Aug. 21, 2025 | Take a deep breath. Now let it out. Your body’s natural defenses protect your lungs from germs and large particles like dust and pollen. Unfortunately, they can’t protect you from air pollutants, which harm your lung tissue and weaken those important defenses. Air pollution can make your eyes water, irritate your nose and throat and make you cough and wheeze. It can also worsen lung diseases like asthma, bronchitis and emphysema. Gas and diesel engines, power plants, wildfires and volcanic ash are just a few of the more common sources of outdoor air pollutants. Outdoor air pollution threatens the lives and health of millions of people in the United States. Despite great progress since passage of the modern Clean Air Act in 1970, outdoor air can be unhealthy and dangerous. Even as we explore the complex challenges of global warming and energy use, air pollution remains a widespread problem.

Aug. 21, 2025 | Ozone is a gas found in the air that we breathe. It can be good or bad, depending on where it occurs. Good ozone is present naturally in the Earth’s upper atmosphere, approximately six to 30 miles above the Earth’s surface. This natural ozone shields us from the sun’s harmful ultraviolet rays. Bad ozone forms near the ground when pollutants react chemically in sunlight. Ozone pollution is more likely to form during warmer months. Ozone is particularly likely to reach unhealthy levels on hot sunny days in urban environments. It is a major part of urban smog.  Ozone can also be transported long distances by wind.  For this reason, even rural areas can experience high ozone levels.  Breathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ground level ozone also can inflame the linings of the lungs.

Aug. 21, 2025 | Particle pollution, also known as particulate matter, consists of a mixture of solids and liquid droplets. Some particles are emitted directly. Others form when pollutants emitted by various sources react in the atmosphere. Particle pollution levels can be very unhealthy and even hazardous during events such as forest fires. Particle levels can be elevated indoors, especially when outdoor particle levels are high. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope. The size of particles is directly linked to their potential for causing health problems. Particles smaller than 10 micrometers in diameter can cause or aggravate a number of health problems. Particle pollution also can increase susceptibility to respiratory infections and can aggravate existing respiratory diseases.

Aug. 21, 2025 | Carbon monoxide is an odorless, colorless gas. It forms when the carbon in fuels does not completely burn. Vehicle exhaust contributes roughly 75 percent of all carbon monoxide emissions nationwide. Other sources include fuel combustion in industrial processes and natural sources such as wildfires. Carbon monoxide levels typically are highest during cold weather, because cold temperatures make combustion less complete and cause inversions that trap pollutants close to the ground. Carbon monoxide enters the bloodstream through the lungs and binds to hemoglobin, the substance in blood that carries oxygen to cells. In doing so, it reduces the amount of oxygen reaching the body’s organs and tissues. This form of pollution poses a high risk to people with cardiovascular disease. They may experience chest pain and other cardiovascular symptoms if exposed to carbon monoxide, particularly while exercising.

Aug. 21, 2025 | Some people are more susceptible to the harm that air pollution can cause then others. Teens, for example, tend to inhale more pollution because spend more time outdoors than adults. Children face greater risk of infection, coughing and bronchitis from air pollution. They may even suffer from lower lung function, putting them at greater risk of lung disease as they age. Older adults are also at increased risk from air pollution. As people age, their bodies become increasingly susceptible to the assault from dirty air. Studies have found older adults face a greater risk of respiratory and cardiovascular problems after breathing ozone and particle pollution. People with lower incomes are more likely to endure problems from air pollution because they often live closer to the sources of pollution like major highways and factories. They are also more likely to have diseases like asthma and diabetes that put them at higher risk.