Viral infection, especially respiratory viral infection (RVI), is currently one of the infectious diseases with the highest mortality, and the hospital admissions of viral infection rises every year particularly in the developing countries. Researchers currently suspect that there is a certain correlation between levels of air pollution and the ease of viral transmission. In most cases, the hospital admissions of airborne diseases show a positive correlation with the level of air pollutant in that area. Several reasonable explanations for this association have been given based on observations, but none of these theories has yet been well justified, and more researches have to be done. The aim of this article is to discuss the correlation between level of air pollution and the ease of viral transmission, the possible causes of this association, including the physical traits of air pollutant trapping viruses, and the reduced amount of virus-killing rays in sunlight due to air pollution, to offer possible solutions to lower incidence rate of viral infections, and to attract more attentions on exploring this correlation.