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: 588 - 538

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

588. Patrap
8:02 AM CDT on May 03, 2007
The GFSx shows the trouble here tommorrow..then slides it toward Fla and weakens it,..sadly. Link
Member Since: Posts: Comments:
587. MissBennet
7:54 AM CDT on May 03, 2007
you too Pat! Me, I'll probably forget my umbrella like always. =(
Member Since: Posts: Comments:
586. kmanislander
12:54 PM GMT on May 03, 2007
Thanks SJ. I had to step away for a bit
Member Since: Posts: Comments:
585. MissBennet
7:52 AM CDT on May 03, 2007
I just realized yours is completely different from mine. =)
Member Since: Posts: Comments:
584. Patrap
7:50 AM CDT on May 03, 2007
But we aint a-skeered,..LOL, Stay dry MissBennet!
Member Since: Posts: Comments:
583. Patrap
7:47 AM CDT on May 03, 2007
Its all about the passing of info,...best to be informed.Instead of 1st. The system has the potential to train T-storms over the same areas for extended periods tommorrow.
Member Since: Posts: Comments:
582. MissBennet
7:45 AM CDT on May 03, 2007
Nevermind...
Member Since: Posts: Comments:
581. TheCaneWhisperer
8:26 AM EDT on May 03, 2007
Posted By: Crisis57 at 12:36 AM EDT on May 03, 2007.

I agree with you Story so far this season looks to shape up to be a busy one, Anyone know when it would be a good time to start investigating the Bermuda High and its location since right now may be to early


The Bermuda High usually anchors into place in July! Consistent High Pressure over the east coast will make the CONUS lows travel further North and West, thus having less of an impact on the movement of the high. High pressure has been lingering on the east coast and the long range forcast is for this to continue. That being said, if the forcast holds, I don't think we will see much movement in the BH before it anchors into place in July! Keep in mind that these are long range forcast and are subject to large errors.
Member Since: Posts: Comments:
580. Patrap
7:28 AM CDT on May 03, 2007

241
fxus64 klix 030948
afdlix


Area forecast discussion
National Weather Service New Orleans la
448 am CDT Thursday may 3 2007


Discussion...
main forecast concerns for the period will focus primarily on the
convection expected over the next 36 hours and the possibility of
heavy rain and severe weather. Difficult forecast through Friday
with very different model solutions with regards to convective
development and the associated heavy rain threat across the forecast
area. Middle/upper trough currently over west/central Texas early this
morning is forecast to be kicked out across the lower Mississippi
Valley tonight and Friday as an upper trough digs into the western
Continental U.S.. as this takes place...the ejected upper trough is prodg to
take on a negative tilt as it moves across the lower Mississippi
Valley. The GFS is very aggressive with convective development
across the area later tonight and Friday and forecasts several
inches of rain across sections of the forecast area. While the GFS
is most definitely an outlier with respect to quantitative precipitation forecast totals and
convective feedback is a possible cause...it is noteworthy that it
has been quite consistent for several model runs in forecasting
heavy rainfall over the forecast area. The NAM...UKMET and
Canadian all agree in moving significant convection across the
area tonight and Friday...most likely in the form of an mesoscale convective system or
two...but they are much less generous with the quantitative precipitation forecast amounts. It
should be noted that the models have performed somewhat poorly
tonight in forecasting the rainfall over Texas. It is also
interesting to note that despite the GFS forecasting such heavy
rain over western sections of the forecast area tonight...GFS mav
guidance probability of precipitation are no higher than 40 percent during the period.


Although the forecast upper level jet pattern tonight and Friday
is not all that impressive...significant large scale ascent and dfln
aloft will prevail over lower Mississippi Valley late tonight into
Friday as the increasingly negatively tilted upper trough swings
across the lower Mississippi Valley. In addition...a very moist
and unstable atmosphere will be in place for this system to work
with high precipitable water values...precipitable waters of nearly 2 inches
forecast by the GFS and around 1.6 inches by the NAM...as a
forecasted low level jet of 30 to 35 knots brings moisture north
from the Gulf as it develops and translates eastward across the
lower Mississippi Valley. Both GFS and to some degree the NAM forecast
a low level boundary or convergence zone across the forecast area
late tonight and Friday that may well serve as a focus for
convective development and heavy rain. As far as the GFS is
concerned...it is not clear if this forecast boundary is
associated with any possible convective feedback. With all this
said...the inherited Flood Watch will be maintained but the
starting time will be pushed back until midnight tonight since any
heavy rain threat will not be until late tonight or early Friday
morning. Rainfall amounts of 3 to 6 inches with locally higher
values are certainly possible. Plan to also mention the severe
threat late tonight with damaging winds and large hail being the
primary threats.
Member Since: Posts: Comments:
579. MissBennet
7:21 AM CDT on May 03, 2007
Sorry to all you Floridians, but it looks like we're going to get all your rain over here in Louisiana:

Statement as of 5:26 AM CDT on May 03, 2007


...FLOOD WATCH NOW IN EFFECT FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON...

THE FLOOD WATCH IS NOW IN EFFECT FOR

* PORTIONS OF SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI... INCLUDING THE FOLLOWING AREAS...IN SOUTHEAST LOUISIANA... ASCENSION... ASSUMPTION...EAST BATON ROUGE...EAST FELICIANA... IBERVILLE... LIVINGSTON...LOWER JEFFERSON...LOWER LAFOURCHE... LOWER PLAQUEMINES... LOWER ST. BERNARD...LOWER TERREBONNE... ORLEANS...POINTE COUPEE...ST. CHARLES...ST. HELENA... ST. JAMES...ST. JOHN THE BAPTIST... ST. TAMMANY...TANGIPAHOA... UPPER JEFFERSON...UPPER LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD... UPPER TERREBONNE...WASHINGTON...WEST BATON ROUGE AND WEST FELICIANA. IN SOUTHERN MISSISSIPPI...AMITE... HANCOCK...HARRISON...JACKSON...PEARL RIVER...PIKE...WALTHALL AND WILKINSON.

* FROM LATE TONIGHT THROUGH FRIDAY AFTERNOON

* A STRONG UPPER LEVEL DISTURBANCE MOVING ACROSS TEXAS TODAY WILL MOVE SLOWLY ACROSS THE LOWER MISSISSIPPI VALLEY TONIGHT AND FRIDAY. A MOISTURE RICH ATMOSPHERE WILL BE IN PLACE AS SOUTHERLY FLOW PERSISTS AND INCREASES IN STRENGTH TONIGHT AND FRIDAY OVER THE AREA. RAINFALL RATES OF ONE TO TWO INCHES PER HOUR WILL BE POSSIBLE AT TIMES WITH THUNDERSTORMS LATE TONIGHT AND FRIDAY RESULTING IN THE THREAT OF FLOODING. SOME NUMERICAL FORECAST MODELS ARE INDICATING COPIOUS RAINFALL AMOUNTS THAT MAY MATERIALIZE... INCLUDING ACCUMULATIONS BETWEEN 3 AND 6 INCHES WITHIN SIX HOUR PERIODS. IF THIS OCCURS...THEN FLOODING CAN ENSUE AND POSSIBLY BECOME EXTENSIVE.

* POTENTIAL IMPACTS OF FLOODING INCLUDE EXTENSIVE PONDING AND FLOODING OF STREETS AND URBAN AREAS WHERE TORRENTIAL RAINS MAY BRIEFLY OVERWHELM DRAINAGE SYSTEM CAPACITY. EXCESSIVE RAINFALL RUNOFF TYPICALLY CAUSES RIVES AND STREAMS TO RISE RAPIDLY. MOST AREA STEAMS ARE AT LOW FLOWS AND SHOULD BE ABLE TO ACCOMMODATE LOW TO MODERATE RAIN RATES AND ACCUMULATIONS. IF RAIN RATES BECOME TORRENTIAL...TYPICALLY EXCEEDING TWO INCHES PER HOUR...THEN RIVER AND STREAM FLOODING MAY RESULT. THE LOWER MISSISSIPPI RIVER FORECAST CENTER WILL BE EVALUATING THE RIVER FLOWS THROUGHOUT THE DAY AND MAY ISSUE A HYDROLOGIC OUTLOOK HIGHLIGHTING ANY POTENTIAL RIVER FLOOD CONCERNS.

Member Since: Posts: Comments:
577. StormJunkie
12:08 PM GMT on May 03, 2007
Morning kman

It is run 4 times per day if I am not mistaken. 00z, 06z, 12z, and 18z. It usually is a several hours later that we get the output. Ex the 06z run should be available a little before the 12z starts running.

Member Since: August 17, 2005 Posts: 26 Comments: 16607
576. kmanislander
11:56 AM GMT on May 03, 2007
good morning

anyone know how often the GFS is run ?
It is still showing that low N of Panama but now only 8 days out instead of 384 hrs.
Member Since: Posts: Comments:
575. StormJunkie
9:33 AM GMT on May 03, 2007
Morning all

lmao SOTC.
Someone who predicts every blob will develop and hit there home town is a wishcaster. Someone who always goes against the models is a wishcaster. Someone who insists that they can tell you where a storm is going 2 weeks out is arrogant.

Personally I don't think there are any forecasters here, only data interpreters.

Forecasting is like weather, you need to be very fluid, and sometimes people just get too rigid when trying to forecast, or geusscast.


Someome who noncasts as you call it is smart.

Anywho, off to work y'all.

Member Since: August 17, 2005 Posts: 26 Comments: 16607
572. Tazmanian
10:04 PM PDT on May 02, 2007
Crisis57 ok will talk more on thusday ok come by my blog some times ok
Member Since: May 21, 2006 Posts: 5091 Comments: 115129
571. Crisis57
5:03 AM GMT on May 03, 2007
good night TAZ take it easy
Member Since: Posts: Comments:
570. lightning10
10:01 PM PDT on May 02, 2007
I am late to the party but one reason LA has such bad air is that its one of the few citys from about May-October its not that unlikely to have no rain and little wind.
Member Since: Posts: Comments:
569. Tazmanian
9:58 PM PDT on May 02, 2007
Crisis57 well good night we sould get some sleep now at this point its now looking good
Member Since: May 21, 2006 Posts: 5091 Comments: 115129
568. Tazmanian
9:54 PM PDT on May 02, 2007
well has of now i think are Bermuda High is seting up shop and it looks like it is not moveing any time soon bad news for FL
Member Since: May 21, 2006 Posts: 5091 Comments: 115129
567. Crisis57
4:54 AM GMT on May 03, 2007
yea Taz as hard as it is for me to say your right
Member Since: Posts: Comments:
566. Tazmanian
9:52 PM PDT on May 02, 2007
well time for me to say good night lol
Member Since: May 21, 2006 Posts: 5091 Comments: 115129
565. Tazmanian
9:51 PM PDT on May 02, 2007
FL is going to take a hard hit this year i can this tell
Member Since: May 21, 2006 Posts: 5091 Comments: 115129
564. Tazmanian
9:49 PM PDT on May 02, 2007
: StoryOfTheCane i am going with you on that bet of $100 bucks
Member Since: May 21, 2006 Posts: 5091 Comments: 115129
563. Crisis57
4:47 AM GMT on May 03, 2007
i truly hope your wrong because we here in south florida truly don't need anymore
Member Since: Posts: Comments:
562. StoryOfTheCane
4:40 AM GMT on May 03, 2007
its anybody's guess but if I had to bet I would bet $100 bucks its going to be a rough year for the U.S. coastline, I hope Im wrong



Member Since: Posts: Comments:
561. StoryOfTheCane
4:39 AM GMT on May 03, 2007
the high is definitely holding its own, east coast troughs dont seem to be phasing it at all like they were last year, they are weaker and further north
Member Since: Posts: Comments:
560. Crisis57
4:35 AM GMT on May 03, 2007
I agree with you Story so far this season looks to shape up to be a busy one, Anyone know when it would be a good time to start investigating the Bermuda High and its location since right now may be to early
Member Since: Posts: Comments:
559. StoryOfTheCane
4:11 AM GMT on May 03, 2007
i personally don't even like the labels but I might as well clarify them since they are getting thrown around so much lately, I have been victimized myself many times
Member Since: Posts: Comments:
558. StoryOfTheCane
4:06 AM GMT on May 03, 2007
yeah, this is more impressive than most of the waves we saw in September of last year. Once SSTs rise and Shear falls we'll be seeing Verde storms like hotcakes

Member Since: Posts: Comments:
557. KEEPEROFTHEGATE (Mod)
4:01 AM GMT on May 03, 2007
nie little bubble just leaving west africa lets see if it will pop
Member Since: Posts: Comments:
556. StoryOfTheCane
4:04 AM GMT on May 03, 2007
Posted By: hornfan at 3:53 AM GMT on May 03, 2007.
i think it just applies to what you say on this blog

Hmmm - applies to what

Posted By: StoryOfTheCane at 3:56 AM GMT on May 03, 2007.
what you are classified under.



Thats what I was answering. I now see I didn't do it very well. If you warn your friends that there is going to be something coming before the NHC does you are a "wishcaster", you are basing it off of what NHC says you are a "noncaster"
Member Since: Posts: Comments:
555. StoryOfTheCane
4:02 AM GMT on May 03, 2007
a lot of us are "wishcasters", a select few of us like StormTop are "crazycasters", Story out
Member Since: Posts: Comments:
554. StoryOfTheCane
4:00 AM GMT on May 03, 2007
we need to for sure begin the implementation of "Crazycaster" into the blog dictionary.
Member Since: Posts: Comments:
553. hornfan
4:00 AM GMT on May 03, 2007
what you are classified under

That was not a question - because I don't care
Member Since: Posts: Comments:
552. Bamatracker
4:00 AM GMT on May 03, 2007
alright..im out for the evening. Somebody give me a call if anything develops!!! LOL
Member Since: May 17, 2006 Posts: 6 Comments: 1367
551. StoryOfTheCane
3:59 AM GMT on May 03, 2007
yeah its pretty entertaining lol
Member Since: Posts: Comments:
550. Bamatracker
3:59 AM GMT on May 03, 2007
hey hey.......no need to use the e-word
Member Since: May 17, 2006 Posts: 6 Comments: 1367
549. Bamatracker
3:57 AM GMT on May 03, 2007
i think ill just laugh at the fights between the different caster groups
Member Since: May 17, 2006 Posts: 6 Comments: 1367
548. StoryOfTheCane
3:56 AM GMT on May 03, 2007
youll see it when the season starts, people are so sensitive in here if you even mention the word "eye" they all freak out
Member Since: Posts: Comments:
547. Bamatracker
3:56 AM GMT on May 03, 2007
now im just confused
Member Since: May 17, 2006 Posts: 6 Comments: 1367
546. StoryOfTheCane
3:55 AM GMT on May 03, 2007
what you are classified under. the funny thing about it is that only the "Noncasters" tend to label anyone a "Wishcaster", when they should be only labelling "Crazycasters"
Member Since: Posts: Comments:
545. hornfan
3:52 AM GMT on May 03, 2007
i think it just applies to what you say on this blog

Hmmm - applies to what
Member Since: Posts: Comments:
544. StoryOfTheCane
3:48 AM GMT on May 03, 2007
i think it just applies to what you say on this blog
Member Since: Posts: Comments:
543. hornfan
3:46 AM GMT on May 03, 2007
What about the caster that listen to the information, digests the information and chooses not the make a forecast but warns all his friends?
Member Since: Posts: Comments:
542. Bamatracker
3:46 AM GMT on May 03, 2007
but they fit the critera of the other categories
Member Since: May 17, 2006 Posts: 6 Comments: 1367
541. Bamatracker
3:46 AM GMT on May 03, 2007
ok...they make this decision when conditions arent favoriable.
Member Since: May 17, 2006 Posts: 6 Comments: 1367
540. StoryOfTheCane
3:45 AM GMT on May 03, 2007
Posted By: Bamatracker at 3:44 AM GMT on May 03, 2007.
so what would you call someone who predicts major big storms that never hit land while using only nhc info as the bases of their prediction?


Noncaster - they are only basing it off of NHC predictions. They arent making their own predictions.
Member Since: Posts: Comments:
539. StoryOfTheCane
3:43 AM GMT on May 03, 2007
ok, here is a revised list of types of people on the blog:

Wishcaster - Takes an early approach at predicting formation.

Hatecaster - Never thinks a storm will develop.

Noncaster - Never predicts formation. Relays NHC information.

Crazycaster - Predicts formation when conditions are unfavorable.
Member Since: Posts: Comments:
538. Bamatracker
3:40 AM GMT on May 03, 2007
so what would you call someone who predicts major big storms that never hit land while using only nhc info as the bases of their prediction?
Member Since: May 17, 2006 Posts: 6 Comments: 1367

Viewing: 588 - 538

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

Overcast
69 °F
Overcast