NYC 9/11 Public Portal Document
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PARTICULATE MATTER
AIR QUALITY; PARTICULATE MATTER
NOTE: This document was designed to assist public health officials in communicating specific air
quality issues to the general public. Additional materials (e.g., fact sheets) will be supplied for public I
distribution.
Air Quality:
The Environmental Assessment Workgroup, comprised of members from the Agency for To.xic Substances and
Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), Environmental Protection
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Agency (EPA) and Occupational Safety and Health Administration (OSHA), is recommending that people in
New York City make an effort to reduce their exposure to air contaminants due to the fires, smoke, and dust
(also known as particulate matter) created by the collapse of WTC and on-going response in Lower Manhattan.
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It is especially important for people with heart or respiratory disease, the elderly and young children to reduce
their e.xposure to smoke and dust since they are likely to be more sensitive to the effects of particulate matter.
Health complaints from the area have been primarily irritant and respiratory in nature (such as coughing,
irritation of the eyes, nose and throat, wheezing, difficulty in breathing and shortness of breath). Airborne
particulate matter known to cause these types of acute health effects include smoke, fiberglass, and inhalable
dust (e.g., cement and g\psum). Certain compounds in airborne particles may be present that may result in
chronic health problems, including respirable silica and asbestos. Efforts to measure air quality are focusing on
all these types of airborne particles.
Particulate Matter:
The term "particulate matter" (PM) includes both solid particles and liquid droplets found in air. Many human
activities and natural events emit PM directly or emit other pollutants that react in the air to form PM. These
solid and hquid particles come in a wide range of size. Particles less than 10 micrometers in aerodynamic
diameter tend to pose the greatest health concern because they can pass through the nose and throat and be
deposited in the lungs. 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, fires, etc.) and some
industrial processes. Particles with diameters between 2.5 and 10 micrometers are referred to as "coarse"
particles. Sources of coarse particles include crushing and grinding operations, and dust from paved and
unpaved roads. The particle mix in most U.S. cities is dominated by fine particles generated by combustion with
smaller amounts of coarse dust. The coarse dust resulting from the collapse of World Trade Center (WTC)
buildings and the removal of rubble contains-particles from building materials.
In order to address public health issues associated with PM in air, some characterization of airborne particulate
matter is warranted to provide additional information. The likelihood for particles to produce certain health
effects is also related to particle size. Larger particles are less likely to penetrate deeply into the hings and can
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