The Health Effects of Particulate Matter From the 9/11 WTC Attacks

What is Particulate Matter? PM is visible air pollution (haze) PM exists in the air as aerosols: suspensions of solid and liquid particles in the air Three Classifications: Very Fine (PM0.1): diameter < 0.1 μm Fine (PM2.5): 0.1 μm < diameter < 2.5 μm Coarse (PM100): 2.5 μm < diameter < 100 μm Talk about constituents of fine and coarse PM.

PM Has Numerous Health Risks Eye, nose, throat, lung irritation Increased respiratory related hospital admissions and ER visits Aggravated asthma Aggravated coughing Difficult or painful breathing

PM Has Numerous Health Risks Decreased lung function Aggravated chronic obstructive pulmonary disease (COPD) Increased deaths from COPD and cardiovascular causes Chronic bronchitis Increased deaths from lung cancer

Fine PM Is Worse Than Coarse PM Stays in the air longer Penetrates deeper into the respiratory system Coarse PM is filtered out in nose and pharynx Fine PM deposits inside trachea, bronchi, lungs EPA Recommendations (PM2.5): Sensitive Groups: 40 μg/m3 per day General Population: 65 μg/m3 per day Say who sensitive groups are.

WTC Findings Two studies: UC Davis DELTA EPA Composition analysis Air monitoring Animal toxicology experiments

UC Davis Study DELTA 8 DRUM Impactor [Taken from Cahill,2003] 201 Varick St. WTC 1.8 km Courtesy of Mapquest From 10/2 to 10/30/01, researchers collected samples at 201 Varick St. Used 8-stage rotating drum impactor to collect samples Analyzed samples to determine composition

UC Davis Study Found 4/5 classes of hazardous particles: Acidic aerosols - burn cilia and lungs Very fine insoluble aerosols (glass) - pass through the lungs into the bloodstream Fine transition metals (V, Ni, Cu, Hg, etc.) - disrupt lung chemistry High temperature organics - carcinogens Biological aerosols (bacteria, viruses, molds) - not found

UC Davis Study Abnormally high levels of very fine PM Disproportionate amount of coarse PM3.5 Figure 3. Anomalous Size Distribution of Aerosols from the WTC [Taken from Cahill, 2004] WTC PM shows uncharacteristic peaks at 3 μg and 0.25 μg. WTC Sulfates show uncharacteristic peak at 0.25 μg

UC Davis Study High levels of very fine PM  “extraordinarily large number of particles that have the ability to penetrate deep into the lung”

But It’s Not That Bad! During October, enough PM in the air to cause acute reactions However, amount of PM steadily declined By May 2002, PM < 10% of October levels

WTC Findings Two studies: UC Davis DELTA EPA Composition analysis Air monitoring Animal toxicology experiments

EPA Air Monitoring Asbestos – shown (by Prof. Wilson!) to pose insignificant risk Of 9608 samples taken in Lower Manhattan, only 21 samples (0.22%) > screening level Lead – 5/321 (1.56%) > screening level PM2.5 – 935/91,305 (1.02%) > 40 μg/m3 33 (0.04%) > 65 μg/m3 Everything else (organics, metals) < 1%

EPA Air Monitoring If only 0.04% > 65 μg/m3, why does PM2.5 matter? Long-term: very few overall number of violations Short-term: very many violations EPA tested throughout the city Lower Manhattan at greater than average risk

EPA Air Monitoring Short-term (before Dec. 19) 31/170 = 18.24% > 65 μg/m3 81/170 = 47.65% > 40 μg/m3 Long-term (after Dec. 19) 0/142 = 0% > 65 μg/m3 18/142 = 12.68% > 40 μg/m3

WTC Findings Two studies: UC Davis DELTA EPA Composition analysis Air monitoring Animal toxicology experiments (mice)

EPA Animal Toxicology Experiment A Compare effects of WTC PM2.5 to ROFA (toxic control) and MST (low toxicity control) Results: Aspiration of 100 μg WTC PM directly into the lungs did not cause acute lung injury Did cause significant increase in airway hyperresponsiveness (narrowing of bronchial tract)

EPA Animal Toxicology Experiment B Experiment C Investigate effects of nose-only exposure to WTC PM2.5 Inconsistent/unclear results caused by very low deposition efficiency: Only ~14 μg deposited in lungs vs. 100 μg in Exp. A Experiment C Compare effects of PM from different WTC sites No differences!

WTC Findings - Summary High levels of PM in short-term, but relatively safe in long-term WTC PM did not cause acute lung injury, although it did increase airway responsiveness Both studies concluded that general population not at significant risk, but sensitive groups should reduce exposure

Weaknesses in Studies UC Davis and EPA failed to investigate: Effects of chronic/repeated exposures Long-term effects Both are possible for residents/workers of Lower Manhattan, especially rescue/cleanup workers

Recommendations Ensure that homes are properly cleaned by licensed professionals Minimize exposure: Close windows Use wet vacuums Limit time outdoors (but do exercise!)

Or If You Really Want to Be Safe MOVE TO THE COUNTRY! Avoids WTC dust Also reduces overall pollution, which is associated with all sorts of health risks