# Tag Info

17

This is an interesting phenomenon that I haven't seen before. To start off with a discussion of coronas in general, they are fundamentally caused by diffraction, a form of optical scattering where the path of light from the sun is "bent" as it passes by the edge of a small particle. A simple illustration is case D in this example figure showing ...

10

The air quality in Los Angeles does not meet federal air quality standards. That being said, the air quality has improved immensely since the 1970s. From the California Air Resource Board, in 1965 the maximum one-hour ozone concentration was 0.58 ppm. Since then, that number has come down to about 0.12 ppm. You can obtain the latest ozone data from EPA....

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, ...

8

A figure downloaded from this site. It represent the history trends of the pollutants related to the photochemical pollution from 1960s to 2000s We can find that $O_3$, $PAN$, $VOCs$, $NO_x$ have all declined. And O3 variation trends were strongly correlated to $NO_x$ which can be explained by the VOC-NOx chemistry. Another material I have ...

7

Depends on what type of pollution you are talking about Moreno et al., 2015 studied this problem in Barcelona, and compared Metro (subway) to trams, buses, and walking in various parts of the city. There is a massive overabundance of data in this paper that mostly speaks for itself, but let me summarize. The subway was in first place or last place in most ...

7

Acid/Base Chemistry Gaseous ammonia (NH$_3$) acts as a base when it dissolves in water. The reactions are below. NH$_3$(g) + H$_2$O(l) $\rightleftharpoons$ NH$_3$(aq) NH$_3$(aq) + H$_3$O$^+$(aq) $\rightleftharpoons$ NH$_4^+$(aq) + H$_2$O(l) The end product is an ammonium ion. We also have gas phase species SO$_2$ and NO$_2$ in air. They dissolve in water ...

3

I took a class once, and we had an approximate equation for an particle (equation sheet is still up): $$\frac{d\vec{v}}{dt}=\frac{\rho_{particle}-\rho_{air}}{\rho_{particle}}\vec{g}-\frac{3\rho_{air}C_D}{4\rho_{particle}CD_{particle}}\vec{v}|\vec{v}|$$ where $\rho$ is density, $\vec{g}$ is the gravity vector (usually $=g\hat{k}$ but can be changed if the ...

3

Following @ Friddy's comment, I started reading Aethlabs AE51 FAQ and was quite surprised! While a conventional aethalometer use a long tape and move it to the new position after each measurement (which could be as fast as one measurement per minute), the compact device shown in the image in question uses a single filter position, and just keeps measuring as ...

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

You can find diagrams of air flow in hurricanes. If your balloon has neutral buoyancy it will go with the flow. Good luck in the complicated currents in the rainbands and eyewall.

1

Considering there are evaporation ponds worldwide (San Francisco Bay is full of them, and Morton used to, and may still, have the majority) used for harvesting sea salt, it's doubtful that any salt deposits would end up in the Martian atmosphere. And the atmosphere of Mars is too thin to hold salt blown from existing salt deposits, so salt blown into the ...

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