Air - Environmental Transformations - page 50

by nitrous oxides, which are also produced within
the burning of coal and oil, reacting with water
molecules to produce nitric acid). Various inter-
national scientific studies that were commissioned
in the 1960s and 1970s began to show the signifi-
cant environmental impacts associated with acid
rain. Scientists in Scandinavia discovered that air
pollution originating in Britain was travelling
thousands of miles before being deposited as acid
rain in Sweden and Norway (McNeill, 2000: 100).
In the 1970s, studies conducted in the UK also
illustrated that large areas of rural Britain were
being affected by the acid rain originating from
urban centres and power stations in the UK (Hajer,
1995: 128). North America has also suffered the
consequences of acid rain. Here the prevailing
transmission of acid rain was north from the US
into Canada, with Canada receiving an estimated
half of all its SO 2 pollution from the US (McNeill,
2000: 101). In Asia the geography of acid rain saw
Japan being inundated with acid-bearing rain
clouds from China and the Korean peninsula
(McNeill, 2000).
Acid rain deposition is associated with a diverse
range of ecological problems. When deposited in
rivers and lakes, acid rain can severely erode an
aquatic environment's levels of biodiversity. In this
context, the acidification of water is toxic to fish,
while the hatching of fish eggs is inhibited as water
pH increases. In relation to forest systems, acid
rain has the effect of weakening trees by attacking
their leaves and inhibiting their ability to absorb
nutrients (acid present in the soils of woodlands
is know to dissolve nutrients stored there, meaning
the minerals can be more easily washed away
before being absorbed by tree roots). In addition
to these ecological problems, acid rain is also
responsible for the erosion of buildings and bridges
and generates significant restoration costs.

their most commonly encountered form of air
pollution:

Late August to early October is the infernal
season in Los Angeles. Downtown is
shrouded in acrid yellow smog while heat
waves bellow down Wiltshire Boulevard.
Outside air-conditioned skyscrapers, home-
less people huddle miserably in every
available shadow.

Two things are worthy of particular note in this
excerpt. First, is the fact that Davis's observations
come from Los Angeles. During the 1940s Los
Angeles became the first home to a new form
of atmospheric pollution: photochemical smog
(see Plate 3.3) . As a low-slung city of sprawl and
suburb, Los Angeles was arguably the first city to
be built for the automobile (see Chapter 6 for a
more detailed discussion of this pattern of
urbanization). Indeed, it was the combination of
Los Angelinos' love of the motorcar and the
geographical location of the city that generated this
new form of air pollution. In order to understand
the nature of this air pollution phenomenon, it is
important to recognize a second feature of Davis's
quote: its seasonality. While the infamous fogs of
older industrial cities were traditionally associated
with the cold air of winter, when high-pressure
weather systems trapped air pollution that mixed
with water vapour to produce thick fogs, by
contrast, Los Angeles's fog is a phenomenon of the
late summer.
Like their early industrial predecessors, photo-
chemical smogs are produced under high-pressure
weather conditions. Unlike older industrial fogs,
where smoke pollution becomes trapped under a
layer of warm air, photochemical smogs are a
product of sunlight reacting with the nitrous
oxides and volatile organic compounds (VOCs),
which are emitted from vehicular exhausts,
producing ground-level ozone and airborne
particles. While harmful to human health in and
of itself, this mix of ozone and airborne particles
also provides a kind of catalytic chemical soup,
which when it comes into contact with the sun's

3.2.4 Parasols of pollution:
automobiles, smogs and
particulates
In his book Ecology of Fear , Mike Davis (1999: 95)
describes what has for many people become