Diesel Cars Emit More Air Pollution On Hot Days, Study Finds (theguardian.com) 107
An anonymous reader quotes a report from The Guardian: Emissions from diesel cars – even newer and supposedly cleaner models -- increase on hot days, a new study has found, raising questions over how cities suffering from air pollution can deal with urban heat islands and the climate crisis. Research in Paris by The Real Urban Emissions (True) initiative found that diesel car emissions of nitrogen oxides (NOx) rose by 20% to 30% when temperatures topped 30C -- a common event this summer.
Emissions from a range of vehicles were found to be many times higher than those declared by manufacturers in laboratory tests, confirming earlier findings following the 2015 Dieselgate scandal, in which Volkswagen cars were found to emit 40 times more NOx on the road than during laboratory tests. Certain pollutants from motorcycles -- often considered a cleaner alternative to four-wheeled vehicles -- were also found to "greatly exceed" averages for both petrol and diesel cars. Yoann Bernard of the International Council on Clean Transportation, which carried out the study, said real NOx emissions had been found to be up to 18 times higher than those recorded in vehicle manufacturers' tests, even in newer vehicles that are supposed to be cleaner.
Emissions from a range of vehicles were found to be many times higher than those declared by manufacturers in laboratory tests, confirming earlier findings following the 2015 Dieselgate scandal, in which Volkswagen cars were found to emit 40 times more NOx on the road than during laboratory tests. Certain pollutants from motorcycles -- often considered a cleaner alternative to four-wheeled vehicles -- were also found to "greatly exceed" averages for both petrol and diesel cars. Yoann Bernard of the International Council on Clean Transportation, which carried out the study, said real NOx emissions had been found to be up to 18 times higher than those recorded in vehicle manufacturers' tests, even in newer vehicles that are supposed to be cleaner.
NOx / CO2 (Score:1)
All of the focus has been on CO2 emissions, and regulations/taxes in various countries are based on that... Therefore cars were designed to emit less CO2, but there was no concern for emitting anything else.
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NOx is a non-issue. CO2 and particulate have immediate effect on human health and long-term outlook for the planet.
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NOx is a non-issue.
That depends upon whom you ask. https://theicct.org/news/natur... [theicct.org]
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NOx is a local issue
... magically elevated from the lowly status of "non-issue" to that. Schweet. Thanks.
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Its an issue in localised areas of heavy traffic... go figure that the problem is NOx rather than heavy traffic by interests that don't want to address the real cause of localised pollution along roads that are increasingly carrying more and more traffic.
It gives them the chance to raises taxes ("congestion charges") or reduce traffic by banning diesels cars only, not trucks and vans.
All comes down to the same old problem - too many people all wanting to live in the same place.
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I don't think CO2 either is going to kill the human species, though it will make living as we now do more difficult and expensive (and kill some of us, but not all).
Re:NOx / CO2 (Score:4, Insightful)
It's not a "non-issue"; NOx has very meaningful health impacts for people who breathe it - breathing problems, headaches, chronically lung damage, eye irritation, and even things like loss of appetite and increased tooth enamel wear have been tied to it. People with preexisting breathing disorders and the elderly are particularly sensitive.
And regardless, it's not exactly a secret why emissions have been rising significantly on hot days: VW's fix for their cheat has been found to itself be a cheat [wallstreet-online.de]. The fix (at least for a particular engine model) apparently is only operational between 10-32C (said temperature measurements potentially being somewhat off from ambient temperature measurements). Which means that it spends half the year disabled.
Re: NOx / CO2 (Score:2)
I wish we would standardize on a single fuel. At least until we don't need to burn hydrocarbons any more. When I served in the navy from 1989-1995, everything was standardized on JP5. The aircraft used it, the helos used it, our diesel engines used it, the boiler ships burned it, even the gas turbine fast frigates used it I believe. The only time I saw one of those was being heloâ(TM)d onto it to help them do damage control/repair after hitting a mine and flooding compartments.
Ideally id prefer hydroge
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Hydrogen is hard to contain, because the atoms are so small it is extremely prone to leakage. It also needs to be stored pressurised, which requires strong containment vessels which can rupture violently if damaged, and even more violently if subsequently ignited.
When it comes to using the same fuel for everything, thats convenient in theory but in practice different fuels have different properties, which result in engines with different characteristics. Sports cars typically don't use diesel, while large t
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a couple of decades ago Alan Alda had a informational video about hydrogen. One segment interviewed a guy that had invented a material for h2 storage. He was trying to sell/license the use of the tech to automobile companies. It apparently avoided the pressurized aspect. found a link to that specific segment
https://www.youtube.com/watch?... [youtube.com]
check it out
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here is another no-pressure storage of h2.
https://www.youtube.com/watch?... [youtube.com]
btw there really doesnt have to be a different fuel for race cars... i mean we seriously powered jet engines with jp5 and that fuel is similar to diesel. Now your race car might evolve into a gas turbine style engine instead of compressed fuel/air ignition, but its not a deal killer :-)
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The problem with standardizing on a single fuel, at least so long as we're using petroleum based fuels, is what do you do with the rest of the oil?
Refineries don't take in oil and make it into gasoline the way a paper company takes in wood and makes it into paper. Instead they take in crude oil - a complex soup of different kinds of hydrocarbons, and essentially perform a fractional distillation to separate it into various grades of fuel - I'm not sure about orders, but I think gasoline is the lighter, mor
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Most of the focus on car pollutants historically has not been CO2, it's been NOx, unburned hydrocarbons, pollutants, etc. Catalytic converters were the main technological advance to reduce vehicle pollutants and they worked by emitting MORE CO2.
Goodbye, diesel (Score:5, Interesting)
Diesel engines for private transportation are going to disappear in our lifetime. Maybe diesel will disappear entirely, since now we're hearing about more fleets of trucks, school buses, etc dropping diesel. You guys got all mad and modded me down last time I said this, but like it or not, it's happening.
Re: Goodbye, diesel (Score:2)
Goodbye diesel and gasoline too.
We are a couple years from batteries reaching price parity at which point except for specialty vehicles and oddball cases you would be crazy not to go electric when buying a new car.
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Re: Goodbye, diesel (Score:4, Interesting)
I don't see batteries solving the charging time problem any time soon.
I have an electric car. It charges overnight in my garage while I am sleeping.
A few times per year, I use it for longer trips and have to charge enroute. It can charge to 80% in about 20 minutes, while I grab something to eat.
Overall, I spend far less time waiting for my car to charge than you spend filling your tank at gas stations.
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Personally I think it just makes a safer way to drive. If you have to stop for 20 minutes every 3 hours (I'm not sure how accurate that is), then so be it. We'll be better off if people don't spend 8 hours straight driving between cities.
Also, with the number of people who have 2 or 3 cars, I see no problem with people having 1 gas car if they feel they need it for longer trips, and the other 1 or 2 cars being electric while things switch over. Or just rent when you go on vacation. Once the cost of the ac
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If you have to stop for 20 minutes every 3 hours (I'm not sure how accurate that is) ...
That's about right. The range is 240 miles, but I keep 20% in reserve, and the charging rate tapers off as it gets closer to 100%. So the battery can charge from 20% to 80% in 20 minutes, but then take nearly an hour to get to 100%. So I am using power between 20% and 80% which means ~150 miles, or about 3 hours, between stops.
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Another option is portable charging systems. A generator-trailer is maybe not the safest thing to put on the road, especially given how bad most people are with trailers, but if it could be made safe enough you could have (or rent) just the trailer to recharge as you're driving. Or maybe even something more like those trailer-hitch mounted cargo racks to avoid the complexity of maneuvering a trailer.
Or alternately, you could include a small generator and fuel tank in the car itself - though then you're st
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The Chevy Volt, and the BMW i3's range extender, both discontinued offered the ability to get fuel while on the road. I am surprised that more automakers have not done series hybrids. An engine that only needs to rev in a certain power band is relatively easy to make, compared to a modern vehicle engine that has to have a wide range that it can produce usable torque or horsepower. All the generator's engine has to do is run at a certain RPM constantly to keep the vehicle battery bank charged. With this
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I would imagine that a constant load engine might also be simpler to make flex-fuel. Even better than being able to swap out the generator, is to not need to - just make one engine that burns gasoline, diesel, kerosene, alcohol, etc, etc, etc.
And you don't need any real power from a generator. Let the batteries do the heavy lifting during acceleration, you just need to produce at least a bit more power than consumed on average while cruising down the highway. And it sounds like that's only around15kW(20h
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Tesla have already solved it. A combination of:
* home charging at night, so you only charge on the go for road trips.
* very efficient car (all aspects, not just low drag and efficient motor)
* fast charging (what everyone focuses on, but only a part of the equation)
* seamless charging - no dongle, no logging on, no need for app, just plug it in and charge
* chargers along major routes between cities.
* every charging site has many (between 8 and 40) chargers, so you only very very rarely have to wait (like pu
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fixed electrified path (Score:2)
You want a fixed route, with electrical power that you don't need to drive personally ?
Congratulations, you've successfully invented trains / tramway / metro.
Oh, but you want to drive yourself between the exit point of the network and your destination or home ?
Several cities have successfully deployed car sharing, either in stations (and usually, city train stations have car sharing station where youbcan pick up a car) or "dockless" (pick them wherevr you find them, park them wherever you want in the zone.
Re: fixed electrified path (Score:2)
You want a fixed route, with electrical power that you don't need to drive personally ?
If you omit the electrical power part, you get the highway system in the near future. Swedes are trying to add the electrical power part as well.
to bad for you that it can't work in the huge urban sprawl of 2-levels of house you have in the US, we're very happy with it in Europe.
I happen to live in Central Europe and I still want this. Apparently Swedes want this even more than I do. Hell, Germany too.
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I doubt it, hydrogen is really inefficient and that means much more expensive. Sure you greater enegy density but you also get that from other fuels - like biodiesel or ethanol.
I think cars will simply have a small ethanol engine to charge for longer trips, the "self-charging hybrid" model that will kick in when battery charge drops below a certain level, though it might be easier to have a standardised and replaceable battery pack that you can swap for a full one at a service station for a fee.
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I don't see batteries solving the charging time problem any time soon.
I bet the average daily-commute-electric-car owner spends less time charging than you do going out of your way to find gas stations.
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Price parity for batteries is unlikely to happen, unless we develop a new battery technology that isn't dependent on a rapidly dwindling resource. If more people want battery powered cars, we will need more of the rare elements that are already in ever shorter supply.
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The 2020 crop of EVs totally tick all the boxes for me on everything but price. So now my plan is to eke another three years out of my 2005 Volvo XC70 and then buy a used 2020 EV when they start to come off lease.
If my current Volvo doesn't make it three years, I'll buy a 2009/2010 model gas Volvo to bridge the gap, and THEN get an EV when that one dies.
Long story short, the role of gasoline in my day-to-day life has an end date of no more than 7ish years. Interesting times we live in!
Comment removed (Score:4, Interesting)
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Stop bashing petroleum without considering production.
Car batteries and hydrogen production is very polluting today. Granted, petroleum had decades of research, but all the clean/green that manufacturers advertise is incomplete (not to mention unsustainable to replace all petroleum engines). The way to be green is to work closer to home and/or not drive, especially alone.
Also, NOx is impossible to completely remove as air is 78% N, 20% O2...any high-temperature burn will create NOx.
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Car batteries and hydrogen production is very polluting today.
Got any comparative numbers on that, next to petroleum extraction, refining, and burning + IC engine manufacture? You'll have a hard time showing that batteries are worse than the tens of thousands of annual deaths [ucsusa.org] just from burning fossil juice, plus all the extra pollution from finding and processing it, regular oil spills etc.
And while hydrogen has often been produced from hydrocarbons in the past, these days there are large-scale commercial hydrolysis plants available that need only water and energy.
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Do you think batteries grow on trees?
Lithium extraction is bad for the soil and air. And 1 car needs the equivalent of over 1000 laptops.
How do you think hydrolisys is done?
Wether you charge a battery or make hydrogen, you still need electricity which comes mostly from coal and fuels.
The fuels come from the same refining of crude oil, just like gas/diesel.
So instead of loses at each stage:
- fuel -> electricity -> hydrogen -> acceleration
- fuel -> electricity -> stored charge -> acceleratio
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Yes, all of those lithium extraction plants where they take lithium and dump it into our soil and air (how do they even aerosolize the lithium anyway? Is that how they make chemtrails? ;) ). This also being in an alternative reality where lithium is bad for you, rather than being a neuroprotective compound that probably should be supplemented in water in the same manner as fluoride [nytimes.com].
Lithium is primarily produced from two resources - salars (predominantly in So
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1st search of "energy production worldwide".
https://en.wikipedia.org/wiki/... [wikipedia.org]
I don't know how much is oil and how much is gas, but even US is predominantly (2/3rds) generating from those. And like I said, oil burned has shared production with diesel and gas.
How about Diesel that can reach 45% in trucks and busses?
One of the problems with batteries is that Lithium is not as abundant as steel. I didn't check about other minerals as batteries are "branded" as Lithium, and I remember news about Lithium shortage
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The link you cited does not say what you say it says.
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Well, i protest against using steel for auto body. It's stupid. Aluminum is better in every way except initial energy expenditure, and it makes that back up the first or second time you recycle it. Every time you recycle steel you have to add stuff back into it that is lost in the recycling process, but aluminum doesn't have that problem. So long as you sort alloys (which is cost-effective using laser spectroscopy) the recycled metal has the same properties as the original, less heat treating.
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But it is polluting away from where people live, and that's after all all we care about.
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It's polluting another planet? Because right now, except for a few people on the ISS, Earth is where everyone live.
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Nah, just like our clothing is polluting India and Bangladesh, and our microelectronics are polluting China, it's somewhere where we don't see it so it doesn't exist.
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Modern diesel engines are over 40% efficient [wikipedia.org]. Which actually puts them at about the same efficiency as EVs using electricity generated from fossil fuel plants (40%-60% generation efficiency, 97% transmission efficiency, ~80% battery charging efficiency = 31%-47% efficient, but I've never been able to find reliable figures for battery discharge efficiency). Larger diesel engines like in ships, locomotives, and gene
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You're confusing peak efficiency and average efficiency. A typical diesel ICE averages about 25% efficiency. You can get closer to the peak using a hybrid drivetrain, but that adds in some extra losses.
But remain not even close to electric vehicles [electrek.co].
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That's only true if the diesel fuel takes no energy to make and transport. The figure I just saw (too lazy to look it up again) is that petroleum products take about 30% of their energy content to extract petroleum,
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Most diesel vehicles will be replaced by battery electric ones. More torque, lower running and maintenance costs.
Some places have already replaced all the diesel buses with electric ones. Electric semis are available from several manufacturers and shipping companies are compensating for the limited range by doing relays, such are the massive savings in fuel and maintenance. Construction vehicles don't go very far and can be charged overnight, along with all the battery powered tools.
Hydrogen might find a ni
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Hydrogen in a fuel cell can deliver up to 80% efficiency,
Except the hydrogen creation through green electrolysis is going to be more like 40%. So 80% * 40% and you're back to diesel efficiency.
Hydrogen is just a fancy way to burn Natural Gas until someone can invent a super efficient means of splitting water.
hello diesel (cough, cough my nose is burning) (Score:2)
in the here and now diesel fuel production is growing, was 30% of the growth of world oil demand in 2018
Yes, someday electric or something even better (fuel cells? biofuel?) might supplant fossil fuel vehicles, but.... that day is not today.
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Diesel engines for private transportation are going to disappear in our lifetime.
The IAA (International Motor Show) is running in Frankfurt right now. It would be interesting to see what new models are being presented from the German crew. Due to some new court decisions, diesels can be banned from cities on "Bad Hair" days.
The resell value of used diesels has fallen to zero. I haven't seen any number on diesel sales, but I can't imagine that any of the German auto makers are investing in diesel.
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Not yet. The price of diesel fuel is still at the bottom of many or even most industrial processes and that will not change soon. Moreover, there's no substitute for diesel for long distance transportation.
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Sad isnt it ?
Biodiesel with Hemp Oil is a viable renewable energy source. Batteries are not renewable. Switching fossil fuels from petroleum to minerals is not a good long term plan
EU so wanted diesel transport (Score:1)
Now the EU wants electric cars.
Wonder how that EU big gov idea will work out?
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"EU isnâ(TM)t going anywhere asshole"
Its spelt ARSEhole yankee , so mind your own business. And if you think the EU is stable you might want to take a look at whats happening in eastern europe and even east germany right now. Oh, and thats before we mention the bankrupt italian, spanish and greek economies being kept alive by EU bailouts. How long will that continue when germany - the EUs cheque writer - finally goes into recession?
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It's spelled asshole. Only a redneck yankee would spell it ARSEhole.
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Use google you clueless twat. In the UK its spelt a-r-s-e. An a-s-s is a donkey.
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Not my fault if the UK are spelling it the wrong way. :p
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You can spell your dialect words however you want mate, but proper English is spoken and written in England. The clue's in the name.
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Everyone was so sure of the Soviet Union too
The East German gov felt safe into the early 1980's
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Well of course! They needed to bulldoze the area to build the new prosperity buildings!
Conclusion: (Score:2)
If you like driving a diesel car, drive at night or move to Iceland.
Is that blue stuff supposed to fix this? (Score:2, Interesting)
I thought diesel engines were supposed to have the blue stuff added to the exhaust to fix this.
https://en.wikipedia.org/wiki/... [wikipedia.org]
What are the proposals to fix this? A carbon tax? Some other tax?
What allows people to give a damn about the environment is having enough money to do something about it. Lower the stupid taxes and then people can afford to buy new cars that use the blue fluid to reduce NOx emissions. Or they might buy electric cars.
From the article:
In 2017, research suggested that globally at least 38,000 people a year die early due to the failure of diesel vehicles to meet official limits in real driving conditions.
People die of a lot of things, like not being
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Taxes DID get lowered, two years ago. Remember the "biggest tax cut in US history"? Corporate taxes were slashed drastically too. Was there a spike in sales of less-polluting cars?
In fact, no. Most taxpayers didn't even notice a difference (apart from the 1-percenters maybe). And the corporate windfall was spent not on employee bonuses but on stock buybacks. Instead it just ramped up the national debt even faster. Anyone hoping for trickle-down was probably disappointed.
You know what encourages people to bu
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LOWER THE TAXES AND PEOPLE WILL BUY CLEANER BURNING CARS!!
No. Just raise taxes on dirty cars without giving a handout to the CO2 supported transportation industry. You want cleaner cars then look at what happened when the oil price rose a few years ago, normal America almost got within arms reach of buying normal cars. But no, fuel got cheap again and you guys went back to rolling coal.
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But no, fuel got cheap again and you guys went back to rolling coal.
A switch to diesel was actually a response to higher gas prices. Diesel being more efficient. Of course, this was a total failure in the USA, where manufacturers built junk passenger car engines. In Europe, diesel for higher efficiency is still a thing.
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The problem is the test methodology. It's done at specific temperatures so they optimize the car for those temperatures. At other temperatures it doesn't work very well.
As for medicine, all the evidence suggests that government funding of medicines reduces the costs dramatically.
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By not providing needed services
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One of the main reasons that the US is demanding access to the UK's National Health Service (NHS) as part of any future trade deal is that the NHS forces medicine and treatment prices down. A mixture of bargaining power and strict rules about what prices are acceptable for new treatments keep prices at a fraction of the US ones.
Insurance companies in the US then use the NHS price as a baseline for their negotiations, so it also helps keep prices down for you guys too.
If the US can force the NHS to pay "comm
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A nation can get great deals on 1970's medicine.
Then offer a less from the 1980's.
Much less from a list of approved medicine the 1990's.
The negotiations are not for new medicine. Just the decades old care options in bulk.
With a good news story about a new medical product finally getting UK approval.
The "commercial" rates are paid. Just not for new products.
A gov cant pay for the latest for everyone. So it wont approve the best care an
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How much effect does the ambient air temperature have on the temperature in the combustion chamber and the exhaust system?
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Diesel cars do have airconditioning too (Score:2)
So what do drivers usually do on hot days?
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They wear sunglasses?
This is really not news. (Score:2)
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EGR is actually a means of keeping cylinder temperatures UP without burning fuel. Exhaust gases are hotter than intake air, QED it's obvious that EGR isn't there just to lower temps, which you could do by just taking in more air without adding more fuel... In a direct injected diesel where you don't have to worry so much about AFR as in a gasser. But diesel exhaust under load can be so hot that it is TOO hot, so they use a cooled EGR for emissions control. Pre-emissions diesels have neither EGR nor even PCV
Petrol isn't much cleaner (Score:2)
It also emits its fair share of unpleasant end products even with a catalyst and it also emits particulates too but unlike diesel particulates these are too small to see so you don't get the black smoke. Plus more CO2 , which IMO is far more of an issue than temporary pollutants such as NOx and particulates which would be gone within 24hours if traffic stopped.
The other problem with petrol is that unlike diesel its highly volatile which means theres a huge amount of hydrocarbon pollution aroundthe vicinity
The answer to our problems (Score:3)
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Great, kill yourself.
The problem is not the population. The planet could support far more people. The problems are greed and waste.
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They wouldn't if their politics didn't suck. Central America is quite rural, but run by socialists. Maybe if we elected Bernie, they'd stay put.
Thermodynamics strikes again (Score:5, Interesting)
Why the hell did they need a study to find out tha a diesel engine emits more pollution on a warm day? Look so does a freaking petrol/gasoline engine. It is basic high school thermodynamics 101.
This was all worked out nearly 200 years ago when French physicist Sadi Carnot in 1824 proposed the ideal thermodynamic cycle aka the Carnot cycle.
Efficiency depends on temperature differential between the hot and cold portions of the cycle. So on a warmer day the cold portion of the cycle aka ambient, is higher than on a cold day and hence the efficiency of the cycle goes down.
It's why you have intercoolers on turbo charged engines for crying out loud. The turbo compresses the air making it hot (the turbo is basically adiabatic in nature) in the process so you pass it through a chiller (basically a radiator with ambient air passing over it) to drop the temperature to increase the efficiency.
Can someone please go and give the people writing this study a good beating with a clue stick and send them back to high school for some physics lessons.
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The intercooler is used not to increase efficiency directly, but to permit more boost overall (which increases efficiency... Indirectly)
As you know, temperature and pressure are linked. Therefore temperature limits maximum boost. By cooling the intake charge, you can run more boost without causing predetonation (on indirectly injected engines) or melting of pistons (which occurs at only 1250 degrees for aluminum.) I've had exhaust temps over 1200 before... On a non-intercooled diesel.
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Thermodynamic efficiency is not necessarily chemical efficiency.
Also, theory is not necessarily practice.
To be fair... (Score:3)
... a difference of 10-20C for the input air isn't going to make a whole heap of difference to a reaction that can go up to 1000C+. And using p = P / (R * T) where p is gas density and T is absolute temperature , you can see that going from say 283K (10C) to 303K (30C) isn't going to make the intake air a hell of a lot less dense either.
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It's (depending how you take into account the humidities) about a 10% difference, which is small but not insignificant.
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Did you know all aircraft need to take air temp into consideration? Hot air is less dense, which allows less fuel to be burned and therefore less power from a given engine cycle. Jets, piston, rotary - they can actually be grounded in some cases.
Will "they" get to the point of outlawing all vehicles in high altitude locations because they are less efficient than at s
What's the average? Testing requirement? (Score:2)
Didn't we already know this? (Score:2)
Every time a heat wave comes through, the electronic signs on the freeway are talking about air quality alerts, etc. Didn't we already know there was a strong correlation between ambient temperatures and diesel combustion efficiency?
Diesel Emissions Control 101 (Score:1)
I just thought I would share the evolution of the Diesel emissions control system we have today, for those who wish to learn something useful.
Chapter 1: Why diesel?
Diesel engines are very efficient by design. The efficiency of an ICE is determined largely by the compression ratio of the combustion chamber. The higher the compression ratio, the more energy is extracted from the combusted fuel/air mix. This makes diesel an attractive choice for the termodynamic cycle used in an ICE.
Diesel engines are also ver
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Too bad I don't have mod points to help highlight your post....
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Interesting, but I'm having a bit of problems with the following:
One of the consequences of running a super-lean fuel/air mixture is low combustion temperature.
and
And, NOx is created in higher amounts at higher temperatures in a lean burn environment.
So, which is it? Lean burning causes higher or lower combustion temperatures? What actually happens is that, once the cylinder compression reaches a certain pressure, the air temperature reaches an ignition point and the fuel burns. As it burns, cylinder pressures rise and with them the gas temperature, ensuring further combustion. Soot is produced at the rich end of the mixture curve where there is too much fuel (and too little air) to ens
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Sorry, I could have been more clear.
"Low combustion temperature" relative to stoich, but "low combustion temperature relative to stoich" is still sufficiently high to create NOx. Combustion temperature increases between "super lean" and stoich, creating more NOx.
Soot is created at super lean mixture as well. As the compression stroke reduces the pressure in the cylinder, temperature drops rapidly. This causes the flame to go out before all the fuel is combusted.
On an idling diesel motor you can actually wat
Re: Mua ngay van phong pham gia tot tai day (Score:2)
At last someone is making sense