Air Quality Particulate Matter Fact Sheet, NYC, Oct 2001

NYC 9/11 Public Portal Document

DRAFT10/17/01 @11:30 a.m.

In order to address public health issues associated with PM in air, some characterization of airborne particulate 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 lungs and can be deposited on mucous membranes of the eyes, nose and throat as part of the body’s natural defense system. Particles deposited on these surfaces can cause irritation. As particle size decreases the likelihood for them to reach more deeply into the lungs increases. Particles depositing in the lower regions of the lungs can produce both short term effects, such as coughing and longer term effects such as changes in lung function. Specific characteristics (e.g. chemical composition) of these particles can also influence the types of health effects seen following exposure.

Based upon their ability to cause health effects, the United States EPA sets ambient (outdoor) air standards for particulate matter. Currently EPA has a set of standards, one that is set for airborne particles that are 10 micrometers in diameter or smaller( PM,o), and one that is set for the finer particles that are part of PM,o that are 2.5 micrometers or less in diameter( PM,o). While it has been reported that levels of fine particulate were below the federal air standards, health complaints (eye, nose and throat irritation) continue to occur. In environments where fine and coarse particles are below levels of concern, people may still experience eye, nose, and throat irritation due to the presence of other substances such as larger particles or irritating gases.

It is possible that PM from the WTC fire and collapse could have entered homes. Indoor air quality may have been affected by the WTC fire and collapse even if the windows and doors were closed since smaller particles can enter through very small openings and cracks. Additionally, settled dust can be re-suspended into the air during routine activities, and it can also be tracked inside from outdoors by people, pets, and other activities. Therefore, if dust is in the home (e.g., on the couch, floors, counter tops, etc...), people should pay particular attention to the recommendations regarding: 1) cleaning the home, 2) checking the air conditioning system, and . 3) ways to prevent tracking dust indoors.

Health Effects of Particulate Matter:

1. Dust and smoke may irritate healthy people's eyes, nose, throat, and lungs, and might cause more serious problems in sensitive populations. Because dust and smoke are mixtures of different chemicals with different sizes, not everyone will experience the same effects. Most healthy adults and children will recover quickly from the symptoms short-term dust and smoke exposures and will not likely suffer long-term consequences.

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