Urban air quality Flashcards
Where does particulate pollution come from in urban areas?
Vehicle exhausts- produce very fine particulates. About 80% of fine particulates in urban areas are from vehicle exhausts.
> Burning of refuse, cigarettes and fuel e.g. coal- this produces both fine and course particulates e.g. soot and ash.
> Construction mining and quarrying- these activities produce coarse particulates e.g. tiny fragments of rock.
> Planta and moulds- also generate coarse particulates e.g. pollen.
What is photochemical smog?
> When pollutants e.g. nitrogen oxides come into contact with sunlight, the UV light causes them to break down into harmful chemicals which form photochemical smog.
> Photochemical smog is linked to health problems such as breathing difficulties, respiratory disorders and headaches.
How does congestion charging reduce air pollution?
> People are charged if they use their vehicles in certain places at certain times.
> This reduces pollution by reducing road traffic.
> However, some people travel around the edge of zones to avoid being charged, increasing traffic in these areas.
How does pedestrianisation reduce air pollution?
> Vehicles are restricted from entering certain places at certain times. It reduces pollution by reducing road traffic.
> Pedestrianisation can lead to shops receiving fewer customers because people can only get to them on foot.
How does public transport improvements reduce air pollution?
Encouraging people to use public transport instead of their own transport, reduce pollution. For example, many cities have:
> Improved bus services to make journeys cheaper, faster and more efficient.
Park and ride schemes to make it easier to access public transport.
Trams and railway services so that they don’t get caught up in traffic congestion. They also pollute less than buses.
EVALUATION:
> Public transport improvements are usually highly expensive and can also cause problems.
What scheme is used in Mexico City to reduce traffic?
In Mexico City, drivers are banned from using their cars one weekday per week, based on the last digit of their number plate.
How does the legislation of laws reduce air pollution?
Laws aim to reduce pollution by limiting emissions and setting air quality standards. For example:
> The UK clean air act of 1956 and 1968 reduced domestic pollution by introducing smoke control areas where only smokeless fuels can be burnt and reduced industrial pollution by introducing the use of tall chimneys.
> The road vehicle regulations reduce exhaust emissions by ensuring cars pass an emission test in their MOT.
How can alternative fuels reduce pollution?
e.g. petrol and diesel being replaced with cleaner fuels.
> Biofuels are produced from plants. They can directly replace petrol and diesel and have lower particulate emissions. However, growing crops for biofuels can reduce biodiversity.
> Electric vehicles have lower emissions because they run off batteries, rather than conventional fuel. Electric vehicles need recharge points, and producing and disposing of the batteries can cause environmental problems.
