 We breathe air to live, each of us over 3,000 gallons of air every day. Normally, we don't think about the next breath where it comes from or what's in it. You take it for granted, except on smoggy days. When along with the oxygen we need, we often get air pollution. Sometimes you can see it, that telltale haze. It's not just Los Angeles or the Bay Area in the north. It's in much of California's central valley and high desert too. We see the visible haze, but there's more to smog than meets the eye, or irritates the eye. Smog takes a big toll on our health. 90% of all Californians breathe unhealthy air. In Southern California alone, 3,300,000 workdays are lost each year due to smog health effects. State-wide, air pollution causes over 6,000 premature deaths each year. Many thousands more are forced to visit hospital emergency rooms on smoggy days. Through years of research, we've only discovered some of the effects of smog on the body. But before we look at these effects, let's define the problem. What is smog? You can think of smog as an atmospheric soup of harmful gases and very small solid or liquid particles called particulate matter. The most prevalent gases are ozone and oxides of nitrogen, NOx, called NOx. Carbon monoxide and sulfur dioxide are other air pollutant gases, but we're going to focus on ozone, NOx, and particulate matter because they're California's worst air pollution problems. NOx gases come from just about any kind of source where fuels are burned. From cars, trucks, power plants, and factories. Natural oxygen and nitrogen in the air combine under high temperature to make NOx. Every morning, thousands of tons of NOx and hydrocarbon gases are spewed into the air. Hydrocarbons come from fossil fuels, mainly gasoline and diesel when they are burned. They also come from the evaporation of fuels, chemicals, and solvents. Together, hydrocarbons and NOx gases react under strong sunlight to form ozone and other hazardous air pollutants. Ozone by itself is a colorless, invisible gas, but the smog-forming process also generates very small particulate matter, which contributes to the haze everyone associates with smog. As evening approaches and sunlight weakens, less ozone and particulate matter are formed and smog levels drop. Over the past 30 years, we've made progress cleaning up the air. Ozone and NOx levels have come down, but not far enough. Ozone and NOx are still big problems, but today particulate matter is taking center stage. Smog is not the only source of particulate matter. Other particles come from the combustion of fuels, small, nearly invisible toxic particles of smoke and soot. Many of these particles are so small, they can stay suspended in the air for days, even weeks at a time, traveling many miles before settling to the ground. You know when you see visible dust that it's a good idea to stay away from it, but it's what you can't see that can get you. So how small are we talking? Well this is a human hair about 70 microns in diameter. And here is a piece of small particulate matter, about 10 microns in diameter. Particles 10 microns or less are classified as PM10. Things like pollen, windblown dust and tire rubber particles are size PM10, which is small enough to penetrate into the small airways of the lungs. Some particles formed by smog or from smoke and diesel soot are even smaller. This piece of particulate matter and smog is about 2 microns wide. Very small particles less than 2.5 microns in size are called PM2.5 and are more dangerous because they are small enough to penetrate into the deepest parts of the lung. The worst particles are those under one-tenth micron in size, the ultrafine. Found near fresh emissions from cars, trucks and buses, they can number more than 100,000 per cubic centimeter. When we breathe smog, we breathe a mixture of ozone, NOx and particulate matter from a variety of sources. Even though we can't see ozone when levels are high, it gets our attention. Eyes may burn in water. There can be wheezing and coughing. The throat is irritated and feels scratchy. The chest might hurt. There is a shortness of breath. Unconsciously, the body shifts to a shallow breathing pattern similar to that caused by fear. When we breathe polluted air, our bodies begin a series of natural steps to purge the pollution. The nose removes half of the ozone we breathe. Ozone reacts with tissues, killing cells and damaging the nose. Our airways are lined with cells that are covered with tiny hairs called cilia. They beat in a rhythmic pattern, moving mucus up to the throat where it is swallowed. Mucus is important because it sweeps up harmful particles as well as bacteria and viruses. Ozone and particulate matter paralyze cilia, making them move less or not at all. They can't do the job they were designed to do. Clean out the lungs. This makes us more vulnerable to disease. Like ozone, NOx irritates mucus membranes. Scientists have found that people exposed to high levels of NOx have more colds that settle in their chests. They develop chronic wheezing and cough, bronchitis and episodes of respiratory illness. Animals exposed to NOx and lab experiments become more susceptible to viral infection and are less able to ward off bacterial infections. They die earlier. With every breath, air moves through the bronchial tubes down to the lung space. Deep in the lung are tiny sacs called alveoli, where oxygen is transferred to the blood and waste carbon dioxide is removed. An average adult lung has 300 million alveoli. If they were to spread out, they would have a surface area of 6 to 900 square feet. PM2.5-sized particles sneak past fine hairs in the nose and cilia in the respiratory tract to penetrate deep into the lungs, reaching the alveoli. Here, special cells called macrophages roam around eating up particles, bacteria and viruses, but smog can damage the macrophages and they can't do their job. Scientists are also finding that there is a link between fine particulate matter air pollution and heart attacks, even sudden heart failure resulting in death. Here's a comparison. This is a healthy open airway. And this is what an airway on smog looks like. Inflammation swells the tissue, restricting airflow. This is not good. Ozone damages the delicate, thin-walled cells in the alveoli. Within a few days, damaged cells are replaced, much like the way skin peels after a sunburn. Laboratory tests show that healthy people breathing smog can lose up to half their breathing capacity. Researchers fear that repeated episodes of lung inflammation may cause permanent lung changes and long-term health effects. Some people think they adapt to smog because symptoms may disappear after a few days. While symptoms may in fact go away over time, it doesn't mean they develop a resistance to smog. Smog continues to cause lung damage even when outward symptoms disappear. A constant cycle of damage and repair may lead to premature aging of the lung. Over days, months, or years, the damaged cells are replaced with thicker, stiffer cells, scar tissue called fibrosis. Scar tissue won't allow life-giving oxygen to enter the bloodstream. When we can't get oxygen, we're in real trouble. Ask anyone with emphysema what it's like simply trying to breathe. Three groups of people are more vulnerable to smog health effects. The first group are people with chronic obstructive pulmonary disease, which includes respiratory diseases such as asthma, emphysema, and bronchitis. 11% of all Californians fall into this category. They suffer the ill effects of air pollution sooner, and at lower pollution levels than healthy people. When smog levels are high, asthmatics can develop serious health problems, many serious enough to require medical attention. Up to 1,300,000 asthma attacks each year in California are aggravated by air pollution. The ozone in smog also makes people more sensitive to allergens, such as dust mites, pet hair, mold, and pollen. The second group at high risk includes babies and small children. Their lungs are still developing and are more sensitive to smog. They also breathe in more air pollution because they breathe faster, bringing in three to four times more air per pound of body weight than adults. And smog reduces a child's breathing capacity even more than it does in adults. Because children have smaller airways, more particles stick to airway walls. Particular matter may increase the incidence of sudden infant death syndrome. Children living in smoggy areas have more respiratory infections, and studies show that they are more likely to develop poorly functioning lungs later in life. Even when children active in unhealthy air don't show symptoms, they are still likely to suffer loss compared to children who grow up in cleaner air. Research is showing that children who live in areas with high particulate matter levels are at risk for poor lung development, making them more susceptible to lung disease as adults. Research also shows that active children living in the most ozone-polluted communities develop more cases of asthma than children in other areas. When ozone levels peak, kids miss more school days. A third group is at increased air pollution risk, healthy adults of all ages who exercise or work hard outdoors. During exercise, we breathe in as much as 10 times our resting volume of air, exposing us to 10 times more air pollution. We breathe through the mouth instead of the nose, bypassing filters in the nose that otherwise would filter out half of the particles inhaled. We're learning more every year about the harmful health effects of air pollution, so it's important that we continue to reduce smog levels. To do this, we need answers to questions, such as how much smog is too much smog. Air quality standards have been established for the main ingredients in smog, ozone, NOx, and particulate matter. These standards are the concentration levels in the air environment that have been determined as reasonably safe for most people. Air quality standards give a number that planners and government can target to reduce air pollution to healthy levels. Hundreds of air pollution monitoring stations are spread across California, continuously monitoring the air, recording air pollution levels. Air quality agencies use the data to see if air quality standards are being achieved. How can people find out about air pollution levels where they live? Well, there's a simple way. The Air Quality Index, or AQI, gives people a gauge of air pollution severity where they live and work. The AQI takes into account levels of ozone and sometimes other air pollutants. Readings of 0 to 50 indicate good air quality. 50 to 100 is moderate. When levels reach 100 to 150, it's considered unhealthy for sensitive groups. 150 to 200 is unhealthy for all groups. And 200 to 300 is very unhealthy. When air quality worsens to unhealthy levels, what can we do to protect our health? First of all, try to stay indoors. Reduce any outdoor activity that requires heavy exertion, such as running or heavy labor. Walk instead of run. Because small levels are usually lower in the early morning and evening, you should schedule outdoor exercise during these times. Children should avoid strenuous outdoor play. For some air pollutants, any amount is too much. We call these pollutants air toxics because any measurable level can impact your health. California has nearly 200 chemical substances on the list of air toxics. To be on the list, the substance must be one, an irritant. Two, a carcinogen, a substance that increases the likelihood of getting cancer. Or three, a reproductive toxin. Air toxics can be localized around fixed industrial sites, and people who live near such sites can be more at risk. Other air toxics are not localized to a specific area. Benzene, which comes from gasoline and diesel exhaust, affect people over a wide region because they're emitted from cars, trucks and buses. Scientists have found increased risk of lung cancer among people exposed to diesel exhaust particles. Exposure to air toxics causes over 300 cases of cancer each year in California. It's the subject of intensive research. The health effects of air pollution produce serious economic consequences. Air pollution means increased health care costs, increased doctor visits, increased hospital admissions, babies born prematurely or with low birth weight, babies born with developmental defects, children who can't go to school or have trouble doing well even when they're there. It means workers who don't go to work, families who pack up and look for jobs somewhere else, suffering and premature death to the most sensitive. An Air District study in Southern California discovered that smog causes nearly 18 million person days a year of headaches, sore throats, coughing, chest pain and burning eyes. The human ill health effects of smog cost us over $9.4 billion every year, and that's just in Southern California. These are the real costs that everyone pays for. Smog not only harms our health, but it hurts the economy, today and for future generations. But the good news is that fighting air pollution pays off. The US EPA figured the cost and benefits of fighting air pollution nationwide between 1970 and 1990. Cost of fight? About $523 billion. But the benefit in terms of sickness and premature death prevented was about $22 trillion. The net benefit to the country was about $21 trillion. We've made a lot of progress cleaning up the air over the past 50 years, but we still have further to go. Industry and transportation will continue to run cleaner. But there is also a role for each of us as individuals. How you get to work, to school or to the store makes an air quality difference. Choose a carpool, take the bus or light rail, walk or ride a bike if you can. Your clean air choices are critical in the fight against air pollution. With every breath you take, you can be part of the fight for clean air. Thanks for watching.