Mayor's office air quality assessment memo, February 2002

NYC 9/11 Public Portal Document

‘ E-maiithissioiv frircable version

Trade Center Air Held Unprecedented Amounts of Very Fine Particles, Silicon, Sulfates, Metals, Say UC Davis Scientists February 11,2002 in the most thorough analysis yet of the dust and smoke blown through lower Manhattan after the collapse of the World Trade Center, researchers at the University of California. Daws, today desenbed unprecedented clouds of very fine particles that should be considered in evaluating rescue workers' and residents' heath problems Based on their findings, the UC Daws researchers also recommended speunc cleaning methods for contaminated apartments, offices, schools and other indoor spaces "No one has ever reported a situaton like the one we see in the World Trade Center samples." said UC Davis researche-Thomas Cahill Ph D. an international authority on tne consttuents ano transport of a.rbome particles "The air from Ground Zero was laden wth extremely high amounts of very small particles, probably associated with high temperatures in the underground debns pile Normally, in New York City and in most of the world, situations like this just dont exist" Cahill, a UC Daws professor ementjs of physics and atmosphenc sciences and a research professor in applied science, heads the UC Davis DELTA Group (for Detecton and Evaiuaton of Long-range Transport of Aerosols), a collaboratve association of aerosol scientsts at severe' ur.iversites and natonal laboratories The DELTA Group has made detailed studies of aerosols from the 1991 Gulf War oil fires volcanic eruptons global dust storms, and most recentty Asia The Manhattan air samples were collected at the request of a U S Department of Energy scentstfrom Oct 2 through rmd-December. by a DEL^A Group air monitor placed on a rooftop at 201 Vanek St. one mile north­ northeast of the traoe center complex The samples were collected contmuousy in eight separate size modes from coarse (12 micrometers diameter) to uttra-fine (0 09 micrometers diameter) Regional meteorology showed that the Site at Janek. Street could have received matenal from the World Trade Center site about halt the time The samples were periodically shipped back to Davis, where tie DELTa Group aneLteo the samples for size, shape and compositon They used a suite of seven teenmques including synchroton-induced x-ray fluorescence (at DOE's Advanced Light source at Lawrence Be-keiey Laboratory) scanning ransmission ion microscopy ar-d proton elastc scattenng analysis lat DOE's Lawrence Livermore Natonal Laboratory), ano soft beta mass measurements ana scanning electon microscopy (at UC Davis) "The UC Daws DELTA Group’s abiirt/tp measure and analyze particle size, composition and nme contnuoush. day and night is unequaled." Cahill said All analyses were done on a volunteer basis and wir be avaJable as public documents We report today on the data from Oct 2 through Oct 31.2001 Airborne particles and human health in general, there are myriad ways that matenals released into the air can affect human health What the particles are made of matters, so do size, shape and quantity The DELTA team analyzed me samples tor the unique chem cai ano physica' signatures c’ dozens o' substances including elements from concrete and glass. Such as silicon from burning fuel oil, suer, as sulfur vanadium and nickel, and from burning computers anq electrical systems, sucn as lead They also looked for organic, or carbon-based, compounds from burning wood, plastic and carpets And they tested for glass shards and asbestos Some of these materials are known to cause health problems m some people when they a-e inhaled in sufficient amounts Sulfur, for example, can imtate lung tssues Lead can damage the cental ner','Ous system Some carborkbased compounds can cause cancer Sc can the mineral asbestos Just as the composition of inhaled partcles car. affect health, so can size The team analyzed the particles by size m eight ranges fronn coarse 112 micrometers to 5 micrometers in diameter) tc very fine (0 2A micrometers to 0 03 micrometers in diameter) Most of the ultrafine mode (part'Cles less than 01 micrometers) was not collected Coarse partcles are typically filtered by the nose or coughed out of the throat and upper lungs They can imtate the mucous membranes, causing coughs and nosebleeds In some individuals, they can cause allergic reactions such as diy eyes. nose, throat and skin irritation, coughing, sneezing and respiratory distess They can also cause breathing problems or aggravate pre-exisbng breatiing problems, such as asthma However, very fine panicles can tavel deep into numan lungs Such small particles may have no immediate apparent health effects in moderate concentrations. Put they typically are removeo from the lungs through tne bloodstream and heart, increasing the possibility of health impacts There ere no established safe limits for inhaled veyfine particles The closest re'erence is ttie U S ERA "PM2 5" standard, which limits the allowable mass-of airborne particles m the size range 2 5 m-cromete's to 0 micrometers That standard is based on health studies of typical air samples in wruch veiy fine particles are a smaii fracton of the total mass in contrast, in the World Trade Cente' samples analyzed at UC Daws, the very fine pamcies are a large fraction of the total mass In a news conference today, the DELTA researchers desenbed key findings m these categones very fine particles, coarse particles, metals asbestos and glass Very line particles There were numerous events when bursts of wind lastng six to eight hours earned unprecedented amounts of very fine particles to the sampling site In the largest spike, the DELTA Group analysis found 56 micrograms per cubic rrieter of very fine particles in one 45-minute penod - "an extemefy high peak." Cahill said Cahill said the very fine particles contained high levels of sulfur and suifur-based compounds, which in early analyses appear to have been dominated by suifunc acid The very fine particles also contain high levels of veiy fine silicon, potentally from the tiousands of tons of glass in tie debris Cahill noted that even those large amounts were likely to be smaller than those present at Ground Zero and some other parts of Lower Manhattan, since weather data show that typically only part of the oust clouds traveled directly over the sampling site “Even on the worst air days in Beijing, downwind from coal-fired powerplants, or in the Kuwait oil tres, we did not see these levels of very tne particulates." Cahill said The amounts of very tne particles particularly very fine silicon, decreased sharply dunng tie month of October Coarse particles Similar to the high concentrations of very fine particles, virtually al' the ar samples from the trade center s-.e earned high concentrations of coarse particles - those about 12 micrometers to 5 micrometers in diameter "These particles s.mply should not be there," Cahill saio ' It had rained, sometimes neavity, on six days in the pnor three weeks That rain should have sewed these coarse particles" The finding suggests that coarse particles were being ; ontnually generated from tne hot debns pile This observation is at least qualitatively supported, tor while they are still being analyzed, the coarse particles appear to be coated with combustion products, including soot. Cahill said Metals Many different metals were found in the Sampo'S of very tme particles, and some were found at the highest levels ever reco'ded in air in the United States However, there are few established safety guidelines tor airborne rrieials One metal for which there is a guideline lead, was present at low levels in tine and vetyfme particles Some of the metals for which there are no guidelines that were present in very fine particles m relatively high concentrations were iron, titanium (some associated with powdered concrete,-, vanadium ar.d nickel (often associated with, fuekoii combustion), copper and zme Mercury was seen occasionally in fine particles but at low concentracons Many of those metals are widely used in building construct on. wmng and plumbing Some are common m computers The metal content of the coarse particles is sen being analyzed Asbestos and glass Although some asbestos was used in the buildings for fireproofing and m floor ties, and the DELTA group checked for it carefully using the elector microscope, they founo very few asbestos fibers even in tne very fine panicles

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