I wrote this so people can understand what is actually happening.  No magic just science.

First off we need to realize that heat is nothing more than the movement of particles. The more momentum a particle has the greater the heat.  The faster a particle moves the greater the stored energy that single particle has. Faster moving particle whack into slower moving particles and depart energy into the slower moving particle. This is not absorption but simple mechanical resolution.

Heavier particle retain more momentum at the same velocity as less massive particles. This is simple mechanical physics.  If you remember, a body in motion will continue to move at the same velocity unless acted upon by an outside force.

Einstein proclaimed, light acts like a particle in generating heat because it has relativistic mass.

He believed light is a particle (photon) and the flow of photons is a wave. The main point of Einstein's light quantum theory is that light's energy is related to its oscillation frequency.
Albert Einstein in 1905 drew the conclusion that light sometimes behaves as particles through an ingenious statistical analysis of Wien's formula for the wave length distribution of heat radiation

Einstein won the noble prize for this observation. The 1921 Nobel Prize to Albert Einstein (awarded in 1922). This is nothing new, but completely misunderstood by today’s so-called environmentalist.

So when light whacks into a particle of any gas in the air, some or all of the relativistic mass is imparted to the particle increasing the particle’s momentum.  Even when there is reflection some of the energy is imparted to the particle. When this happens to light the wave length will be elongate as predicted by Albert Einstein in 1905.

Bigger particle are harder to move.  It’s the old equation, F=MA where F is Force, M is Mass and A is acceleration.  More force is required to acceleration more massive particle.

Each GAS in the air has a different Coefficient and reacts differently. Smaller particle move faster and larger particle move slower at the same level of interaction with light.

Consider the case of the gas CO2. It’s a heavy particle and requires more energy to accelerate. So it’s harder to heat and harder to cool. CO2’s heat conductivity is controlled by a coefficient. This tells us how it interacts with other particles in the air. When you combine all the coefficients for all the particles together you get the overall coefficient of air.

Co2 is heavy and once accelerated will contain more momentum. However; since there is almost none in the air it has little or no effect on the temperature of the air.

For more details See: Dispelling the myth of man caused "Global Warming ." (theolddub.com)