Please have a look at this link and PDF attachments.

https://www.researchgate.net/publication/310466187_Biomonitoring_of_Air_Pollution_Using_Mosses_and_Lichens_A_Passive_and_Active_Approach_State_of_the_Art_Research_and_Perspectives

Book Biomonitoring of Air Pollution Using Mosses and Lichens, A P...

Please have a look at this link and PDF attachment also.

https://www.researchgate.net/publication/228062368_Moss_bag_biomonitoring_A_methodological_review

Article Moss bag biomonitoring: A methodological review

Dear David, the idea of studying pollution status of industrial areas is very good. Infact, mosses have been noted to be the best biological organism to monitor atmospheric pollutants, especially from industries and emissions. 

The idea can be grouped into two: the use of mosses can be applied as either passive biomonitoring or active biomonitoring. Passive biomonitoring is when you adopt the indigenous or native moss species in the study area to biomonitor pollutants whereas the active utilizes mosses from non polluted or isolated areas and being transported to the area of study and left for certain period of time to bioaccumulate pollutant.

In most cases, active biomonitoring is preferred because it gives idea of depositing rate, period which are important in the study. David, I hope this brief intro to the use of mosses for biomonitoring will assist you in getting a foot hold in this area of your study. Regards Clement

yes it is a good idea of measuring pollution percentage by using mosses but before starting the study how can you get the data of mosses before year its only an assumption but not confirm

@Make. That was a good question but it's not a problem. The best way is to adopt the active monitoring by transplanting mosses from non polluted areas and use it innpolluted areas. This is always done using moss bags

Dear Anjana:

You can also use an area of mosses like blank