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© 2015 Pearson Education, Inc.

Human Effects

on the

Atmosphere

Chapter 14 Lecture

Redina L. Herman

Western Illinois University

Understanding

Weather and

Climate

Seventh Edition

Frode Stordal, University of Oslo

Department of Geosciences Nature, Outlook, 14 October 2010

Department of Geosciences

Crutzen’s issues in 2002/2003 papers

• Synthetically fixed N from fertilizers – From atmospheric nitrogen to ammonia: More than in all natural ecosystems

– Microbiological production of N2O, greenhouse gas + stratospheric ozone

• Release of NOx from fossil fuel larger than natural inputs – Leads to photochemical «smog»

• Several greenhouse gases have substantially increased – Fossil fuel burning, agricultural activities, deforestation, animal husbandry

• Antarctic spring time «ozone hole» caused byCFC gases

• Ozone in the troposphere – Impacts human health, agricultural and plant productivity

• OH, main oxidizing agent in the troposphere, impacted

Crutzen 2002, J.Phys IV France & J Environ Sci Health

© 2015 Pearson Education, Inc. Steffen et al 2004

Human

activities have

increased

dramatically

over the last

century

Carbon dioxide Nitrous oxide Methane

Ozone depletion Temperature Floods

Ocean ecosystems Coastal structure Biogeochem

Forest loss Domesticated land Biodiversity

Population GDP Investment

Damming rivers Water use Fertiliser use

Urban population Paper use McDonalds

Motor vehicles Telephones Tourism


Atmospheric Pollutants

• Introduction

– Air pollutants are gases, liquids, or solids in the air that can

adversely affect plant and/or animal life.

• Primary pollutants are pollutants that are emitted directly by natural or anthropogenic (manmade) processes.

• Secondary pollutants are pollutants that arise from chemical reactions of atmospheric gases with gases emitted by natural or anthropogenic processes.


• Introduction



• Particulates

– Particulates (aerosols) are solid or liquid matter suspended

in the air (from 0.1 to 100 µm in size).

– Natural sources: natural fires, volcanic eruptions, salt spray

from the oceans, pollen.

– Anthropogenic sources: burning of fossil fuels.

– Although particulates can remain in the air for some time

due to their small size, rain removes them.

– PM10 (<10 µm) enters lungs (associated with asthma);

PM2.5 even more dangerous (lung cancer).



• Carbon Oxides

– Carbon monoxide (CO) is a colorless, odorless gas that

comes from volcanic eruptions, forest fires, and other

processes.

– Extremely toxic and dangerous to humans and animals.

– Carbon dioxide (CO2) is an important greenhouse gas but

is officially considered a pollutant by the U.S. EPA.



• Carbon Oxides



• Sulfur Compounds

– Sulfur compounds can occur as gaseous or aerosol forms.

– Natural sources: steam vents, volcanic eruptions, sea spray.

– Anthropogenic sources: burning sulfur containing fossil fuels

(particularly coal and oil) and ore smelting.

• Sulfur dioxide (SO2) is a respiratory irritant.

• Forms sulfate aerosols that contributes to acid fog and acid

rain.



• Sulfur Compounds



• Nitrogen Oxides (NOX) – Nitric oxide (NO) is a nontoxic, colorless, and odorless gas.

• Natural sources: biological processes in soil and water.

– Nitrogen dioxide (NO2) is a toxic, yellow to reddish-brown gas that is pungent and corrosive.

• Provides polluted air with the yellow to reddish brown color.

• Anthropogenic sources: vehicle traffic.

• Can cause pulmonary health problems.



• Volatile Organic Compounds (Hydrocarbons)

– Volatile Organic Compounds (Hydrocarbons) are made

of carbon and hydrogen. Examples: methane, butane,

propane, octane, etc.

– Natural sources: plant and animal emissions and

decomposition of organic matter.

– Anthropogenic sources: primarily combustion from

automobiles, trucks, buses, and other fossil fuel motors; also

evaporation of gasoline and other chemicals.



• Photochemical Smog

– Ozone, NO2, formaldehyde, and other gases combine with

solar radiation to form Los Angeles-type photochemical

smog.

– Ozone causes respiratory and heart problems.

– High levels of ozone result in environmental degradation.



• Air Quality Index

– The EPA created an index for air pollution monitoring called

the Air Quality Index (AQI).

– A formula applies to ozone, particulates, carbon monoxide,

sulfur dioxide, and nitrogen dioxide by expressing each

pollutant on a scale that ranges from 0 to 500.

– The official AQI for any location at a particular time is the

highest of the five individual pollutant values.



• Air Quality Index



Loss agricultural production due to ozone

Tropospheric ozone: Crops


Atmospheric Conditions and Air Pollution

• Effect of Winds on Horizontal Transport

– High concentrations of pollutants in a small area (usually

due to anthropogenic sources) are the biggest air pollution

problems.

– The horizontal and vertical transport of air pollutants by

winds help control the local concentrations of pollutants.

– Concentrations are inversely related to wind speed.

– Eddies can mix air vertically.


• Effect of Atmospheric Stability

– Inversions can trap pollutants near the Earth’s surface.

Atmospheric Conditions and Air Pollution

Department of Geosciences Credit: Jesse Allen/NASA Earth Observatory

Department of Geosciences Cooper et al., 2014

Tropospheric ozone


Tropospheric ozone

IPCC, AR5, Fig. 8.2


CO2

Atmosphere O3 damaging to plants

O3 H2O

Tropospheric ozone: Vegetation


Loss agricultural production due to ozone

Van Dingenen et al., 2009

Tropospheric ozone: Crops

Wheat

7-12%

loss

Soyb

6-16%

loss

Rice

3-4%

loss

Maize

3-5%

loss

human effects on the atmosphere - forsiden - · pdf filehuman effects on the atmosphere ......

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