The Journal of Exposure Science & Environmental Epidemiology studied the particles in the air at a 2017
vaping convention in Maryland. It concluded that, in large quantities, vaping does result in a significant amount of air pollutants.
However, the National Center for Biotechnology Information (NCBI) also conducted a
study to test the indoor air quality in places where people vape. Their conclusion is that exposure of vaping chemicals to bystanders are below regulatory standards used for workplaces or general indoor air quality.
A third study, conducted by environmentalists, titled
Comparison of the Effects of E-Cigarette Vapor and Cigarette Smoke on Indoor Air Quality concluded that vaping results in a minute exposure of chemicals that poses no risk to human health.
When looking at the results of these studies, it appears that having a person vaping nearby may not cause any issues, while attending a place with a high concentration of vapers would expose people to poor air quality.