Unlocking Cities’ Dirty Secrets.

Unlocking cities’ dirty secrets.

Grime is found on every surface in urban environments. Buildings, statues, street signs and pavements are all covered with a grimy layer of chemicals from cars, factories and other polluting sources.

We’ve always thought that once this layer has been deposited on a surface the complex mixture of organic and inorganic chemical pollutants contained within it are locked in, remaining in their resting place until a window cleaner or street sweeper scrapes them off.

New observations suggest this isn’t correct. James Donaldson from the University of Toronto, Canada, and his collaborators in Leipzig, Germany, now believe sunlight can cause nitrogen compounds to be re-released from the grime and recycled back into the atmosphere. Here, these compounds once again contribute to ozone and smog.

The researchers have carried out a series of lab and field – or in this case, city street – experiments that support their claim. First, grime collected in Toronto was examined using infrared spectrometry to determine its composition. It was then exposed to artificial sunlight in the lab, and its composition reassessed. Nitrate components in the sample were observed to rapidly leave the grime when it was exposed to light.

The next series of experiments took place over a six week period on a street in Leipzig. The team collected grime on glass beads (made of the same type of glass as windows) stored on a two-tiered structure that resembled takeaway pizza boxes stacked on top of each other. The beads in the top tier were exposed to natural sunlight, while those in the lower tier were shaded from the sun’s rays.

The team then took both sets of beads back to the lab and analysed the chemicals deposited on them. The beads kept in the shade contained 10% more nitrates than those exposed to the sun, supporting the earlier lab-based findings that nitrogen compounds can escape grime with the help of light. An extended year-long version of this study is still running in Toronto.

Back in the lab, the Toronto arm of the team have analysed the gas phase products released when artificial sunlight is shone on real grime, finding that nitrogen dioxide and nitrous acid are both released. Both are important air pollutants.

These findings may eventually lead to improved models for estimating the quality of urban air, but there remain a number of questions – such as the effect of humidity or varying amounts of sunlight – to be answered first.

Efforts to reveal the secrets of urban air pollution, and therefore improve our models, are vital for enabling policymakers to make good decisions about keeping air pollution at safe levels. The end goal is, of course, to ensure we can all breathe easily when spending time in our cities.

Smog Eating Panels & 150 Foot Lifts

Alcoa, Toto unveil green building panels that eat smog: A skyscraper that devours the smog around it? Now that’s what I call a smart idea. Alcoa on Monday launched a coil-coated architectural panel that helps clean itself and the air around it. Called “Reynobond with EcoClean,” the product is a partnership between the aluminum giant and design-forward Japanese manufacturer Toto. Alcoa says the panels reduce maintenance costs and helps decompose smog and other pollutants in the air that cling to building surfaces, from dirt to diesel fumes.

Architectural panels that help clean themselves and the air around them.

How effective is the technology? About 10,000 square feet of the panels can clean the air as well as 80 medium-sized deciduous trees, Alcoa says. It’s enough to offset four cars each day. You can imagine the applications of this green building technology: Times Square would glimmer a little brighter. Ultra-high skyscrapers wouldn’t need to hire daring window cleaners to keep floor-to-ceiling windows transparent. And, at scale, a smog-choked Los Angeles could breathe a bit easier. At the core of the concept is a proprietary process that takes Toto’s patented Hydrotect technology — which helps keep microbes at bay on that company’s toilets, bath tubs and other bathroom fixtures — and applies it to a hydrophilic titanium dioxide coating on the pre-painted aluminum surface of a Reynobond panel.

The result: an aluminum panel that, in the presence of sunlight, acts as a catalyst to break down organic pollutants on its surface and in the air around it. Once broken down, rainwater simply rinses them away.

High Access directors Peter Metcalfe and Neil Bethell.

High Access invests £250,000 in new kit: A business that provides high level cleaning and maintenance services to the commercial property sector is investing £250,000 in equipment as it prepares for further growth. Manchester-based High Access was established 10 years ago as a rope-access window cleaning company, later moving into full maintenance services which include pointing, re-glazing and cladding replacement. Clients include Jones Lang La Salle, Living City and Savills, which has extended a three-year contract with High Access covering more than 50 commercial properties.

Niel Bethell, founding and managing director of High Access, said the company has bought a £125,000 Ruthmann truck mounted platform which will reach heights of 27 metres and will this month take delivery of a new £250,000 truck which will reach 46 metres. “It will be the largest truck mounted platform in Manchester,” said Niel. “For the business it's a huge investment but it will also mean that we will be able to win new clients as we will be able to tackle buildings at a higher reach.

“Over the last five years we have invested heavily in new plant and equipment and we now have 20 vehicles. “The advantage to having our own fleet is that we are able to keep our costs down and stay ahead in the market, as we're not reliant on hiring equipment. “We've grown steadily year-on-year and that is down to retaining clients and not moving into the new-build property sector, which was affected heavily during the recession.”

The business, which employs 30 staff, has recently extended its warehouse and office facilities at a cost of £30,000 and will launch a fleet hire division, HighAccessHire, this month. Niel said: “We don't use all our fleet at once, so we decided to hire them out instead.” He added the business is on track to reach revenues of £2m this year, up from £1.6m in 2010.