Overall Health Effects Many of us experience some kind of air pollution-related symptoms such as watery eyes, coughing, or wheezing. Even for healthy people, polluted air can cause respiratory irritation or breathing difficulties during exercise or outdoor activities. Your actual risk depends on your current health status, the pollutant type and concentration, and the length of your exposure to the polluted air. People most susceptible to severe health problems from air pollution are: Individuals with heart disease - such as coronary artery disease or congestive heart failure Individuals with lung disease - such as asthma, emphysema or chronic obstructive pulmonary disease (COPD) Pregnant women Outdoor workers Children under age 14, whose lungs are still developing Athletes who exercise vigorously outdoors High air pollution levels can cause immediate health problems: Aggravated cardiovascular and respiratory illness Added stress to heart and lungs, which must work harder to supply the body with oxygen Damaged cells in the respiratory system Long-term exposure to polluted air can have permanent health effects: Accelerated aging of the lungs Loss of lung capacity Decreased lung function Development of diseases such as asthma, bronchitis, emphysema, and possibly cancer Shortened life span Back to Top Health Effects from Specific Pollutants Ground-level Ozone Ground-level ozone is formed when volatile organic compounds (VOCs) and oxides of nitrogen (NOx) react with the sun's ultraviolet rays. The primary source of VOCs and NOx is mobile sources, including cars, trucks, buses, construction equipment and agricultural equipment. Ground-level ozone reaches its highest level during the afternoon and early evening hours. High levels occur most often during the summer months. It is a strong irritant that can cause constriction of the airways, forcing the respiratory system to work harder in order to provide oxygen. It can also cause other health problems: Aggravated respiratory disease such as emphysema, bronchitis and asthma Damage to deep portions of the lungs, even after symptoms such as coughing or a sore throat disappear Wheezing, chest pain, dry throat, headache or nausea Reduced resistance to infection Increased fatigue Weakened athletic performance Particulate Matter (PM) Particulate Matter is a complex mixture that may contain soot, smoke, metals, nitrates, sulfates, dust, water and tire rubber. It can be directly emitted, as in smoke from a fire, or it can form in the atmosphere from reactions of gases such as nitrogen oxides. The size of particles is directly linked to their potential for causing health problems. Small particles (known as PM2.5 or fine particulate matter) pose the greatest problems because they can get deep into your lungs and some may even get into your bloodstream. Exposure to such particles can affect both your lungs and your heart. Scientific studies have linked long-term particle pollution, especially fine particles, with significant health problems including: Increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing Decreased lung function Aggravated asthma Development of chronic respiratory disease in children Development of chronic bronchitis or chronic obstructive lung disease Irregular heartbeat Nonfatal heart attacks Premature death in people with heart or lung disease, including death from lung cancer   Short-term exposure to particles (hours or days) can:   Aggravate lung disease causing asthma attacks and acute bronchitis Increase susceptibility to respiratory infections Cause heart attacks and arrhythmias in people with heart disease   Even if you are healthy, you may experience temporary symptoms, such as: Irritation of the eyes, nose and throat Coughing Chest tightness Shortness of breath