EPA NW Research Center for Particulate Air Pollution and Health
Newsletter
Summer 2001
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Contents: Research Proposal Products on Fire smoke health website |
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EPA NW Research Center for Particulate Air Pollution and Health Newsletter
Summer 2001
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The 2001 summer fire season hadn't yet started, but the immense fires of 2000 prompted officials to convene a fire, smoke, and health workshop in June. Seventy-five environmental specialists and researchers working on the exposure health effects, management, and measurement of smoke came from Montana, Idaho, Washington, Oregon, California, Texas, Colorado, Wyoming, and as far away as Georgia, North Carolina, Florida, and Washington, DC. The workshop was held at the University of Washington with the support of an Environmental Protection Agency (EPA) grant and travel support by the Centers for Disease Control (CDC) and the United States Forest Service (USFS). Dr. Michael Lipsett, a leader of the health research work group from the Office of Environmental Health Hazard Assessment in Oakland, California, spoke for all participants when he said the workshop's greatest benefit was the reinforcement of collaborative relationships between federal, state, local, and academic institutions to deploy research projects. The workshop also brought public health professionals (e.g., CDC, Agency for Toxic Substances Disease Registry (ATSDR), state, and local health agencies) together with fire and smoke management specialists (USFS, EPA, and other state and federal agencies). Workshop goals included developing health advisory information (included with this newsletter) and information to assist local officials in reaching out to and communicating with the public. Capturing data from smoke events can be likened to attempting to catch fireflies one at a time in a jar. Every time you open the lid to snag a firefly, one or more fly out. Vegetative burning events ranging from planned or wild forest fires to agricultural burns (e.g., wheat stubble or grass seed) often result in very high exposures to smoke for relatively short time periods. These exposures often occur in rural communities without adequate air monitoring. Researchers hope that networks established at this workshop and shared scarce public resources will ensure that usable field data can be gathered that will help describe the health effects of particulate matter in vegetative smoke. The workshop was initiated by a congressional request to EPA and CDC from former congressman Rick Hill from Montana who asked for assistance in understanding the public health impacts of the 2000 fires in Montana and other western states. Joellen Lewtas, senior scientist with EPA's Office of Research and Development, developed EPA's initial plans for the workshop after visiting Missoula and Helena, Montana and meeting with state and local public health and air pollution monitoring officials as well as the USFS fire research laboratory. Dave Kalman, Chair of the Department of Environmental Health at the University of Washington and many of the staff of the EPA NW Research Center for Particulate Air Pollution and Health made the workshop a reality in record time. The Seattle workshop was followed by a workshop held in Missoula, Montana with the support of the Montana participants and the Center for Environmental Health Sciences at the University of Montana. Information shared by these attendees can be accessed on the workshop website: http://depts.washington.edu/wildfire/ or http://firesmokehealth.org/. This newsletter is devoted to making available substantial portions of the summaries generated by each of the four work groups: Outreach, Research/Monitoring & Forecasting, Research/Health & Exposure, and Health Advisory. |
Work Group Leaders Outreach Alison Davis, EPA davis.alison@epa.gov Rick Kreutzer, CA Dept. of Health Services rkreutze@dhs.ca.gov Carol Trenga, Univ. of WA ctrenga@u.washington.edu Research/Monitoring & Forecasting Tim Larson, Univ. of WA tlarson@u.washington.edu Janice Peterson, US Forest Service jlpeterson@fs.fed.us Research/Health & Exposure Joellen Lewtas, EPA lewtas.joellen@epa.gov Josh Mott, CDC zud9@cdc.gov Jeff Sullivan, Univ. of WA sulljh@u.washington.edu Health Advisory Michael Lipsett, OEHHA mlipsett@oehha.ca.gov Susan Stone, EPA stone.susan@epa.gov |
Holian Heads New Research CenterResearchers at the year-old Center for Environmental Health Sciences (CEHS) at the University of Montana strive to understand the mechanisms and genetics of lung and neurological diseases and how environmental and occupational exposures contribute to these diseases. One CEHS research goal is to help shed light on the human health effects of vegetative burning. Andrij Holian was appointed the first director of CEHS in July, 2000. His primary area of research interest is determining mechanisms of lung inflammation, fibrosis, and asthma in response to particles, which include particulate matter, silica, and asbestos. Holian was Director of Research of the Mickey Leland National Urban Air Toxics Research Center from its inception in 1990 until 2000. For more information about research plans at the Center for Environmental Health Sciences at the University of Montana contact Dr. Holian at: aholian@selway.umt.edu or Dr. Jean Pfau at: jpfau@selway.umt.edu.
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 Dr. Andrij Holian, Courtesy of A. Holian |
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Characteristics of SmokeHow smoke
behaves depends on many factors, including the fire's size and location,
topography of the area, and weather. National Weather Service satellite photos, weather and wind forecasts, and knowledge of the area help to predict how much smoke will affect an area, but predictions are rarely accurate for more than a few hours. The National Weather Service's website provides a great deal of information, including satellite photos continually updated throughout the day. For the western United States, the web address is www.wrh.noaa.gov. Health Effects of SmokeSmoke causes eye and respiratory tract irritation along with asthma, bronchitis, and reduced lung function, and can contribute to premature death. Studies have found that fine particulate matter is linked (alone or with other pollutants) with a number of significant respiratory and cardiovascular-related effects, including increased mortality and aggravation of existing respiratory and cardiovascular disease. Airborne particles are respiratory irritants, and laboratory studies show that high concentrations of particulate matter (PM) cause persistent cough, phlegm, wheezing, and physical discomfort in breathing. PM can alter the body's immune system and affect removal of foreign materials from lungs, such as pollen or bacteria. Carbon monoxide (CO) enters the bloodstream through the lungs and reduces oxygen delivery to the body's organs and tissues. Even low levels of CO are serious for those with cardio-vascular disease. At higher levels, carbon monoxide exposure can cause headaches, dizziness, visual impairment, reduced work capacity, and reduced manual dexterity even in otherwise healthy individuals. At even higher levels (seldom associated solely with a forest fire), carbon monoxide can be deadly. People exposed to toxic air pollutants at sufficient concentrations and durations potentially have an increased risk of cancer or other serious health problems. However, in general, the long-term risk of toxic air pollutants from most vegetative fires such as forest fires is believed to be low due to the short exposure duration. More research is needed in this area to measure exposures to toxic air pollutants from wild fires and other vegetative burning exposures. Some components of smoke, such as many polycyclic aromatic hydrocarbons (PAHs), are carcinogenic. One of the most carcinogenic is benzo-a-pyrene (BaP). Other components, such as the aldehydes, are acute irritants. Examples of three air toxics of concern from wildfires are:
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Recommendations Stay Indoors The most common advisory issued during a smoke pollution episode is to stay indoors. The usefulness of this strategy depends on the quality of the indoor air. Indoor air-quality studies indicate that this strategy can usually provide some protection, especially in a tightly closed, air-conditioned house. Staying inside can usually reduce ambient air pollution by about a third. In homes that are not air-conditioned, anywhere from 70100% of fine particulate will penetrate indoors from the outside air. In very "leaky" homes and buildings, staying inside with doors and windows closed may offer little protection. Certainly, if doors and windows are left open, indoor and outdoor air will be about the same. One of the biggest problems with people staying indoors during smoke events is the risk of heat stress. Fire season is often accompanied by high temperatures, and for those who depend on open windows and doors for ventilation, keeping them closed can be a problem. Older individuals and those in frail health run the risk of heat exhaustion or heat stroke. Smoke events can last several weeks or months. These longer events are usually punctuated by times of relatively clean air. When air quality improves, even temporarily, residents should "air out" their homes to reduce indoor air pollution. Air conditioners The effect of air conditioners and air filters on indoor air pollutant concentrations is limited to a few pollutants. The evidence is that air conditioners reduce the amount of outside particulate matter coming indoors, if for no other reason than air conditioned homes usually have lower air exchange rates than homes that use open windows for ventilation. Some air conditioners can be fitted with HEPA (high efficiency particulate air) filters that can capture most of the tiny particles associated with smoke and reduce the amount of outside particulate air pollution coming indoors, however filters alone do not remove the gaseous organics. Organic gases can be reduced using charcoal or carbon impregnated filters, however these are not normally found in home air conditioners or cleaners.
Air cleaners Air cleaners can be effective at reducing indoor particulate levels, provided the specific cleaner is adequately matched to the indoor environment. However, most air cleaners are not effective at removing gases and odors. The two basic types of air cleaners for particle removal are: (a) Mechanicalcontaining a fiber or fabric filter. The filters need to be sealed tightly in their holders and cleaned or replaced regularly. (b) Electronicsuch as electrostatic precipitators (ESP) and ionizers. ESPs use a small electrical charge to collect particles from air pulled through the device. Ionizers, or negative ion generators, cause particles to stick to materials (such as carpet and walls) near the device. Electronic air cleaners usually produce small amounts of ozone as a byproduct. The effectiveness of an air cleaner is usually reported in terms of efficiency, which can be misleading, as it only tells half of the story. The other important factor is air flow. Together, these two factors equal the Clean Air Delivery Rate (CADR), which is a better measure of how a device will actually perform. Most portable units have packaging that states the unit's air flow rate, the size room it cleans, and perhaps its particle removal efficiency and its CADR. Central system air units should handle at least 0.5 air changes per hour, the air exchange rate necessary to reasonably ventilate a house continuously under most conditions. For central air conditioning systems and electrostatic precipitators, high efficiency and medium-efficiency media filters can be added to keep particle level in indoor air within acceptable levels during a prolonged smoke event. However, these filters create more air resistance, and may require modifications to the system. Some devices,
known as ozone generators, personal ozone devices, "energized oxygen"
generators, and "pure air" generators, are sold as air cleaners,
but they probably do more harm than good. These devices intentionally
produce ozone gas to react with pollutants in the air. The EPA has found
that ozone Humidifiers are not air cleaners and will not significantly reduce the amount of particulate in the air nor remove gases such as carbon monoxide. However, humidifiers and dehumidifiers may slightly reduce pollutants through condensation, absorption, and other mechanisms. The benefit of running a humidifier in an arid environment during a smoke event would be to reduce stress on the respiratory system by keeping mucus membranes moist. For more information about residential air cleaners, see www.epa.gov/iaq/pubs/residair.html. For more information about reducing air pollution indoors, see www.healthhouse.org or www.lungusa.org
In vehicles Particulate
levels in vehicles can be reduced by keeping
Reduced activity Reducing physical activity minimizes the dose of inhaled air pollutants, and may reduce the risk of health impacts. Exercise during exposure causes more particulate matter to be inhaled more deeply into the lungs, and increases the risk of harmful respiratory effects.
Other sources of air pollution Many indoor
sources of air pollution can emit large amounts Besides cigarette smoke, combustion sources that do not vent to the outdoors contribute most to indoor pollutant levels and are of greatest concern. On average, reducing indoor air emissions as much as possible during smoke events may reduce indoor particulate levels by one quarter to one third or more, and levels of PAHs, volatile organic compounds (VOCs) and other pollutants by an even greater amount. These reductions can help compensate for the increased loading from the outdoor air.
Masks In order
for a mask to provide protection during a smoke event, it must be able
to filter very small particles (0.30.1 microns), and provide an
airtight seal around the wearer's face. Commonly available paper dust
masks, which are designed to filter out larger particles, typically offer
little protection. The same Surgical masks trap smaller particles, but are designed to filter air coming out of the wearer's mouth, and do not provide a good seal. They perform no better than dust masks. Some masks (technically called respirators, but that look more like paper masks) filter out 95% of the particulate matter
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In vehicles Particulate
levels in vehicles can be reduced by keeping
Reduced activity Reducing physical activity minimizes the dose of inhaled air pollutants, and may reduce the risk of health impacts. Exercise during exposure causes more particulate matter to be inhaled more deeply into the lungs, and increases the risk of harmful respiratory effects.
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 Patti Hirami, United States Forest Service. Photo by Collen Marquist |
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Other sources of air pollution Many indoor
sources of air pollution can emit large amounts Besides cigarette smoke, combustion sources that do not vent to the outdoors contribute most to indoor pollutant levels and are of greatest concern. On average, reducing indoor air emissions as much as possible during smoke events may reduce indoor particulate levels by one quarter to one third or more, and levels of PAHs, volatile organic compounds (VOCs) and other pollutants by an even greater amount. These reductions can help compensate for the increased loading from the outdoor air.
Masks In order
for a mask to provide protection during a smoke event, it must be able
to filter very small particles (0.30.1 microns), and provide an
airtight seal around the wearer's face. Commonly available paper dust
masks, which are designed to filter out larger particles, typically offer
little protection. The same Surgical masks trap smaller particles, but are designed to filter air coming out of the wearer's mouth, and do not provide a good seal. They perform no better than dust masks. Some masks (technically called respirators, but that look more like paper masks) filter out 95% of the particulate matter that are 0.3 microns and larger. Smoke particulate matter aver-ages about 0.3 microns, so these masks will filter out a significant portion of the smoke if they fit properly. These masks, which may include an exhale valve, do not require cartridge filters. Soft masks which filter out even more particulates are also available. Respirators
with HEPA (high efficiency particulate air) There are
several drawbacks to recommending widespread mask use in an area affected
by wildfire smoke. Most people won't use the masks correctly and won't
understand the importance of having an airtight seal. And, people with
Masks are uncomfortable. They increase resistance to air flow, which makes breathing more difficult and may lead to physiological stresses, such as increased respiratory and heart rates. Mask use by those with cardiopulmonary and respiratory diseases should only be contemplated under a doctor's super-vision. Even healthy adults may find that the increased effort required for breathing makes it uncomfortable to wear a mask for more than short periods of time. Breathing resistance increases with respirator efficiency. Most healthy adults can use a 95% efficient respirator without undue breathing resistance. Another problem with masks is that most of them will not reduce carbon monoxide. There are
instances where mask use can be beneficial.
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Clean Air Sanctuaries Staying inside may not adequately protect susceptible individuals. Many homes do not have air conditioning and depend on open windows and doors for cooling; other homes may be so leaky that pollution levels will soon equal that of outside air. During severe smoke events, clean air sanctuaries or shelters can be designated to provide a place to get out of the smoke. These can be in large commercial buildings, schools, shopping malls, or anyplace with effective air conditioning and particle filtration.
Closures The decision to close or curtail business activities will depend on considerations of traffic, health, environmental and socioeconomic factors, and other local conditions. Depending on building design and presence of air filtration, exposures inside schools and businesses may be similar to or better than those in homes. Children's physical activity may also be better controlled in schools than in homes. Curtailing outside activities, such as sporting events and practices, can reduce exposures by encouraging people to stay inside and reducing physical activity. Restrictions on industrial emissions may be warranted.
Evacuation The most common call for evacuation during a wildfire is due to the direct threat of the fire instead of smoke. Leaving the area of thick smoke may be a good protective measure for members of sensitive groups, but it is often difficult to predict the duration, intensity, and direction of smoke, making this an unattractive option to many people. For fires that go on for months, evacuation may not be possible for a large percentage of the population.
Bibliography Brauer, Michael. 1999. Health Impacts of Biomass Air Pollution. World Health Organization. Background papers for Health Guidelines for Vegetation Fire Events, Lima, Peru, 6-9 October 1998. www.firesmokehealth.org. Ostermann, Kathryn and Micheal Brauer. Air Quality During Haze Episodes and Its Impact on Health. www.firesmokehealth.org. Smith, Andy. 1999. Handling Air Pollution Episodes: Lessons learned from Big Bar Complex Wildfire. www.firesmokehealth.org. United States Environmental Protection Agency. 2001. Ozone Generators That are Sold as Air Cleaners: An Assessment of Effectiveness and Health Consequences. www.epa.gov/iaq/pubs/ozonegen.html. United States Environmental Protection Agency. 1990. Residential Air Cleaning Devices: A summary of available information. Office of Air and Radiation, Washington, DC, 20460. EPA 400/1-90-002. (www.epa.gov/iaq/pubs/residair.html). May 22, 2000. Summary of Forest Fire/Prescribed Burning Smoke Meeting. Oakland, California. www.firesmokehealth.org. June 5 & 6, 2001. Reports from Fire, Smoke, and Health Workshop. |
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February seminar: Alex Polissar, PhD, Clarkston University, Comparison of CAMS, RAMS, TEOM and nephelometer measurements at Beacon Hill during winter March seminar:
Delbert Eatough, PhD, Brigham Young University, Assessment Judson Kenoyer, Battelle, Discussion of research collaboration April Dr. Richard Corley/Dr. Charles Timchalk, Battelle May Assessment of Exposures to Fine Atmospheric Particulates: Challenges and Progress, PM Center/Continuing Education Course, David V. Bates, MD, Chair, PM Center External Science Advisory Committee Ralph Delfino, PhD, MD, Department of Medicine, University of California at Irvine, Assessment of exposures to fine atmospheric particulates: Challenges and progress Jonathan Samet, MD, MPH, Chair Epidemiology, Johns Hopkins University School of Public Health, member PM Center External Science Advisory Committee John Williamson, Washington Department of Ecology, DOE's Seattle Air Toxics Study June seminar: Andrij Holian, PhD, Director University of Montana Center for Environmental Health Sciences, Mechanisms of particulate-induced lung inflammation Larry Cupitt, Acting Associate Director for Health at the National Exposure Research Laboratory, EPA, Exposure Research at EPA Past, present & future 3rd PM Center's Directors Meeting, Boston, MA July Judson Kenoyer/Dr. Bob Stenner, Battelle August Naydene Maykut, PhD, Member External Science Advisory Committee, Puget Sound Clean Air Agency, Seattle Speciation Modeling
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Publications Dills, R.L., X. Zhu and D.A. Kalman, Measurements of Urinary Methoxyphenols and Their Use for Biological Monitoring of Wood Smoke Exposure. Environ. Res., 2001. 85(2):145158. Levy, D., et al., A Case-Crossover Analysis of Particulate Matter Air Pollution and Out-of-Hospital Primary Cardiac Arrest. Epidemiology, 2001. 12(2): 193199. Levy, D., et al., Referent Selection in Case-Crossover Analyses of Acute Health Effects of Air Pollution. Epidemiology, 2001. 12(2): 186192. Lumley, T. and L. Sheppard, Assessing Seasonal Confounding and Model Selection Bias in Air Pollution Epidemiology Using Positive and Negative Control Analyses. Environmetrics, 2000. 11:705717. Lumley, T. and D. Levy, Bias in the Case-Crossover Design: Implications for studies of Air Pollution. Environmetrics, 2000. 11:689704. Sheppard, L., D. Levy, and H. Checkoway. Correcting for the Efforts of Location and Atmospheric Conditions on Air Pollution Exposures in a Case-Crossover Study. J Exp Anal Environ Epidemiol, 2001. 11:8696. Presentations May 8: Collen Marquist, Eaton School, Environmental Careers May 20: Jeff Sullivan, American Thoracic Society, Association Between Personal Levels of Fine Particulate Matter Exposure and Heart Rate Variability in Older Subject With and Without COPD May 20: Carol Trenga, American Thoracic Society, Symptoms and Personal Particulate Matter Exposure in Subjects With and Without COPD May 22: Carol Trenga, American Thoracic Society. Antioxidant Vitamin Intake, Diet, and Asthma June 11: Carol Trenga, III World Congress on Vitamin C, Vitamin C and Asthma June 16: Jane Koenig, American Chemistry Society NW Section meeting |
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EPA NW Research Center for Particulate Air Pollution and Health 1107 NE 45th Street, Suite 355 University
of Washington, Box 354803 Director: Jane Q. Koenig, PhD Phone:
(206) 543-2026 Web
sites: http://depts.washington.edu/pmcenter/ Principal Investigators Atmospheric
Sciences, UW: David S. Covert, PhD |
Illustrations: ©2001 www.arttoday.com
