1 00:00:00,010 --> 00:00:04,010 [chiming music] 2 00:00:04,030 --> 00:00:08,050 [music fades out] [new music starts] 3 00:00:08,070 --> 00:00:12,090 [upbeat but concerned music] 4 00:00:12,110 --> 00:00:16,110 >>BRYAN: I'm going to tell you a tale of air quality in three very different 5 00:00:16,130 --> 00:00:20,150 cities. Beijing, China; Los Angeles, California; and 6 00:00:20,170 --> 00:00:24,180 Atlanta, Georgia. And since I work for NASA, I'll be telling this from the perspective of 7 00:00:24,200 --> 00:00:28,190 space. This is a satellite image 8 00:00:28,210 --> 00:00:32,210 of northeastern China. And you can see this thick, thick 9 00:00:32,230 --> 00:00:36,230 smog enveloping the entire area, and 10 00:00:36,250 --> 00:00:40,270 including the city of Beijing, China. 11 00:00:40,290 --> 00:00:44,330 And from the ground, the pollution, the smog is stifling. It's not uncommon 12 00:00:44,350 --> 00:00:48,360 to see people wearing these face masks to help protect 13 00:00:48,380 --> 00:00:52,390 them from the pollution. So, 14 00:00:52,410 --> 00:00:56,420 what is smog? Smog is a combination of the word "smoke" and 15 00:00:56,440 --> 00:01:00,450 "fog", and it's really just a catch-all for any 16 00:01:00,470 --> 00:01:04,470 noxious soup of pollutants. In the case of Beijing, the primary 17 00:01:04,490 --> 00:01:08,540 component is particulates coming out of the tailpipes of cars, and out of 18 00:01:08,560 --> 00:01:12,570 smoke stacks. So it occurs whenever you burn fuel, 19 00:01:12,590 --> 00:01:16,640 such as gasoline and coal. And the problem with these particulates is 20 00:01:16,660 --> 00:01:20,700 that when we inhale them, they can go deep into our 21 00:01:20,720 --> 00:01:24,760 lungs and they're toxic, and they can embed themselves into the lining of our lungs. 22 00:01:24,780 --> 00:01:28,800 And the smallest of these particles can actually 23 00:01:28,820 --> 00:01:32,820 enter our bloodstream. Okay, here is 24 00:01:32,840 --> 00:01:36,840 an image of the Forbidden City, one of Beijing's top tourist attractions. 25 00:01:36,860 --> 00:01:40,850 And this is on a clear day. 26 00:01:40,870 --> 00:01:44,880 And this is on a horribly polluted day. So I'd rather be a tourist on the 27 00:01:44,900 --> 00:01:48,950 clear day here. Now on the polluted day, the levels of 28 00:01:48,970 --> 00:01:53,020 pollutants can be ten times greater than what's considered 29 00:01:53,040 --> 00:01:57,070 hazardous, and 40 times greater than what's considered to be healthy. 30 00:01:57,090 --> 00:02:01,140 Okay, now the Chinese government has 31 00:02:01,160 --> 00:02:05,170 developed their own air quality index, similar to the one we have in the US. 32 00:02:05,190 --> 00:02:09,210 And they developed, or they created these cartoon characters 33 00:02:09,230 --> 00:02:13,220 to convey the daily air quality index to the Chinese people, and 34 00:02:13,240 --> 00:02:17,250 they call these the Shanghai girls. 35 00:02:17,270 --> 00:02:21,270 The Shanghai girls become increasingly distressed as the AQI goes up, 36 00:02:21,290 --> 00:02:25,310 as the pollution worsens. 37 00:02:25,330 --> 00:02:29,350 [no sound] 38 00:02:29,370 --> 00:02:33,410 [no sound] [laughter] Okay, 39 00:02:33,430 --> 00:02:37,430 you wouldn't be surprised to hear that this is not an official Shanghai girl, 40 00:02:37,450 --> 00:02:41,450 this is called the "Beijing girl", and she's created by a concerned Chinese 41 00:02:41,470 --> 00:02:45,470 citizen. And this citizen was concerned because 42 00:02:45,490 --> 00:02:49,490 these levels are above the highest level of the air quality index. 43 00:02:49,510 --> 00:02:53,510 And in these situations, 44 00:02:53,530 --> 00:02:57,540 this air quality is considered to be beyond index. 45 00:02:57,560 --> 00:03:01,570 So, why is China so polluted? 46 00:03:01,590 --> 00:03:05,630 Well, in the last several decades, they've undergone an industrial revolution 47 00:03:05,650 --> 00:03:09,650 and this has been fueled by China's cheap and abundant 48 00:03:09,670 --> 00:03:13,670 coal. And along with this industrialization, 49 00:03:13,690 --> 00:03:17,690 there's been an increase in urbanization as well as 50 00:03:17,710 --> 00:03:21,710 the standard of living. So the Chinese people are manufacturing more goods 51 00:03:21,730 --> 00:03:25,730 and they're consuming more goods. But more importantly, they are exporting 52 00:03:25,750 --> 00:03:29,750 many of these goods and is considered to be the world's manufacturing hub. 53 00:03:29,770 --> 00:03:33,780 When you burn coal, sulfur dioxide is 54 00:03:33,800 --> 00:03:37,850 released, and it's a precursor to acid rain, it's a 55 00:03:37,870 --> 00:03:41,860 primary ingredient. And it also is a contributor to these particulates that 56 00:03:41,880 --> 00:03:45,880 plague Chinese cities. Here's a representation of satellite data, 57 00:03:45,900 --> 00:03:49,900 of sulfur dioxide, and you can see it's pretty high over much of China. 58 00:03:49,920 --> 00:03:53,920 And it's highest here in this region and that region where there's 59 00:03:53,940 --> 00:03:57,960 a high density of power plants. 60 00:03:57,980 --> 00:04:01,980 For perspective, here is the United States, and you 61 00:04:02,000 --> 00:04:06,010 can see that the pollutant levels are much, much lower. 62 00:04:06,030 --> 00:04:10,020 The Ohio River Valley has the highest concentration of power plants in the 63 00:04:10,040 --> 00:04:14,090 US. And it's much lower in the US because 64 00:04:14,110 --> 00:04:18,160 it's required by law for these power plants to operate scrubber 65 00:04:18,180 --> 00:04:22,190 technology. And these scrubbers literally scrub or remove 66 00:04:22,210 --> 00:04:26,240 the SO2, the sulfur dioxide from the effluent of the power plant 67 00:04:26,260 --> 00:04:30,270 before it's released to the atmosphere. The problem here is 68 00:04:30,290 --> 00:04:34,320 the scrubber technology is incredibly expensive to operate. So places like 69 00:04:34,340 --> 00:04:38,350 China and India simply can't afford to. 70 00:04:38,370 --> 00:04:42,390 But it wasn't so long ago that pollutant levels in the US 71 00:04:42,410 --> 00:04:46,390 were very high, and some of the most polluted cities in the world were in the US. 72 00:04:46,410 --> 00:04:50,430 And Los Angeles was a poster child for this. 73 00:04:50,450 --> 00:04:54,450 And you can see in this image, which is not a satellite image, it's actually 74 00:04:54,470 --> 00:04:58,500 a photograph from NASA's Skylab space station in 1973, 75 00:04:58,520 --> 00:05:02,520 you can see this thick smog in the Los Angeles basin. 76 00:05:02,540 --> 00:05:06,570 The first smog event, 77 00:05:06,590 --> 00:05:10,600 major smog event, occured in 1943 during World War II. 78 00:05:10,620 --> 00:05:14,640 And the residents of LA initially thought they were under attack by a foreign power. 79 00:05:14,660 --> 00:05:18,660 And this is because the smog was stinging their eyes, 80 00:05:18,680 --> 00:05:22,680 burning their throats, and there was an odd bleach-like odor. 81 00:05:22,700 --> 00:05:26,710 It smelled like chemicals. 82 00:05:26,730 --> 00:05:30,770 And interestingly, they noticed during these smog events 83 00:05:30,790 --> 00:05:34,790 that the rubber tires on their cars were cracking. 84 00:05:34,810 --> 00:05:38,840 So, the residents of LA, they 85 00:05:38,860 --> 00:05:42,890 protested to the city government. They said they wanted cleaner air. 86 00:05:42,910 --> 00:05:46,900 And this is a protest by the Highland Park Optimists club. 87 00:05:46,920 --> 00:05:50,940 So city officials responded by 88 00:05:50,960 --> 00:05:54,970 initially banning the burning of trash, which was a common practice 89 00:05:54,990 --> 00:05:58,990 at the time. And they also shuttered a few factories 90 00:05:59,010 --> 00:06:03,020 that they thought were particularly polluting. But unfortunately the smog 91 00:06:03,040 --> 00:06:07,040 persisted. Scientists finally figured out 92 00:06:07,060 --> 00:06:11,100 that the primary ingredient in this smog 93 00:06:11,120 --> 00:06:15,150 was ozone. And as 94 00:06:15,170 --> 00:06:19,200 time went on, these ozone episodes just got worse. Here's an example 95 00:06:19,220 --> 00:06:23,230 of 1955 and 1956, 96 00:06:23,250 --> 00:06:27,250 all the days listed here had ozone levels above 500 ppb, that's 97 00:06:27,270 --> 00:06:31,280 an incredible level. And on this one horrible day, September 13th, 98 00:06:31,300 --> 00:06:35,300 it was as high as 900 ppb. And that's 15 times acceptable levels. 99 00:06:35,320 --> 00:06:39,370 Just for reference, from personal experience, 100 00:06:39,390 --> 00:06:43,440 I actually experienced 350 ppb 101 00:06:43,460 --> 00:06:47,500 quite by accident in a lab one time. I was working with a chemical 102 00:06:47,520 --> 00:06:51,540 instrument that generated ozone internally to the instrument, and 103 00:06:51,560 --> 00:06:55,580 unknown to me, a hose cracked and was allowing this ozone to build up in the lab. 104 00:06:55,600 --> 00:06:59,620 And at first my eyes were stinging, my throat was burning, and finally 105 00:06:59,640 --> 00:07:03,640 when I smelled this chemical odor, this bleach-like odor, I knew it was ozone. So I took a quick 106 00:07:03,660 --> 00:07:07,670 reading, and it was only 350 ppb. I can't imagine 107 00:07:07,690 --> 00:07:11,700 what it would feel like to experience 500 ppb regularly, and 108 00:07:11,720 --> 00:07:15,790 900 ppb for hours on end. Okay, 109 00:07:15,810 --> 00:07:19,860 so, the question still remained, where was this ozone coming from? 110 00:07:19,880 --> 00:07:23,930 Scientists figured out it wasn't coming from tailpipes and smoke stacks, so it 111 00:07:23,950 --> 00:07:27,990 wasn't directly being emitted. Instead, it was being 112 00:07:28,010 --> 00:07:32,020 generated within the smog itself. 113 00:07:32,040 --> 00:07:36,070 So here, today we know that there are three primary ingredients necessary 114 00:07:36,090 --> 00:07:40,090 to form these unhealthy levels of ozone in an urban environment. 115 00:07:40,110 --> 00:07:44,110 The first, sunlight, that drives these chemical 116 00:07:44,130 --> 00:07:48,130 reactions, that provides energy. And of course LA is in sunny California. 117 00:07:48,150 --> 00:07:52,140 The second is a family of compounds called nitrogen oxides 118 00:07:52,160 --> 00:07:56,180 and they are generated whenever coal and gasoline are combusted, 119 00:07:56,200 --> 00:08:00,230 so it comes out of tailpipes and smoke stacks. The third 120 00:08:00,250 --> 00:08:04,260 ingredient are volatile organic compounds, and they primarily come out of the tailpipes of 121 00:08:04,280 --> 00:08:08,280 cars and some factories. And if you've ever smelled gasoline 122 00:08:08,300 --> 00:08:12,320 or paint fumes, you've smelled VOCs, they're very common. There are literally thousands of 123 00:08:12,340 --> 00:08:16,360 these in the urban environment. 124 00:08:16,380 --> 00:08:20,380 Here is a representation 125 00:08:20,400 --> 00:08:24,400 of satellite data, nitrogen dioxide, it's one of the nitrogen oxides. 126 00:08:24,420 --> 00:08:28,410 And you can see all these red 127 00:08:28,430 --> 00:08:32,430 splotches on here, they're high levels of nitrogen dioxide. 128 00:08:32,450 --> 00:08:36,480 And the highest, one of the highest levels is here in Los Angeles. 129 00:08:36,500 --> 00:08:40,510 And all of these occur or coincide with America's largest 130 00:08:40,530 --> 00:08:44,550 cities. The most populated areas. 131 00:08:44,570 --> 00:08:48,580 Okay, so scientists have figured out that 132 00:08:48,600 --> 00:08:52,610 ozone was a primary ingredient in this smog, and they had a basic 133 00:08:52,630 --> 00:08:56,630 understanding of how it was being generated within this smog. So initially 134 00:08:56,650 --> 00:09:00,650 government officials controlled the emissions of 135 00:09:00,670 --> 00:09:04,730 volatile organic compounds from cars and from factories, and the ozone levels went down. 136 00:09:04,750 --> 00:09:08,760 Then they later, they tried to control 137 00:09:08,780 --> 00:09:12,780 nitrogen oxide emissions from power plants and cars and the ozone went down even further. 138 00:09:12,800 --> 00:09:16,810 As an example, cars were required to have 139 00:09:16,830 --> 00:09:20,860 catalytic converters installed on them, and a car today 140 00:09:20,880 --> 00:09:24,910 is about 20 times less polluting than a car was in 1960. 141 00:09:24,930 --> 00:09:28,940 But the situation was a little harder in the eastern US, 142 00:09:28,960 --> 00:09:32,960 they had an ozone problem, but it wasn't so easy to reduce the ozone as it was in 143 00:09:32,980 --> 00:09:36,980 California. Here is a satellite image of 144 00:09:37,000 --> 00:09:41,020 the Atlanta metro area, and the thing you notice is that there are a lot of trees. 145 00:09:41,040 --> 00:09:45,030 And that's the case for many cities in the US, or eastern US. 146 00:09:45,050 --> 00:09:49,100 And these trees 147 00:09:49,120 --> 00:09:53,120 put out lots of volatile organic compounds naturally. 148 00:09:53,140 --> 00:09:57,150 Here is a representation of satellite data of one of these 149 00:09:57,170 --> 00:10:01,180 VOCs. On a hot summer day, you see that their concentrations are very high. 150 00:10:01,200 --> 00:10:05,190 Less so on a warm summer day, and 151 00:10:05,210 --> 00:10:09,200 even lower still on a cool summer day. And it's not exactly 152 00:10:09,220 --> 00:10:13,210 understood why trees are doing this. It's thought that maybe somehow 153 00:10:13,230 --> 00:10:17,280 releasing these VOCs protects them from heat stress. But the exact mechanisms 154 00:10:17,300 --> 00:10:21,330 are just not known yet. Okay, 155 00:10:21,350 --> 00:10:25,380 so, in a city, in the eastern cities like Atlanta, 156 00:10:25,400 --> 00:10:29,400 the only way that you can really reduce ozone 157 00:10:29,420 --> 00:10:33,430 is to reduce nitrogen oxides. It's because there are so many 158 00:10:33,450 --> 00:10:37,460 VOCs occurring naturally from these trees 159 00:10:37,480 --> 00:10:41,500 that the amount coming out of the tailpipe of a car or factory is just very 160 00:10:41,520 --> 00:10:45,520 small in comparison. Over the last two decades, there's been 161 00:10:45,540 --> 00:10:49,540 a tremendous decrease in emissions of what the EPA calls 162 00:10:49,560 --> 00:10:53,600 the six common pollutants. They've gone down by almost 60 percent. 163 00:10:53,620 --> 00:10:57,660 And I've talked about five of these, sulfur dioxide, 164 00:10:57,680 --> 00:11:01,710 nitrogen dioxide, ozone, volatile organic compounds, and particulates. 165 00:11:01,730 --> 00:11:05,750 I didn't talk about lead because as far as I'm aware, we can't measure that from space yet. 166 00:11:05,770 --> 00:11:09,770 And even though this may seem pretty 167 00:11:09,790 --> 00:11:13,830 impressive or significant that it went down by 60 percent, it's even more 168 00:11:13,850 --> 00:11:17,860 impressive when you take into account that our economy 169 00:11:17,880 --> 00:11:21,860 has grown, our population has gone up, the number of cars on the road 170 00:11:21,880 --> 00:11:25,880 have gone up, and the amount of energy we're consuming has gone up. 171 00:11:25,900 --> 00:11:29,960 [silence] 172 00:11:29,980 --> 00:11:34,040 And we can see this from space, this major decrease 173 00:11:34,060 --> 00:11:38,070 in emissions just in the last decade. Here's a representation of nitrogen dioxide, 174 00:11:38,090 --> 00:11:42,100 one of the nitrogen oxides, in 2005 and 2011. 175 00:11:42,120 --> 00:11:46,130 And the concentrations went down by 30-40 percent just over that time. 176 00:11:46,150 --> 00:11:50,160 Sulfur dioxide, a similar story. Emissions 177 00:11:50,180 --> 00:11:54,180 went down by anywhere from 50 to about 90 178 00:11:54,200 --> 00:11:58,220 percent. So it's been a real success story. 179 00:11:58,240 --> 00:12:02,240 But the job isn't done yet, because about 180 00:12:02,260 --> 00:12:06,250 120 million Americans still live in areas with poor air quality. 181 00:12:06,270 --> 00:12:10,290 So we need to keep reducing our emissions. Now 182 00:12:10,310 --> 00:12:14,340 most smog that we're breathing in any particular city is home-grown, 183 00:12:14,360 --> 00:12:18,390 it's locally produced or regionally emitted. However, 184 00:12:18,410 --> 00:12:22,450 the pollution that we emit today will affect someone downwind tomorrow. 185 00:12:22,470 --> 00:12:26,500 For instance, Europeans grumble that American 186 00:12:26,520 --> 00:12:30,520 pollution is blowing in the wind across the Atlantic and degrading their air quality. 187 00:12:30,540 --> 00:12:34,540 And people in California complain that Asian pollution 188 00:12:34,560 --> 00:12:38,560 is blowing across the Pacific and impacting them. 189 00:12:38,580 --> 00:12:42,580 So, air quality is not just a local or regional problem, it's actually 190 00:12:42,600 --> 00:12:46,650 a global problem now these days. So we need satellites to continue 191 00:12:46,670 --> 00:12:50,700 to monitor our air quality from space. There's a fleet of satellites, 192 00:12:50,720 --> 00:12:54,740 Earth-observing satellites, that are orbiting the planet right now. And they observe 193 00:12:54,760 --> 00:12:58,770 everything from ice sheets to oceans to forests and so on 194 00:12:58,790 --> 00:13:02,790 and including our air quality. And I've presented data from 195 00:13:02,810 --> 00:13:06,810 some of those satellites, primarily the Aura satellite mission. And NASA will 196 00:13:06,830 --> 00:13:10,850 continue to design and build bigger and better satellites and monitor our 197 00:13:10,870 --> 00:13:14,880 Earth and our air quality in the future. Thank you. 198 00:13:14,900 --> 00:13:18,900 [applause] 199 00:13:18,920 --> 00:13:22,950 [applause] 200 00:13:22,970 --> 00:13:26,980 [no sound] 201 00:13:27,000 --> 00:13:31,040 [no sound] [whoosh] 202 00:13:31,060 --> 00:13:35,090 [beep beep, beep beep, beep beep] 203 00:13:35,110 --> 00:13:38,065