We are exposed to all manner of chemicals, pharmacueticals ,EMFs that were not around in 1850 , but this does not mean there is any conspiracy to poison the masses. In general , the powers that be don't keep the effects of chemicals or drugs a secret. For example, formaldehyde is a known carcinogen . If you check the PDR, you will see that most drugs have a myriad of side effects but people choose to use them anyway , just as they choose to smoke, douse their houses with pesticide when they see one spider and eat too much and become obese.
I don't believe that chemtrails are deliberate poisoning or that they are more harmful than auto exaust. There are much more efficient ways of poisoning the masses.If the elites are trying to get rid of the peasants, why do several presidential candidates and/or family members have cancer?
According to several articles, persistant contrails can form and expand depending on many factors including temperature, dewpoint , supersaturation of the air. In certain circumstances , contrails can cause overcast and rain. The relative humidity on the ground is vastly different from that in the air and thats why these trails appear in Las Vegas.Under certain conditions, a sturated layer can fall.
Plane exaust is toxic but so are many other things . If the barium content in wells is up, maybe it's our toxic composite fillings or other sources.
If you want to lower your cancer risk you're btter off getting rid of household toxins than worrying about jets.