本帖最後由 Quest 於 2013-7-9 17:57 編輯
Would the gas make a difference too? I think China's gas is lower number (not like our 87 and up)?
fibbi 發表於 2013-7-9 16:01 
gasoline/diesel quality makes a whole lot of difference as well, citing that even North America, it wasn't until about 6 yrs ago that sulphur mandate was imposed to gasoline and diesel, as a result: pump diesel here in US and Canada are now ULSD (ultra low sulphur diesel); gasoline is now low sulphur varieties (Canada was still @ >100ppm in late 90s (CBC did a test report back then), with PetroCanada/Shell being the highest around 136ppm. Now most of the pump gas in Canada/US are less than 30ppm in sulphur.
Referencing to: http://www.atmos-chem-phys.net/11/9465/2011/acp-11-9465-2011.pdf
section 2.2.2: gasoline sulphur content (in yr 2000) was @ 1200ppm; diesel was set to 1630ppm (except Northern China where diesel was set to 350ppm).
sulphur gets burned inside the engine and released into the air will form acid rain, esp. emissions-controlled gasoline automobile where catalytic converter will combine sulphur and residual oxygen into acid...and the H2O as combustion byproducts will mix it together and not only eat your exhaust muffler/tailpipe away quickly, but NOx (which I don't think they even care about) will cause smog.
burning high sulphur diesel in unregulated(non emission controlled) engine will contribute to airborne particulates (will lead to asthma, lung cancer, etc.) as micro-fine soots, etc.
Coupled with lax/no emissions standards, lack of proper pollution standards and directions, etc. it has now become a major air-pollution issues in China, esp. in Northern metro areas like Shanghai, Beijing, etc. where smog and airborne particulates lead to that foggy pictures famous all over the internet.
Most of North America are now on the low sulphur standards of 30ppm or less for gasoline:
http://www.epa.gov/otaq/standards/fuels/gas-sulfur.htm
ULSD is pretty much less than 15ppm for automobile use (since late 2006), with the exception of locomotive which is capped at less than 500ppm (except Cali where locomotive is also <15ppm)
Canada's federal emissions mandate pretty much mirrors to that of typical US EPA standards (except Cali):
http://www.caribbeanpetroleum.com/new_standards_a.html
An as far as smelters, coal-fired generating facilities, etc. I have not heard a lot of improvements on that part yet (esp. before 2011):
http://cornerstonemag.net/clean-and-high-efficiency-coal-fired-power-generation-in-the-shenhua-group/
also: coal burning is the major contributor to airborne Hg (mercury) globally, and when it comes down from the atmosphere as rain into rivers, streams and ended up in the ocean, it follows the food chain up to the predator fish varieties, such as skate fish, sharks, tuna, etc. which we consume a lot as either shark fins soup, tuna sashimi, etc.
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發表於 2013-7-9 11:42
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