Particulate
Matter Air Pollution
What
is Particulate Matter?
Particulate matter -- particulates
or PM for short -- refers to the many types and sizes of particles suspended in
the air we breathe each day. Particulates include products of combustion, such
as soot or ashes, wind blown dust, and minute droplets of liquids known as
aerosols. PM can range in size from visible pieces of sand and dirt to microscopic
particles so small that 500,000 of them could fit on the period at the end of
this sentence.
Why
should you be concerned about PM?
Particulate matter not only impairs
visibility, it also poses a serious health threat to citizens. Our respiratory
systems are equipped to filter out larger particles. However, the lungs are
vulnerable to particles less than 10 microns in diameter (PM10),
which can slip
past the respiratory system's
natural defenses. Very tiny particles (PM2.5) can penetrate deeply
into the lungs and do the most harm.
The particulates we breathe enter
the lungs and pass through progressively smaller airways until they reach the
alveoli, tiny air sacs where oxygen enters the blood stream. Particulates that
get trapped in these most sensitive tissues interfere with oxygen uptake. Toxic
and cancer-causing compounds can "hitchhike" into the lung on these
particulates and be directly absorbed into the lungs.
What
are the health effects of PM air pollution?
PM air pollution can cause coughing,
wheezing, and overall decreased lung function in otherwise healthy children and
adults. Particulate pollution can trigger asthma attacks and respiratory
illness in the more sensitive subgroups of the population, such as the elderly
and those with heart and lung disease. Children are more susceptible to
particulates because they have smaller lungs and less mature immune systems. In
the past 10 years, more than two dozen health studies have linked high
concentrations of particulate air pollution with an increase in emergency room
visits, hospital admissions, and even premature death.
What
causes PM air pollution?
PM is introduced to the air through
both natural and human causes. The primary sources of PM in California,
excluding agricultural dust, are motor vehicles; diesel trucks and buses;
residential wood stoves and fireplaces; industrial emissions; agricultural,
slash and yard waste burning; and even exhaust from lawn mowers and boats. PM
concentrations tend to be especially high in area with greater population density,
nearby industries or agriculture, or where local topography or weather
conditions contribute to air stagnation.
Here are a couple of quick facts
about sources of particulate matter:
During wintertime air inversions, wood stoves and fireplaces
release more hazardous particles.
Diesel trucks and buses are major producers of particulate
matter and should be replaced with natural gas-, methanol-, or electric-powered
vehicles.
As our population increases, our vehicle miles traveled
increases at a much higher rate, which means more cars on the road and more air
pollution from motor vehicle exhaust.
Industrial
emissions are a major source of air pollution. The best control technologies
should be encouraged to protect human health and the environment.
What is being done to control PM air pollution?
Our nation's Clean Air Act of 1970,
in combination with important amendments adopted in 1977 and 1990, requires
that the United States Environmental Protection Agency (EPA) identify and set
standards for air pollutants. These National Ambient Air Quality Standards
(NAAQS) must be strict enough to protect the health of even the most sensitive
members of the population. PM10 is currently one of six "criteria"
pollutants identified by the EPA. Here in California, the Department of Ecology
and local air pollution control agencies cooperate with the EPA to implement
laws designed to reduce PM levels.
A new PM standard
Though our air quality has improved since
adoption of these laws, our visibility has worsened. There is also mounting
evidence that the PM10 standards may not be strict enough to protect
lung health. A 1996 analysis by the Natural Resources Defense Council (NRDC)
estimates that PM levels far below current air pollution limits contribute to
over 1,000 premature deaths each year in Washington state. Experts suggest that
changing the PM standard to contain limits on fine particles (those 2.5 microns
or less in diameter) would better protect lung health. A PM2.5
standard might mean tougher restrictions on diesel trucks and buses, wood stove
and fireplace usage, outdoor burning, and industrial sources. It will also mean
that citizens will breathe easier and spend less on health care to treat
PM-induced illnesses.
POLLUTANT : PARTICULATE MATTER (PM)
SOURCES : Wood burning, motor
vehicles, industry, outdoor burning, windblown dust, construction, mining,
unpaved roads, diesel
HEALTH EFFECTS : Eye and nose
irritation, airway irritation, cough, decreased lung function, increased
respiratory illness, premature mortality
STANDARD : 3 PM10 150 µg/m (24-hour
average) PM 50 µg/m3 10 (annual average)
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.