Indoor Air Pollution Sara Lance Kim Kubera Arsineh Hecobian Rick Peltier
Introduction and Summary • Sources of Indoor Air Pollutants • Transportation/Movement • Unique Chemistry • Specific Health Effects
Indoor Air Pollution - Overview • People spend most of their time indoors. • The EPA has shown that indoor levels of some pollutants, such as formaldehyde, chloroform, and styrene, range from 2 to 50 times higher than outdoor levels. • Exposure to pollutants such as environmental tobacco smoke and radon occurs almost entirely indoors.
Indoor Air Pollution • Main Categories: 1) toxic gases e.g. carbon monoxide, ozone, formaldehyde 2) particulate matter e.g. candles, incense, smoke, pet dander 3) radiogenic species e.g. Radon-220, Polonium-210 4) biological organisms e.g. mold, dust mites, bacteria
Some Specific Indoor Air Pollutants • Acetone - in cosmetics, fragrances, human breath • Ammonia - in cleaning products • Benzene - in laser printers, particle board, paint, tobacco • Benzaldehyde - in detergents and fragrances • Benzyl acetate - in air fresheners, fragrances • Chloroform - in chlorinated tap water • Formaldehyde - in particle boards, carpets, clothes, glue • Limonene - in deodorants, disinfectants, fragrances • Terpinen - in deodorants, fragrances • Toulene - in glue, laser printers, paint and particle board • Trichloroethyl - in photocopiers • Xylene - in glue, laser printers, paint and particle board
Indoor Sources of Ozone • Laser printers • Photocopiers • Fax machines • Ozone Generators • touted as “Air Cleaning” devices
EPA’s Stance on Ozone Generators • ozone generators are not effective at removing many of the most harmful chemicals--including carbon monoxide and formaldehyde--commonly found in indoor environments. • for many of the chemicals with which ozone does readily react, ozone forms a variety of harmful or irritating by-products, including aldehydes and other organic chemicals. • ozone does not remove particles (such as dust and pollen) from the air.
Ozone Generator - http://www.purennatural.com Coverage - up to 2,000 square feet Maximum Ozone Output - 750 mg/hr
The “Ozone Zapper”- According to Specs • With “perfect mixing”, the maximum output rate (750 mg/hr) combined with the maximum area coverage (2,000 ft2) gives an ozone production rate of 920 ppb/hr. • Ozone concentrations will be greater near the “Ozone Zapper” source. • 920 ppb O3 is more than 10 times the EPA’s eight-hour standard.
Lead Particulates - Candle Burning • The core of candle wicks may contain lead. • Out of the molten wax, lead can be emitted as particulate to the air. • In an EPA study, of 100 sets of candles that appeared to have metal-core wicks, 8% contained lead wicks.
Environmental Tobacco Smoke (ETS) • The EPA has classified environmental tobacco smoke as a class A carcinogen, responsible for approximately 3,000 lung cancer deaths and 62,000 heart disease deaths annually in U.S. non-smokers. • ETS includes toxic gases, particulate matter and radiogenic species.
Tobacco Toxins Among the powerful poisons in Environmental Tobacco Smoke (ETS) are: • Carbon monoxide • Nitrogen oxide • Ammonia • Methyl isocyanate • Hydrogen cyanide • Phenol • Among the carcinogens in ETS are: • Benzo [a] pyrene • Nitrosamines • Aromatic amines • Benzene • Formaldehyde • Polonium-210 (radioactive)
Radon • A colorless, odorless, invisible radioactive gas, is released into the air from the uranium found naturally in rocks and soil.
Radon Exposure – EPA Guidelines • EPA Standard for Radon = 4 pCi/L • Out of 1,000 people exposed to 4 pCi/L over a lifetime, 2 non-smokers and 29 smokers are predicted to get lung cancer. • Smoking and radon gas exposure show a synergistic relationship with respect to lung cancer.
Estimated Fraction of Homes with Long-term, Living-Area Average Radon Concentrations over 4 pCi/L
Legionnaires’ Disease • “A bacterial disease commonly associated with water-based aerosols and often a result of poorly maintained air conditioning cooling towers and potable water systems.” (OSHA) • Cases have been reported in the US, Australia, Netherlands, UK…
Dust Mites “Typical places to find mites are the mattress, and the carpeting next to the bed, because the bed is where we spend the majority of our time -- at least 8 hours a day sleeping, so we lose a lot of skin cells there,” said Glass. “The average person sheds enough skin cells every day to feed thousands of mites for a month.” These microscopic insects excrete proteins that can trigger asthma and allergy attacks in people.
Indoor Pollution Transport • Indoor to Outdoor, Outdoor to Indoor Transport (basic methods/terminology) • How do you improve indoor air pollution
Basic Transportation • Infiltration - flows into the house through openings, joints, and cracks in walls, floors, and ceilings, and around windows and doors.
Transport - Continued • Natural ventilation - air moves through opened windows and doors. (Air movement associated with infiltration and natural ventilation is caused by air temperature differences between indoors and outdoors and by wind.)
Mechanical ventilation - 1.outdoor-vented fans that intermittently remove air from a single room - 2. air handling systems that use fans and duct work to continuously remove indoor air and distribute filtered and conditioned outdoor air to strategic points throughout the house.
The rate at which outdoor air replaces indoor air is described as the air exchange rate. When there is little infiltration, natural ventilation, or mechanical ventilation, the air exchange rate is low and pollutant levels can increase.
Source Control • eliminate individual sources of pollution or to reduce their emissions. - seal or enclose (asbestos) - adjust to decrease the amount of emissions. (gas stoves) • In many cases, source control is also a more cost-efficient approach to protecting indoor air quality than increasing ventilation because increasing ventilation can increase energy costs.
Ventilation Improvements • increase the amount of outdoor air coming indoors. - Opening windows and doors, operating window or attic fans, when the weather permits, or running a window air conditioner with the vent control open increases the outdoor ventilation rate.
Ventilation - Continued • important to take as many of these steps as possible while you are involved in short-term activities that can generate high levels of pollutants. - painting, paint stripping, heating with kerosene heaters, cooking, or engaging in maintenance and hobby activities such as welding, soldering, or sanding.
Air Cleaners • many types and sizes of air cleaners on the market - ranging from relatively inexpensive table-top models to sophisticated and expensive whole-house systems. • Some are highly effective at particle removal, while others, including most table-top models, are much less so. • Air cleaners are generally not designed to remove gaseous pollutants.
Air Cleaners - Continued • The effectiveness of an air cleaner depends on how well it collects pollutants from indoor air and how much air it draws through the cleaning or filtering element. • A very efficient collector with a low air-circulation rate will not be effective, nor will a cleaner with a high air-circulation rate but a less efficient collector. • The long-term performance of any air cleaner depends on maintaining it according to the manufacturer's directions.
Another important factor in determining the effectiveness of an air cleaner is the strength of the pollutant source. • Table-top air cleaners may not remove satisfactory amounts of pollutants from strong nearby sources.
Indoor Chemical Pollutants • Sources (physical and chemical) • Sinks (physical and chemical) • Reactions (chemical sources and sinks)
Some Chemical Air Pollutants • Sulfur Dioxide • Carbon Monoxide • Nitrogen Dioxide • Particulate Matter • Ozone
Some Volatile Organic Compounds Compound Health Effects Benzene Carcinogen; respiratory tract irritant Xylenes Narcotic; irritant; affects heart, liver, kidney, and nervous system Toluene Narcotic; possible cause of anemia Styrene Narcotic; affects control of nervous system; probable human carcinogen Toluene diisocyanate (TDI) Sensitizer; probable human carcinogen Trichlaroethane Affects central nervous system Ethyl benzene Severe irritation of eyes and respiratory tract; affects central nervous system Dichloromethane Narcotic; affects nervous system; probable human carcinogen 1.4-Dichlorobenzene Narcotic; affect liver, kidney, and central nervous system; eye and respiratory tract irritant Benzyl chloride Central nervous system depressant; affects liver and kidney; eye and respiratory tract irritant 2-Butanone (MEK) Irritant; central nervous system depressant Petroleum distillates Affects central nervous system, liver, and kidneys 4-Phenylcyclohexene Eye and respiratory tract irritant; central nervous system Source: U.S. Environmental Protection Agency (EPA). Introduction to Indoor Air Quality. Report no. EPA/400/3–91/ 003, Washington, DC: U.S. Environmental Protection Agency, 1991.
Reaction between -pinene and O3 Source: The significance of secondary organic aerosol formation and growth in buildings: experimental and computational evidence Golam Sarwar, Richard Corsi, David Allen and Charles Weschler
What Chemicals are IMPORTANT? • Free Radicals (OH) • Oxidizers (O3)
NOx • Sources • Transport • Combustion Processes • Range: • Indoor: 20-50 ppb • Outdoor: 10-500 ppt (Ludwig et al, 1974) • O3+NO NO2+O2
The importance of NOx • O3+NO2 NO3+O2 • NO3+RH HNO3+Ro
OH Radical • Outdoor to indoor transport • Reactions with VOC
Calculated rate constants for removal of hydroxyl radical Source: Free radical chemistry and its concern with indoor air quality: an open problem, Giovanni Ingrosso
Tobacco Smoke: Inert Chemicals Source:Indoor Chemistry: Ozone and Volatile Organic Compounds Found in Tobacco Smoke Richard J. Shaughnessy, T. J. McDaniels, and Charles J. Weschler
Tobacco Smoke: Reactive Chemicals Source:Indoor Chemistry: Ozone and Volatile Organic Compounds Found in Tobacco Smoke Richard J. Shaughnessy, T. J. McDaniels, and Charles J. Weschler
Chemicals Produced From Ozone Reactions Source:Indoor Chemistry: Ozone and Volatile Organic Compounds Found in Tobacco Smoke Richard J. Shaughnessy, T. J. McDaniels, and Charles J. Weschler
Surface Deposition • More surface areas • Different types of surfaces • Relative Humidity
The Bigger Picture: Impacts on Humanity • Americans spend majority of their day in an indoor environment. • Other cultures can spend more/less time indoors
Health Effects - Respiratory Physiology affords a uniquely reactive environment Direct pathways to internal systems Although low in tidal volume, high in frequency (69000 liter/day = 6900 m3/day (= 13.2 kilogram at PM10 standard of 75mg over lifetime)
Health Effects - Cardiac • Peters et al. – strong correlation between ST segment elevation and PM2.5 mass. • Acid deposition (gas and particle) and linkage to cardiac ischemia???
Biogenic Air Pollutants • Chew et al. – Cockroach allergen and sensitivity to Asthma • Consistent 8-10 hour exposure to Epidermal detritus • Pet dander