Researchers behind an “ecologic analysis” estimated the impact of medical or recreational cannabis legalization on the number of pediatric asthma cases, reported New Medical. The Dangers Of Secondhand Smoke On the other hand, the new study refers to secondhand smoke, as did a recent University of California, Berkeley study that revealed secondhand marijuana smoke to be more harmful than secondhand tobacco smoke. As cannabis legalization and popularization grow, so does exposure to secondhand smoke, which can lead to pediatric asthma. Asthma is considered the most prevalent chronic condition among children in the U.S., with pediatric asthma estimated to affect over 6 million children. Furthermore, the study discovered no significant difference in asthma prevalence between states with legal medical marijuana and recreational programs.