Innovation for the environment's sake has been one factor to consider when it comes to construction. One method, the green roof, has been around since ancient times. Considering the planet's present condition, modern adaptations of the green roof are being incorporated into recent building designs. 

Consequently, green roofs or vegetated roofing has started to take over various rooftops; commercial, residential, and institutional buildings alike. 

Green roofs are now more than just a trend; it is now one of the clear choices when it comes to the type of roofing that any environmental-friendly building owner should consider. Why not when the innovative roof offers benefits such as reducing carbon dioxide, decreasing stormwater runoff, and cutting down on urban heat.

A team of researchers for Portland State University (PSU) devised an experiment to investigate the potential of green roofs to affect ozone levels in a building's ventilation air supply.

The team comprised of members from the different departments of PSU including Mechanical and Materials Engineering, Biology, and the university's Honors College.

Their experiment took place on the roof of a big-box retails store in North Portland. The team had set up measuring devices on the roof which was a combination roof, the half being a green roof, while a conventional white membrane roof makes up the other half.

The data gathered by the team showed that air coming in from the green roof area had significantly lower levels of ozone as compared to the air that came in from the conventional roof area. They concluded that this was because the air passed through the planted area and the vegetation had trapped and filtered the ozone from the outdoor air. The data was obtained when the team measured the air that came into the building from outdoor intake vents.

The team explained that the air is filtered in the way mentioned was a natural process. It is a trapping effect that is known as dry disposition which is key to removing pollutants in the atmosphere. This happens when particles in the atmosphere are deposited on the solid surfaces that it encounters.

The group's experiment gives support to the concept that green roofs can reduce indoor pollution and, in effect, improve indoor air quality.

The team has conducted the study for two days. However, the researchers pointed out that the study would benefit from a long term of experimentation and possibly including the measurement of other pollutants aside from ozone.