Ground-level Ozone

dms1972

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Hi there, need a little help on this from someone who has background in chemistry or studying air condition.

Would large reductions in road traffic (by half to three quarters) be likely to result in higher levels of Ground Level Ozone?

Would those higher levels balance out eventually, or become problematic?

Its being looked at here in the UK because of the Lockdown. A couple of area including the where i live are showing higher levels of NO2 compared to the five year average, whilst most areas have showed a decline in NO2.

While the NO2 levels in a couple of areas may present an anomaly, what about the possibility of higher levels of Ground level Ozone?

Lockdown prompts clear fall in UK air pollution

The following paragraph in particular:

"It's possible ozone, another respiratory irritant, could climb in city centres. Its formation at ground level is dependent on some very complex chemical reactions which, in the absence of certain exhaust gases, might actually give a boost to the three-oxygen molecule in the air."


I have noticed a definite change in air quality where I live, but its also slightly more irritant I think, could that be because of higher levels of Ozone at ground levels, and what would likely happen, would that balance out or continue to increase during a lockdown?
 
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essentialsaltes

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Hi there, need a little help on this from someone who has background in chemistry or studying air condition.

Would large reductions in road traffic (by half to three quarters) be likely to result in higher levels of Ground Level Ozone?

I would imagine the opposite. EPA:

Tropospheric, or ground level ozone, is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC). This happens when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources chemically react in the presence of sunlight.

Ozone is most likely to reach unhealthy levels on hot sunny days in urban environments, but can still reach high levels during colder months. Ozone can also be transported long distances by wind, so even rural areas can experience high ozone levels.


But from your source:
"It's possible ozone, another respiratory irritant, could climb in city centres. Its formation at ground level is dependent on some very complex chemical reactions which, in the absence of certain exhaust gases, might actually give a boost to the three-oxygen molecule in the air."

I don't know enough to state categorically that this possibility is absurd. It seems unlikely to me, but I am not the expert you're looking for.
 
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Ophiolite

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I also am no expert, but I did locate this paper on pollution in Beijing. It contains this observation:
"The correlation at the PKU site indicated clearly that ozone formation at this site was a VOC controlled process; abatement of VOCs would effectively result in a drop in peak ozone levels. However, a reduction in NOx emissions would lead to an increase in ozone."

VOCs = Volatile Organic Compounds

I would have thought that VOCs would also fall with reduced traffic and industrial activity, but clearly there are at least some circumstances in which a fall in NOx may correlate with an increase in ozone. References in the paper may lead you on to other possibilities, or check papers that have cited this one.
 
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dms1972

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I also am no expert, but I did locate this paper on pollution in Beijing. It contains this observation:
"The correlation at the PKU site indicated clearly that ozone formation at this site was a VOC controlled process; abatement of VOCs would effectively result in a drop in peak ozone levels. However, a reduction in NOx emissions would lead to an increase in ozone."

VOCs = Volatile Organic Compounds

I would have thought that VOCs would also fall with reduced traffic and industrial activity, but clearly there are at least some circumstances in which a fall in NOx may correlate with an increase in ozone. References in the paper may lead you on to other possibilities, or check papers that have cited this one.

Yeah, I think its very complex chemistry, and when was the last lockdown, so I think this is a golden opportunity in a way for them to get in as much study as possible, so I hope they are taking it, but I also hope levels of ozone are not getting too high - because for days I was wondering what was up with my airways - I am not asthmatic that I am aware - I am not having trouble taking in breaths but I am aware of a change in the air quality, and it is affecting my lungs a bit. I wonder if many people are experiencing that?

It used to be thought Ozone came off the sea and was good for you but i have learned recently its actually Dimethyl Sulphide that gives sea air the bracing quality, not ozone. I don't know when that was first discovered, or if it is widely known. Ozone on the contrary is not known to have any direct health benefits, although it does deoderise and is used sometimes for car valetting. It may also kill germs, because ozone (sometimes called trioxygen) has three oxygen atoms, and the third one sometimes breaks off and attaches to viruses and can kill them - nice - but the concentration of ozone needed to kill viruses can also damage the lining in ones lungs - so I believe that is why Ozone machines are banned in some US states.

Also sometime when my laptop fan starts going, its almost as if there is something from the computer affecting me a bit. I know photocopiers and some other equipment give off ozone, never had thought about it in regard to my laptop though???

Any thoughts on that anyone?
 
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Ophiolite

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It used to be thought Ozone came off the sea and was good for you but i have learned recently its actually Dimethyl Sulphide that gives sea air the bracing quality, not ozone. I don't know when that was first discovered. Ozone on the contrary is not known to have any health benefits.
Interesting. I didn't know that. I had long heard the same tale of seaside ozone - I lived by the sea throughout my childhood. While I was looking for the material posted earlier I did ask myself "how come we get ozone from the sea", but I made no effort to answer the question. Now you have provided the answer.

Also sometime when my laptop fan starts going, its almost as if there is something from the computer affecting me a bit. I know photocopiers and some other equipment give off ozone, never had thought about it in regard to my laptop though???
Possibilities:
  • Coincidence
  • Imagination
  • Problem fan frequency (think nails scratching on a blackboard, but working subconsciously)
  • Ozone, as you suspect
  • Other chemicals given off by components in the laptop
  • Etc.
An article on the dimethyl-sulphide you mentioned: Ozone Smell at the Seaside › News in Science (ABC Science)
 
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dms1972

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Interesting. I didn't know that. I had long heard the same tale of seaside ozone - I lived by the sea throughout my childhood. While I was looking for the material posted earlier I did ask myself "how come we get ozone from the sea", but I made no effort to answer the question. Now you have provided the answer.


Possibilities:
  • Coincidence
  • Imagination
  • Problem fan frequency (think nails scratching on a blackboard, but working subconsciously)
  • Ozone, as you suspect
  • Other chemicals given off by components in the laptop
  • Etc.
An article on the dimethyl-sulphide you mentioned: Ozone Smell at the Seaside › News in Science (ABC Science)

Yes that is the article and another one I was reading yesterday.




:) Thanks had not thought of the fan frequency one.
 
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sjastro

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Also sometime when my laptop fan starts going, its almost as if there is something from the computer affecting me a bit. I know photocopiers and some other equipment give off ozone, never had thought about it in regard to my laptop though???

Any thoughts on that anyone?

Definitely not ozone but more likely volatiles.
The Japanese have a standard for the emission rates of volatiles from computers.
1.jpg

A study of Toluene, Xylene, and Styrene emissions from various components from Desktops revealed the following.
2.jpg
 
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