Hi!
The substance that could be found in air, water or soil that is harmful to humans or animals is called pollutant.
Pollutants are the only harmful substances that can be found in these three places. Carbon Dioxide (CO₂) is commonly found in the air, fossil fuels are found in soil and water and smog is found in the air. Only pollutant can be found in these three places as there are varied in its chemical structure. Common pollutants include Sulfur Dioxide (SO₂) which can be found in the air, and Lead, which can be found in water or soil.
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