Air pollution reduces amount of sunlight reaching Earth's surface: Study

Air pollution absorbs and disperses sunlight and thereby reduces the amount that reaches the Earth's surface under the clear sky, reveals a study.

The study published in the journal 'Advances in Atmospheric Sciences,' also reported that the smaller the particles, the more harmful the impacts are.

The study highlighted findings that have several implications, the most consequential of which is the negative effect of air pollution on renewable energy harvest and the associated economic burden.

These findings also increase awareness of how pollution affects air purity and can thereby usher in potential methods to enhance it and thereby increase air quality.

The sun delivers energy to Earth's surface in the form of solar radiation, called surface solar radiation (SSR). The amount of sunlight that reaches Earth's surface fluctuates over time. Cloud cover and aerosols - particulates like dust or ash, kicked up into the air or coughed out of smokestacks - can disperse or scatter sunlight, resulting in less of it actually arriving on Earth.

Based on observations and numerical simulations, the study aimed to determine how much air pollution affects SSR under cloud-free skies in Nanjing, China.

"To the best of our knowledge, few studies have analyzed the effects of different levels of air pollution on SSR under clear skies," added Yong Han, professor at the school of Atmospheric Sciences, Sun Yat-Sen University, Guangzhou, China.

The comprehensive study has gathered information during all four seasons and under different weather and light conditions.

The researchers reported that the ratio of scattered radiation to global radiation increases with the increase in air pollution levels, meaning that less sunlight is actually reaching the Earth's surface.

They found that an increased amount in particulate matter prevents the direct incidence of solar radiation to the surface of the Earth and improves the ability of solar radiation in the polluted atmosphere to scatter away.

In addition, the variation of scattered radiation is dominated by fine particles, and coarse particles have little effects.

When considered in the context of solar power energy, this means that air pollution could potentially reduce the amount of energy that is gained from solar panels as it blocks a considerable amount of sunlight reaching the Earth's surface. This could have consequential implications for future solar power efforts to obtain renewable energy both in China and worldwide.

"Our ultimate goal is to understand processes related to aerosol, cloud, and radiation, and develop measurable parameters to improve climate and weather prediction models," added corresponding author Chunsong Lu, professor at the Key Laboratory for Aerosol-Cloud-Precipitation of China.