|
 Volkswagen's Chief Executive Martin Winterkorn resigned on Wednesday
over the falsification of test data from diesel cars in the United
States, the latest twist in a scandal that has rocked the global car
industry and raised concerns about what it may mean for the
environment and public health.
For now the main focus is on the United States, but VW says 11
million cars worldwide may be affected and experts note that
diesel-fueled cars account for just 3 percent of passenger vehicles
in America, compared with some 50 percent in Europe.
Volkswagen was not immediately available to comment on Wednesday on
the potential health impact of its falsified emissions tests.
Carmakers argue that diesel vehicles account for only a fraction of
pollutants in the air, but experts say the health risks are greater
because most cars are driven in urban areas where large numbers of
people live and breathe.
The World Health Organization (WHO) says air choked with tiny
particles, ozone and other pollutants currently kills some 3.7
million people a year -- a toll predicted to double by 2050 if big
polluters do not clean up their act.
Some specialists estimate that the bogus Volkswagen test results may
mean that between 300,000 and 900,000 tonnes of extra nitrogen oxide
(NOx) a year could have been pumped out by VW cars alone, based on
average mileage.
However, a spokesman for the European Environment Agency (EEA) said
accurate estimates of how much extra NOx the 11 million vehicles
would emit annually would depend on how far they drive and in what
kind of conditions.
The spokesman said estimates of the direct impact of extra nitrogen
oxide on rates of death and disease were difficult to quantify,
although he added: "NOx is also a precursor to ozone and particulate
matter, which forms in the atmosphere and also affects health."
Alastair Lewis, a professor of atmospheric chemistry at Britain's
York University, said: "In key cities, which is where most people
live, cars are a very significant source of the pollution people
breathe in, so any failure in emissions controls is very significant
for health," said
RISKS
Air pollution increases the risk of lung and cardiovascular diseases
in the population and has its most severe impacts
on people already suffering with conditions such as heart disease,
asthma and other respiratory diseases.
Children, old people and the poor are more susceptible.
[to top of second column] |
In 2012, the WHO's specialist cancer research agency reclassified
diesel engine fumes as carcinogenic, saying they can cause lung
cancer and belong in the same potentially deadly category as
asbestos, arsenic and mustard gas.
The WHO says epidemiological studies show that symptoms of
bronchitis in asthmatic children increase with long-term exposure to
NOx and nitrogen dioxide (NO2).
Reduced lung function is also linked to NO2 at the concentrations
currently measured in cities of Europe and North America, it says.
Environmental scientists said they have observed for some time that
"real world driving conditions" do not appear to deliver the scale
of emissions reductions shown in the lab.
A study published in the Environmental Science and Technology
journal earlier this year found that in London, NOx emissions in
total from road transport are almost two times higher than those
estimated based on laboratory data - a finding that scientists say
may be explained in part by unreliable emissions testing.
James Longhurst, a professor of environmental science and director
of the Air Quality Management Resource Centre at the University of
Western England (UWE), says concentrations of NOx have not fallen as
much as expected in developed countries, despite the introduction of
new technology on vehicles.
"If the deliberate bypassing of emission control systems is more
widespread than just VW diesel sales in the U.S., then it may help
explain what has been observed in measurements of air pollution in
cities," he said.
"At this point we don't know the exact size of the problem, but it
will, without doubt, have added to the health burden."
(Editing by Gareth Jones)
[© 2015 Thomson Reuters. All rights
reserved.] Copyright 2015 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed. |
