Health and Environmental Impacts of SO2
Sulfur Dioxide
- SO2 Home
- Emission Sources
- Causes for Concern
- Health & Enviro Impacts
- EPA Efforts to Reduce SO2
- EPA Offices
SO2 causes a wide variety of health and environmental impacts because of the way it reacts with other substances in the air. Particularly sensitive groups include people with asthma who are active outdoors and children, the elderly, and people with heart or lung disease.
Respiratory Effects from Gaseous
SO2 -
Peak levels of SO2 in the air can cause temporary breathing difficulty
for people with asthma who are active outdoors. Longer-term exposures
to high levels of SO2 gas and particles cause respiratory illness
and aggravate existing heart disease.
Respiratory Effects from Sulfate Particles -
SO2 reacts with other chemicals in the air to form tiny sulfate
particles. When these are breathed, they gather in the lungs and
are associated with increased respiratory symptoms and disease, difficulty
in breathing, and premature death.
Visibility Impairment - Haze occurs when light is scattered or absorbed by particles and gases in the air. Sulfate particles are the major cause of reduced visibility in many parts of the U.S., including our national parks.
Acid Rain - SO2 and nitrogen oxides react with other substances in the air to form acids, which fall to earth as rain, fog, snow, or dry particles. Some may be carried by the wind for hundreds of miles.
Plant and Water Damage - Acid rain damages forests and crops, changes the makeup of soil, and makes lakes and streams acidic and unsuitable for fish. Continued exposure over a long time changes the natural variety of plants and animals in an ecosystem.
Aesthetic Damage - SO2 accelerates the decay of building materials and paints, including irreplaceable monuments, statues, and sculptures that are part of our nation's cultural heritage.