Ozone pollution improving in the U.S.

By: Dr. Jeff Masters , 7:03 PM GMT on May 01, 2007

Share this Blog
2
+

Air pollution season is here, and the good news is that ozone pollution in 2006 was considerably better than in previous years. Along with pollution due to small particles (particulate matter), ground-level ozone is the most serious pollutant in the U.S. Ozone levels in 2006 showed improvement in 23 out of 35 of the major cities in the U.S. (Figure 1) compared to 2005, and was at or below the 10-year average in all but five cities. Atlanta, Georgia, showed the greatest jump in the number of unhealthy days, from 17 in 2005 to 30 days in 2006; however, this number was still below the 10-year average. Many western cities reached levels at or above the 10-year average, including San Diego, Sacramento, Denver, and Las Vegas. This was in part due to much above average summertime temperatures in the western U.S. (Figure 2). Los Angeles had the worst ozone pollution in the U.S., with 46 unhealthy days. Los Angeles also was the most polluted city overall in 2006, according to the American Lung Association. However, Los Angeles' bad ozone days declined by 16% in 2006 compared to 2005.


Figure 1. The number of days in May through September of 2005 and 2006 in which ground-level ozone reached Unhealthy for Sensitive Groups--an Air Quality Index (AQI) above 100. Corresponding 10-year averages are also shown. Image credit: EPA.

Ozone pollution has improved
Is the improvement seen in ozone levels in 2006 merely due to a lack of meteorological conditions that favor air pollution? To check, I've plotted the difference in surface temperature (degrees C) from May-September 2006, compared to the 10-year average from 1995-2005 (Figure 2). The chemical reactions that form ozone are most efficient at high temperatures, so if the summer of 2006 was cooler than usual, we'd expect a drop in ozone levels. However, the summer of 2006 was the second warmest in U.S. history--but ozone levels still dropped. All of the cities where ozone increased significantly in 2006 over 2005 levels were areas where temperatures were above average. Los Angeles had summer temperatures more than 1 degree C above normal, yet still recorded a drop in ozone, suggesting that strategies to control ozone pollution there are paying dividends. In fact, new rules to limit nitrogen oxide emissions from power plants have been enacted nation-wide in the past few years, and the ozone pollution statistics from 2006 are evidence that these emissions rules are working. Ozone pollution since 1980 has dropped 21% (Figure 3), despite the fact that the average summer temperatures have generally been increasing.


Figure 2. The difference in surface temperature (degrees C) from May-September 2006, compared to the 10-year average from 1995-2005. Temperatures were above the 10-year average across most of the country, except for New Mexico, and portions of the Ohio Valley surrounding Kentucky. Image credit: NCAR/NCEP.


Figure 3. Trends in ozone air pollution in the U.S. (white line) and uncertainty (blue areas, marking the standard deviation). The federal standard of 0.08 ppm is indicated by the dashed line. Since 1980, maximum ozone levels have declined 21%. Since 1990, the decline has been 9%. Note that the lowest ozone levels were recorded in 2004, which was an exceptionally cool summer across most of the U.S. Image credit: U.S. EPA.

Next blog (Thursday): Pollution costs and deaths exceed the impact of a new Hurricane Katrina hitting the U.S. each year.

Jeff Masters

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 88 - 38

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13Blog Index

88. StormJunkie
11:52 PM GMT on May 01, 2007
Don't worry xyz, I have trouble with lots of stuff and need it explained to me several times before I get it. I did not really get the high either until some one threw out the mountain and valley analogy ☺
Member Since: August 17, 2005 Posts: 26 Comments: 16823
87. StormJunkie
11:46 PM GMT on May 01, 2007
Not exactly xyz, It was explained to me like this. Think of the high as a big old mountain. The highest pressures being the summit and everything out from that gradually slopes down. Tropical systems are going to look for the valley and that is where they will go. Those lines are basically contour lines extending out from the highest pressures. So storms can not exactly butt right up against the high, but they will move around the periphery. In this situation, the high looks strong enough to get a storm to at least Fla if not the Gulf. Again though all of this will fluctuate, and jsut because it is this way now does not mean this will be the pattern that we see during the season.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
86. Stormxyz
11:41 PM GMT on May 01, 2007
Thanks SJ. Now, quick newbie question. While viewing that first link you gave me, im guessing that the Bermuda High is the big H setup in the mid atlantic with the 1 circle around it and the 2nd ring around that is the "extended" bermuda high??

Looking at that, it seems like its not extending all the way to the US coastline, which would allow the storms to recurve out to sea? Correct? incorrect? i think im missing something.

Thanks for all the help. its been one of the things ive been having trouble with lately.
85. StormJunkie
11:30 PM GMT on May 01, 2007
xyz, you can also find most of the forecast models from the here. If you look at several of the models at the 6hr time frame for sea level pressure you get a decent idea of where the high is also.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
84. StormJunkie
11:24 PM GMT on May 01, 2007
Here is one, but prior to you asking I was just thinking I have not seen a surface analysis map for the entire Atlantic that I really like. I usually use the models at the 6hr time frame...Not the best though. I would much rather find a good surface analysis map that I like. There is also a pretty good one in wabits blog.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
83. stormhank
11:28 PM GMT on May 01, 2007
thanks sj
Member Since: Posts: Comments:
82. StormJunkie
11:22 PM GMT on May 01, 2007
If you have heard that SH, it could very well be true. Although that high will kinda breath throughout the season. Receding and building back in. Troughs will erode it some times. Timming will be critical when we get to that point.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
81. Stormxyz
11:20 PM GMT on May 01, 2007
Hey SJ, you mind posting a link to an illustration showing where the Bermuda High is currently? thanks in advance

80. stormhank
11:19 PM GMT on May 01, 2007
thanks for help.. SJ.. that pattern thats in place now with the bermuda high.. I wonder is that the reason Ive read about the gulf n carribean as bein prime targets this year for landfall?
Member Since: Posts: Comments:
79. StormJunkie
11:16 PM GMT on May 01, 2007
That is part of the Bermuda high Taz, but it is really only about 1020 off the e coast. Notice that big tongue extending much further S and W from last year. Not to say it will not erode away over the next month, but as of now I do not like it.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
78. chessrascal
11:15 PM GMT on May 01, 2007
Link
this is a cool image of the frontal boundary
Member Since: Posts: Comments:
77. StormJunkie
11:12 PM GMT on May 01, 2007
Can someone explain SOI to me in laymens terms?
Member Since: August 17, 2005 Posts: 26 Comments: 16823
76. Skyepony (Mod)
11:11 PM GMT on May 01, 2007
Evening! Excellent blog entry Dr Masters put up for us.
Member Since: Posts: Comments:
75. Tazmanian
4:07 PM PDT on May 01, 2007
weatherboykris there is a 1022 high off the E coast is that are Bermuda high?
Member Since: May 21, 2006 Posts: 5091 Comments: 115247
74. StormJunkie
11:08 PM GMT on May 01, 2007
Evening Skye, good to see you!
Member Since: August 17, 2005 Posts: 26 Comments: 16823
73. StormJunkie
11:06 PM GMT on May 01, 2007
Thanks kris☺, knew all large storms and usually ones that are strenghtening have anticyclones, just did not understand that a omega block worked the same way. I wrongly assumed at first that it was a lower level high pressure.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
72. Skyepony (Mod)
11:06 PM GMT on May 01, 2007
Stormhank~ I like the NHC charts scroll down to the bottom.
Member Since: Posts: Comments:
71. StormJunkie
11:05 PM GMT on May 01, 2007
No sweat chess, and like I said, right now it is not a huge deal but things will get crazy in here when the tropics heat up. It gets hard to keep up with the blog even...
Member Since: August 17, 2005 Posts: 26 Comments: 16823
70. weatherboykris
11:05 PM GMT on May 01, 2007
Hurricane KATRINA
--------------------------------------------------------------------------------

ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM
HURRICANE KATRINA DISCUSSION NUMBER 26
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT MON AUG 29 2005

AIR FORCE RECON HAS BEEN INVESTIGATING KATRINA THIS MORNING AND HAS
REPORTED SOME MECHANICAL PROBLEMS WHICH HAS PREVENTED MAKING A
COMPLETE ASSESSMENT OF THE INTENSITY IN THE NORTHEAST QUADRANT.
HOWEVER...FLIGHT-LEVEL WINDS OF 132-134 KT HAVE BEEN REPORTED IN
THE SOUTHEAST QUADRANT...WHILE NOAA DOPPLER RADAR VELOCITIES FROM
WFO SLIDELL EXCEEDING 123 KT HAVE BEEN OBSERVED IN THE NORTHEAST
QUADRANT BETWEEN 12000-16000 FT. THESE WIND VALUES WOULD SUPPORT AT
LEAST 125 KT SURFACE WINDS. ALTHOUGH THE CENTRAL PRESSURE HAS
CONTINUED TO INCREASE AND IS NOW 915 MB...THIS WOULD USUALLY
SUPPORT ABOUT 145 KT SURFACE. THE INITIAL INTENSITY OF 130 KT IS A
BLEND OF THESE VALUES.

THE INITIAL MOTION IS 360/13. KATRINA IS MOVING NORTHWARD AROUND THE
WESTERN PERIPHERY OF A LARGE-SCALE MID- TO UPPER-LEVEL RIDGE
LOCATED OVER THE FLORIDA PENINSULA AND EXTENDING NORTHWESTWARD
ACROSS THE SOUTHEASTERN UNITED STATES. THE COMBINATION OF THE
STRONG RIDGE AND AN APPROACHING MID-LEVEL TROUGH FROM THE WEST
SHOULD ACT TO KEEP KATRINA MOVING GENERALLY NORTHWARD FOR THE NEXT
12 HOURS OR SO. BY 24 HOURS...THE HURRICANE IS EXPECTED TO TURN
NORTHEASTWARD AS A STRONGER TROUGH LIFTS OUT THE SYSTEM AND
TRANSITIONS IT INTO AN EXTRATROPICAL LOW OVER THE GREAT LAKES
REGION. THE OFFICIAL FORECAST TRACK IS JUST A LITTLE TO THE LEFT OF
THE PREVIOUS TRACK AND IS SIMILAR TO THE NHC MODEL CONSENSUS.

SOME FLUCTUATIONS IN INTENSITY ARE POSSIBLE RIGHT UP UNTIL LANDFALL
OCCURS. HOWEVER...IT APPEARS THAT KATRINA WILL MAKE LANDFALL AS A
CATEGORY 4 HURRICANE LATER THIS MORNING. THE CLOUD PATTERN IN
SATELLITE IMAGERY HAS ERODED ON THE WEST SIDE DUE TO DRY AIR
ENTRAINMENT...AND THE EYEWALL HAS OPENED UP TO THE SOUTH AND
SOUTHWEST IN RADAR IMAGERY. HOWEVER...THE WATER REMAINS QUITE WARM
UNDERNEATH THE CENTER...AND CONVECTION CAN EASILY REDEVELOP AND THE
EYEWALL CLOSE OFF AGAIN BEFORE LANDFALL OCCURS. SOME DISRUPTION OF
THE CIRCULATION WILL OCCUR ONCE THE CENTER MOVES OVER SOUTHEASTERN
LOUISIANA. HOWEVER...THE FORECAST TRACK KEEPS THE EYE CLOSE ENOUGH
TO WARM WATER NEAR THE LOUISIANA AND MISSISSIPPI COASTS. THE
UPPER-LEVEL OUTFLOW PATTERN REMAINS QUITE IMPRESSIVE AND EVEN
CONTAINS A RARE 200 MB INDRAFT ANTICYCLONE TO THE EAST NEAR TAMPA
BAY. THE COMBINATION OF THE OUTFLOW REGIME AND THE CLOSE PROXIMITY
TO WARM WATER MAY BE ENOUGH TO KEEP KATRINA A MAJOR HURRICANE WHEN
IT REACHES THE LOUISIANA-MISSISSIPPI BORDER AREA THIS AFTERNOON.
JUST BECAUSE KATRINA IS NO LONGER A CATGEORY 5 HURRICANE DOES NOT
MEAN THAT EXTENSIVE DAMAGE AND STORM SURGE FLOODING WILL NOT OCCUR.
THIS IS STILL AN EXTREMELY DANGEROUS AND POTENTIALLY DEADLY



Member Since: Posts: Comments:
69. StormJunkie
11:03 PM GMT on May 01, 2007
SH, check the preparedness links here. Not sure if any of them will do what you are looking for. Could always go to a kinkos or something and get them to blow it up a little for you. At least 11 x 17....
Member Since: August 17, 2005 Posts: 26 Comments: 16823
68. chessrascal
10:59 PM GMT on May 01, 2007
Thanks SJ I will keep that in mind for anything that doesnt have to be posted as a pic.
Member Since: Posts: Comments:
67. edith
11:02 PM GMT on May 01, 2007
Thanks, SJ.
Member Since: Posts: Comments:
66. weatherboykris
11:02 PM GMT on May 01, 2007
SJ,exactly.An Omega block is an upper level anticyclone,which has very light winds at it's center.All major hurricanes,and epecially Cat 4 or 5,have an upper level anticyclone positioned directly above them.Or at least close.
Member Since: Posts: Comments:
65. StormJunkie
11:02 PM GMT on May 01, 2007
Me too BT. I think it keeps us weather freaks sane...☺
Member Since: August 17, 2005 Posts: 26 Comments: 16823
64. StormJunkie
11:00 PM GMT on May 01, 2007
edith, as of right now it is too early to tell, but it is much further south and west of where it was last year and that pattern has been sustained for sometime now. This would not be a good pattern to have during the season as it would drive storms to the W, but still wait and see. Props to '03 for answering the same question earlier...
Member Since: August 17, 2005 Posts: 26 Comments: 16823
63. Bamatracker
11:00 PM GMT on May 01, 2007
good to see you too SJ I took the winter off but im back and ready for the season!!! Ill be back later.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
62. Tazmanian
4:00 PM PDT on May 01, 2007
there is a 1022 high off the E coast
Member Since: May 21, 2006 Posts: 5091 Comments: 115247
61. stormhank
10:57 PM GMT on May 01, 2007
Hi everyone! does anyone know a good site where I can go n print out hurricane tracking charts? Everytime i try to print one it never comes out plain enough to read the latitude longitude lines?
Member Since: Posts: Comments:
60. StormJunkie
10:54 PM GMT on May 01, 2007
lol BT ☺

And by the way, for the umptenth time, good to see you! I posted that a few times already, not sure if you ever saw it or not...

I asked TCW about the Omega block and one thing I did not understand is how it could be conducive for tropical development if it was a high. I think, and this is what he stated, that it is an upper air high. Therefore creating a upper level environment that is conducive to development of tropical systems as opposed to sea level highs which will only increase shear and deflect tropical systems. I hope I explained that right and hope I did not misrepresent TCW.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
59. Inyo
10:55 PM GMT on May 01, 2007
The only reasonable political voices on global warming are those who say we need to develop technologies that emit less carbon, and that we need to plan out how to adapt to what is coming. We're just not going to solve this overnight, even if we can solve it.

I agree with this, of course... hopefully, ultimately we won't be emitting carbon at all (except when we breathe). I just don't buy the whole conspiracy thing... I don't believe environmentalists and liberals are a secret conspiracy created to steal our freedom and turn us into russia (no environmentalist would support communism if they have ever done any research into the environmental policies of China, Russia, and North Korea).

The problem is simply that our current capitalist society does a poor job representing the complex ecological costs of our actions. For instance, if someone can't develop their parcel, they may lose 10 million dollars of land value. This is well represented now. However, if they do develop it, and urban runoff or channel alterations lead to flooding that destroys part of a city downstream, which costs us 20 million dollars and kills off a dozen or two people, this is not represented well in our capitalist society right now. (although like i said, we do a much better job than the communists are doing.)
Member Since: Posts: Comments:
58. edith
10:56 PM GMT on May 01, 2007
Any climatological speculation on the possible location of the Bermuda high, for this season? Or is it way too early?
Member Since: Posts: Comments:
57. Bamatracker
10:57 PM GMT on May 01, 2007
seems like it. People always get mad on here. fun to read.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
56. hurricaneman23
10:56 PM GMT on May 01, 2007
was wunderground this heated last year a month away from hurricane season?
Member Since: Posts: Comments:
55. Bamatracker
10:52 PM GMT on May 01, 2007
aahhh...the craziness of a storm on weatherunderground...dont yall just miss it?!
Member Since: May 17, 2006 Posts: 6 Comments: 1367
54. Bamatracker
10:50 PM GMT on May 01, 2007
ok...i just googled rex block....i thought i was something real. YOur right weatherboy it was an omega block they were talking about yesterday.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
53. Tazmanian
3:47 PM PDT on May 01, 2007
ok but the more and more raders/loop you put on her it this blog will get slower and sloweer so you may want to think about uesing links too but do want you want to do
Member Since: May 21, 2006 Posts: 5091 Comments: 115247
52. StormJunkie
10:46 PM GMT on May 01, 2007
Thanks chess, I know he does not own a radar, but he did say my radar. Just 23.

As for links, you would be very suprised how often people will click on links. Not to mention come busy time everyone and there brother tries to one up each other with sat pics and radar. The links work well and it keeps the blog somewhat dial up friendly.

And all in all if folks don't click a link it is because they did not want to see it. Why not give them the option. Right now it is really not that big of a deal, but as June 1 approaches and then the 1st storm forms it will get flat out crazy in here. Not to mention all the folks just reading trying to get informatin about the storms.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
51. weatherboykris
10:49 PM GMT on May 01, 2007
Link
Member Since: Posts: Comments:
50. Bamatracker
10:49 PM GMT on May 01, 2007
LOL my bad...dont know what i was thinking about..
Member Since: May 17, 2006 Posts: 6 Comments: 1367
49. weatherboykris
10:45 PM GMT on May 01, 2007
Posted By: Bamatracker at 10:37 PM GMT on May 01, 2007.

so whats up with that rex block everyone was talking about yesterday? Is it happening or what?


It's an omega block,not a rex block.And omega blocks are not that unusual,or at least not as unusual as rex blocks.
Member Since: Posts: Comments:
48. chessrascal
10:44 PM GMT on May 01, 2007
people dont like going to links Taz they just like seeing it without bothering to go to a link.
Member Since: Posts: Comments:
47. chessrascal
10:41 PM GMT on May 01, 2007
23 doesnt own a radar he has radar software heres the link to it Link

I have Storm Predators radar sofware
Member Since: Posts: Comments:
46. Tazmanian
3:40 PM PDT on May 01, 2007
could we Please start uesing links to post rader loops and raders thank this blog will get slower and slower
Member Since: May 21, 2006 Posts: 5091 Comments: 115247
45. StormJunkie
10:39 PM GMT on May 01, 2007
You are correct chess. There are not that many of them to memorize anyway.
Member Since: August 17, 2005 Posts: 26 Comments: 16823
44. StormJunkie
10:38 PM GMT on May 01, 2007
Wow 23 you own a radar, that is way cool!

.....
Member Since: August 17, 2005 Posts: 26 Comments: 16823
43. Bamatracker
10:36 PM GMT on May 01, 2007
so whats up with that rex block everyone was talking about yesterday? Is it happening or what?
Member Since: May 17, 2006 Posts: 6 Comments: 1367
42. chessrascal
10:33 PM GMT on May 01, 2007
it would be nice to have any kind of precipitation here
Member Since: Posts: Comments:
41. Bamatracker
10:23 PM GMT on May 01, 2007
wish we had some hail around here.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
40. hurricane23
6:21 PM EDT on May 01, 2007
Large hail with this thunderstorm...GR.

gg
Member Since: May 14, 2006 Posts: 8 Comments: 13804
39. chessrascal
10:11 PM GMT on May 01, 2007
23 what radar do u use?
Member Since: Posts: Comments:
38. RL3AO
5:08 PM CDT on May 01, 2007
cleradar
Member Since: Posts: Comments:

Viewing: 88 - 38

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13Blog Index

Top of Page

About

Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

Local Weather

Scattered Clouds
51 °F
Scattered Clouds