As we breathe, the toxic gases and small particles of diesel exhaust are drawn into the lungs. The microscopic particles in diesel exhaust are less than one-fifth the thickness of a human hair and are small enough to penetrate deep into the lungs, where they contribute to a range of health problems.

Diesel exhaust and many individual substances contained in it (including arsenic, benzene, formaldehyde and nickel) have the potential to contribute to mutations in cells that can lead to cancer. In fact, long-term exposure to diesel exhaust particles poses the highest cancer risk of any toxic air contaminant evaluated by OEHHA. ARB estimates that about 70 percent of the cancer risk that the average Californian faces from breathing toxic air pollutants stems from diesel exhaust particles.

Exposure to diesel exhaust can have immediate health effects. Diesel exhaust can irritate the eyes, nose, throat and lungs, and it can cause coughs, headaches, lightheadedness and nausea. In studies with human volunteers, diesel exhaust particles made people with allergies more susceptible to the materials to which they are allergic, such as dust and pollen. Exposure to diesel exhaust also causes inflammation in the lungs, which may aggravate chronic respiratory symptoms and increase the frequency or intensity of asthma attacks.

Diesel engines are a major source of fine-particle pollution. The elderly and people with emphysema, asthma, and chronic heart and lung disease are especially sensitive to fine-particle pollution. Numerous studies have linked elevated particle levels in the air to increased hospital admissions, emergency room visits, asthma attacks and premature deaths among those suffering from respiratory problems. Because children's lungs and respiratory systems are still developing, they are also more susceptible than healthy adults to fine particles. Exposure to fine particles is associated with increased frequency of childhood illnesses and can also reduce lung function in children.

Like all fuel-burning equipment, diesel engines produce nitrogen oxides, a common air pollutant in California. Nitrogen oxides can damage lung tissue, lower the body's resistance to respiratory infection and worsen chronic lung diseases, such as asthma. They also react with other pollutants in the atmosphere to form ozone, a major component of smog.

More research:

Children’s Exposure to Diesel Exhaust on School Buses

• http://www.ehhi.org/reports/diesel/dieselintro.pdf
• http://www.nrdc.org/air/transportation/schoolbus/schoolbus.pdf
• http://oee.nrcan.gc.ca/transportation/idling/material/reports-research/idling-health-effects.cfm
• http://www.nb.lung.ca/pdf/School%20Bus%20Report%20EN%20Final.pdf

The International Climate Change Taskforce has produced a report that argues that Governments and individuals must take decisive action if irreversible climate change is to be avoided before climate change reaches a point of no return.

Scientists say we have 10 years to change our ways or we will reach a ‘tipping point’ where we will NOT be able to reverse the effects of climate change. One person at a time, lets try to make a difference.

As gasoline prices rise, there has never been a better time to think about driving more sustainable.

Regardless of the vehicle you are driving, here are techniques to help you save fuel and minimize your impact on the environment.

Do you really need to drive?
The shortest journeys of less than three kilometres cause the most pollution and are inefficient in terms of fuel consumption. A straining cold engine will produce 60% more pollution than a warm one. Yet it is these shorter journeys that are ideal for walking or cycling.

Plan your route wisely
A bit of forethought can save much wear and tear - for the car and the driver. Try to take the most direct route, go off peak if possible: trip plan! Sitting in congestion means you are often doing zero kilometres per litre. If you have to commute by car, think about car sharing, Park & Ride schemes or public transport.

Have your vehicle serviced regularly
This helps maintain efficient running and good economy. Inefficient, under-serviced engines can reduce fuel economy by 10% or more. Catalytic converters are environmentally friendly - but only if they are properly maintained.

Check your tires
Correct tire pressures will keep wear down and fuel economy up. Under-inflated tires need replacing more often (itself an environmental problem) as well as being dangerous. (Anybody who has cycled on under-inflated tires will appreciate how much extra effort is involved!) Make a point of checking them at least once a week.

Obey the speed limits
Try to "feather" the throttle as you reach your cruising speed. Doing 90 kilometres per hour uses 25% less fuel than 110 km and a smoother driving style can bring significant fuel saving. But never coast to save fuel; vehicle control must not be compromised.

Reduce the drag factor by removing roof racks and carriers when not in use.
Driving with the window open also increases drag and lowers fuel economy. Remove unnecessary and heavy materials from the trunk. Avoid using wide tires that add rolling resistance. Limit your use of air conditioning (which lowers fuel economy) by using the vent settings as much as possible instead.

Use less fuel and buy green fuel.
Don't idle your engine after stopping for more than 10 seconds! Some gasoline stations sell ethanol gasoline.

Use "accelerator" sense
Do you go straight from accelerator to the brake? Rather than having to brake as you hit traffic, gently let the speed of the vehicle bring you to a halt as you merge with traffic. There is no point in rushing and then having to brake to come to a sudden halt.

Back in the vehicle when you park.
When you start off again, the engine will be cold and at its most fuel inefficient. If you can drive smoothly away without having to reverse when the engine is cold, not only will you save fuel, you will also have better visibility.

Consider buying a hybrid vehicle for your next car purchase
A hybrid vehicle uses an electric motor and an internal combustion engine. With a hybrid vehicle, the electric motor kicks in during idling and slow speeds, such as with city traffic driving, saving on gasoline and reducing air emissions.

Five years ago, hybrid cars were a rarity. Today, hybrids are quickly gaining in popularity, yet many myths still prevail about them. Here are the most popular myths about hybrids, finally debunked.

• Hybrids are expensive:

  At the beginning of 2006, hybrids were available in 10 different models ranging in price from $19,000 to $53,000. The most efficient models (the Civic and Prius) are available below $30,000. By the end of the decade, more than 50 hybrid models are expected on the market, representing the full range of sizes, shapes, and costs.

  Rechargeable batteries, electric motors, and sophisticated computer controls do add to the cost of producing a hybrid car. However, as production numbers increase, economies of scale are expected to reduce those costs. Toyota plans to offer hybrid versions of all its most popular models, thus cutting the initial cost of hybrids in half.

  Additional advantages of hybrid vehicles include lower maintenance costs and extraordinarily strong resale values. In fact, used Toyota Priuses are reportedly being sold at prices approaching the cost of new ones. Also, oil changes in hybrid vehicles are required every 10,000 to 12,000 kilometres rather than every 5,000 kilometres.

  In fact, the Ontario government is offering a $2,000 rebate on provincial sales tax for eligible vehicles. For more information, visit this Ontario government website http://www.trd.fin.gov.on.ca/userfiles/HTML/cma_3_6551_1.html (www access required).

• Hybrids are a new phenomenon:

  Not really. In 1900, American car companies were producing steam, electric and gasoline cars in equal numbers. In 1905, an American engineer named H. Piper filed the first patent for a gas-electric hybrid vehicle. Piper's innovation was almost completely wiped out (along with steam and electric cars) in 1913 with the introduction of the electric self-starting car, which made it easier for car engines to turn over and start.

  The following 80 years, characterized by cheap oil and limited care for the environment, gave auto engineers little incentive to develop alternatives.

  The oil shortage in the 1970s, and a growing awareness of the environmental problems linked to automobile emissions, led to new research and experimentation by governments and car companies in the 1980s and 1990s, and to the re-emergence of hybrids in 2000.

• People buy hybrids only to save money on gas:

  Hybrid cars top the list of the most fuel-efficient vehicles on the road and allow owners to go farther on a litre of gas. But consumers who are looking for a new car rarely buy purely for economic reasons. As critics of hybrid vehicles often point out, the savings gained seldom add up to the extra cost of buying a hybrid over a comparable conventional vehicle.

  So if it's not to save money, why are more consumers buying hybrid vehicles? Many buy hybrids to minimize their impact on the environment; others to reduce the world's dependence to oil. Others simply feel strongly about the message that driving a hybrid car sends out.

  The car you drive sends a powerful message about who you are and what you think about the world. Hybrid drivers take pride in letting other drivers, especially those behind the wheel of gas guzzling car, know that getting from point A to point B doesn't have to lead to an uncertain environmental and economic future.

• Only celebrity environmentalists buy hybrids:

  While a large number of celebrities are extolling the virtues of hybrid vehicles, many non-celebrities are also embracing the benefits of hybrids. Many non-celebrities and every-day consumers are concerned about the many costs (economic, political, environmental) of being an oil-dependent nation and are moved to do something about it.

• Hybrid batteries need to be replaced:

  Many potential buyers of hybrid vehicles worry about the potentially expensive cost of replacing the batteries within hybrid cars. This worry is unfounded. By keeping the battery charge between 40% and 60% -- never fully charged and never fully drained --car makers have greatly extended the longevity of nickel metal hydride batteries

  The standard warranty on hybrid batteries and other components is between 80,000 and 100,000 miles, but that doesn't mean the batteries will die at 100,000 miles. The United States Energy Department stopped its tests of hybrid batteries when their capacity remained almost like new after 160,000 miles.

  There's little to no accurate information about the cost for replacing a hybrid battery, because it hasn't been a requirement with today's models.

• Hybrids are small and underpowered:

  The Honda Accord hybrid is the fastest selling family sedan on the market. The Lexus Rx400h and Toyota Highlander Hybrid share the same 270 horsepower system. The Lexus GS 450h hybrid sedan exceeds 300 horsepower with 0-to-60 performance below six seconds. And the Toyota Volta concept is a 408-horsepower scream machine.

  These vehicles prove that adding an electric motor and batteries to the driving experience doesn't mean diminished performance.

• You need to plug in a hybrid car:

  As soon as people hear the word "electricity", they think about plugs, cords and wall sockets. But today's hybrid cars, although they run on electricity, don't need to be plugged in. Auto engineers developed an ingenious system in hybrids known as regenerative braking, which allows the energy usually lost when a vehicle is slowing down to be reclaimed and routed to the hybrid's rechargeable batteries. The process is automatic, so no special requirements are placed on the driver.

  Car companies explain that drivers don't have to plug in their vehicles, but a growing number of users wish that they had a plug-in hybrid for the following reason. Being able to plug a hybrid into an electric grid overnight to charge a larger set of batteries would mean that most city driving could be done without burning a single drop of gasoline.

  So far, auto makers have been reluctant to bring plug-in hybrids to the mass market, claiming that today's batteries can't take the extra demand. Until a car company takes a chance on the great potential of plug-in technology, hybrids don't require plugging into the grid.

• Hybrids pose a threat to Emergency Services:

  Some critics have wondered if public safety agencies should be concerned about the increased number of hybrid cars, cruising the highways with high-voltage battery packs.

  A first responder must race to save the lives of accident victims. In that rush, the responder has to make dozens of rapid technical decisions about how to safely remove passengers from vehicles. Adding the complication of unfamiliar hybrid technology can slow things down.

  However, first responders are trained in emergency situations and are becoming more familiar with hybrid cars, from the location and construction of battery compartments, to the location of fuses that will isolate the electrical system. Emergency responders have coped with advancing automotive technologies for years and hybrid cars are no exception.

• Hybrid technology is only a fad:

  Hybrid technology is often compared against fuel cells, diesel engines and hydrogen as the key to sustainable mobility. The greatest hope and investment has been placed in hydrogen fuel. However, in 2005, the International Energy Agency (IEA) concluded that even under the most favourable conditions, hydrogen vehicles would represent only 30% of the global fleet by 2050. The failure of hydrogen-powered cars to materialize rapidly underscores the risk of focusing on a single solution.

  The debate over the future of automotive technology has now turned toward finding the best ways to combine systems and fuels in a single hybrid vehicle. The experience of mass-producing hybrid gas-electric vehicles has given engineers the insight needed to develop complex systems needed to combine multiple sources of power.

  In an Associated Press interview, Jim Press, president of Toyota Motor Sales USA, said: "I think everything will be a hybrid, eventually. It will either be a gas hybrid, a diesel hybrid, or a fuel-cell hybrid."

• Hybrids will solve our transportation, energy and environmental problems:

  While the growth and popularity of hybrid vehicles is important, it needs to be viewed in the overall context of the car market.

  The 200,000 hybrid car sales in 2005 represent only 1.2% of the 17 million new cars sold that year. Market forecasters predict a continued annual doubling of hybrid car sales for the next few years. By 2007, it is possible that 1 million hybrid cars could be on American roads, which would be a major milestone.

  This looks promising until you consider that there are approximately 200 million cars in the United States today -- and over 700 million vehicles worldwide. If car numbers keep increasing at the present rate, there will be more than a billion cars and trucks on the road across the world in 20 years. Hybrid cars can only be viewed as a partial solution.