CHAPTER 19.3Pollution and Recycling

What Causes Pollution?

Pollution is the contamination of air, water, or soil

What Causes Pollution?Pollution can be caused by natural causes

-volcanic eruption

fills air with dust and ash

What Causes Pollution?Most pollution is caused by human activities -reactions create products that if not used properly, add to the pollution problem

Air PollutionAir pollution comes in many forms -individual molecules to clumps of dust and matter , called particulates

Air PollutionBurning of fossil fuels produces energy, along with carbon dioxide and water vapor

-escape into air

as invisible gases

Air PollutionCarbon dioxide is found naturally in the atmosphere -greenhouse gas that helps keep Earth’s temperature balanced

-without it, Earth’s temperature would be about 33 degrees lower -humans put billions of tons into the air each year

Air Pollution-burning of fossil fuels also releases sulfur dioxide and nitrogen dioxide into the air -react with other atmospheric gases to form acid rain -makes streams and lakes acidic -can harm or kill aquatic life-can acidify soil-corrode metals and stone buildings

Air Pollution-nitrogen oxide can react with sunlight to form photochemical smog -brown haze that stings eyes and cause severe headaches and breathing difficulties

-most common in sunny, densely

populated cities

Water Pollution-most water pollution can be traced to industrial waste, agricultural fertilizers, and everyday human activities -fertilizers get washed away by rain into lakes and rivers-contain nitrate ions, which encourage growth of bacteria and algae

Water Pollution-feeding on the nitrates, bacteria and algae grow so fast that they use up most of the oxygen in the water-algal bloom -kills fish and other aquatic wildlife-process is called eutrophication

Water Pollution-pesticides can be washed into lakes and rivers by rain -eaten by fish and other aquatic animals

-passed along food chain

Land Pollution-a common type of land pollution occurs when hazardous chemicals soak into the soil.

Reducing Pollution-government regulation discourages pollution of air, water, and land-use of alternative energy and conserving energy can reduce pollution

Reducing Pollution-recycling allows materials to be used again rather than being thrown away -saves landfill space and conserves scarce resources