Time transcripts of G2015-017_Air_Quality_TedTalk_youtube_hq

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[00:00:12:030]	>>BRYAN: I'm going to tell you a tale of air quality in three very different

[00:00:16:040]	cities. Beijing, China; Los Angeles, California; and 

[00:00:20:050]	Atlanta, Georgia. And since I work for NASA, I'll be telling this from the perspective of 

[00:00:24:060]	space. This is a satellite image

[00:00:28:060]	of northeastern China. And you can see this thick, thick

[00:00:32:070]	smog enveloping the entire area, and

[00:00:36:080]	including the city of Beijing, China. 

[00:00:40:090]	And from the ground, the pollution, the smog is stifling. It's not uncommon

[00:00:44:100]	to see people wearing these face masks to help protect

[00:00:48:110]	them from the pollution. So, 

[00:00:52:120]	what is smog? Smog is a combination of the word "smoke" and 

[00:00:56:130]	"fog", and it's really just a catch-all for any 

[00:01:00:140]	noxious soup of pollutants. In the case of Beijing, the primary 

[00:01:04:150]	component is particulates coming out of the tailpipes of cars, and out of

[00:01:08:170]	smoke stacks. So it occurs whenever you burn fuel, 

[00:01:12:180]	such as gasoline and coal. And the problem with these particulates is 

[00:01:16:200]	that when we inhale them, they can go deep into our 

[00:01:20:220]	lungs and they're toxic, and they can embed themselves into the lining of our lungs. 

[00:01:24:230]	And the smallest of these particles can actually

[00:01:28:250]	enter our bloodstream. Okay, here is 

[00:01:32:250]	an image of the Forbidden City, one of Beijing's top tourist attractions. 

[00:01:36:260]	And this is on a clear day. 

[00:01:40:260]	And this is on a horribly polluted day. So I'd rather be a tourist on the

[00:01:44:270]	clear day here. Now on the polluted day, the levels of 

[00:01:48:290]	pollutants can be ten times greater than what's considered 

[00:01:53:010]	hazardous, and 40 times greater than what's considered to be healthy. 

[00:01:57:030]	Okay, now the Chinese government has

[00:02:01:050]	developed their own air quality index, similar to the one we have in the US. 

[00:02:05:060]	And they developed, or they created these cartoon characters

[00:02:09:070]	to convey the daily air quality index to the Chinese people, and 

[00:02:13:070]	they call these the Shanghai girls. 

[00:02:17:080]	The Shanghai girls become increasingly distressed as the AQI goes up, 

[00:02:21:090]	as the pollution worsens. 

[00:02:25:100]	[no sound]

[00:02:29:110]	[no sound] [laughter] Okay, 

[00:02:33:130]	you wouldn't be surprised to hear that this is not an official Shanghai girl, 

[00:02:37:140]	this is called the "Beijing girl", and she's created by a concerned Chinese 

[00:02:41:140]	citizen. And this citizen was concerned because 

[00:02:45:150]	these levels are above the highest level of the air quality index. 

[00:02:49:150]	And in these situations, 

[00:02:53:160]	this air quality is considered to be beyond index. 

[00:02:57:170]	So, why is China so polluted? 

[00:03:01:180]	Well, in the last several decades, they've undergone an industrial revolution

[00:03:05:200]	and this has been fueled by China's cheap and abundant

[00:03:09:200]	coal. And along with this industrialization, 

[00:03:13:210]	there's been an increase in urbanization as well as

[00:03:17:210]	the standard of living. So the Chinese people are manufacturing more goods

[00:03:21:220]	and they're consuming more goods. But more importantly, they are exporting 

[00:03:25:220]	many of these goods and is considered to be the world's manufacturing hub. 

[00:03:29:230]	When you burn coal, sulfur dioxide is

[00:03:33:240]	released, and it's a precursor to acid rain, it's a 

[00:03:37:260]	primary ingredient. And it also is a contributor to these particulates that

[00:03:41:260]	plague Chinese cities. Here's a representation of satellite data, 

[00:03:45:270]	of sulfur dioxide, and you can see it's pretty high over much of China. 

[00:03:49:280]	And it's highest here in this region and that region where there's

[00:03:53:280]	a high density of power plants. 

[00:03:57:290]	For perspective, here is the United States, and you 

[00:04:02:000]	can see that the pollutant levels are much, much lower. 

[00:04:06:010]	The Ohio River Valley has the highest concentration of power plants in the 

[00:04:10:010]	US. And it's much lower in the US because

[00:04:14:030]	it's required by law for these power plants to operate scrubber

[00:04:18:050]	technology. And these scrubbers literally scrub or remove 

[00:04:22:060]	the SO2, the sulfur dioxide from the effluent of the power plant

[00:04:26:080]	before it's released to the atmosphere. The problem here is

[00:04:30:090]	the scrubber technology is incredibly expensive to operate. So places like 

[00:04:34:100]	China and India simply can't afford to. 

[00:04:38:110]	But it wasn't so long ago that pollutant levels in the US

[00:04:42:120]	were very high, and some of the most polluted cities in the world were in the US. 

[00:04:46:120]	And Los Angeles was a poster child for this. 

[00:04:50:140]	And you can see in this image, which is not a satellite image, it's actually 

[00:04:54:140]	a photograph from NASA's Skylab space station in 1973, 

[00:04:58:160]	you can see this thick smog in the Los Angeles basin. 

[00:05:02:160]	The first smog event,

[00:05:06:180]	major smog event, occured in 1943 during World War II. 

[00:05:10:190]	And the residents of LA initially thought they were under attack by a foreign power.

[00:05:14:200]	And this is because the smog was stinging their eyes, 

[00:05:18:200]	burning their throats, and there was an odd bleach-like odor. 

[00:05:22:210]	It smelled like chemicals. 

[00:05:26:220]	And interestingly, they noticed during these smog events

[00:05:30:240]	that the rubber tires on their cars were cracking. 

[00:05:34:240]	So, the residents of LA, they 

[00:05:38:260]	protested to the city government. They said they wanted cleaner air. 

[00:05:42:270]	And this is a protest by the Highland Park Optimists club. 

[00:05:46:280]	So city officials responded by 

[00:05:50:290]	initially banning the burning of trash, which was a common practice

[00:05:54:300]	at the time. And they also shuttered a few factories

[00:05:59:000]	that they thought were particularly polluting. But unfortunately the smog

[00:06:03:010]	persisted. Scientists finally figured out

[00:06:07:020]	that the primary ingredient in this smog 

[00:06:11:040]	was ozone. And as 

[00:06:15:050]	time went on, these ozone episodes just got worse. Here's an example

[00:06:19:070]	of 1955 and 1956, 

[00:06:23:080]	all the days listed here had ozone levels above 500 ppb, that's 

[00:06:27:080]	an incredible level. And on this one horrible day, September 13th, 

[00:06:31:090]	it was as high as 900 ppb. And that's 15 times acceptable levels. 

[00:06:35:100]	Just for reference, from personal experience, 

[00:06:39:120]	I actually experienced 350 ppb

[00:06:43:140]	quite by accident in a lab one time. I was working with a chemical 

[00:06:47:160]	instrument that generated ozone internally to the instrument, and 

[00:06:51:170]	unknown to me, a hose cracked and was allowing this ozone to build up in the lab. 

[00:06:55:180]	And at first my eyes were stinging, my throat was burning, and finally 

[00:06:59:190]	when I smelled this chemical odor, this bleach-like odor, I knew it was ozone. So I took a quick

[00:07:03:200]	reading, and it was only 350 ppb. I can't imagine 

[00:07:07:210]	what it would feel like to experience 500 ppb regularly, and

[00:07:11:220]	900 ppb for hours on end. Okay,

[00:07:15:240]	so, the question still remained, where was this ozone coming from? 

[00:07:19:260]	Scientists figured out it wasn't coming from tailpipes and smoke stacks, so it 

[00:07:23:280]	wasn't directly being emitted. Instead, it was being

[00:07:28:000]	generated within the smog itself. 

[00:07:32:010]	So here, today we know that there are three primary ingredients necessary 

[00:07:36:030]	to form these unhealthy levels of ozone in an urban environment. 

[00:07:40:030]	The first, sunlight, that drives these chemical 

[00:07:44:040]	reactions, that provides energy. And of course LA is in sunny California.

[00:07:48:040]	The second is a family of compounds called nitrogen oxides

[00:07:52:050]	and they are generated whenever coal and gasoline are combusted, 

[00:07:56:060]	so it comes out of tailpipes and smoke stacks. The third 

[00:08:00:080]	ingredient are volatile organic compounds, and they primarily come out of the tailpipes of

[00:08:04:080]	cars and some factories. And if you've ever smelled gasoline

[00:08:08:090]	or paint fumes, you've smelled VOCs, they're very common. There are literally thousands of 

[00:08:12:100]	these in the urban environment. 

[00:08:16:110]	Here is a representation

[00:08:20:120]	of satellite data, nitrogen dioxide, it's one of the nitrogen oxides.

[00:08:24:130]	And you can see all these red

[00:08:28:130]	splotches on here, they're high levels of nitrogen dioxide. 

[00:08:32:140]	And the highest, one of the highest levels is here in Los Angeles. 

[00:08:36:150]	And all of these occur or coincide with America's largest 

[00:08:40:160]	cities. The most populated areas. 

[00:08:44:170]	Okay, so scientists have figured out that 

[00:08:48:180]	ozone was a primary ingredient in this smog, and they had a basic 

[00:08:52:190]	understanding of how it was being generated within this smog. So initially 

[00:08:56:200]	government officials controlled the emissions of

[00:09:00:200]	volatile organic compounds from cars and from factories, and the ozone levels went down. 

[00:09:04:220]	Then they later, they tried to control 

[00:09:08:230]	nitrogen oxide emissions from power plants and cars and the ozone went down even further. 

[00:09:12:240]	As an example, cars were required to have 

[00:09:16:250]	catalytic converters installed on them, and a car today

[00:09:20:260]	is about 20 times less polluting than a car was in 1960. 

[00:09:24:280]	But the situation was a little harder in the eastern US, 

[00:09:28:290]	they had an ozone problem, but it wasn't so easy to reduce the ozone as it was in 

[00:09:32:290]	California. Here is a satellite image of 

[00:09:37:000]	the Atlanta metro area, and the thing you notice is that there are a lot of trees. 

[00:09:41:010]	And that's the case for many cities in the US, or eastern US. 

[00:09:45:020]	And these trees

[00:09:49:040]	put out lots of volatile organic compounds naturally. 

[00:09:53:040]	Here is a representation of satellite data of one of these 

[00:09:57:050]	VOCs. On a hot summer day, you see that their concentrations are very high. 

[00:10:01:060]	Less so on a warm summer day, and 

[00:10:05:060]	even lower still on a cool summer day. And it's not exactly 

[00:10:09:070]	understood why trees are doing this. It's thought that maybe somehow 

[00:10:13:070]	releasing these VOCs protects them from heat stress. But the exact mechanisms

[00:10:17:090]	are just not known yet. Okay, 

[00:10:21:100]	so, in a city, in the eastern cities like Atlanta, 

[00:10:25:120]	the only way that you can really reduce ozone

[00:10:29:130]	is to reduce nitrogen oxides. It's because there are so many 

[00:10:33:140]	VOCs occurring naturally from these trees

[00:10:37:140]	that the amount coming out of the tailpipe of a car or factory is just very 

[00:10:41:160]	small in comparison. Over the last two decades, there's been 

[00:10:45:160]	a tremendous decrease in emissions of what the EPA calls 

[00:10:49:170]	the six common pollutants. They've gone down by almost 60 percent. 

[00:10:53:190]	And I've talked about five of these, sulfur dioxide,

[00:10:57:200]	nitrogen dioxide, ozone, volatile organic compounds, and particulates. 

[00:11:01:220]	I didn't talk about lead because as far as I'm aware, we can't measure that from space yet. 

[00:11:05:230]	And even though this may seem pretty 

[00:11:09:240]	impressive or significant that it went down by 60 percent, it's even more

[00:11:13:260]	impressive when you take into account that our economy

[00:11:17:260]	has grown, our population has gone up, the number of cars on the road

[00:11:21:260]	have gone up, and the amount of energy we're consuming has gone up. 

[00:11:25:270]	[silence]

[00:11:29:290]	And we can see this from space, this major decrease 

[00:11:34:020]	in emissions just in the last decade. Here's a representation of nitrogen dioxide,

[00:11:38:030]	one of the nitrogen oxides, in 2005 and 2011. 

[00:11:42:040]	And the concentrations went down by 30-40 percent just over that time. 

[00:11:46:040]	Sulfur dioxide, a similar story. Emissions 

[00:11:50:050]	went down by anywhere from 50 to about 90

[00:11:54:060]	percent. So it's been a real success story. 

[00:11:58:070]	But the job isn't done yet, because about 

[00:12:02:080]	120 million Americans still live in areas with poor air quality. 

[00:12:06:080]	So we need to keep reducing our emissions. Now

[00:12:10:090]	most smog that we're breathing in any particular city is home-grown, 

[00:12:14:110]	it's locally produced or regionally emitted. However, 

[00:12:18:120]	the pollution that we emit today will affect someone downwind tomorrow. 

[00:12:22:140]	For instance, Europeans grumble that American

[00:12:26:160]	pollution is blowing in the wind across the Atlantic and degrading their air quality. 

[00:12:30:160]	And people in California complain that Asian pollution 

[00:12:34:170]	is blowing across the Pacific and impacting them. 

[00:12:38:170]	So, air quality is not just a local or regional problem, it's actually 

[00:12:42:180]	a global problem now these days. So we need satellites to continue 

[00:12:46:200]	to monitor our air quality from space. There's a fleet of satellites,

[00:12:50:220]	Earth-observing satellites, that are orbiting the planet right now. And they observe

[00:12:54:230]	everything from ice sheets to oceans to forests and so on

[00:12:58:240]	and including our air quality. And I've presented data from

[00:13:02:240]	some of those satellites, primarily the Aura satellite mission. And NASA will 

[00:13:06:250]	continue to design and build bigger and better satellites and monitor our 

[00:13:10:260]	Earth and our air quality in the future. Thank you. 

[00:13:14:270]	[applause]

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