Nitric oxide (NO) and nitrogen dioxide (NO2) together are represented by NOx. Most of the emissions from combustion devices (approximately 90%) are in the form of NO.
NOx react in the air to form ground-level ozone and fine particulates, which are associated with adverse health effects.
NOx contributes to a wide range of environmental effects directly and when combined with other precursors in acid rain and ozone.
Acidification of soils causes the loss of essential plant nutrients and increased levels of soluble aluminum that are toxic to plants. Acidification of surface waters creates conditions of low pH and levels of aluminum that are toxic to fish and other aquatic organisms. NOx also contributes to visibility impairment.
Particles smaller than or equal to 10 µm (micro meter or millionth of a meter) in diameter can get into the lungs and can cause numerous health problems. Inhalation of these tiny particles has been linked with illness and death from heart and lung disease. Various health problems have been associated with long-term (e.g., multi-year) exposures to these particles. Shorter-term daily and potentially even shorter term peak (e.g., 1-hour) exposures to these particles can also be associated with health problems.
Particles can aggravate respiratory conditions, such as asthma and bronchitis, and have been associated with cardiac arrhythmias (heartbeat irregularities) and heart attacks. People with heart or lung disease, the elderly, and children are at highest risk from exposure to particles.
Particles of concern can include both fine and coarse-fraction particles, although fine particles have been more clearly linked to the most serious health effects.
In addition to health problems, PM is the major cause of reduced visibility in many parts of the United States by scattering and absorbing some of the light emitted or reflected by the body reducing the contrast. Airborne particles can also impact vegetation and ecosystems, and can cause damage to paints and building materials.
Instructions: Click the name of each size of particulate matter and observe what happens for each.
Exposure to lead occurs mainly through inhalation of air and ingestion of lead in food, water, soil, or dust. It accumulates in the blood, bones, and soft tissues and can adversely affect the kidneys, liver, nervous system, and other organs.
Instructions: Click the "start" button to see the impact of using unleaded rather than leaded gasoline.