Could we forecast smog???

[Storm Struck]

It occured to me on Friday night while crizing into town that the amount of smog was very high infact so thick in places it was hard to see in front of you aspecially on the northern motorway.
Iam guessing that the lower lying smog which can be thick would occur around the outskirts of the city where it's more exposed like pockets of fog or frost for example.
But the question is could we forecast Smog? we certainly can't forecast how many people will use thier fires in one night but we can get to know that when winter night's are calm with not much wind EG (high dominant situations where there are no winds overnight and frosts possible).
Because to me it seems it's going to be awhile for technology to evolve where we can drive more polution free cars or evolve away from fires.
So will we have to walk or bike to work in the near furture brrr i hope not it seems to me the bigger our population gets the more gas emissions we are going to let off.
So really could we forecast smog so that people know to be cautous in areas where it may be thick we obvoiusly can't prevent it but we might be able to forecast it.
What do others think
Cheers
JASON

[NZstorm]

To make sure we are refering to the same thing, smog is air pollution mixed with fog. As I understand it, the carbon acts as a condensation nuclei making the fog more persistent.

I guess anytime fog looks likely during the colder winter months, smog is possible.

Auckland has an air conditioning system that works most winter days (Tasman sea westerlies) which blows all of our air pollution away.


Photo of air pollution over Auckland within a winter anticyclone.

[03Stormchaser]

smog in chch is usualy associsted with a lack of wind and a frost. When theres a frost theres smog!

This silent, 25-second video (it's a big file - 3.5 MB) clearly shows Christchurch's major winter air quality issue: solid fuel heating.
Video footage was taken from a point above the "smog zone" on the Port Hills.

http://www.ecan.govt.nz/Our+Environment ... -video.htm

[jeffsweather]

But the question is could we forecast Smog? we certainly can't forecast how many people will use thier fires in one night but we can get to know that when winter night's are calm with not much wind EG (high dominant situations where there are no winds overnight and frosts possible).
Cheers
JASON

Ecan has a smog forecast but its just general.
http://www.ecan.govt.nz/Our+Environment ... recast.htm
The risk for Ch'ch tonight is low but now with clear sky and frost forecast, I think its probably wrong. I'm assuming that they base this forecast on info from Metservice and perhaps their weather monitoring if they have any.
Ch'ch PM10 graphs are here
http://www.ecan.govt.nz/Our%20Environme ... te_no=9722

[03Stormchaser]

looking at that 4 days all ready over!! and we havent really had a frost yet this year! not very good!

[TonyT]

Ecan has a smog forecast but its just general.
http://www.ecan.govt.nz/Our+Environment ... recast.htm
The risk for Ch'ch tonight is low but now with clear sky and frost forecast, I think its probably wrong. I'm assuming that they base this forecast on info from Metservice and perhaps their weather monitoring if they have any.
Ch'ch PM10 graphs are here
http://www.ecan.govt.nz/Our%20Environme ... te_no=9722

No, we do it for Ecan. We like to think we know a bit about local weather conditions We have been doing this forecast for about ten years now. The relationship between smog level and weather parameters works well at a general level, but not at all well in detail. Thats why its a general forecast. We and Ecan did a lot of analysis a few years ago and found that the best indicator of whether there would be an exceedance of the guideline (which is 50micrograms of PM10 per cubic metre of air over a 24 hour period (9am to 9am) ) is at least four consecutive hours of inversion and light winds (less than 2m/s) during the evening between 4pm and midnight. We issue the forecast around 8am each morning, and have the option to update it during the day if conditions (or our opinions of them!) change.

So the forecast (over three categories, low risk, medium risk, high risk) is actually a forecast of the likelihood of getting the four hours in the time period specified. Even so, the relationship is not perfect - a 50mg average over 24 hours can be obtained with fewer than 4 hours during the evening, if, for example, levels are very high the following morning. Conversely, a few nights with more than four hours can end up under 50mg if, for example, a NW starts up mid evening. So the relationship between 4 hours and the 50mg is not perfect, but it does seem to produce the best results overall. For the last few years we have averaged around 75-85% accuracy. Thats driven largely by the number of low nights, which are usually fairly easy to predict. High nights are harder, and we seem to average around 65% for those - ie 2 out of every three high nights we predict as high, but about 1 in three sneak up on us, usually on nights when we are unsure and have issued a medium forecast.

As for tonight, experience shows that a dying SW wind drops out rather slowly if the flow is more S than SW as has been the case today, plus the inversion doesnt form as quickly or strongly when there is moisture around. The showers have cleared late enough and the flow stayed strong enough through the afternoon to make me think that the inversion wont become well established until later in the night. Thats the way I saw it at 8am, and I had no reason to want to change it at 4pm. Yes, I too expect a frost in the morning but I dont expect four consecutive hours of inversion and no wind before midnight, hence the low risk forecast. I did go for medium risk for Timaru, on the basis they would be nearer the ridge and have the wind drop out earlier, and have had a few extra hours for the ground to dry out prior to sunet.

So you see, there is quite a bit of thought that goes into it, and its a frustrating forecast to make because of the imperfection in the relationship so that sometimes we call the weather right, but the smog outcome doesnt quite work.

[TonyT]

It occured to me on Friday night while crizing into town that the amount of smog was very high infact so thick in places it was hard to see in front of you aspecially on the northern motorway.
Iam guessing that the lower lying smog which can be thick would occur around the outskirts of the city where it's more exposed like pockets of fog or frost for example.
But the question is could we forecast Smog? we certainly can't forecast how many people will use thier fires in one night but we can get to know that when winter night's are calm with not much wind EG (high dominant situations where there are no winds overnight and frosts possible).
Because to me it seems it's going to be awhile for technology to evolve where we can drive more polution free cars or evolve away from fires.
So will we have to walk or bike to work in the near furture brrr i hope not it seems to me the bigger our population gets the more gas emissions we are going to let off.
So really could we forecast smog so that people know to be cautous in areas where it may be thick we obvoiusly can't prevent it but we might be able to forecast it.
What do others think
Cheers
JASON

The thinking behind Ecan's forecast is twofold - firstly to highlight potentially high nights and encourage people to use clean heating on those nights in an effort to reduce overall smog levels; and secondly to provide a warning to people with asthma, emphasema, and similar bronchial complaints that high levels are likely, so they tend to stay inside. There are people who actually leave the city for the night on high pollution nights because the PM10 levels can get so uncomfortable, or even medically dangerous, for them.

Actually forecasting smog levels is quite difficult, because the relationship between actual PM10 levels and weather parameters is quite varied - two nights with identical weather conditions can have rather different PM10 levels, and vice versa. It is somewhat easier to forecast just the weather conditions and hope the smog levels follow.

The worst days are those winter NW days when a NW arch (7/8ths of AltoStratus for you non-Cantabrians) develops around or soon after dawn, and the overnight inversion hangs around till mid morning, or worst case, mid afternoon. Wind is non-existent, so is solar radiation, so all the morning pollution from people reviving their fires, as well as all the transport pollution from people driving to work, gets trapped under the inversion, which goes nowhere (ie it doesnt rise, nor does it break up). That can give Pm10 readings of 100-200mg/m3 through the daylight hours, which is higher than many night time readings. That can often give a 24 hour reading above the 50mg guideline, even if the evening levels are not too high.

[TonyT]

To make sure we are refering to the same thing, smog is air pollution mixed with fog. As I understand it, the carbon acts as a condensation nuclei making the fog more persistent.

Thats the popular definition, but in Christchurch there seems to be very little fog component to the classic winter pollution which everyone calls smog. On high smog nights there is often fog around the rivers and streams, but not elsewhere, and little if any mixing of the fog which stays close to ground level. Mind you, the pollution stays close to ground too, the mixing height is typically 30m or less. You can go to the top of some of the tall buildings and be above the smog layer!

In the photo you have of Auckland the boundary layer is relatively high (in comparison to Chch) as it looks to be a bit above the top of the sky tower. In Chch, on most days when there is enough radiation to lift the boundary layer to that height there is also a light NE breeze starting to develop and the inversion starts to break up, allowing the polluted layer to "escape".

However, there is an interesting phenonmenon, which occurs on a few days with totally calm clear mornings. The inversion starts out low, so the tops of the tall buildings are sticking out the top in clear air, with white looking air beneath. As the morning goes on the layer gets deeper as solar radiation heats the surface so the top of the inversion layer rises, but with no wind the inversion layer doesnt break up. The smog goes brown (photochemical effect on the nitrous oxides from the morning vehicle pollution) and rises up the Port Hills. When the inversion reaches the top of the Port Hills this brown smelly air spills over the hills and rolls down the other side into Lyttelton. So Lyttelton, which has generally been fairly clear all morning, suddenly gets a dose of badly polluted air between 11am and noon.

[NZ Thunderstorm Soc]

To me smog is ugly weather , like Michael and SW gales and the persistence of weather.
I try to avoid it and discussion on it.
I don't think we are as smoggy as what we we years ago.
The fifties were the worst in Christchurch with the Gas Works, Steam trains ( those Sunday Linwood light-ups), people smoking everywhere?
Coal fires, etc

JohnGaul
NZTS

[Gary Roberts]

To me smog is ugly weather , like Michael and SW gales and the persistence of weather.
I try to avoid it and discussion on it.
I don't think we are as smoggy as what we we years ago.
The fifties were the worst in Christchurch with the Gas Works, Steam trains ( those Sunday Linwood light-ups), people smoking everywhere?
Coal fires, etc

JohnGaul
NZTS

I remember Auckland in the '70s John, with no pollution controls and more heavy industry. There'd be so much crap flying out of factory chimneys at night (when nobody could see them doing it) that the houses would be covered with a kind of sooty ash in the morning. Across the road from one of my old schools, the Reid Rubber plant (now extinct) had two big stacks belching stuff day-in-day-out. All that is gone now...

...and has been replaced by internal-combustion engine emissions. Lots and lots of it. From Rangitoto, the murky brown layer so clearly visible in that photo is very obvious, hanging over the city like a shroud. I'd look at it and think about the fact that I was breathing it in 24/7. So I left.

Pollution is pollution, and bloody horrible it is too.

[NZstorm]

I'd look at it and think about the fact that I was breathing it in 24/7. So I left.

Auckland is a breezy place, so air pollution is not much of a problem here. Only in the big winter anticyclones. I think many small rural towns in NZ that burn fuel every night for there heating have much worse air pollution problems than Auckland.

[Andy]

I would think that Alexandra has some of the highest levels of air pollution in New Zealand

[TonyT]

To follow up with the outcome from last night:

In Timaru the weather conditions criteria were met but the 24 hour PM10 value stayed below the guideline at 21mg/m3, so our forecast of medium risk was a good one.

In Christchurch, the reverse happened, the weather conditions criteria were not met due to some 2m/s breeze between 7pm and 9pm, but the 24 hour PM10 value breached the guideline and came out at 67mg/m3, with most of that Pm10 coming in after midnight, when the wind dropped to calm. I consider that a good result for our forecast as we correctly predicted the evening weather conditions, but a medium risk forecast would have better reflected the overall outcome.

Just to clarify - PM10 is measured in micrograms per cubic metre, which I write on here as mg/m3, so please dont think I mean milligrams per cubic metre (we would all be dead with lungs full of black stuff if we had had a night with 67 milligrams of PM10/m3!).

[Gary Roberts]

To follow up with the outcome from last night:

In Timaru the weather conditions criteria were met but the 24 hour PM10 value stayed below the guideline at 21mg/m3, so our forecast of medium risk was a good one.

In Christchurch, the reverse happened, the weather conditions criteria were not met due to some 2m/s breeze between 7pm and 9pm, but the 24 hour PM10 value breached the guideline and came out at 67mg/m3, with most of that Pm10 coming in after midnight, when the wind dropped to calm. I consider that a good result for our forecast as we correctly predicted the evening weather conditions, but a medium risk forecast would have better reflected the overall outcome.

Just to clarify - PM10 is measured in micrograms per cubic metre, which I write on here as mg/m3, so please dont think I mean milligrams per cubic metre (we would all be dead with lungs full of black stuff if we had had a night with 67 milligrams of PM10/m3!).

Righto, but how does it relate to PMS?

[TonyT]

Perhaps a bit of clarification would be helpful. PM10 is Particulate Matter 10 microns or smaller in size. In other words, bits of stuff which are floating around in the air and 10 thousandths of a millimetre long.

There are natural sources of PM10 like soil dust and salt particles over the ocean, but most PM10 is man made, the carbon byproducts of combustion (ie smoke). High levels of PM10 have been linked to many health issues, including asthma, emphysema etc and the complications which arise from them (eg heart attacks, lung cancer etc).

Just to drive the point home, PM10 is the black stuff you see in pictures of the lungs of people who have died from smoking.

[Gary Roberts]

Perhaps a bit of clarification would be helpful. PM10 is Particulate Matter 10 microns or smaller in size. In other words, bits of stuff which are floating around in the air and 10 thousandths of a millimetre long.

There are natural sources of PM10 like soil dust and salt particles over the ocean, but most PM10 is man made, the carbon byproducts of combustion (ie smoke). High levels of PM10 have been linked to many health issues, including asthma, emphysema etc and the complications which arise from them (eg heart attacks, lung cancer etc).

Just to drive the point home, PM10 is the black stuff you see in pictures of the lungs of people who have died from smoking.

What are these "airborne particles" of which you speak?

A quote from a NIWA scientist's e-mail to me:

"What we do know about the...site from lidar observations of the aersol concentration in the lower boundary layer is that [it] has the lowest measured aersol concentrations in the world, even better, surprisingly, than Mauna Loa, where equivalent measurements are made in Hawaii. We believe this is an unusual combination of air that is "cleansed" through the predominanly SW Alpine flow, but having a humidity that is still high enough to remove aerosols by wet deposition."

[Manukau heads obs]

here is an article on Londons worse smog period:
http://www.npr.org/templates/story/stor ... yId=873954

where 1000s died

for interest

[Willoughby]

On the topic... Marion Hobbs is set to virtually outlaw air pollution

Hobbs ready to clear New Zealand's air
11 May 2005
By JOANNA NORRIS

Environment Minister Marian Hobbs is poised to effectively outlaw pollution, despite fears the move will stymie economic growth in Christchurch, Timaru, Nelson and Auckland and push smog elsewhere.

Hobbs is preparing to sign off the tough new national air-quality standards, an act which will dash the hopes of regional councils calling for last-minute changes.

Under the proposed rules, businesses, schools and hospitals in Christchurch, Timaru, Nelson and Alexandra will be unable to get new resource consents for heating or industry, unless householders drastically reduce pollution from fires and woodburners. Auckland – where vehicles cause heavy pollution – will also be affected.

Hobbs yesterday met ministry officials to discuss the rules, and last night confirmed she wanted a gradual reduction of smog levels, as required by the proposed standards.

Under the standards, which are proposed to come into effect on October 1, polluted regions must reduce smog incrementally every year until 2013 by drawing a straight line between current smog levels and the target. In any given year, levels must not go above that line.

Hobbs said she did not want to allow regions to leave the smog problem until 2013 because it was too hard.

However, she said last-minute tweaking by officials might give councils some flexibility.

One option being considered was to allow industries and organisations the option of proving they could reduce smog levels in other areas in order to allow them to renew their existing consents. They would not, however, be able to renew their consent if pollution was not reduced elsewhere.

"I really do want this issue tackled," Hobbs said. "I do not want it to be impossible to apply, but I absolutely want to see movement that is gradual, does not leave it all until the end, and is measurable."

The changes will be sent to regional councils for comment and a decision made within a few weeks.

If she does approve the straight line-rule, the Christchurch City Council could be the first significant consent holder to face problems. The council will be unable to legally heat its Tuam Street offices after November, when consents for its coal-fired boilers expire.

Several Canterbury schools – including Waimairi, Aorangi and Isleworth – are also due to renew their consents soon after the standards come into force, as is Fulton Hogan in Timaru.

Environment Canterbury (ECan) chairman Sir Kerry Burke yesterday confirmed the council would not be able to issue discharge consents to those organisations, which in turn would break the law if they fired up their boilers.

"How would they provide their energy source if they've got a boiler? Illegally, because they haven't got a consent."

Canterbury Manufacturers Association chief executive John Walley said the introduction of the standards would be "a black day for economic development in Christchurch".

"We can't add a single new emitter without taking one away. The industry goes, the jobs go," he said.

The move would push industry into places "that don't have the same problems as Christchurch".

Smog in Christchurch and Timaru exceeds national guidelines on average 30 times every winter – 30 times the national standard – often by more than twice the acceptable limit.

ECan has spent the past eight years and at least $8 million trying to regulate smog through its air plan, which is still not operative due to political and legal hiccups.

Christchurch City Councillor Anna Crighton said if the city council boilers were shut down, the council's energy bills would skyrocket. She planned to table a motion at tomorrow's council meeting calling on it to consider other forms of heating

-The Press/Fairfax

[Michael]

People will get more work done in a showery wet windy place rather than going to the beach all day

On the topic... Marion Hobbs is set to virtually outlaw air pollution

Hobbs ready to clear New Zealand's air
11 May 2005
By JOANNA NORRIS

"We can't add a single new emitter without taking one away. The industry goes, the jobs go," he said.

The move would push industry into places "that don't have the same problems as Christchurch".

-The Press/Fairfax