Why is nitrogen dioxide less visible in the winter?

Thought that might help, i'm not very good in chem, but I can find sources.

Explanation:

Nitrogen oxides (NOx) and ground–level ozone (O3) were measured and meteorological parameters, wind speed, temperature, relative humidity and barometric pressure were monitored, to determine the seasonal variations of gas–phase pollutants in the Meadowlands. O3 and NOx were inversely related; the highest average NOx concentration (29 ppb) occurred in winter while average O3 concentrations peaked in summer up to 36.2 ppb. The seasonal variations of O3 were more distinct than NOx. In multiple linear and principal component regression analysis, ambient levels of NO2 and O3 were influenced primarily by wind speed. In time series and regression analysis, NO2 and O3 displayed an inverse relationship with wind speed but O3 paradoxically increased with wind speed downwind.

The seasonality of O3 was amplified mainly by wind speed and temperature, while NOx displayed stronger dependence on diurnal source emissions. Concentrations of NOx and O3 were also influenced by differences in chemical processing through their complex emission–production and consumption mechanisms, making them interdependent. In intense solar radiation, O3 was NOx–dependent but as O3 levels were inhibited by lower temperatures, NOx concentrations increased. Higher O3 on weekends indicated an apparent sensitivity to VOC precursors. This study provides a basis for improved air quality standards primarily in summer and during daily O3 peaks. Additionally, plans for protection against health problems caused by O3 and NOX are feasible in this region.

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.