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Particulate Matter:
Little things can cause big problems
What
is particulate matter?
Where does it come from?
PM 10 & PM 2.5 ... Huh?
Why should you be concerned?
Health
Environment
What is being done?
What can you do about it?
What is particulate matter?
Thick, black smoke
belching out of the exhaust pipes of vehicles. Swirls of dust
picked up by the wind. Ash and soot coming
from your campfire. These are all examples of
particulate matter (PM).
PM
is the term used for solid or liquid particles emitted to the
air. Some particles are large enough to be seen, and others are
so small they can only be detected with an electron microscope.
Where does
particulate matter come from?
Particulate
matter can come from many sources.
Generally, any
activity which involves burning of materials or any dust
generating activities are sources of PM. Some sources are
natural, such as volcanoes and water mist.
Humans create
huge quantities of particulate and many of these sources are regulated, such as smoke stacks at factories,
power plants, and
auto paint shops. However, there are many sources that are not
regulated and your home is one of them. We often burn wood or
coal for heat in the winter, we can release dust into the air
in our yards, and during renovation, large amounts of dust may be
released if they are not kept in check. Vehicles, like our cars
and SUVs, produce particulates, as do gas powered lawn mowers,
leaf blowers, and weed whackers.
PM 10 &
PM 2.5 ... Huh?
The Environmental
Protection Agency (EPA), many health professionals, and, of
course, the Hamilton County Department of Environmental Services are
all very concerned about particulate pollution. In fact, the
concern about particulates is related to their very small size.
Since the late 1970's, we only
monitored particulate matter pollution that was 10 microns in diameter or
less, called PM 10. A micron (or micrometer) is a millionth of a
meter. To give you an idea of how small PM 10 is, the dot above
the letter "i" in a typical newspaper measures about 400
microns!
2000 particles of PM2.5 could fit
end-to-end across one end of a paper clip!
PM 10 particles are small
enough to be inhaled and accumulate in the respiratory system. In the last decade,
health studies indicated that particles even smaller than PM 10 can
cause even more health problems! Now, in addition to monitoring PM 10,
scientists and technicians monitor fine particles called PM 2.5,
these particles measure 2.5 microns in diameter or smaller, or
about 1/10,000 of an inch. These tiny particles are about
30 times smaller than the width of a hair on your head! These tiny particles
are small enough to get inhaled past our defensive nose hairs
and into our lungs. But it doesn't stop there! PM 2.5 can pass from
our lungs into our blood supply and be carried throughout our
bodies.
To protect us from the
harm of air pollutants, the U.S. Environmental Protection Agency
(USEPA) established National Ambient Air Quality Standards (NAAQS)
for criteria air pollutants that are thought to cause the most
harm to the health of humans and the environment. Particulate
matter is one of these criteria pollutants.
There are two PM
10 standards, a 24-hour standard and an annual standard. These
standards are:
To determine if an area
meets the annual standard, data is collected daily and averaged
over the entire year. The last three years of annual
averages are used to determine attainment. An area will meet
the 24-hour standard if the number of days per calendar year
above 150 ug/m3 is equal to or less than "1."
In 1997, the USEPA
revised their PM standard to take into account new findings
about significant health problems associated with fine
particulates, PM 2.5 and smaller. To the old PM10 standards, the USEPA added two new
PM 2.5 standards set at:
Based on the 1999, 2000,
and 2001 data, southwestern Ohio will not meet the new fine
particulate standard.
Why should you be concerned about particulate matter?
Health
As you have just found out in the
section above, some tiny pieces of particulate matter, PM 2.5,
are small enough to pass from our lungs to our bloodstream.
PM can alter the body's defense
systems against foreign materials, damage lung tissues,
aggravate existing respiratory and cardiovascular disease, and
can lead to cancer. In some cases, PM exposure can even lead to
premature death. Adverse health effects have
been associated with exposures to PM over both short periods
(such as a day) and longer periods (a year or more).
The people who are most at risk are
people with asthma, influenza, lung, heart, or cardiovascular disease,
the elderly, and children.
The human immune system developed in a
time and
environment where dust was made of large particles. Humans have
developed a means of protecting themselves against these large particles.
Particles larger than 10 microns generally get caught in the
nose and throat, never making it as far as the lungs.
Unfortunately, more recent human activity has created many
particles that are much smaller, which can make it past our
natural defenses, and can enter our systems. This is
why particles smaller than 10 microns are often called "inhaleable
particulates" and are regulated by the USEPA. Particles that are
smaller than 5 microns can get into the bronchial tubes and the
top of the lungs. Particles smaller than 2.5 microns in diameter
can get into the deepest portion of the lungs where the gas
exchange occurs between the air and blood stream. These are the
dangerous particles because the body has no efficient mechanisms
for removing them.
New studies have shown that there is
an 18% increase in deaths from heart disease among people with
long term exposure to particulate matter. "It's very different
from what we thought previously," said professor and
epidemiologist Arden Pope of Brigham Young University, who led
the study. While exposure clearly impacts the lungs, "long-term,
chronic exposure to air pollution seems to manifest more in
cardiovascular disease than it does in respiratory disease."
This study shows
the biological mechanism by which long-term exposure to
tiny-particle pollution can actually lead to ischemic heart
disease, which causes heart attacks, as well as irregular heart
rhythms, heart failure and cardiac arrest. The key is
inflammation, Pope said. While strong bouts of pollution can
make breathing hard and increase respiratory problems, they also
provoke low-grade pulmonary inflammation, accelerating the
development of atherosclerosis - a leading cause of heart
disease - and altering heart function.
The Air Quality Index (AQI) for
particulate matter provides information on the health effects of
different levels of particulate in the air.
Air
Quality Index (AQI): Particulate Matter (PM)
Index
Values |
Levels
of Health
Concern |
Cautionary
Statements* |
|
PM2.5 |
PM10 |
| 0
- 50 |
Good |
None |
None |
| 51
- 100** |
Moderate |
None |
None |
|
101 - 150 |
Unhealthy for Sensitive Groups |
People with respiratory or heart disease, the elderly, and
children should limit prolonged exertion. |
People with respiratory disease, such as asthma, should
limit outdoor exertion. |
|
151 - 200 |
Unhealthy |
People with
respiratory or heart disease, the elderly, and children
should avoid prolonged exertion; everyone else should limit
prolonged exertion. |
People with
respiratory disease, such as asthma, should avoid outdoor
exertion; everyone else, especially the elderly and
children, should limit prolonged outdoor exertion. |
|
201 - 300 |
Very Unhealthy |
People with
respiratory or heart disease, the elderly, and children
should avoid any outdoor activity; everyone else should
avoid prolonged exertion. |
People with
respiratory disease, such as asthma, should avoid any
outdoor activity; everyone else, especially the elderly and
children, should limit outdoor exertion. |
|
301 - 500 |
Hazardous |
Everyone should
avoid any outdoor exertion; people with respiratory or heart
disease, the elderly, and children should remain indoors. |
Everyone should
avoid any outdoor exertion; people with respiratory disease,
such as asthma, should remain indoors. |
|
* 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)
|
| ** |
• An AQI of 100 for
PM2.5 corresponds to a PM2.5 level of 40
micrograms per cubic meter (averaged over 24 hours).
• An AQI of 100 for PM10 corresponds to a PM10
level of 150 micrograms per cubic meter (averaged over 24
hours). |
Environment
PM impacts the environment by
decreasing visibility. You can see this by viewing the
Haze Camera
that is situated on the roof of the AQMD building in Clifton in
Cincinnati. This page has more in-depth information about the
effects of particulates on visibility and the types of
particulates that cause visibility problems. Compare the
haze here in Cincinnati to the haze in your neighborhood. Or
perhaps you would like to compare your haze to that in Chicago,
Indianapolis, or one of the other cities linked to
the Haze Camera network.
PM also affects the environment by
harming plant life. This has an effect on the wildlife of the
area, as many animals are dependant on the plants for food.
This effect can be passed on up the food chain.
Wildlife can also be effected in
the same way that humans can, by breathing in the particulates.
What is
being done to reduce particulates?
In 1997, the EPA proposed to create a
new limit for fine particulate matter (PM 2.5 and smaller). The new limits would allow
less than a third of the soot that was permitted by the old PM10
standard to enter the air.
For the first time, even the tiniest particles would be
controlled. Regions that failed to meet the limits would lose
federal highway funds and other federal money.
The rules are part of a move to
toughen the Clean Air Act of 1970. That Act sets limits on six
kinds of air pollution (known as criteria pollutants): carbon monoxide, lead, nitrogen dioxide,
sulfur dioxide, ozone, and particulates. Every few years, the EPA reviews
these limits, as they did in 1997.
Data from 1999, 2000, and 2001
indicate that southwestern Ohio will not meet the new fine
particulate standard.
Industries must have emission
equipment in place to reduce particulate pollution. In
southwest Ohio, this is monitored by Environmental Compliance
Specialists here at the Hamilton County Department of
Environmental Services, Air Quality Management Division. All
facilities that plan to install or operate a regulated emission
unit are required to have a
permit. The Environmental Compliance Specialist also
conducts
inspections to ensure that the facility is operating within
their permit.
Construction zones try to wet the
area they are working in to avoid dust. At the landfill (where
our garbage goes) the dirt roads are kept wet and the vehicles
clean their wheels before going back onto the street again, all
to avoid dust problems. There are many different things that are
done that we may not be aware of that try and
limit particulate pollution.
What can you
do about particulate matter?
There are
many simple things that you can do to reduce particulate
pollution. Try to cut down on opportunities for combustion to
occur by conserving energy in your home and workplace. Remember, the regulations about
open burning, make sure that your vehicle is properly
maintained, think about alternative ways to travel such as
walking, biking, taking the bus, or ridesharing. If there is a
dust, smoke, or other particulate problem within the air near your
home, school, or office, please remember to call the Air Quality
Complaint Hotline at 513-946-7777 (for Butler, Clermont,
Hamilton, and Warren Counties).
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