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

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

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 ...


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

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

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 ...


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

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!


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

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 ...


1

If you're in the open air you will be exposed to the full concentration of the pollutants in the air. By being inside, there's a reasonable assumption that the rate of interchange of air between inside a house and outside will be low and that inside there will be a lower concentration of pollutants. Houses and buildings are not hermetically sealed. The gaps ...


1

Most atmospheric science researchers use back-trajectory analysis in qualitative sense to explain source of a pollutant. And as pointed out by the questioner, it is not possible to associate trajectories calculated at a particular time to the measurement that is average of say several hours. However, quantitative analysis of observed concentration with ...


1

Ambient or roadside concentrations for each pollutant, over different averaging times, will be converted into an index value. In general, there are three common methods to achieve this. The most popular approach is often called the US-based system. Pollutant concentrations for each pollutant are transformed onto a normalised numerical scale of 0 to ...


1

While the prospects are more of an economic question, I can answer that there is at least one study using machine learning methods (https://etda.libraries.psu.edu/catalog/13561nvb5011). There are problems such as the attribution of error to physical processes are not feasible, the spatial extent of the model is very limited, the accuracy of the model is ...


Only top voted, non community-wiki answers of a minimum length are eligible