8

The data that you are having are called emission fluxes. If these data are available as global averages then one can calculate global mean concentration by multiplying the residence time of the species with emission flux. However, at the city or grid level, it is not straightforward to calculate concentration from emission fluxes. In order to calculate, ...


7

My guess would be a combination of boundary layer, cloud cover, and emissions (though that isn't terribly specific). Smog is a combination of nitrogen oxides (which cause smog's brown color), ozone, and particulate matter. These in turn form from emissions of hydrocarbons and nitrogen oxides from vehicles and industrial combustion. If those emissions are ...


6

I think it is important to keep in mind the mechanisms that form PM$_{2.5}$ are different than the mechanisms that form O$_3$. From the data your provided you can draw some simple conclusions: Increasing SO$_2$ increases PM$_{2.5}$ Increasing NO$_2$ increases PM$_{2.5}$ Increasing NO$_2$ doesn't necessarily increase O$_{3}$ The last point is what you ...


6

The difference between advection and convection in Chemistry Transport models (CTMs) is a question of scale: Advection is driven by winds that are provided by the meteorological input dataset. Thus, the wind is resolved in the meteorological data. Convection is driven by sub grid processes (e.g. temperature gradients) and is paramterized in CTMs. See for ...


5

This is a topic of almost continual discussion in the South China Morning Post, scmp.com , an English language newspaper in Hong Kong. This is both because air quality is a major problem in China (but one to which they are paying a good deal of attention) and because massive economic interruptions are relatively frequent. The Olympics were a big one, ...


5

The first thing to do is to stop putting pollution in the air, particularly very small particulate matter that are produced by combustion. For the Beijing Olympic Games of 2008, the Chinese government forced the polluting plants and factories in the vicinity of Beijing and nearby areas to stop operating for weeks prior to the games and during the games to ...


5

The AQI calculation does not require that all pollutants be measured. Instead, it uses the pollutants that are available and then uses a function (chosen by the overarching regulatory agency) that equates health risk categories to the pollutant concentrations. The pollutant with the highest health risk (at present concentrations) will effectively determine ...


4

In order to put your question in perspective, you need to consider atmospheric mixing and the size of the system you are curious about. The troposphere is several kilometers thick and the mixed layer of atmosphere above the ground can occupy a significant fraction of the troposphere. Granted, during cold events, the temperature of the air can be so cold ...


4

Provide a monthly average in every grid cell, and describe how many measurements were used for each cell. There is no fixed rule for the minimum number of days for reporting a monthly average. A reasonable threshold will depend on the geophysical quantity of interest y, in particular on how much y varies on short and long timescales. If y varies from ...


4

The hydroxyl radical chemistry is not modeled explicitly in air quality models, so numerical stability is not an issue. Instead, OH is held in pseudo-steady-state. For instance, see CMAQ's documentation which states: In CMAQ's gas phase, OH is assumed to be in pseudo-steady state, and it is not a transported species. This is because hydroxyl radical ...


4

Ozone is most closely correlated to temperature. Yes you need NOx and VOCs to create ozone, but you also need enough photolysis driven by sunlight in order for ozone to form. The day analyzed in the question is during the middle of winter, which generally does not have enough sunlight to allow ozone to build up in the atmosphere. Furthermore, when there ...


4

NO2 uptake by plants It has been observed that plants can lead to a reduction of atmospheric NO2 concentrations [Breuninger et al, 2013]. Currently, it is assumed that NO2 is taken up through stomata of plant leaves when the atmospheric NO2 concentrations are above a certain threshold. However, when the atmospheric NO2 concentrations are below this ...


3

In fact, there are many chemical transport models which solve the radical chemistry without steady-state approximations. The equations are very stiff but can be integrated with suitable methods, usually implicit. Some approaches are discussed in this review. The Kinetic Preprocessor, mentioned in the comment, includes a set solvers for stiff systems and has ...


3

I add some information here to present the control strategies which have been done by China government. A series of paper have reported that coal combustion is the main cause of the air pollution in China. This issue usually gets worse in the winter months due to the fact that coal is used for domestic heating. In the winter of 2017, China ...


3

In addition to satellite measurements of carbon dioxide, there are numerous ground based stations that also measure carbon dioxide: Italy, Hawaii, Australia, just to name a few. If you want to catch carbon dioxide emitting cheaters, a dense network of such ground based stations would be needed around the world. The measurements would need to combined with ...


3

Evergreen trees grow faster than most hardwood deciduous trees, so their absorption and oxygen emission is greater. Note that trees do not "clean" air. Plants emit oxygen which is why air in a house with lots of plants will seem more fresh. In the global environment algae and other primitive organics are primarily responsible for converting CO2 to ...


3

You mention "volume" which is the crux of the problem: the surface mixing layer changes height throughout the day as solar heating influences the surface. Consider that the same emission rate can cause different concentrations at different heights and at different times of day and year. Meteorology drives all mixing and deposition, so whatever ...


2

I'll add to Freds answer and just provide some detail about the satellite measurements: The keyword you're looking for is "remote sensing of the atmosphere" or "remote sensing of XYZ", where XYZ is any chemical. As with many things scientific in google, you need to know the right keyword to be able to look for them, maybe that's why you didn't get ...


2

There is an EU programme having exactly this aim. See this press release. Monitoring anthropogenic CO2 emissions needs the combination of in-situ measurements, satellite observations and modelling of both the atmosphere and biosphere.


2

Sounds like you want a dataset that is unadjusted for rainfall. I'm not sure what you have to gain from that, but there are ways to do it. One way to do this would be to find the inverse correlation between rain and black carbon concentrations, and extrapolate to zero rainfall. Or, if you have any months that have zero rainfall, you could use that for ...


2

What advanced method? Stop burning fossil fuels. Run vehicles on electricity. Produce electricity using solar/wind/nuclear methods. Develop new methods. Sell methods to other countries. Profit!


2

Pre-industrial would mean that a lot of energy use would be the in-efficient use of wood burning. I recall that part of J. S. Bach's payment at one of his posts was firewood provided by his employer -- something like "8 cords of birch wood, 2 cords of Alder, split for kitchen use.... I think the list was about 15 cords of wood for a year. Bach had a big ...


2

I used the R package eixport (Ibarra-Espinosa et al., 2018) to download EDGAR data (5 and spec voc 4.3.2) and then include several speciations for chemical mechanisms according to Carter (2015) and Lopez-Norena et al (2019). The functions to download EDGAR are commented. This means that you must download all NetCDF files before running chem_edgar. library(...


2

Most locations in the US don't see high concentrations of pollutants like NO2 and CO anymore. They are largely no longer an air quality problem and air is "Good" in regards to those pollutants. Especially during "lockdown", when traffic is light. This is largely thanks to tailpipe emissions standards for vehicles and a much more fuel efficient fleet. On ...


1

From Wikipedia: In automobiles, a start-stop system or stop-start system automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, thereby reducing fuel consumption and emissions. This is most advantageous for vehicles which spend significant amounts of time waiting at traffic lights or ...


1

Generally idling will cause pollution in specific isolated areas and start stop technology could irradicate that pollution. Here I will concentrate not on the global impact of the pollutants but at the location where the pollution is released. The differing scenarios are important to how much of an effect start-stop / idling will have on air quality. The ...


1

Thank you all for your suggestions, I greatly appreciate it. I was able to get a solution to this problem which essentially obtains correlated errors (using ARMA correlation) in a linear (or non-linear model) and the resulting residual values are subtracted from the original values to provide some adjustment for effects. Please see this post for more ...


1

There is no technology that makes air pollution disappear on such a large scale after it has already been emitted into the atmosphere. However, timing burns so that air quality impacts are minimized is possible if meteorology is considered. If there is a meteorological forecast that mixing heights will be low, a "burn ban" should be put in place. If ...


1

If I understand your question correctly, you are asking why air inside is usually cleaner than air outside, especially if it is smokey. Smoke is actually not a gas, but solid particles that are suspended. Because of this, the smoke particles fall down, but at a very slow rate due to resistance. When the air is blown against the wall, the smoke can either ...


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