 miles. In the
west, the current range is 33-90 miles vs. a natural visibility
of 140 miles.
- Fine particles can remain suspended in the air and travel
long distances. For example, a puff of exhaust from a diesel
truck in Los Angeles can end up over the Grand Canyon, where
one-third of the haze comes from Southern California. Emissions
from a Los Angeles oil refinery can form particles that in a
few days will effect visibility in the Rocky Mountain National
Park. Twenty percent of the problem on dirtiest days in that
Park is attributed to Los Angeles-generated smog.
- Airborne particles can also cause soiling and damage to
Background: What is Particulate Matter and What are "Fine"
- EPA's new standards will provide increased health protection
from the following effects:
- About 15,000 lives each year will be saved, especially
among the elderly and those with existing heart and lung
- Reduced risk of hospital admissions by thousands each year,
and fewer emergency room visits, especially in the elderly and
those with existing heart and lung diseases.
- Reduced risk of symptoms associated with chronic
bronchitis, tens of thousands fewer cases each year.
- Reduced risk of respiratory symptoms in children, hundreds
of thousands fewer incidences each year of symptoms such as
aggravated coughing and difficult or painful breathing.
- Reduced risk of aggravation of asthma, hundreds of
thousands fewer incidences each year, in children and adults
- Reduced risks of susceptibility to childhood illnesses.
- Improved visibility over broad regions in the east and
- The Clean Air Act placed special emphasis on preserving
visibility in certain national parks and wilderness areas.
In response, EPA is developing a "regional haze" program
intended to ensure all parts of the country make continued
progress toward the national visibility goal of "no manmade
- New standards that EPA has promulgated, together with
the "regional haze" program under development, will protect
against visibility impairment, soiling and material damage
effects, and will further reduce acid rain.
- Particulate matter originates from a variety of sources,
including diesel trucks, power plants, wood stoves and industrial
processes. The chemical and physical composition of these various
particles vary widely. While individual particles cannot be seen
with the naked eye, collectively they can appear as black soot,
dust clouds, or grey hazes.
- Those particles that are less than 2.5 micrometers in
diameter are known as "fine" particles; those larger than 2.5
micrometers are known as "coarse" particles. Fine particles
result from fuel combustion (from motor vehicles, power
generation, industrial facilities), residential fireplaces
and wood stoves. Fine particles can be formed in the atmosphere
from gases such as sulfur dioxide, nitrogen oxides, and volatile
organic compounds. Coarse particles are generally emitted from
sources such as vehicles traveling on unpaved roads, materials
handling, and crushing and grinding operations, and windblown
- EPA is also maintaining a national air quality standard
focused on small particles less than 10 micrometers in diameter
(known as "PM10") to protect against coarse particle
effects. Ten micrometers are about one-seventh the diameter of a
- Before 1987, EPA's standards regulated larger particles
(so called "total suspended particulates"), including those
larger than 10 micrometers. By 1987, research had shown that
the particles of greatest health concern were those equal to or
less than 10 micrometers that can penetrate into sensitive
regions of the respiratory tract. At that time EPA and states
took action to monitor and regulate particulate matter 10
micrometers and smaller.
- In the years since the previous standard was enacted,
hundreds of significant new scientific studies have been
published on the health effects of particulate matter. Recent
health effects studies suggest those adverse public health
effects, such as premature deaths and increased morbidity in
children and other sensitive populations, have been associated
with exposure to particle levels well below those allowed by
the current standard.