What would a well ventilated port city such as Honolulu, Hawaii, USA have for the concentrations (in parts per million) of CO2 or NOx, compared to a city like Linfen, China which is the site of a large coal industry?

By how much would concentration change between different regions in the same city? That is, what range of concentrations are we looking at when it comes to NO2, for example? Feel free to post information on other gasses such as O3 and general pollutants.

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    While this is borderline OK on Chem (borderline because it's not really asking anything conceptual in chemistry terms), I'll migrate this to Sustainable Living as it seems to be a better platform for this question. – Manishearth Jul 2 '13 at 3:47
  • Note to self or others answering: see Jacobson on urban dome effect for CO2 – EnergyNumbers Jul 4 '13 at 9:19
  • @EnergyNumbers, the small amount of research I've done seems to show that the most comprehensive (free) collection of data that addresses this question (at least the CO2 part) is found at co2science.org, run by the Drs Idso. While they publish lots of conclusions about CO2 levels, and climate change, that I find bogus, it's not clear to me that the data on their site, most of which was collected by other scientists, is invalid, or has been massaged in any way. But, I'm not in academia either. Do you have an opinion on this? – Nate Jul 4 '13 at 21:50
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    @Nate IMO: Not a reliable source, and not a trustworthy conveyer of data; if it's referenced, then go to the original source. If it's not, then ignore it. So either way, no need to cite cranks. – EnergyNumbers Jul 5 '13 at 11:08
  • acrobotic.com/smart-citizen might be worth watching, it's an attempt to get this data in an open-source way. Cheap compared to the alternatives, and the dataset should start being useful by the end of the year. – Móż Jul 14 '13 at 22:42


Don't have time to fully address this now, but here's an interesting plot of results from Boston, USA:

BU CO2 Plot

As you can see from this graph, CO2 levels can vary quite a bit over time simply within one city.

You can see a seasonal amplitude of +/- ~12 ppm that's due to plant photosynthesis speeding up (reducing CO2) in summer, and slowing down (allowing CO2 to increase) in winter.

Based on this, you can imagine that areas with different levels of sun or vegetation would then also experience different average CO2 levels as well. From the previous web page:

The CO2 concentration level in Boston is almost always several ppm higher than the global average, because cities, with their buildings and vehicles burning natural gas, gasoline, and oil, are relatively large sources of CO2. For example, in May 2011 the monthly average CO2 level at Mauna Loa was 394 ppm; at BU (Boston University), it was 405.

NOAA CarbonTracker

Because it's displaying CO2 1 to 5 km above the ground, it's going to smooth out the variations due to local forests, or power plants. But, you certainly can see areas of high CO2 concentration over eastern Europe / Black Sea (downwind from central Europe) and also China / Korea / Japan (downwind from China's industrial hubs).


The US Environmental Protection Agency has a report on NOx here (see page 6 for a US "heat map" of local NOx concentrations).

This University of Washington report also contains a global NOx map, for both surface and 5km altitudes (page 10).

  • Thank you so much! Would it be OK if I leave the answer open so that other people can post other gasses, besides the ones mentioned? – stackOverFlew Jul 13 '13 at 6:16
  • @stackOverFlew, yes, absolutely. I planned on coming back tomorrow and expanding on my answer as well. I have some more sources that address your answer more directly than what I've already written. But, certainly, feel free to wait until you get a more complete answer before accepting. – Nate Jul 13 '13 at 8:08

The Vulcan Project at the University of Arizona provides GHG emissions by geography and source.


We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

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    Welcome to Sustainable Living! The link you've posted does look interesting, but just the link doesn't really answer the OPs question. Would it be possible to compile an answer? – THelper Mar 3 '14 at 19:54

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