-airborned substances that occur in concentrations high enough to threaten the health of people and animals, to harm vegetation and structures, or to toxify a given environment.

PRIMARY AIR POLLUTANTS

-they enter the atmosphere directly, from smokestacks and tail pipes

SECONDARY AIR POLLUTANTS

-form only when a chemical reaction occurs between a primary pollutant and some other component of air, such as water vapor or another pollutant

-the primary source for all pollutants is transportation

-represents a group of solid particles and liquid droplets that are small enough to remain suspended in the air

-collectively known as aerosols

-often dramatically reduces vision in urban environments (therefore is the most noticable)

-can affect the lungs and interfere with the rythm of a person's heart rate.

-can remain in atmosphere for a long time

PM-10 is the name for finer particles with diameters smaller than 10 micrometers, that remain suspended

Arctic Haze and Asian dust are two examples of pollution from certain areas being blown to others

-the smaller the particular matter, the more dangerous

-rain and snow remove many of these particles from the air

-many of them act as condensation nuclei

colorless, odorless, poisonous gas that forms during hte incomplete combustion of carbon-containing fuels

-is the most plentiful of the primary pollutants

-more than half comes from highway vehicles

-levels have decreased by around 40% since the 70s

CO is quickly removed from the atmosphere by microorganisms in the soil, for even in small amounts this gas is dangerous.

-serious problem in poorly ventilated areas (parking garages and highway tunnels)

problem: hemoglobin prefers CO to oxygen, so if there is too much CO in the air, your brain will be starved of oxygen.

-colorles gas that comes primarily from the burning of sulfur-containing fuels (coal/oil)

-primary source is power plants, heating devices, smelters, petroleum refineries, and paper mills.

-also volcanoes and ocean spray

-readily oxidizes to form sulfur trioxide, and , in moist air, highly corrosive sulfuric acid.

-winds can carry these particles great distances before they reach the earth as undesirable contaminants.

-C02 aggrivates respiratory problems, and damages plants

Volatile Organic Compounds represent a class of organic compounds that are mainly hydrocarbons (individual organic compounds composed of hydrogen and carbon)

-methane is the most abundant, others are benzene, formaldehyde, and some chlorofluorocarbons.

-around 50% of VOCs come from industrial processes, and 35% from transportation

-certain are known to be carcenogenics, though many VOCs are not intrinsically harmful, though some react to produce secondary pollutants

-gases that form when some of the nitrogen in the air reacts with oxygen during the high-temperature combustion of fuel

-the two primary nitrogen pollutants are NO2 and NO, which are together commonly referred to as NOx

-concentrations in urban environments is between 10 and 100 times greater than in nonurban areas

-in moist air, nitrogen dioxide reacts with water vapor to form corrosive nitric acid (HNO2), a substance that adds to the problem of acid rain

-primary sources are motor vehicles, power plants, and waste disposal systems

-contribute to heart and lung problems, as well as lowering body's resistance to respiratory infections.

-studies on animals say that nitrogen oxides may encourage the spread of cancer

-also, nitrogen oxides are highly reactive gases that play a key role in producing ozone and other ingredients of photochemical smog

-originally meant the combining of smoke and fog, to it refers to the type of smog that forms in large cities, such as LA

-forms when chemical reactions take place in the presence of sunlight, itis termed photochemical smog, or LA-type smog

-called London-type cmog when it is composed of sulfurous smoke and foggy air

-ozone is the main component of photochemical smog

-noxious substance wit han unpleasant odor that irritates eyes nd the mucous membranes of the respiratory system, aggrivating chronc diseases such as asthma and bronchitis

 -is responsible for crop yield losses of several billion dollars each year

-is a secondary pollutant that is not emitted directly into the air

-requires sunlight, thus concentrations are relatively high in afternoon

-nitrogen dioxide is broken down by solar radiation, and the resultant single oxygen combines with O2

 -if NO reacts with other gasses(ie. hydrocarbons), rather than reforming NO2, then ozone can have a long life

-

-ozone is most dense at around 25km

-still only 12ppm

-it shields earth's inhabitants from harmful amounts of ultraviolet radiation (at wavelengths below 0.3 micrometers UV causes skin cancer)

-also cataracts, sun burns, immune system, crops and animals, reduction in growth of phytoplankton, and cooling of the stratosphere (alter wind patters)

-ozone is broken down by absorbing UV radiation

-CFCs deplete, by entering troposphere through breaks or in thunderstorms

-a single Cl atom can remove as many as 100 000 ozone molecules before being taken out of action

-average CFC lifetime is 50-100 years

ozone hole - sharp drop in ozone, located over springtime Antarctica mainly

Air Quality Index, developped by th Environmental Protection Agency, to indicate the air quality in a particular region

-includes CO, SO2, NO2, particulate matter, and ozone (5 things)

-number ranges from 0 to 500

-when the pollutant's value is the same as the primary ambient air quality standard, the pollutant is assigned an AQI of 100... considered unhealthy when 100 is exceeded (300-500 is hazardous)

-type of inversion that typically forms during the night and early morning hours when the sky is clear and the winds are light

-provides a very stable atmosphere, and smoke cannot rise from short chimneys

-this is why taller chimneys have replaced many of the shorter ones (though this contributes to acid rain)

-by afternoon, the atmosphere is sufficiently unstable that pollution can disperse vertically

-may persist for several days or longer

-are the ones commonly associated with major air pollution episodes (they form as the air above a deep anticyclone slowly sinks and warms)

-the air that extends from the surface to the base of the inversion is referred to as the mixing layer

-the vertical extent of the mixing layer is called the mixing depth

-generally see the greatest mixing depth in the afternoon and the most shallow one in the early morning

-the position of the semipermanent pacific high off the coast of california contributes greatly to the air pollution in that region

-the pacific high promotes subsiding air, which warms the air aloft

-surface winds around the high promote upwelling of ocean water, which makes the surface water cool, and in turn cools the air above

-these two factos together can produce strong subsidence inversions

-shape of landscape plays important role in trapping pollutants

-valleys prone to pollution are those completely encased by mountains and hills

-this creates light winds and a shallow mixing layer

-poorly ventilated cold valley air has nowhere to go

-valley pollution tends to be worst during cold months (no upslope winds from daytime heating)

LA is surrounded on 3 sides by hills and mountains, and cool marine air from the ocean moves inland and pushes against the hills, which tend to block the air's eastward progress.

ingredients for a major buildup of atmospheric pollution are:

-many sources of air pollution

-a deep high pressure area that becomes stationary over a region

-light surface winds that are unable to disperse pollutants

-strong subsidence inversion produced by the sinking of air aloft

-a shallw mixing layer with poor ventilation

-a valley

-clear skies so that radiational cooling at night will produce a surface inversion, which can cause an even greater buildup at ground level

-adequate sunlight to produce secondary pollutants such as ozone from photochemical smog

-a condition produced by light winds and poor vertical mixing

-when this condition prevails for several days or longer, the buildup of pollutants can lead to some of the worst air pollution disasters on record, such as the one in the valley city of Donora, Pennsylvania, where seventeed people died within fourteen hours.

-region of city warmth, which can influence concentration of air pollution

-caused by industrial and urban development... structures absorb sunlight

strongest:

1)at night when compensating sunlight is absent

2)during the winter when nights are longer and there is more heat generated in the city

3)when region is dominated by a high pressure area with light winds, clear skies, and less humid air

-studies suggest that precip may be greater in cities than in the surrounding countryside

country breeze -

-a light breeze that blows from the countrysie to the city

-this can carry pollutants from industrial areas on the outskirst into the center of town

acid rain

-term used to describe wet depostion

acid deposition

-encompasses both dry and wet acidic substances

-can be surfuric acid (H2SO4) or nitric acid (HNO3)

-may fall slowly to earth or adhere to cloud droplets producing acid fog

-pollutants for acid rain may be carried hundreds of miles away from their sources

-rain is naaturally acidic (5-5.6 pH)

-precipitation is considered acidic when below 5

climatic controls

-the relatively permanent factors that govern the nature of the climate of a region.

are:

-intensity of sunshine and its variation with altitude

-distribution of land and water

-ocean currents

-prevailing winds

-positions of high and low pressure areas

-mountain barriers

-altitude

-equatorial regions are typically wet

-subtropics and polar regions are relatively dry

-precip more abundant where air rises (ITCZ,polar front), and less where air sinks (subtropical highs, polar highs)

-a widely used classification of world climates based on the accual and monthly averages of temperatures and precipitation.

Five major types:

A)Tropical Moist Climates

B)Dry Climates

C)Moist mid-latitude Climates with Mild Winters

D)Moist mid-latitude Climates with Severe Winters

E)Polar Climates

H)highland climates (mountain regions where changes in elevation bring about sharp changes in climatic type... delineating climating regions is impossible)

-each of these major groups contains subgroups that descrive special regional characteristics (ie seasonal changes in temperature and precipitation)

-year-round warm temperatures (all months have a mean temperature above 18C)

-abundant raingfall

-occurs from equator to around 15-25 lat

major types:

1)tropical wet (Af)

2)tropical monsoon (Am)

3)tropical wet and dry (Aw)

-a type of forest consisting mainly of lofty trees and a sense undergrowth near the ground

-created by combination of high temperatures and abundant yearlyl rainfall

-tropical wet climate

-small seasonal temperature variations

-noon sun always high... number daylight hours is relatively constant

-greater variation b/w day/night temperatures and warm/cold months.

-high humidity and cloud cover keeps temperatures from reaching extremely high values

-example is Iquitos, Peru, located near equator

laterite

-when Af forests are cleard for agricultural purposes, or for timber, what is left is a thick red soil called laterite

-as heavy rain falls on the soil, the water works its way downward, removing nutrients in a process called leeching

-tropical monsoon climates

-where monthly precipitation totals drop below 6 cm for perhaps one or tow months

-rainfal totals are similar to Af, though amount in a month fluctuates

-can be seen along the coasts of Southeast Asia, India, and in northeastern South America

-tropical wet and dry climate

-total annual rainfall deminishes

-a distinct dry season prevails

-still large amounts of rain, but all at one time of the year

-tropical rainforests cannot survive this drought... jungle becomes tall coarse savanna grass

-wet in summer, dry in winter

-mostly western central america, South America (north and south of Amazon Basin, southcentral and eastern Africa, parts of India, Northern Australia.....

*monsoon is mostly responsible for marked changes in precipitation.

Dry Climates

-deficient precipitation most of the year; potential evaporation and transpiration  exceed precipitation

-the subtropical deserts extend from approx 20 to 30 lat in large continental regions of the middle latitudes

-major types are arid(BW) and semi-arid(BS)

-occupy the most land area (26%) of any climatic type

-deficiency of water exists

can be further devided:

BWh/BSh (h means heiss, German for hot)

BWk/BSk (k means kalt, German for cold)

h=above 18C average

k=below 18C average

-arid climates

-accupy around 12% of world's land area

-W coast of South America and Africa, and interior of Australia

-also exists in mexico, USA(Sierra Navada), and Asia)

-much of the time, rain evaporates before touching ground (virga)

-most of native plants are xerophytes

-(capable of surviving prolonged periods of drought)

-in BWh, intense sunlight produces scorching heat

-highest temperatures in the world (can be 50+)

-rapid radiational cooling at night

**large daily temperature ranges

-temperatures much much more moderate during winter (can drop below freezing)

-BWk average annual temperatures are lower

-winter temperatures extremely cold

-semi arid

-region is called steppe and typically has short bunch grass, scattered low bushes, trees, or sagebrush.

 -located around margins of arid regions

-as average rainfall amounts increase, the climate dradually changes to one that is mroe humid.

-this area is the transition between desert and humid climatic regions

-Moist Subtropical Mid-Latitude Climates

-humid with mild winters (average temperature of coldest month is below 18C and above -3C)

-on the eastern and western regions of most continents, from about 25-40 latitude

-TYPES:

-humid subtropical (Cfa)

-marine (Cfb)

-Dry-Summer Subtropical/Mediterranean (Cs)

-all have distinct summer and winter seasons

-enough precipitation that they are not classified as dry

-humid subtropical climate

-found principally along east coast of continents, roughly b/w 25 and 40 lat

-dominate SE USA, E China, and S Japan

-gets hot muggy summers

-because location is to W of subtropical highs, where maritime tropical air from lower latitudes is swept poleward into these regions.

-winters relatively mils, rarely below freezing temperatures

-lots of precipitation and well distributed (no drought season)

-west coast marine, or just "marine"

-where mountains parallel the coastline, such as along the west coasts of North and South America, the marine influence is restricted to narrow belts

-Europe is the main place for this, as it is unobstructed by mountains]

-low clouds, fog, drizzle... adequate precipitation in all months.... falls in association witm Maratime Polar air masses

 -thus most precipitation falls in winter

-very low annual temperature range for a station at such high altitude

-dry-summer subtropical (or Mediterranean)

-along the west coast of North America, Portland, Oregon, because it has rather dry summers, marks the transition between the marine climate and the dry-summer subtropical climate to the south

-extreme summer aridity (subtropical highs)

-much rainfall during winter

*mild-wet winters, and mild-hot-dry summers*

COASTAL MEDITERRANEAN(Csb)

-where surface winds parallel the coast, upwelling of cold water helps keep the water itself and the air above it cool all summer long

-daytime max temperatures around 21C

INTERIOR MEDITERRANEAN (Csa

-inland, away from the ocean's influence, summers are hot and winters are a little cooler than coastal areas

-summer afternoon temperatures usually climb above 34C and occasionally above 40C

chaparral- due to summer dryness, the land supports only a scrubby type of low-growing woody plants and trees called chaparral

Cw- when the dry season is in winter

-many lower latitude regions with a Cw climate would be tropical if it were not for the fact they are too high in elevation and, consequently, too cool to be designated as tropical

Moist Continental Climates-

-warm to cool summers and cold winters

 (warmest month average 10C+, and coldest month average below -3C)

 -extent is north of moist subtropical mid latitude climates

-TYPES:

-humic continental with hot summers (Dfa)

-humid continental with cool summers (Dfb)

-subpolar (Dfc)

-these climates are controlled by large landmasses

-only found in Northern Hemisphere

-from around 40-70 lat

-cold winters and cool/warm summers

-winter snow stays on grounds for extended periods in these climates

Dfa/Dfb = humid continental

 -precipitation is adequate and fairly evenly distributed throughout the year.. totals rangee from 50-100 cm

-divided on basis of summer temperatures

-Dfa (summers long and hot)

-5-6 months frost free

Dfb -summers not as hot

-also much less humid that Dfa

-temperatures may exceed 35, but rare for it to last.

-winters are long cold and windy

-temperatures can drop below -30

Dfc - subpolar

-a broad belt across Canada and Alaska

-Norway, much of Siberia

-primary sources for continental polar and continental arctic air masses

-extremely cold winters coupled with cool summers produce large annual temperature ranges

-light precipitation (<50cm)

-cold air prevents little snow from melting

 taiga - because of the low temperatures, there is a low annual rate of evaporation that ensures adequate moisture to support the boreal forests of conifers and birches known as taiga

-hence, the subpolar climate is known also as boreal climate and as a taiga climate.

Dfc = subpolar

-year-round low temperatures (average temp of warmest month is below 10C)

-northern coastal areas of North America and Eurasia; Greenland; Antarctica

-TYPES:

polar tundra (ET)

polar ice caps (EF)

-polar tundra

-the average temperature of the warmest month is below 10C.. but above freezing

-here, the ground is permanently frozen to depths of hundreds of meters (permafrost)

-summer weather is just warm enough to thaw out the ipper meter or so of soil

-becomes very swampy during summer

-annual precipitation usually less than 20cm

-vegetation is mostly mosses, lichens, dwarf trees, and scattered woody vegetation

-even though summer days are long, the sun is never very high above the horizon

-polar ice cap

-average temperature for every month is below freezing

-plant growth is impossible

-interior ice sheets of Greenland and Antarctica, where the depth of ice in some places measures thousands of meters

-even during middle of summer, temperatures rarely above freezing

-nearly no precipitation (<10cm)

Highland Climates

-temperature decreases with altitude, thus climbing 300m equals about travelling 300km north

-at base of mountains, the climate and vegetation represent semi-arid conditions, while in the foothills the climate becomes Mediterranean, and the vegetation changes to chaparral. Higher up, thick fir and pine forests prevail. Higher, the climate is subpolar and the taiga gives way to dwarf trees and tundra vegetation.Near the summit there are permanent patches of ice and snow.

-hence, can change from semi-arid to polar in 13,000 vertical feet.

-CLIMAP (Climate: long-range investigation mapping and prediciton)

 -core samples taken from ocean floor sediments and ice from Greenland/Antarctica for evidence of global climatic change

-studied past million years

 -uses organisms and oxygen-isotope ratio (ratio of oxygen 18 to 16)(18 stays in water... does not evaporate)

-cold/glacier advance = more 18

dendrochronology:

-study of annual growth rings of trees

-only useful with trees experiencing an annual cycle

other data:

1)records of natural lake-bottom sediment and soil deposits

2)the study of pollen in deep ice caves, soil deposits and sea sediments

3)certain geologica evidence (ancient coal beds, sand dunes, and fossils) and the change in the water level of closed-basin lakes.

4)documents concerning droughs, floods, and crop yields

5)the study of oxygen-isotope ratios of corals

6)dating calcium carbonate layers of stalactites in caves

7)borehole temperature profiles, which can be inverted to give records of past termperature change at the surface

8)deuterium (heavy hydrogen) ratios in ice cores, which indicate temperature change

-Pleistocene epoch

-period of glaciation beginning around 2.5 mya

-other ice ages were 700million years ago and 300 mya

-about 65mya, the earth was warmer than now, and polar ice caps did not exist.

-long cooling trend began around 55mya

-about 10mya, ice covered the antarctic

-continental glaciers appeared in the northern hemisphere around 2.5 mya

*the ice age was not a period of continuous glaciation, but a time when glaciers alternately advanced and retreated over large portions of North America and Europe... between glacial advances were warmer periods called interglacial periods which lasted 10 000 years or more.

-most recent reached maximum thickness around 18 000 years ago

-water was around 120 meters lower than today

a period from about 1550 to 1850 when average temperatures over Europe were lower, and alpine glaciers icnreased in size and advanced

-average global surface temperature began to rise in early 1900s

-from 1900 to 1945, average temperature rose nearly 0.5C, then there was a cooling trend until the mid-70s, until finally there was a warming trend until current day

-1998/2005 are two hottest years in past 1000

1)changes in incoming solar radiation

2)changes in the composition ofthe atmosphere

3)changes in the earth's surface

-during times of rapid spreading, increased volcanic activity may promote global warming by enriching C02 in the air

subduction- when an oceanic plate encounters a lighter continental plate, it responds by diving under it, in a process called subduction

ridge - where plates form, where dense, molten material from inside the earth wells up to the surface forming new sea floor material as it hardens

-a theory proposed by Milankovitch in th 1930s suggesting that changes in the earth's orbit were responsible for variations in solar energy reaching the earth's surface and climatic changes... 3 cycles

1)eccentricity.. deals with the changes in the shape of the earth's orbit as it revolves around the sun

-goes from elliptical to nearly circular and back again in approx 100 000 years.

-the greater the eccentricity (the more elliptical the orbit), the greater the variation in solar energy received by the earth between its closest and farthest approach to the sun.

-presently we are in a period of low eccentricity

2)- as the earth rotates on its axis, it wobbls like a spinning top. this is known as precession of the earth's axis... and ocurs in a cycle of approx 23000 years

-currently, the earth is closer to the sun in January and Farther in Jule, though the opposite will be true in 11 thousand years

3)obliquity- relates to changes in tilt of the earth as it orbits the sun

-cycle every 41K years

-presently, tilt is approximately 23.5 degrees, but this varies between 22 and 24.5 degrees.

-the smaller the tilt, the less seasonal variation there is between summer and winter in the middle and high latitudes; thus winters milder and summers cooler

***When all of the Milakovich cycles are taken into account, the present trend should be toward cooler summers over high altitudes of the Northern Hemisphere

***CLIMAP has determined that eccentricity is the forcing factor, the main external cause, for the frequency of glaciation

1)Milankovitch cycles

2)CO2

3)the amount of dust and other aerosols in atmosphere

4)the reflectivity of ice sheets

5)the concentration of other RAGs

6)changing characteristics of clouds

7)the rebounding of land, having been depressed by ice

-the majority of these partices come from the combustion of sufur containing fossil fuels  but volcanoes can also be a significant source of tropospheric sulfate aerosols

-mostly SO2 gas when it enters, then becomes sulfate

-reflect incoming sunight, which tends to lower the earth's surface temperature during the day

COOLING!!

-explain why N.Hemisphere has warmed less than South?

-why USA has experienced less warming?

-why global warming is mostly seen at night?

-can cause temperatures to drop by .5C for several years

-1816-year without summer- linked to volcanic eruption (Indonesia)

-findings suggest that little ice age could have been caused by volcanic activity

-sunspots are huge magnetic storms on the sun that show up as cooler (darker) regions on teh surface

-the greater number of bright areas (faculae) around the sunspots radiate more energy, which offsets the effect of the dark spots

-it appears though that the 11-year sunspot cycle has not always prevailed. Apparently, between 1645 and 1715, during the period known as the Maunder minimum, there were few, if any, sunspots.

-the minimum occurred during a cool spell

 -the sun's magnetic cycle is 22 years, rather than 11

-reverse is every 11 years

-models predict that by 2100 mean surface temperature will increase by 1.4-5.8C higher than 1990.

-predicted using a general circulation model

-anything that can disturb the radiative equilibrium of the earth and the sun

-ie. greenhouse gases

-high cirrus-like icy clouds promote warming

-low stratiform clouds promote cooling

-precipitation will increase, but how and where?

-rising sea levels (by 2100 9-88cm)

-intensity of hurricanes

*norhern hemisphere spring and summer sea-ice extent has decreased by about 10 to 15 percent since the 1950s, and will continue to do so

-little effect on El Nino

-more extreme monsoons in asia

-reduction in global heat transfer

Kyoto Protocol- adopted 1997 - put into place 2005

-goal at least 5%

-USA has not signed

geoengineering- reducing the impact of climate change through global-scale technological fixes