1. How is PURETi applied?
PURETi is sold in solution form consisting of 99% water and 1% nano Titanium Oxide (TiO2) encapsulated in water.  When sprayed onto a surface, PURETi dries in seconds and cures in 24-36 hours to form a clear, hard, water permeable, inorganic mineral film that is 40nm thin.  To put this in perspective, 1nm = 1 billionth of a meter, and 40nm (working thickness for PURETi to do its job) = 1/25,000 the thickness of a business card.
Chemical and physical bonds – Van der Waals forces and hydrogen hooks-  bond PURETi to the material being treated, making it a very durable, tightly bonded mineral film that can be described as a polymeric like ceramic.
2. How does PURETi work?
PURETi’s patented 3-day production process results in a solution that can be spray-applied electrostatically to form a clear, durable, 40 nanometer-thin mineral film on virtually any construction material - glass, metal, stone, concrete, paint, plastic, etc.  When ultraviolet light (from the sun or fluorescent tubes) energizes the TiO2 crystal in PURETi-applied nano-thin mineral films, an energy band gap is created within the crystal that causes it to act like a magnet and pull a hydrogen atom off H2O molecules that are present in everyday humidity, leaving a hydroxyl radical (OH-).
The hydroxyl radical (OH-) is the strongest non-poisonous oxidizing agent in nature and literally acts like a pac-man to rip apart the carbon hydrogen bonds in any organic compound that comes in contact with it.  All of this happens in nanoseconds and within angstroms of the PURETi-treated surface.  The TiO2 in PURETi serves as a catalyst to trigger these reactions (safely decomposing organic matter into H2O and CO2) and does not get consumed in these reactions.  In the presence of light, PURETi becomes a perpetual hydroxyl radical creator.  Short-chain hydrocarbons get destroyed the fastest, with longer-chained molecules taking longer.  No heat is generated by the photocatalytic process.
A second set of reactions is equally powerful at combatting urban smog. This happens when the photocatalytic process causes an electron to pop onto an oxygen molecule, creating O2-, a super-oxide aniline.  This interacts with SO2 and NO2, the chief ingredients in smog, reducing these molecules to relatively harmless neutrals.
PURETi is also super-hydrophilic, which makes glass super-slippery. As a result, rain sheets off, taking organic dirt particles with it.  It also makes glass non-fogging.
PURETi is non-flammable, and will quickly disperse if spilled.
3. What substances will damage or remove PURETi once it has cured?
Since TiO2 acts as a catalyst that does not get consumed by the photocatalytic process, it will continue doing its job as long as it is not physically scraped off or painted over. While the layer of TiO2 is extremely thin (40nm), it is inorganic and extremely tough, making it very hard to remove.
4. Warranty?
PURETi warrants its product for 5 years (exterior) and 3 years (interior). Actual life span will probably be longer.
The reason the warranty is shorter with interior spaces is that siloxanes – an inert chemical present in interior environments in increasing numbers - may invisibly cover up the PURETi layer and block receptor sites critical to the photocatalytic process.
5. Is PURETi non-toxic and safe for humans and animals?
Yes. TiO2 is GRAS according to the FDA and European Science Commission has determined TiO2 to be safe in all forms – active and inactive, nano and micro. The National Science Foundation has registered PURETi as safe for material surface contact. NIOSH has found PURETi application methods to be safe. There are no respirable powders with PURETi and near zero risk of human contact. Independent university tests have found that PURETi requires great force to abrade and that it abrades in flakes larger than 100nm and above the threshold of concern.
6. Will PURETi kill germs?
PURETi makes no claims to being to germ-killing in the US, as that would require being regulated by the EPA, which currently classifies germ-killing substances as pesticides. Independent tests have found PURETi to deliver log 4 reductions in gram negative and gram positive bacteria and a variety of viruses in less than an hour. In Asia it is widely believed that TiO2 stopped the spread of the SARS virus back in 1999.
7. What will interfere with PURETi doing its job?
Painting over PURETi will block the light and stop the photocatalytic process (photocatalysis). Similarly, applying wax over PURETi will block the moisture need to activate photocatalysis. Gum, bird droppings and other large masses of light blocking matter will also limit PURETi’s functionality.
Since normal household paint is many times thicker than PURETi, the PURETi layer can readily be painted over if the homeowner wants to change the color of PURETi-treated siding.
8. What materials does PURETi not get along with?
a) Teflon, silicone, wax and polypropylene all reject PURETi’s water based carrier and are the only four materials to which PURETi will not bond.
b) Wax applied over PURETi will block the moisture needed to activate photocatalysis.
c) PURETi may degrade certain organic substrates, such as latex paint or soft plastic, then fall off the material being treated.  In these cases, a first coat of non-photoactive PURETi primer (called Base) can applied that will not damage the organic material, followed by a second coat of photoactive PURETi that will do the job.  In a production process where the cure process is being accelerated from 24 hours down to only seconds, the first coat can be followed immediately by the second.
9. How quickly does PURETi work?
Activation occurs immediately after the source of UV light is turned on; however, it takes a while for all the hydrocarbons, VOC’s, NOx and SOx in a room or in the air outside a building or solar panel to come in contact with the TiO2 crystals.
Effective residence time can be speeded up by pulling more of the polluted air per unit of time in close proximity to PURETi, where it can be destroyed. Deactivation occurs within minutes after the source of UV light is removed.
10. Will PURETi work with reflected light and how much light is needed?
UV light bounces around just like visible light, so reflected or ambient light works fine to activate PURETi.
There is a range of functionality that PURETi delivers that depends on the amount of light it receives.
Outdoors – PURETi claims a full set of self-cleaning and air purifying benefits. These functionalities only require 0.1mW/cm2 of UV-A light. Direct sunlight delivers over 1mW/cm2 and the north side of buildings – even in the shade – receive more than 0.001mW/cm2 of UV-A light.
Indoors – PURETi claims a more limited, but still powerful and highly marketable, set of odor eliminating and IAQ, respiratory health improving benefits. These functionalities only require 0.001mW/cm2 of UV-A light – one hundredth the amount of light required for full self-cleaning. This level of light is found at window surfaces and light fixture surfaces.
11. Will PURETi work under water?
The light intensity needed to activate PURETi falls off sharply under water.  5-6 inches is about the limit of effectiveness in salt water, up to 1 foot in non-salt water, depending on its clarity.
12. Operating limits
a) PURETi will work down to 0 degrees C (32 degrees F), at which point the water PURETi is suspended in will freeze.
b) Since PURETi in solution form is 99%+ water, it is best applied at a temperature that is not too hot to touch, otherwise it will evaporate too quickly.
c) Once cured, PURETi’s upper temperature limit is 600 degrees C.  Above that it melts into the rutile form of TiO2.
In between freezing and 600 degrees C, PURETi is not particularly sensitive to temperature, nor is its performance impacted by pressure.
13. Will PURETi eat dust?
Since most indoor dust consists of skin and hair particles, which are organic, PURETi will consume these forms of dust as they come in contact with a PURETi-treated surface.
Inorganic dust (ie sand) will still be attracted to PURETi-cleaned windows, but without the “stickyâ€ organic grime to stick to, inorganic dust will fall off.
Outdoors, inorganic fine sand on a PURETi-treated solar panel can be easily blown off by a strong wind gust or leaf-blower, whereas it will continue to stick to untreated panels.
PURETi can be overwhelmed if the amount of dust, grime, algae or mold buildup occurs too quickly and blocks light.
PURETi’s ability to eat large volumes of livestock-generated dust, which is a big problem in pig and cattle enclosures, has not been tested.
14. Will PURETi work better on rough or smooth surfaces?
PURETi will work equally well on both surfaces.
15. Can PURETi be sprayed on fluorescent bulbs without impacting the bulb’s performance or life?
It will destroy VOC’s, and shouldn’t impact the bulb’s life. However, the limited surface area makes bulbs a far less significant target for application than the reflectors or lamp shades that surround these bulbs.
16. How do the sprayers know if they’ve missed a spot?
Since PURETi is 99% water, it leaves a visible sheen as it is being applied, so any missed spot is immediately visible.  To make sure PURETi is applied uniformly, sprayers are taught to do a series of sprays across a surface, then a series of up-and-down motions.
17. What does the sprayer have to do differently under windy conditions?
Get closer. Above four stories, extra measures are typically required to block the wind.
18. Surfaces to avoid
Teflon, polypropylene, wax, silicone and embossed stainless steel that’s designed to look like aluminum – (PURETi will tend to pool in the cracks and look milky).