C13: 13.5 - Atmospheric pollutants Flashcards
what is a major source of atmospheric pollutants
combustion of fuels
e..g of fossil fuels
coal, oil, natural gas, oil shales and tar sands
where and how are Non-renewable fossil fuels obtained
obtained from crude oil by fractional distillation
what do Most fuels, including coal, contain
carbon and/or hydrogen and may
also contain some sulfur.
if a fuel is a hydrocarbon, what products are formed during complete combustion
carbon dioxide and water
when does complete combustion occur
when there is an excess of o2
what happens during incomplete combustion of a fuel (containing hydrocarbons)
- particulates of soot (carbon)
- carbon monoxide
- sulfur dioxide (if the fuel contains sulfur impurities)
- nitrogen oxides (if fuel is burnt at very high temps) - e.g. in a car engine.internal combustion engines
what is done to coal so that sulfur dioxide doesn’t enter the atm
scrubbed for sulfure impurities
what are the harmful effects of carbon monoxide
- colourless and odourless toxic gas
- RBCs pick up carbon monoxide instead of O2 and carry it around the body
- the CO will attack to haemoglobin => not enough O2 will reach cells
- so victim will become satrved of O2, drowsy, lose consciousness and die
what are the harmful effects of soot particulates (C)
- particulates enter the upper atm , reflecting sunlight back into space => causing global dimming
- also damage lungs and cause respiratory probs if inhaled
- can cover buildings and statues, making them look unclean and accelerating corrosion
how are oxides of nitrogen formed during combustion
- produced when unreactive nitrogen and oxygen in the air react at high enough temperatures which are reached in a vehicle engine
what are the harmful effects of nitrogen oxides
- react w/ clouds and forms nitric acid => causes acid rain
- produce photochemical smog and breathing difficulties, in particular for people suffering from asthma
what are the harmful effects of sulfur dioxide
- reacts w/ water to form sulfuric acid => falls as acid rain
- acid rain kills plants and animals by decreasing pH below optimum levels
- acid rain also corrodes metals + damages buildings and statues
- SO2 also causes respiratory and breathing difficulties
what are the harmful effects of acid rain
-reacts w/ metals + rocks such as limestone => damage to buildings + statues (esp. those made of limestone - CaCO3)
- increases rate of corrosion of metal structures such as bridges and statues.
- damages the waxy layer on the leaves of trees and makes it more difficult for trees to absorb the minerals they need for healthy growth => death of trees
- makes rivers and lakes too acidic for some aquatic life to survive.
solution for stopping SO2 getting into air
- remove SO2 from the waste gases before they reach the atm.
- scrub coal for sulfure impurities
