The direct aerosol effect consists of any direct interaction of radiation with atmospheric aerosol, such as absorption or scattering. It affects both short and longwave radiation to produce a net negative radiative forcing.  The magnitude of the resultant radiative forcing due to the direct effect of an aerosol is dependent on the albedo of the underlying surface, as this affects the net amount of radiation absorbed or scattered to space. if a highly scattering aerosol is above a surface of low albedo it has a greater radiative forcing than if it was above a surface of high albedo. The converse is true of absorbing aerosol, with the greatest radiative forcing arising from a highly absorbing aerosol over a surface of high albedo.  The direct aerosol effect is a first order effect and is therefore classified as a radiative forcing by the IPCC .  The interaction of an aerosol with radiation is quantified by the single-scattering albedo (SSA), the ratio of scattering alone to scattering plus absorption ( extinction ) of radiation by a particle. The SSA tends to unity if scattering dominates, with relatively little absorption, and decreases as absorption increases, becoming zero for infinite absorption. For example, sea-salt aerosol has an SSA of 1, as a sea-salt particle only scatters, whereas soot has an SSA of , showing that it is a major atmospheric aerosol absorber.
Despite the risks, the major manufacturers of energy drinks continue to aggressively market their products, especially to young people, who are most at risk for health problems if they consume too many of these beverages. The companies sponsor sporting and other events of interest to young people, making false claims about health benefits. Statistics show that sales continue to increase despite all the health risks. Even scrutiny from the . Food and Drug Administration (FDA) has not impacted sales, which have been steadily increasing since 2013.