Impact of development on the quality of Environment

Impact of development

UrbanizationCities as an EcosystemNatural environment

Lithologic Env.Atmospheric Env.Hydrologic Env.Biologic Env.

IndustrializationAir PollutionWater PollutionThermal PollutionNoise Pollution

Cities as an Ecosystem

Biotic components: Man and selected living organisms

Abiotic components: Urban environment

Urbanization involve the modification of the environment or/and the impact of the environmentThe physical environment may influence the form, functions and growth of the city.A change in either the urban environment or the urban man will affect the other component of the urban ecosystem.

Cities as an Ecosystem

Cities as an Ecosystem

It is an Open systemCannot self-containedCannot function in isolation from the other parts of the worldDepends on external food supply and investmentThe change of it will affect the region, the country and the rest of the world

Impact on the lithologic Env.

1. Landslide from cleaning or building on unstable slope

2. Ground subsidencePresence of heavy structural loadsPumping underground water

Impact on the Lithologic Env.

3. Impact of the soilCovered by metropolitan structures (cement)Mineral materials excavated from the earth for construction demandsSoil erosion and sedimentationContamination of soil

Impact on the lithologic Env.

4. Change in reliefRemolding of the land by cutting and fillingDisposal of waste• Refuse dump• Dust deposition from settlement

Impact on the atmospheric Env.Atmos. Com

positionCO, CO2

SO2TSP

200x+, 2x200x3x to 7x

Radiation Sunshine duration

-5 to 15%

Temperature

Winter minimum

+ 1 to 2 degree

Wind speed Annual mean -20 to 30%Fog Winter

Summer+ 100%+ 30%

Precipitation

Total + 5 to 10%

Impact on the atmospheric Env.City Climate

1. Temperature (Heat Island)2. Visibility 3. Humidity 4. Precipitation 5. Wind speed and 6. direction change

Visibility

Humidity

Humidity is lower for following reasons:

higher temperatureWaterproof surfaceLess water is available for evaporation

Precipitation

Precipitation increase

Urban atmosphere contains large amount of condensation nuclei.

Higher temperature intensifies the thermal convection formation of cloud

adiabatic cooling condensation

Wind speed & Direction

Three featuresWind speed will be reduced for rough surface of the cityTurbulence may be created in cities.Air circulation system will be induced by the heat island

Wind speed & Direction

Impact on the Hydrologic Env.

Change in runoffSurface imperviousLack of vegetationLower infiltration capacityIncrease overland flow

Impact on the Hydrologic Env.Increase the magnitude and frequency of flood

Before and after urbanization

Impact on the Hydrologic Env.

Reasons:Increase surface runoff.Rapid erosion cause to reduce river’s capacity.Straighten the channel will shorten the flow concentration period.

Impact on the Hydrologic Env.

Harmful Effects:Degrading water quality• Increase in dissolved mineral contents• Decrease in oxygen (eutrophication)

Water shortageContamination of waterSalt water intrusionChanges in the temperature of water

Impact on the Biologic Env.

Wild life is rareIncrease in domestic pestSubtracts and adds various type of plants

Pollution

Definition:Directly or indirectly through man’s activities into the atmosphere, hydrosphere, lithosphere and biosphere of infusions of matter and energy at levels of quantity or intensity appreciably higher than natural levels and usually with undesirable or harmful effects upon environments.

Air PollutionPollutants

Primary Pollutants: Substances directly produced by a natural process or human activities.Secondary Pollutants: They form in the air when primary pollutants react or interact with other matters.

Air Pollution

PollutantsTotal Suspended Particulates (TSP)

Sulphur dioxide (SO2)

Carbon Monoxide, Carbon dioxide (CO,CO2)

Nitrogen oxides (NOx - NO, NO2)

Ozone (O3) – Secondary Pollutant

Air Pollution

Harmful health effectsEyes irritationRespiratory system illnessReduces oxygen transport in body and causing headaches, dizziness and nauseaImpair brain functionLung cancer

Air Pollution

Other harmful effects (Acid Rain)Degradation of property (devalue)Property damageCorrosion of antiquesHarmful effect of tissuesReproductive abnormalities of aquatic life

Air Pollution

Acid Rain (Acid Precipitation)

Air Pollution ControlPlanning, segregation of industrial and residential land useUsing low sulphur content fuelUse device to control pollutants emission (filters, electrostatic precipitators, improved combustion efficiency)Setup air quality standardLegislation and InspectionSetup Environmental Protection Agency (EPA)Setup smoke control area

Water PollutionDefinition:

Its composition or state is directly or indirectly modified by human activities on a an extent such that it is less suitable for purposes it could have served in its natural state.

Water Pollution

Types of PollutantsDirect Toxicity: soluble metal, radio-active substances…..Oxygen demand: EutrophicationIndirect harm: Heat, suspended matters….Disease organisms: bacteria, pathogens….

Water Pollution

Sources of pollutantsIndustrial waste: heavy metals, toxic matters, heat, radio-active substances….Domestic waste: domestic sewage…Farming waste: pig and poultry waste….Oil: oil spillage, oil leakage…..Others: civil works, construction….

Water Pollution

Effects of water pollutionEutrophication -> upsetting balance of the the natural ecosystemKilling aquatic lifeImpaired recreational sitesHarm for farmingShortage of fresh water supply

Water PollutionSolutions:

Remove sludgeCollecting farming wasteConstructing new sewage treatment plantsUse incinerators to treat domestic wasteUse new technology in industrial productionCentral waste collection and recyclingLegislationEducation

Thermal Pollution

Power plants and some manufacturing processes use large amounts of water for cooling.Heat water flows in the natural water bodies such as lakes, river, sea……

Thermal Pollution

Effects of thermal pollution of waterReduction of dissolved oxygen (DO) : Oxygen is hard to be dissolved over 30oCDisturb the timing of fish hatchKill aquatic life: most fish cannot survive in water over 30oC and almost no aquatic organisms can survive above 50oC

Thermal Pollution

Effects of thermal pollution of atmos.Change urban micro-climateEnhance the heat island effect

Noise Pollution

Definition: Unwanted sound

You don’t want but I want!

Noise Pollution

SourcesAircraft: taking off and landingTraffic: moving and horns….Construction: compressors, excavators…Domestic: air-conditioners, Hi-Fi, recreational activities…..Industrial: machines running…..

Noise Pollution

Effects of NoiseInterfere with sleepIrreversible effects to nervous systemTemporary or permanent deafnessBrain damage / mental illness

Noise PollutionSolutions

Planning: separate industrial zone and airport with residential zoneUse new technology in productionLegislation

• Restrict taking off and landing period of aircraft• Restrict noise from 11pm to 6am in residential areas• Restrict construction period• Imposition of speed limits and setup no horns areas• Noise industries must setup protection devices: eg. W

earing special helmetsEducation

The End