NYC 9/11 Public Portal Document
DRAFT 10/17/01 @ 11:30 a.m.
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 distribution.
Air Quality:
The Environmental Assessment Workgroup, comprised of the Agency for Toxic Substances and
Disease Registry (ATSDR), Centers for Disease Control and Prevention (CDC), Environmental
Protection 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. It is especially important for
people with heart or respiratory disease, the elderly and young children to reduce their exposure
to smoke and dust. People should consult with their physician immediately if health problems
develop.
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 compounds known to cause acute health effects include smoke, fiberglass,
and inhalable dust (e.g., cement and gypsum), also collectively known as particulate matter.
Certain compounds 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
compounds.
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 liquid 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 likely contains-particles from
building materials.
NYC-WTC_000153208
OCR can misread numbers and units. Confirm readings against the page image before using them.