Chapter 15 Lecture

Health The BasicsTenth Edition

PromotingEnvironmental Health

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OBJECTIVES

• Explain the environmental impact associated with global population growth.

• Discuss major causes of air pollution and the consequences of the accumulation of greenhouse gases and ozone depletion.

• Identify sources of water pollution and chemical contaminants often found in water.

• Distinguish municipal solid waste from hazardous waste and list strategies for reducing land pollution.

• Discuss the health concerns associated with ionizing and nonionizing radiation.

• Describe the physiological consequences of noise pollution and how to prevent or reduce its effects.

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Impact of Overpopulation

• Impact on other species

• Impact on our food supply

• Land degradation and contamination of drinking water

• Excessive energy consumption

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Estimated and Projected World Population Growth, 1950-2100

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Overpopulation

• Factors that Affect Population Growth– Fertility rate refers to the number of births a woman

has by the end of her reproductive period.– U.S fertility rate is just over two births per woman.

• Differing Growth Rates– India is expected to have the largest growth by adding

another 600 million people by 2050.

• Zero Population Growth (ZPG)– This is the idea that each couple should produce only

two offspring.– Over 20 countries have a ZPG.

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Air Pollution

• Pollutants are either naturally occurring or anthropogenic (caused by humans).

• Natural air pollutants include particulate matter, such as ash from volcanic eruptions.

• Anthropogenic sources include stationary sources such as power plants, factories, and refineries, and mobile sources, such as vehicles, planes, trains, and watercraft.

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Components of Air Pollution• Sulfur dioxide is the yellowish-brown gaseous

byproduct of the burning of fossil fuels.• Particulate matter is nongaseous air pollutants.• Carbon monoxide is an odorless, colorless gas that

originates primarily from vehicle emissions.• Nitrogen dioxide is an amber-colored gas found in

smog; can cause eye and respiratory irritation.– Smog is a brownish haze that is a form of pollution produced by

the photochemical reaction of sunlight with hydrocarbons, nitrogen compounds, and other gases in vehicle exhausts.

• Ground-level ozone is a molecular form of oxygen and is produced when nitrogen dioxide reacts with sunlight and oxygen molecules.

• Other air pollutants include carbon dioxide and hydrocarbons.

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Air Quality Index (AQI)

• The AQI is a measure of how clean or polluted the air is on any given day.

• The AQI focuses on health effects that can happen within a few hours or days after breathing polluted air.

• Index runs from 0 to 500, with higher values having a greater level of air pollution and health risk.

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Air Quality Index (AQI)

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Indoor Air Pollution

• Indoor air can be 10-40 times more hazardous than outdoor air.

• Indoor air pollution comes primarily from woodstoves, furnaces, passive cigarette smoke exposure, asbestos, formaldehyde, radon, and lead.

• Mold is an emerging form of air pollutant.• Prevention focuses on source control,

ventilation improvements, and air cleaners.

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ABC News Video: Power of 2: Get an Energy Audit

Discussion Questions

1. How does eating less beef help to reduce the effects of climate change?

2. What is an energy audit? How does it help to save energy?

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Ozone Layer Depletion

• The ozone layer protects the planet and its inhabitants from ultraviolet B (UVB) radiation.

• Chlorofluorocarbons (CFCs) contribute to ozone depletion.– They were used as refrigerants, aerosol

propellants, and cleaning solvents and also in medical sterilizers, rigid foam insulation, and Styrofoam.

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The Enhanced Greenhouse Effect

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Global Warming

• An enhanced greenhouse effect is a warming of Earth's surface as a direct result of human activities that release greenhouse gases into the atmosphere, trapping more of the sun's radiation than is normal.

• This causes increasing surface temperatures, perhaps by 5-10 degrees, and the rise will continue unless immediate preventive steps are taken.

• Greenhouse gases include carbon dioxide, nitrous oxide, methane, CFCs, and hydrocarbons.

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Reducing Air Pollution

• Air pollution and climate change problems are rooted in our energy, transportation, and industrial practices.

• Reducing consumption of fossil fuels, shifting to alternative energy sources, improving gas mileage, and using mass transportation are crucial to reducing air pollution.

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Water Pollution and Shortages

• Point source pollutants enter a waterway at a specific location through a pipe, ditch, culvert, or other conduit. – Major sources are sewage treatment plants

and industrial facilities.

• Nonpoint source pollutants seep into waterways from broad areas of land. – Major sources are land practice uses.

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Water Contamination

• Among the pollutants causing the greatest potential harm are– Gasoline and petroleum products– Chemical contaminants– Polychlorinated biphenyls– Dioxins– Pesticides– Lead

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Land Pollution

• Per day, each person generates more than 4.5 pounds of municipal solid waste (MSW), totaling about 243 million tons each year.

• About 90% of waste is recyclable, but only 33.8% of MSW is recycled or composted.

• Strategies to reduce MSW include source reduction, recycling, composting, and combustion with energy recovery.

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What's in Our Trash?

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ABC News Video: Crack Those Recycling Codes

Discussion Questions• Why is the phrase "Reduce, Reuse,

Recycle" particularly important for plastics?• Why do you think the rate of recycling

single-use water bottles is down?• Why is the great Pacific garbage patch an

environmental danger?• Which number of plastic is dangerous for

use and recycling?

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How Much Do We Recycle?

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Hazardous Waste

• Hazardous waste is toxic waste that poses a hazard to humans or to the environment.

• The Comprehensive Environmental Response and Liability Act was enacted to provide funds for cleaning up hazardous waste.

• Many types of waste are now banned from land disposal or are being treated to reduce toxicity before disposal.

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Radiation

• Nonionizing Radiation– Electromagnetic waves having a relatively long

wavelength and enough energy to move atoms around or cause them to vibrate

• Ionizing Radiation– Electromagnetic waves and particles having a short

wavelength and energy high enough to ionize atoms

• Radiation exposure is measured in radiation absorbed doses, or rads. – The maximum "safe" exposure ranges from 0.05 to 5

rads per year.

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Nuclear Power Plants

• Proponents believe it is a safe and efficient way to generate electricity.

• Disposal of nuclear waste is extremely problematic.

• A nuclear meltdown can occur when the temperature in the core of a nuclear reactor increases enough to melt both the nuclear fuel and its containment vessel.

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Noise Pollution

• A sound with a decibel (dB) of 110 is 10 times louder than one at 100 dB.

• The human voice measures about 60 dB; a jet takeoff from 200 feet measures 140 dB.

• Short-term exposure to loud noise reduces concentration and productivity and may affect mental and emotional health.

• Prolonged exposure can lead to hearing loss.

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Noise Levels of Various Sounds

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Noise Pollution

• To protect your hearing– Play home and car stereos at reasonable

volume.– Keep the volume down on your iPod or other

MP3 device.– Wear earplugs when using power equipment.– Close windows to establish a barrier between

yourself and outside noise.– Wear earplugs when attending loud concerts,

and clubs.