Outdoor Air Quality
What
is fine particulate matter?
State and federal agencies have long monitored particulate matter,
or PM10. New research, however, has found that smaller particulate matter,
PM2.5, has a much greater health effect than PM10 because the smaller particles
are inhaled more deeply into the lungs.
This research resulted in new EPA regulations concerning PM2.5
in 1997. In response to this new understanding of the problem, the Connecticut
Department of Environmental Protection has initiated an intensive monitoring
effort statewide, and data are just starting to become available.
What are the sources of fine particulate matter?
Fine particles comprise one of the most widespread and harmful air pollutants
in the Hartford area. PM2.5 is a mixture of acids, metals, petroleum byproducts,
and diesel soot. The particles may be composed of various chemicals, depending
on where they originate.
To date, there is relatively little information on the sources of PM2.5.
It is known that PM2.5, like most other air pollutants, comes primarily
from cars, trucks, and buses. Another significant portion of PM2.5 comes
from industrial uses, coal power generation, and home heating. But because
the standards for fine particulate matter are new, there is as yet no inventory
that lists PM2.5 emitters and the amounts they produce.
What are the health effects
of fine particulate matter?
Some of the health effects of fine particulate matter include:
The EPA's air quality standard for PM2.5 is 15 micrograms per cubic meter for
the yearly average. The EPA's 24-hour average is 65 micrograms per cubic meters.
The 24-hour average is less restrictive than the annual average because the
concentrations vary during the day and between seasons, with summer and winter
being the highest. This means that the average concentration over one year can
not be higher than 0.000000015 grams per cubic meter and the average over one
day cannot be higher than 0.000000065 grams per cubic meter.
| Outdoor PM2.5 is especially dangerous because it can readily move
indoors, especially if windows are open and no air conditioning is used.
In times of high PM2.5 levels, people should limit both outdoor and
indoor exertion. If the weather is hot, people should spend more time
in a cool environment, preferably one that is air-conditioned. Sensitive
individuals, including the elderly, children, and people with asthma,
must be especially careful. |
How do ordinary activities contribute to fine particulate
matter?
Many ordinary day-to-day activities contribute to fine particles
in the environment. The greatest sources of environmental PM2.5 are personal
and commercial vehicles. Greater use of public transportation, carpooling,
and more fuel-efficient vehicles would help to reduce the amounts of dangerous
substances added to the environment.
Hartford's fine particulate matter concerns
Because researchers are only beginning to study PM2.5, little information
is available on its concentrations in the Hartford area. The Connecticut
Department of Environmental Protection
is now operating one PM2.5 monitoring site in Hartford at Sheldon Street.
DEP's Air Quality Index: (860) 424-4167 or (800) 249-1234.
In general, urban areas tend to have higher concentrations of PM2.5 than
do rural areas. A 1998 EPA study of rural sites found that concentrations
in the eastern United States averaged between 10 and 12 micrograms per cubic
meter. Concentrations in Washington, D.C., over the same period averaged
between 15 and 20 micrograms.
Some of the preliminary PM2.5 data in Connecticut show that urban areas
have greater concentrations than do rural areas. Hartford is not significantly
different from other urban areas.
PM2.5 in Hartford and Other Urban Areas
Average Annual Concentration in Micrograms per Cubic Meter
