BodySense Blog

Ozone kills. So what can you do about it?

News broke April 22 that breathing even a little ozone at levels found in many areas in the U.S. is likely to kill some people prematurely. Ozone is a form of oxygen formed when sunlight reacts with air containing pollutants, like hydrocarbons and nitrogen oxide. Ozone is a powerful oxidizer, meaning it can damage essential components and functions of living cells.

Ozone is dangerous when it forms at or near the ground, where people can breathe it; it can cause respiratory problems and worsen heart disease. (The "ozone layer" found in the high atmosphere actually protects Earth from ultraviolet rays.) Ozone levels in the U.S. peak in summer, when longer days with intense sunlight provide ideal conditions for ozone formation. Dangerous ozone levels are more likely in urban and suburban areas, but many rural areas can also have high levels because winds can carry emissions hundreds of miles away from their sources.

We asked Paul S. Auerbach, M.D., clinical professor of surgery in the Division of Emergency Medicine at Stanford University School of Medicine and editor of the textbook Wilderness Medicine (Mosby, 2007) to help explain what this news means to you.    

Revolution Health: What's the most important take-away from this news?

Auerbach: It is crucial that consumers know what the ozone levels mean. (The Environmental Protection Agency posts these data daily, with a U.S. map showing elevated-ozone areas, at http://airnow.gov/; they are also published on the weather pages of many daily newspapers.) If people have access to this information, they can make informed choices about whether to exercise, how much time to spend outdoors, etc.

EPA's air-quality index runs from zero to 500; this covers a range of pollutants, but ozone is a leading factor in determining the air-quality index. Air pollutant levels above a value of 100 could be a concern for people with pre-existing respiratory conditions, and levels above 150 indicate potential for adverse health effects in anyone breathing that air. An air-quality from 201 to 300 is "very unhealthy" and anything above 300 is "hazardous."    

RH: What should people do on days with unhealthy ozone levels?

Auerbach: It sounds obvious, but try to limit exposure by staying in environments with central air conditioning and avoiding outdoor exercise. Even casual exposure to high ozone levels is toxic. That toxicity rises when you exercise because you're breathing more rapidly and deeply, thus shuttling more of the toxin into your bloodstream and into your tissues. There is also a direct irritating effect on the sensitive tissue lining of your throat and air passages.

However, don't assume you're completely protected just by remaining indoors. Wall-unit air conditioners or fans could just be pumping pollution into your home.

RH: Can people just 'listen to their bodies' and avoid exercise when it irritates their lungs? That is, can ozone harm us without us even feeling it?

Auerbach: This week's news confirms that low level, chronic exposure to ozone can still cause long-term damage. It's like biting into a bad piece of fruit: sometimes it's so rotten that you can taste it immediately and stop eating it. But the fruit could also contain an undetectable -- but highly toxic -- amount of bacteria or poison and you could eat the entire piece without realizing the danger.

Clearly, if you walk outside and there's a visible haze and your eyes burn and your throat is irritated, something's not right. If you're exercising in those conditions, you should cease the activity immediately.

RH: We've heard that, on high-ozone days, exercising in the early morning or after dusk could help limit exposure to ozone. Is this true?

Auerbach: It depends. Ozone levels do not automatically correspond to temperature, so just because it is cooler outside doesn't mean the ozone level is safe. EPA notes that ozone levels tend to peak in late afternoon and early evening -- because levels build throughout the day on hot, sunny days -- but they still could be unsafe pre-dawn or after dusk. That's why awareness of the levels is key.

Of course, heat carries its own risks for exercise -- dehydration, harder for the body to shed excess heat (especially in high humidity) -- so you may want to adjust your exercise plans based on temperature alone. But don't assume that ozone levels are safe solely because of time of day.

RH: How much should people worry about past exposure? Are the harmful effects of ozone exposure reversible?

Auerbach: Many reversible conditions can become irreversible over time. Whether it's cigarette smoking, ozone or toxicity from contaminated food products, the body can often repair itself to a certain extent, but in the case of ozone, chronic exposure may eventually cause sufficient persistent inflammation to lead to permanent scarring of tissue. Precisely when permanent damage might occur varies from person to person, so we can't say definitively that, for example, someone who jogged three times a week at midday all summer long in a high-ozone area will develop lung disease. But we can say that, generally, chronic exposure to ozone is a contributor to lung irritation and injury.

Revolution Health Group

Tips for reducing indoor pollutants in your home

Exposure to indoor air pollutants can cause respiratory diseases, including asthma and lung cancer. Pollutants include smoke, pet dander, radon, mold, cleaning products, and other chemicals. You can create a healthier home by following the tips below.

Reduce allergens

• Bathe and groom pets often to reduce dander. Don't allow them to sleep in the bedroom with anyone who has asthma or allergies. If possible, keep them off carpets and furniture.
• Choose window coverings that are easy to clean, such as wood shades or blinds. Drapes are magnets for dust.
• Check houseplants for mold. Repot or move them outside if the soil contains mold.
• Do not allow anyone to smoke in your home.
• Eliminate carpeting and replace it with wood or tile flooring, if possible.
• If the humidity level is more than 50% inside your house, dust mites and molds can be a problem. To control dust mites, get allergen-resistant covers for bedding. Don't use down pillows or comforters. Wash sheets and blankets in hot water.
• Use high-efficiency bags in your vacuum cleaner or install a central vacuum system in your home.
• Don't store firewood indoors. Drying green firewood can contain mold spores.
• Keep trees and shrubs at least 3 ft away from your house. Roots can provide an easy path for water into your basement or crawl space.
• Keep bathrooms, kitchen, and basement—places where allergens are likely to grow—clean and dry.

Control moisture

• Fix leaks and other sources of water intrusion, and remove water-damaged materials.
• Install and keep clean hood exhaust fans in your kitchen. Make sure bathroom vents exhaust the air outdoors and not into basements, crawl spaces, or inside the house.
• Make sure that exhaust fans don't draw too much air out, creating a negative-pressure situation in which the pressure inside the house is lower than outside. Negative pressure can reverse the flow of combustion gases from furnaces, gas stoves, and water heaters, and draw water vapor and dangerous carbon monoxide or nitrogen dioxide into your home.
• Caulk the interior and exterior of your home, especially around windows and vents.
• If you're building a new home, install a waterproofing system that keeps moisture away from your foundation.
• Keep gutters and drains clean.
• Remove any water-damaged carpet. Replace it, if possible, with wood or tile flooring.

Avoid heating problems

• Make sure fuel-burning furnaces, hot water heaters, and gas ranges are checked every year to ensure air intake and exhaust systems are adequate. It is best to have your water heater and furnace outside of your home—for example, in your garage.
• Do not use kerosene space heaters or unvented gas heaters as your primary source of heat.
• Install a carbon monoxide detector in your home. Carbon monoxide is odorless and colorless. You may not notice it until you develop health problems. If you see orange or sputtering flames in your gas furnace or stove, it may indicate you have a problem with carbon monoxide. Call a technician immediately.
• Make sure wood stoves and fireplaces have tight-fitting doors. Check flues and chimneys for cracks that could allow fumes into your house.

Check household furnishings

• Many furnishings contain formaldehyde and other organic compounds. When shopping for new furniture or cabinets, try to buy those that are made of solid hardwood, not particleboard, which usually has a wood-veneer finish. The wood veneer may be attached with glue that contains formaldehyde.
• If someone living in your home has asthma, replace carpet with tile or wood flooring. If carpeting is necessary, use a product with a short nap, or use area rugs that can be cleaned regularly.
• If you are remodeling, use gypsum board, plaster, or real wood for walls. Plastic or wood-fiber paneling may emit formaldehyde.

Be careful with household products

• Take precautions when using cleaning products, paints, solvents, and pesticides. Use a fan to exhaust strong odors and fumes out of your home. Be aware that paint can release trace gases for months after you apply it. Try to use paint without volatile organic compounds (VOCs).
• Use nontoxic adhesives for installing flooring.
• If stripping furniture inside, use products without methylene chloride.
• Do not mix cleaning products. Consider using natural cleaners, such as vinegar, lemon juice, boric acid, or baking soda.
• Chemicals found in many air fresheners, toilet bowl cleaners, mothballs, and other deodorizing products may be harmful to the lungs.¹ Use alternatives—for example, baking soda absorbs odors and can be used instead of an air freshener.
• Don't keep items you're recycling—such as newspapers, rags, cans or bottles—inside your home. They can be sources of toxic vapors.
• If you have a home built prior to 1978, be aware of woodwork or other surfaces that may be covered with lead paint. Call an expert if you have to sand or strip surfaces that are painted with lead paint.
• Install a radon monitor in your basement.
• Sump basins must be sealed and vented to the outdoors.

Improve air filtration

• Make sure your house receives an adequate supply of fresh air.
• Place an air filter in your bedroom, and clean it every 3 months.
• Air conditioning helps keep pollen and other allergens out of your home, but filters must be kept clean.
• Change furnace and air conditioner filters every 2 to 3 months.
• Use exhaust fans in kitchens and bathrooms to vent air outdoors.
• Have older homes checked for asbestos insulation on furnaces and pipes. Make sure to use an inspector familiar with asbestos issues.
• Clean humidifiers and dehumidifiers often.
• Make sure outdoor fresh-air intake vents for ducted heating and air conditioning systems are located above ground and are upwind from sources of contaminated air, such as idling cars or trucks.
• Have ducts for forced-air furnaces cleaned, if necessary.
• Make sure ducts are sealed to prevent air leakage and to keep contaminants from coming into your home.
• Ensure that plumbing drains in your home have full water traps and a connection to a venting system. If you smell a sewer odor coming from a sink or water appliance, it is a sign of improper ventilation.

Healthwise

Air pollution linked with blood clots in veins

Air pollution heavy in small particles may cause blood clots in the legs, the same condition air travelers call "economy class syndrome" from immobility during flight, researchers said on Monday.

Dr. Andrea Baccarelli of the Harvard School of Public Health in Boston and colleagues said they found the link after looking at 870 people in Italy who had developed deep vein thrombosis between 1995 and 2005.

When compared with 1,210 others living in the same region who did not have the problem, they found that for every increase in particulate matter of 10 micrograms per square meter the previous year, the risk of deep vein thrombosis increased by 70 percent.

On top of that, the blood of those with higher levels of exposure to particulate matter was quicker to clot when tested at a clinic, they reported in the Archives of Internal Medicine.

Air pollution from automobiles and industry can contain tiny particles of carbon, nitrates, metals and other materials that have been linked over the years to a variety of health problems.

While lung diseases were an initial concern, later research has indicated it may cause heart disease and stroke, possibly because it increases the rate at which blood can coagulate, Baccarelli and colleagues said.

Until now particulate pollution had not been linked to blood clots in the veins. The mechanism that causes problems for some air travelers is related not to the blood itself but to impaired circulation when sitting in one place without exercise for long periods of time.

The findings introduce a new and common risk for deep vein thrombosis, the researchers said and "give further substance to the call for tighter standards and continued efforts aimed at reducing the impact of urban air pollutants on human health."

In a commentary, Dr. Robert Brook of the of the University of Michigan in Ann Arbor said if the findings are proven by additional research it may turn out that "the actual totality of the health burden posed by air pollution, already known to be tremendous, may be even greater than ever anticipated."

Reuters