For the last 30 years of research, not enough evidence on HAVC cleaning extra benefits was found. Though no one can deny three facts:
Fact 1: The air quality of our planet is getting less day by day in big industrial cities and drawn by the wind to the neighborhoods. Green Ductors are operating in NYC and NJ, both areas are in the zone of most risk if compared to most of the European cities.
Fact 2: The Indoor pollutants concentration in the air is 5 times higher than outdoors. Knowing the statistically proven 90% of the daytime that the US citizens spend indoors - the final picture doesn't seem pleasant.
Fact 3: Out of every 4 kids in the US these days one has asthma. Which makes it 25% of the new populations coming to this planet. And if Air Ducts Cleaning wasn't showing much of a benefit to human health in the 1990s, it does in 2020.
Also with the previous methods of Ducts cleaning the situation of higher contaminants post-cleaning indoor levels than the pre-cleaning levels was usual. With new methods of and tools for cleaning this doesn't happen anymore.