The Geneva-headquartered Word Health Organization now has more information than ever about pollutants in the planet’s air.
By Adrian Wilson, Correspondent
Specialists in the health effects of fine and ultra-fine particles on human health will provide a range of their findings at the EDANA FILTREX 17 filtration conference, which takes place alongside the INDEX 17 nonwovens exhibition in Geneva, Switzerland, from April 5-6.
The challenges and opportunities surrounding this issue will be the subject of a keynote address by Professor Nino Künzli, deputy director of the Swiss Tropical and Public Health Institute (Swiss TPH).
The Swiss have long been aware of the need to protect their natural resources and in fact, Switzerland’s federal forestry law of 1876 is one of the world’s earliest pieces of environmental legislation. Air pollution is now high on the agenda of the country’s environmental bodies.
The Word Health Organization (WHO) is also based in Geneva and its experts have recently reported that nine out of ten people globally are breathing poor quality air. It is calling for dramatic action against the pollution, which is blamed for more than six million deaths a year. The WHO data focuses on dangerous particulate matter with a diameter of less than 2.5 micrometers, or PM2.5. PM2.5 includes many toxins such as sulfate and black carbon, which can penetrate deep into the lungs or cardiovascular system. Air with more than 10 micrograms per cubic meter of PM2.5 on an annual average basis is considered sub-standard. In some regions, WHO satellite data has been complemented by ground-level PM2.5 measurements, but in much of the developing world ground readings remain unavailable, forcing the WHO to rely on cruder estimates. Despite these data gaps, the organization now has more information than ever about pollutants in the planet’s air.
Weapons in the fight
Constantly improving filter media are a key weapon in the on-going fight against air pollution, of course, and a range of companies will describe the development of new fibers and nonwovens for increasing efficiency at the Filtrex conference.
Lenzing’s lyocell micro-fibrillated cellulose fibers, for example, offer a number of advantages in high-efficiency filter constructions.
“The incorporation of our microfibrillated Tencel within a media formulation increases the fine particle filtration efficiency of sheet filters,” explains speaker Andy Slater. “The gradient pore structures, which can be created utilizing multilayer constructions, maximize filter efficiency and capacity.”
Nanoval, based in Berlin, Germany, has developed a new process for the spinning of cellulose nonwovens from a lyocell spin-dope.
The Nanoval split-spinning process is able to produce direct spun cellulose nonwovens with mean filament diameters of a minimum of 3-5µm up to 25µm.
“As far as we now, Japan’s Asahi Kasei is the only other company worldwide which has the know-how for the direct spinning of cellulose nonvovens,” says Nanoval Project Manager Christian Gerking who will present at Filtrex.
Falling midway between pure nanofiber webs and meltblown nonwovens are the Spinnefein, Spider fine and Nanovlisz trademarked webs made from filaments with diameters which can be below 1 µm, produced with the primary spinning technology of Nanoval.
Nanoval will be exhibiting its commercially-available lab-scale spinning unit for testing new polymers and the optimization of web structures at the INDEX show.
Borealis has meanwhile developed new polypropylene polymer grades employing finer fibers to be produced by the meltblown route, enabling such media to consequently be applied in higher-level classes of filter performance. Gustaf Tobieson and Henk van Pariedon will provide full details.
As the established specialist in technology for nanofiber web production, Elmarco has acquired vital know-how in the performance requirements, material handling challenges and relevant test standards over many years. The company’s R&D engineer Lukas Plistil will explain how to solve durability and processing issues with nanofiber webs for air filtration via a consideration of substrate design, adhesion systems, fiber to fiber bonding and the correct polymer selection.
Still on the subject of nanofibers, Mark Levillain, general manager for JX Nippon ANCI, will provide details of the CO2 laser supersonic stretching technology for advanced nanofiber nonwoven production, which it plans to launch shortly.
The technology is solvent-free and produces polypropylene nanofibers with diameters of between 200-500nm – a range difficult to achieve with conventional methods.
The new manufacturing technique combines CO2 laser supersonic stretching, developed by Yamanashi University in Japan, with a fiber dispersion technique obtained through JX Nippon’s own nonwovens business.
Roger Eckrich of Johns Manville and Richard Ringström of Camfil will describe the joint development of hybrid nonwoven media combining synthetic fibers and microglass. This is allowing the production of longer lasting bag filters, which are capable of dealing with the rigors of harsh environments.
Sweden-headquartered Camfil has been a leader in the development of the testing and analysis of filter media for air filtration.
The company opened Europe’s first HEPA filter testing rig as far back as 1967, and later, during the early 1970s, pioneered particulate measurement. Today Camfil has very extensive and semi-robotized testing facilities and its measurement methods have become industry standards.
Chris Ecob, Camfil’s global technical director will be one of a number of speakers addressing the issue of standardization at this year’s Filtrex, and most notably, the implementation of the new ISO 16890 standard, which will apply to all commercial air filters worldwide.
“For years, commercial air filtration companies have been hamstrung by the fact that efficiency standards were not uniform, which made it difficult for consumers to properly compare the worth of air filters on the market,” he explains. “That has all changed with ISO 16890, which is a real game-changer for the commercial air filtration industry.
“Of great significance is the fact that this standard has global applicability. Until now, there was no such global standard. In America, the ASHRAE 52.2 standard dominated, in Europe it was the EN 779, and in Asia and the Middle East both standards have been used side by side.”
Ecob cites the following three key reasons ISO 16890 will provide major benefits for consumers of commercial air filters:
- Existing standards utilize a Minimum Efficiency Reporting Value (MERV), which assigns efficiency based on the number of dust particles and pollutants that a filter traps. The new standard now establishes one uniform standard throughout the world and may eventually supersede the current standards. This will enable consumers to make valid comparisons between air filtration products, and will also help to drive sub-standard air filters out of the market
- Other weaknesses of the current air filtration efficiency standards are that they do not test for particulates that are smaller than three microns. MERV relies heavily on particles larger than three microns, which are less than 0.2% of all particles in the air. Also, the particle size of ASHRAE dust, which is used to determine dust-holding capacity, is 100 times larger than the average particle size found in ambient air, which renders a dust holding capacity test almost useless. The new standard will focus heavily on how well air filters can eliminate the tiniest particles, which have been identified as the most hazardous to human health
- It creates four classes or divisions of particulates against which all commercial air filters will be tested – PM1, PM2.5, PM10 and ISO coarse, which refers to particulates such as sand and hair. Air filters will have to show a minimum efficiency rating of 50 per cent for each particulate class. The old standard did not address the real working conditions of air filters when it came to smaller particles