ABSTRACT: Many, perhaps most, of the air pollutants of concern are more of a risk from indoor sources than from the “usual suspects”—industry, mobile sources, hazardous waste sites. For example, the three volatile organic That Gunk in MY House? compounds (VOCs) at highest carcinogenic risk all have important, sometimes even exclusive, indoor sources. Semivolatile organics (e.g., pesticides) have Personal Exposure to Indoor Air Pollution even greater indoor/outdoor ratios. Airborne particles, implicated in respiratory and cardiovascular morbidity and mortality, have smaller indoor-outdoor ratios, but still a large percentage of children grow up in homes breathing secondhand smoke at about twice the level of the outdoor standard for fine particles. “Deep dust” in carpets seems to concentrate lead and pesticides compared to the upper portion of the carpet—and then typical vacuuming removes the upper portion Lance Wallace but raises the “deep dust” to a more bioavailable spot. I used to think ozone was lwallace73@comcast.net one major exception to the rule that indoors>outdoors, since outdoor ozone is U.S. Environmental Protection Agency (retired) chewed up by chemical reactions as soon as it enters the home, but now Seminar—Clarkson University companies are aggressively marketing “air cleaners” that raise the level of Jan 31, 2005 ozone in homes above the outdoor standard. Lead from gasoline is gone but the lead from paint lingers on in windowsills for children to ingest. The data supporting these statements will be briefly presented and some individual actions that can be taken to reduce exposures will be discussed. TEAM Approach Measuring Personal Exposure (Total Exposure Assessment Methodology) • Direct Method • Probability-Based Selection of Participants – Personal Monitors • Use of Personal Monitors • Indirect Method • Measure All Contributing Pathways – Fixed Indoor and/or Outdoor Monitors • Activity Diaries – Time Budgets/Activity Diaries • Ancillary Fixed Monitors – Calculate the Time-Weighted Average • Exhaled Breath (if possible) 1
Major TEAM Studies • VOCs (8 cities, 800 persons) • CO (2 cities, 1200 persons) • Pesticides (2 cities, 250 persons) • Particles (2 cities, 196 persons) 2
Benzene Emissions Industry (15%) Cigarettes (0.1%) Autos (85%) 25 Smokers Nonsmokers 20 15 µ g/m 3 10 5 0 New Jersey L.A. 1984 L.A. 1987 Baltimore Antioch CA TEAM Study Locations 3
4 Industry (3%) Autos (20%) Smoking (40%) Benzene Exposures Indoor (20%) Driving (12%) ETS (5%)
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WE LIVE INDOORS • National Human Activity Pattern Survey (NHAPS) and ARB surveys of children & adults • >11000 interviews over 2-year period • INDOORS 89% • OUTDOORS 6% • IN VEHICLES 5% 6
INDOOR AIR QUALITY: “RULE OF A THOUSAND” A NATIONAL PRIORITY A pollutant released indoors is about • Three Nationwide Task Forces Compared 1000 times more likely to be inhaled Environmental Priorities • All Find Indoor Air/Consumer Products than that same amount released outdoors Very High Priority • All Conclude “No One Minding the Store” (Nazaroff, 2000) moving vehicle, 1-4 occupants Particles and Health single-zone residence, 1-5 occupants • Fine particles implicated in daily mortality "rule of 1000" • But possibly ultrafines, coarse, CO, SO2…. ground-level line source • High-risk groups are known --COPD elevated point release --Cardiovascular signaling problems well-mixed air basin • Mechanism unknown 1 10 100 1000 10,000 100,000 intake fraction (per million) 7
Are Indoor Particles Dangerous? Are Indoor Particles Toxic? • Major Indoor Source is Combustion • Little is known about relative Toxicities of Indoor vs Outdoor Particles • Smoking • Cooking • One study finds Toxicities about equal • Candles, incense (Long, 2001) • Space heaters Combustion is often specified as the likely source of toxicity of outdoor particles Can Indoor Particles Cause Particle TEAM (PTEAM) Study Short-Term Mortality? • Concentrations are comparable to outdoors • First probability-based particle exposure study • Toxicity may be comparable to outdoors • 178 Residents of Riverside, California • If short-term peaks are important, they are more readily encountered indoors • Two 12-hour samples (Day and Night) • Strong sources exist in some homes of high- • Personal, indoor and outdoor PM 10 risk subpopulations • Indoor and outdoor PM 2.5 • Air change rate measured in 3 rooms 8
Examples of probability-based Probability-Based Studies studies • Survey design as in polls • TEAM Study of VOCs: 1980-85 (Pellizzari 1985; Wallace 1985) • The sampling universe is completely known (e.g., Census information) • PTEAM 1989-90 (Ozkaynak 1996) • Each person in the universe has a known • Toronto Study 1996 (Clayton 1997; probability of being selected Pellizzari 1999) • The only accepted method by which one • Indianapolis Study 1996 (Pellizzari 2001) can extrapolate to larger populations • EXPOLIS (many pubs) PTEAM Study: Results PTEAM: More Results • Personal >> Outdoor > Indoor • Regression Results R 2 = 0.27 – Indoor vs Outdoor • “Personal Cloud” (Personal – Indoor) First Observed: About 35 µ g/m 3 R 2 = 0.16 – Personal vs Outdoor R 2 = 0.49 – Personal vs Indoor • Smoking Again the Major Indoor Source • Cooking the Second Largest Indoor Source 9
Daytime PM 10 Concentrations: PTEAM Study 160 140 120 100 µ g/m 3 80 60 40 20 0 Personal Indoor Outdoor The Personal Cloud • Source unknown; possibilities include – Resuspension off clothes, other indoor surfaces – Proximity to indoor sources (vacuuming, dusting, cooking) • Probably NOT – Skin flakes – Clothes fibers 10
PMF Results from PTEAM The Toronto Study • First study to differentiate personal cloud • Sponsored by Ethyl Corp. (MMT makers) crustal material from indoor crustal material • Largest Probability-Based Study of Particle (about 30% from personal activities, 15% Exposures (180 PM 10 ; 750 PM 2.5 ) from indoor soil) • Personal > Indoor > Outdoor • Strong correlations of indoor and personal • Personal Cloud for PM 10 35 µ g/m 3 ; for exposure with ETS PM 2.5 15 µ g/m 3 • Mean Mn 2.5 = 14.4 ng/m 3 – Yakovleva, Hopke & Wallace, 1999 The Indianapolis Study Exposures of High-Risk Groups • Sponsored by Ethyl (pre-MMT background) • EPA Sponsored Four Major Studies • 250 Subjects --Harvard (Atlanta, Boston, LA.) • PM 2.5 only --University of Washington (Seattle) • Personal = Indoor > Outdoor --New York Univ. School of Medicine • Small Personal Cloud (< 3 µ g/m 3 ) (New York, Anaheim, Seattle) --Research Triangle Institute (RTP,NC) • Mn Mean = 7.2 ng/m 3 ; GM = 2.8 ng/m 3 11
Goal Study Design • Determine relationships between personal • Samples Drawn from High-Risk Groups exposure, indoor air concentrations and (COPD, CV, some healthy controls) outdoor air concentrations of fine particles • Personal, Indoor, Outdoor Samples of (PM 2.5 ) for persons at risk --PM-2.5 and PM-10 --Associated gases (SO2, NO2, CO) • 10-14 days per person, 2-4 seasons Subject ID: Date: Technician: A New Personal Monitor 4. At Work away 3. In Transit from Home 2. In Yard 5. Outside away 6. Indoors away at Home from Home from Home 1. Indoors or Nearby at Home Nearby Cooking Smoker Minutes Activity Description 1 2 3 4 5 6 Minutes Self Other PM 2.5 and PM 10 PEMs 8:00 AM :15 :30 :45 9:00 :15 :30 :45 10:00 :15 :30 :45 11:00 :15 :30 :45 PM 12:00 EC/OC Mini-Sampler :15 :30 :45 Nitrate Mini-Sampler O 3 , SO 2 /NO 2 Samplers 1:00 :15 :30 :45 12
(a) 1.0 Group City N r>0.5 p<0.05 0.8 (%) (%) Longitudinal correlation 0.6 NERL RTP 112 43 14 0.4 -RTI 0.2 Univ. Seattle 98 50 16 0.0 Wash. -0.2 Harv. At-Bos 105 47 21 -0.4 Univ. L.A. -0.6 (N=24) (N=28) (N=24) (N=17) Asthma CHD COPD Healthy Health Status City N Winter SE N Summer SE Finf Finf RTP 29 0.46 25 0.40 0.04 0.05 Los Angeles 15 0.42 15 0.70 0.11 0.08 Boston 14 0.40 0.1 15 0.67 0.10 Bos. sulfate N/A N/A 15 0.75 0.03 N/A Atlanta 24 0.43 0.1 22 0.49 0.14 Atl. sulfate 24 0.40 22 0.45 0.04 0.04 Seattle 55 0.53 0.2 55 0.79 0.18 13
Conclusions • Personal monitors performed well • New personal monitor developed • Personal exposures were similar for healthy and sick cohorts • Difficulties in calculating proportion of exposure due to particles from outdoors Conclusions (cont.) Indoor Air Characterization • Fewer than ½ the persons had longitudinal • Size Distribution Important—Affects… personal-outdoor correlations >0.5 – Penetration • Fewer than ¼ had significant correlations – Deposition • Air exchange rates—Affect… • Some persons in all cohorts had negative correlations – Infiltration – Exfiltration • Sampling for more days might not improve correlations 14
Poured kitty litter 2 rec room utility room 2.5 µ m to 5.0 µ m particles stairs 1 outside 0 ln (particles cm -3 ) -1 -2 -3 -4 -5 36.5 37 37.5 38 38.5 39 39.5 40 time (h) 15
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