Environmental Science: Test 3 Chapter 19

What did the Industrial Revolution Change?

the mixture of atmospheric gases and particles

Air Pollutants

Substances in the atmosphere (gases and aerosols) that have harmful effects

Natural pollutants

• Volcanoes, fires, and dust storms produce smoke, gas, and particles

• Processes in the biosphere/atmosphere to deal with them

Anthropogenic pollutants

Human caused air pollutants from our activities – fuel combustion, industry, etc.

How do we determine the level or air pollution

– The amount of pollutants entering the air

– The amount of space into which the pollutants are dispersed

– The mechanisms that remove pollutants from the air

Troposphere

the lower atmosphere

In the Troposphere ….

Pollutants are removed within hours or days through precipitation and in the upper troposphere it can persist for days

Stratosphere

the layer above the troposphere

In the Stratosphere….

pollutants are resistant to cleansing as there is no water to react with particles and ozone depleting

Aerosols

fine solid or liquid particles suspended in a gas, typically air

What are three mechanisms to remove, assimilate and recycle natural pollutants?

– OH radicals oxidize gaseous pollutants into compounds that are harmless or can be brought down out of the atmosphere by rain

– Sea salt that blows into the air can seed raindrops to help brings pollutants down to the ground/oceans

– Sunlight: breaks down organic molecules

Are we adding more to the atmosphere than can naturally be removed?

Yes

Hydroxyl Radical (OH)

acts as an oxidizer for many gaseous pollutants

Industrial smog

is a combination of smoke + fog and is an irritating grayish mix of soot, sulfur compounds and water vapor

Where can industrial smog be found?

in industrialized, cool areas that use coal but it started to decrease as coal was replaced by other fossil fuels and can still be found in China, India, Korea

Photochemical smog

arises during morning traffic when pollutants like nitrogen oxides and compounds from vehicles exhausts are acted on by the sunlight

Temperature Inversion

when warm air overlays cooler air and often occurs at night

What is bad about Temperature Inversion

cloudy weather prevents heating air so pollutants stay and mountains further trap smog

Primary pollutants

major air pollutants that are direct products of combustion and evaporation

What are some Primary Pollutants?

Particulates, VOCs (volatile organic compounds), CO, NOx, SO2, lead, air toxics

Secondary Pollutants

are reactions of primary pollutants in the air

What are some secondary pollutants

ozone, nitrates, sulfuric and nitric acids

Ozone (O³)

reactive gas composed of three oxygen compounds

In the stratospehere ozone is ?

good

In the tropospehre ozone is?

bad

pH scale

0 is highly acidic, 7 is neutral and 14 is highly basic

What pH is rainfall typically

slightly acidic at 5.6

Acid Precipitation

precipitation with a pH less than 5.5

Acid deposition

acid precipitation plus a dry particle fallout

Chlorofluorocarbons (CFCs)

can be pollutants when they drift into the stratosphere but at ground level are safe

Acute

short term contact ranging from hours to days

Chronic

long terms exposure ranging from months to years

Carcinogenic Pollutants

substances in the environment that can increase risk of developing cancer by damaging DNA like asbestos and particulate matter and exhaust fumes

Are both primary and secondary air pollutants a threat to human health

Yes

Impacts of Air Pollutants

kills plants, crops, orchards and forests

Clean Air Act of 1970

federal law that authorized the Environmental Protection Agency(EPA) to establish national air quality standards