30 Urban Growth Problems CASE STUDY: LOS ANGELES, USA
Since the 1950s, the city of Los Angeles has experienced major problems with air quality when pollution reacts with heat and light to form low-level ozone or smog.
Factors influencing the formation of smog in the Los Angeles area include: zz
high levels of traffic pollution due to car dependency;
zz zz
zz industrial-based pollution from oil refineries and power stations;
the mountains surrounding the city to the north, east and south trap pollutants (Fig. 30.15);
the warm, sunny climate aids the formation of ozone. Mojave Desert
San Gabriel Mountains
Los Angeles
Catalina Island
San Gorgonio Mountain
San Jacinto Mountains
San Bernardino Mountains
USA Pacific Ocean
Salton Sea
KEYWORDS smog
car dependency climate
emission standards electric vehicles mountains
Mexico Impacts
The smog has had a major impact on public health; during periods of high smog levels, vulnerable groups are advised to stay indoors (Fig. 30.16). Economic effects include high healthcare costs and worker absence due to respiratory conditions.
Improvements
Improvements made to tackle the problem include: zz
zz zz zz
new emission standards for cars and strict enforcement of legislation (e.g. the Clean Air Act, 1970);
Fig. 30.16 Smog hanging over Los Angeles. reducing nitrogen oxide and sulphur oxide emissions from refineries;
greater use of electric vehicles, carpools and the sustained promotion of public transport; increasing use of renewable energy to reduce use of fossil fuels.
Current situation
While there have been major improvements, high levels of smog can still occur as a result of temperature inversions or brush and forest fire outbreaks.
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Fig. 30.15 Mountains surrounding Los Angeles trap pollutants.
