| Pollutant |
Health effects |
Where it comes from |
| Carbon monoxide |
Weakens the heart's contractions and lowers the amount of oxygen carried
by the blood. It reduces your ability to exercise and is dangerous for
people with chronic heart disease. It can cause nausea, dizziness, headaches,
and when it's very concentrated, even death.
When carbon monoxide reaches unhealthy levels, people with heart disease are
most at risk. |
Primarily from motor vehicles, but also from incomplete
burning of any fuel. |
| Lead |
Causes damage to the brain and other parts of the body's
nervous system.
Children are most susceptible to the effects of lead. |
Mostly from a few industrial facilities, but also from the
sanding or wearing away of old lead-based paint. |
| Nitrogen dioxide |
Irritates the nose and throat, especially in people with asthma. Appears
to increase susceptibility to respiratory infections. Also combines with
volatile organic compounds (VOCs) to form ozone.
When nitrogen dioxide reaches unhealthy levels, children and people with
respiratory disease are most at risk. |
Power plants, large industrial facilities, and motor
vehicles. |
| Ozone |
Irritates the lungs and breathing passages, causing coughing
and pain in the chest and throat. Increases susceptibility to respiratory
infections and reduces the ability to exercise. Effects are more severe in
people with asthma and other respiratory ailments. Long-term exposure may
lead to scarring of lung tissue and lowered lung efficiency.
When ozone reaches unhealthy levels, children and people with asthma are most
at risk. |
Forms in the air from other pollutants -- volatile organic
compounds (VOCs) and nitrogen oxides (like nitrogen dioxide, above). Ozone
does not come directly from tailpipes or smokestacks. The VOCs that form ozone
come from vehicle and industrial exhaust as well as evaporation of gasoline,
solvents and paints, and many other sources. See also
stratospheric ozone, below. |
| Particulates |
Aggravates existing heart and lung diseases, changes the body's defenses
against inhaled materials, and damages lung tissue. The elderly, children
and those with chronic lung or heart disease are most sensitive. Lung
impairment can persist for 2-3 weeks after exposure to high levels of
particulate matter. Chemicals in and on particulates can also be
toxic. Very fine particulates (called PM2.5, for
particulate matter smaller than 2.5 microns) can be inhaled deeply into the
lungs.
When PM2.5 reaches unhealthy levels, people with respiratory or heart disease,
the elderly and children are most at risk. |
Diesel cars, trucks and buses, power plants, industry and
many other sources. |
| Sulfur dioxide |
Aggravates existing lung diseases, especially bronchitis. Constricts the
breathing passages, especially in asthmatic people and people doing moderate
to heavy exercise. Causes wheezing, shortness of breath, and coughing. High
levels of particulates appear to worsen the effect of sulfur dioxide, and
long-term exposures to both pollutants leads to higher rates of respiratory
illness.
When sulfur dioxide reaches unhealthy levels, people with asthma are most
at risk. |
Power plants, large industrial facilities, diesel vehicles,
and even oil-burning home heaters. |
