2. Air Pollution Flashcards
What values are important to human health and environmental impacts?
For human health impacts:
a) Concentration of the pollutant in the air around humans
b) Exposuretimeofhumanstoacertainconcentrationofthepollutant
For environmental impacts:
a) Total load of pollutants released in the environment
b) Totalloadofgreenhousegasesreleasedintheenvironment
c) Concentration of the pollutants in the ecosystem
Are all pollutants the same?
No, not all pollutants have the same impact
• Direct: a) components of the fuel: Heavy metals e.g. Lead (Pb)
b) products of combustion and other vehicle functions e.g. (SO2) (CO).
• Indirect: products of physical/chemical processes in the environment e.g. (O3)
What kinds are the air pollutants and what are the sources of emissions and the
health/Environmental effects?
1- Carbon dioxide CO2 2- Sulphur Dioxide SO2 3- Carbon monoxide CO 4- Volatile Organic Compounds (VOC) 5- Benzene, Toluene, Xylene (BTX) 6- Nitrogen Oxides (NOx) 7- Particulate Matter (PM) 8- Ozone (O3)
1- Carbon dioxide CO2
• Sources of emission
from the use of leaded gasoline, lead smelters and battery plants.
• Health / Environmental effects:
a) Affects intellectual development of children;
b) Damagesthenervoussystem
c) High concentrations lead to heart failure, comma and death
2- Sulphur Dioxide SO2
• Sources of emission:
The amount of SO2 emitted is proportional to the amount of Sulphur in the fuel. Sulphur is natural in crude oil and is found in both gasoline and diesel fuel unless it is removed.
• Health / Environmental effects:
a) Causes changes in a lung function with asthma and exacerbates respiratory symptoms
in sensitive individuals.
b) Itcontributestoacidrainandtotheformationofsmallparticles,calledsecondary
particulates, through atmospheric reactions.
3- Carbon monoxide CO
• Sources of emission:
incomplete combustion and Motor-vehicle exhaust; some industrial processes, households
• Health / Environmental effects:
a) CO inhibits the capacity of blood to carry oxygen to organs and tissues.
b) PeoplewithchronicheartdiseasemayexperiencechestpainwhenCOlevelsarehigh. c) At very high levels, CO can cause death.
4- Volatile Organic Compounds (VOC)
Group of carbon-based molecules • Sources of emission:
a) Is emitted in vehicle exhausts and from fuel tanks, petrol refining, fuel storage, and manufacturing industry.
b) Theexhaustpipeofavehiclemaythereforebeasimportantasthefueltankasa source of VOC emissions.
• Health / Environmental effects:
a) Eye, nose, and throat irritation; headaches, loss of coordination, nausea; damage to
liver, kidney, and central nervous system; some are suspected or known to cause
cancer.
b) Amajorcontributingfactortoozone.
5- Benzene, Toluene, Xylene (BTX)
• Sources of emissions:
a) admixture in gasoline, industry solvent b) volatilizationduringrefueling,spills
c) incomplete combustion
d) mainpartcomesfromroadtraffic
e) cigarette smoke
• Health / Environmental effects:
a) Benzene (most poisoning BTX): Lower levels: dizziness, rapid heart rate, headaches,
etc. Long term exposure: can damages the liver, renal and marrow, cancer-producing b) Toluene:effectisonthebrainandnervoussystem(fatigue,drowsiness)
c) Xylene: effects on the nervous system (headaches, dizziness, etc.)
6- Nitrogen Oxides (NOx)
Nitric Oxide (NO) and Nitrogen Dioxide (NO2) with High combustion temperatures (>1.800°C) causing bonding of nitrogen and oxygen.
• Sources of emission:
a) Road traffic and electricity generation are the predominant sources of these gases. b) Highnitrogendioxidelevels,combinedwithultra-fineparticlesandotheroxidants,
have become one of the major air pollution problems in urban areas worldwide. c) Nitrogen oxides are one of the main components of the mixture of pollutants
classically referred to as “photochemical smog”.
• Health / Environmental effects:
Causes changes in lung function for people with asthma, contributes to acid rain, and is a precursor of ground level ozone.
7- Particulate Matter (PM)
Fine particles emitted as a by-product of combustion or as a result of friction (Particles with
diameters smaller than 10 μm are considered health-related)
• Sources of emission:
a) Emitted from burning fossil fuels and biomass
b) Flyash
c) Abrasion of the street and tires
d) Diesel-fueledandtwo-strokeenginegasolinevehiclesaretwosignificantsourcesof
PM emissions.
• Health / Environmental effects:
a) Chronic bronchitis, asthma attacks and other forms of respiratory illness, and b) Prematuredeathfromheartandlungdisease
c) Elementary Carbon (EC) has the highest carcinogenic potential
d) Aparticlecancarrycarcinogenicpollutants
PM (10): Fine particles emitted as a by-product of combustion or as a result of friction (Particles with diameters smaller than 10 μm (Ø<10 μm) which are considered health-related)
8- Ozone (O3)
• Sources of emissions
a) Ozone is not emitted directly. It is composition is triggered through other pollutants b) Precursorsubstancesofozone:NOxandVOC
c) Nitrogen oxides: mainly from emissions of motor vehicle traffic and from power
plants and heating facilities
d) VOC:mainlyfromtheuseofsolventsandunburntfuel
• Health / Environmental effects
a) Plants: Damage to the cell membrane, interruption of photosynthesis, destruction of
cell structures
b) Humanbeings:respiratoryproblems;spasms,reductioninlungvolume(athletes,
babies, sick persons), death of cells, inflammations, continuous irritation of the
respiratory tracts
5) What are the Effects of Ozone in the stratosphere and in troposphere?
• Ozone in the stratosphere (Altitude 10 – 50 km)
1- Equilibrium between O2, O3 and UV radiation
2- Builds a protective gas layer that blocks off UV radiation
• Ozone in the troposphere (Altitude 0 – 10 km) 1- Indirect emission from human sources
2- Health effects on humans and animals
3- Does not ascend into the stratosphere
6) Why are Ozone levels higher in rural area?
The nitrous oxides NOx is oxidized by ozone gas, which causes a reduction in ozone levels. Rural areas, which have less traffic and industrial activity, tend to have higher concentrations of ozone
