The team was led by David Booker of AEA Technology, working with the Anglo-American instrument company Graseby Andersen. Booker and his colleagues have designed an instrument which can simultaneously monitor particles in up to four size ranges. Other instruments either cannot work in real time or can only measure the total mass of particles, rather than splitting them into size fractions. Determining the amount of each fraction is important because different sized particles penetrate people’s lungs to different levels and may therefore cause characteristic health problems.

The new instrument is called a vibrating tube impactor (VTI). Duncan Laxen of Air Quality Consultants, who is also a member of the Department of the Environment’s Quality of Urban Air Review Group, welcomes the new instrument. “There is considerable interest in fine, airborne particles because of the evidence that they are having significant health effects,” he says. “We still do not know enough about where these particles come from. Studying the variation in the different size fractions over short time periods will improve our understanding.”

The VTI consists of four glass U-tubes connected in series. Each successive tube has a smaller bore so that dust-laden air accelerates as it passes from tube to tube. The tubes may also be set up to have successively more acute bends. When the air enters the first tube, larger, heavier particles have too much momentum to negotiate the bend, so they collide with the tube wall and stick there. Progressively smaller particles are similarly deposited in the smaller U-tubes. The increased velocity, and therefore momentum, of the particles as they pass from tube to tube makes it more likely that they will be deposited.

Each tube gets heavier as it collects particles. To measure this increase, the tubes are vibrated at a fixed frequency. The heavier each tube becomes, the greater the energy needed to maintain the vibration.

AEA Technology has tested the VTI alongside the best real-time particle monitor previously available, known as a tapered element oscillating microbalance, or TEOM. According to the AEA researchers, there was excellent agreement between the two instruments. But the TEOM relies on capturing particles in a filter, so it can only measure one size range of particles at a time. The VTI’s U-tubes are also much more robust and cheaper to produce than the TEOM’s tapered elements.

If you fly from Kathmandu to Khumbu and back, the journey takes about an hour. Walking the same distance could take some 20 days. So around 65 per cent of Khumbu’s visitors now fly in, with 90 per cent flying back to Kathmandu. The deleterious impact of this tourism is evident. Unfortunately, while many trekkers are environmentally aware, some are oblivious of the damage that they can cause.

All this should soon change. If you visit Khumbu today, on arriving you are likely to receive a small brochure printed by the Sagarmatha Pollution Control Committee (SPCC). It describes the ecology of Khumbu and the Sherpa culture, and outlines ways of conserving Khumbu’s environment.

The brochure was produced by Jane Lusardi and Joseph Murphy, two British conservationists who last year worked as volunteers for the World Wide Fund for Nature in Kathmandu. During their four months’ stay in Nepal they worked for the SPCC on three conservation projects. The couple had contacted the WWF Nepal Programme earlier, volunteering their skills. “We wrote to several organisations,” says Murphy, “and were put in touch with the SPCC by the WWF in Nepal. It was the first to respond and as we wanted to see the Everest National Park, it seemed ideal.”

Murphy says they had no illusions about why they wanted to work there. “Like most forms of travel, we did it for selfish reasons. We wanted to see the park, and working with its people was the best way to learn.” At the same time, they wanted to give something back. “We were aware of the damage that large numbers of visitors can cause and felt that we could use our backgrounds to help them lessen their impact.” Having contacted the SPCC, Lusardi and Murphy went to Kathmandu before starting the 10-day trek to Namche Bazar, the main town in the Sagarmatha National Park.

The Sherpas came to the Khumbu region from eastern Tibet some 500 years ago, says Murphy. They adapted well to the harsh environment, developing an agricultural economy based on yaks, barley, buckwheat and potatoes. And contrary to Western opinions of the 1970s, the Sherpas were very good at managing their environment. Things have changed since Hillary’s successful Everest climb, says Murphy. The Sherpa culture is now based largely on tourism, which in turn has had a deleterious effect on the environment. But Hillary had the vision to see what was happening and persuaded his government to help set up the national park in 1976. But the pressure of ever greater numbers of trekkers and climbers soon took its toll. Most Western visitors dumped their rubbish and spent equipment in Khumbu. As a result, Everest Base Camp became known as the highest rubbish dump in the world.

In 1991, the WWF Nepal Programme and the Department of National Parks and Wildlife Conservation set up the SPCC. The SPCC now receives funding from the Nepalese Ministry of Tourism and Civil Aviation, which is determined to see some of the revenue from tourism ploughed back into conservation in Khumbu. The SPCC is staffed entirely by local people, and one of the first jobs that it took on was to clean up Everest Base Camp. Together with 80 local volunteers, it removed 30 tonnes of rubbish in 500 yak-loads. Now it has set up recycling and waste management programmes. And in the hope that it won’t need to repeat such a cleanup operation it is actively promoting sustainable tourism, explains Murphy.

The SPCC is also committed to reforestation, environmental education and cultural conservation. “This is where we came in,” says Murphy. “We started with three months’ research into Khumbu’s environment and culture, then we helped to set up the visitor centres to promote conservation and developed an environmental syllabus for schoolchildren.” After this, the pair worked on the brochure. They are both experienced travellers, and describe the brochure as a major challenge which stretched their patience and resourcefulness. “We were hindered by a lack of resources and the problems of communication when working in an isolated area,” says Murphy. “For example, when I asked for some Letraset and tracing paper, I had to explain what they were. We needed a few sheets of tracing paper to produce the maps and got a 13-metre roll. Our contacts in Nepal also sent a stencil instead of the Letraset. While the stencil was handy, I eventually received the Letraset minus capital letters or numbers. So we produced the brochure, leaving appropriate gaps, only to discover that we had all the Letraset that the SPCC could get. Eventually we had to travel back to Kathmandu, which took us 10 days, to finish the brochure. The WWF in Kathmandu found a suitable printer, although the colour separations had to be done in Bombay.” The brochure took three months to complete and Murphy says it is one of the most fulfilling things he has ever done.

The simple brochure has been welcomed by the WWF, SPCC and visitors to Khumbu. It contains a wealth of advice and useful information. Many travellers were unaware, for example, that a tourist can easily consume five times more fuel wood than a local, while toilet paper can take 30 years to decompose above 4000 metres.

The British couple are also pleased with their efforts. “You are always on the take when you travel,” says Murphy, “so we were delighted to give something back.”

Science and technology have undoubtedly made the world a smaller place. We take for granted the ability to travel and many of us believe that transport on demand is a right. Yet transport has brought with it a number of environmental problems, particularly through uncontrolled and unsustainable tourism. Murphy and Lusardi clearly understood this, and they are thoroughly honest about their reasons for travelling. They accepted that rights are accompanied by responsibilities. In so doing, the pair used their scientific training to give something important to a land from which they had gained so much.

Cameron’s team was looking at ways to improve the Magnetherm process, one of the main methods for producing magnesium. This involves the reduction of magnesium oxide when it is heated in a partial vacuum with oxides of calcium, aluminium and silicon. The oxides form a molten slag which reacts with a metallic reducing agent, such as ferrosilicon, to generate magnesium, which vaporises in the vacuum. The magnesium is captured by condensing the vapour in a crucible.

The yield of magnesium depends on the temperature and pressure of the furnace, and the composition of the slag. With conventional ore-based feedstocks, the pressure must be kept down to around 5 per cent of atmospheric pressure to encourage the formation of magnesium. But maintaining this partial vacuum in an industrial plant is difficult, and up to 25 per cent of the magnesium vapour may be reoxidised by air that leaks into the system.

Cameron’s team hit on a mixture of materials that would yield magnesium at atmospheric pressure. “We found that we could eliminate the need for operating at a partial vacuum, which should cut nearly all the losses of magnesium and significantly reduce the energy demands,” says Cameron. The new process could cut operating costs by 30 per cent compared to the Magnetherm process. It was piloted using conventional raw materials in a 0.6-megawatt plasma furnace.

An unforeseen benefit is that the revised process can make use of certain kinds of hazardous waste as part of the feedstock. These include asbestos, and cement waste containing asbestos. When blended correctly, these materials contain the correct proportions of the various oxides.

In the conventional Magnetherm process, the molten slag is heated by passing an electric current through it. But the mixtures that produce magnesium at atmospheric pressure do not conduct electricity, so the researchers used a plasma furnace to heat them.

The UMIST team is working with a European consortium to scale up the process and exploit it commercially. The project is known as MAGRAM. Cameron’s team began commissioning a MAGRAM pilot plant last week, based around a 0.3-megawatt furnace. The technology has already been licensed for use by one of the world’s largest producers of magnesium.

The development should allow oil companies to control the evaporation
of hydrocarbons more effectively than has been possible with previous methods,
which relied on estimations derived from mathematical formulae. The LIDAR
technique, which can measure the total emissions from tankers as they load,
has proved to be cost-effective: in its first use, at a land-based oil refinery
in Goth-enburg, Sweden in 1989, the amount of vapour leaking was found to
be more than five times as much as predicted. The emissions were subsequently
cut by several thousand tonnes annually.

Spectrasyne, based in Basingstoke, uses a technique known as differential
absorption LIDAR, or DIAL. Normal LIDAR estimates distances by scanning
a single laser beam over an area being monitored, and detecting interference
effects from laser wavefronts that are reflected back by distant objects.

With DIAL, a dual beam at two different frequencies is scanned over
an area, and particles and aerosols in the atmosphere reflect the beams
back to a detector. Pollutants are monitored by tuning one beam to an absorption
frequency of a target pollutant: if the pollutant is present, it will absorb
the beam, so less laser energy is reflected back to the detector. Integrating
the results for a whole area can produce three-dimensional emission profiles
of air pollutants.

This is the first time DIAL has been used to monitor emissions at sea.
‘For the technique to work, you need to know exactly where the laser beam
is pointing,’ says Spectrasyne’s technical director, Jan Moncrieff. Until
now, DIAL required a stationary platform for the laser projector and detector;
otherwise wind and wave motions affected the direction of the outgoing laser
beam and the returning signal.

To overcome this problem the scientists developed an orientation sensor
which detects motion and tilt, and mounted the whole system on a barge.
The sensor links up with the data acquisition system for the laser beams,
enabling it to compensate for changes in the position of the barge.

The new technique will be ideal for monitoring tankers with several
tanks and vents. Oil companies can already monitor emissions by measuring
the losses at each vent, but this is at best an estimate because there are
many points besides the vents where leaks can occur.

It can also take up to 24 hours to load a marine tanker, so monitoring
is complex and requires tight coordination. The seaborne DIAL technique
can measure total losses as it integrates all the measurements over the
time that the tanker is loading.

The products are claimed to be lighter, more resistant to corrosion
and easier to fit than conventional steel pipelines. Many existing filling
stations were built using steel tanks and pipelines, which are then encased
in concrete below the forecourt. The metal components are prone to severe
corrosion, leading to leaks, and researchers in Europe and North America
have found that up to 30 per cent of petrol stations leak, contaminating
the soil and ground-water. In London, for example, the London Fire and Civil
Defence Authority found that 70 per cent of the leaks at petrol stations
and underground storage tanks are due to leaking pipes. Once, a filling
station leaked into a tunnel on the London Underground.

New environmental and safety legislation in a number of countries means
that petrol companies must prevent leaks. This can be done using technology
such as double-skinned tanks made from glass-reinforced plastic, and multiskinned
pipes made of nylon and polyamides. But such pipes are hard to install
or connect.

The British pipe being used at the M40’s only service station, at Cherwell
Valley, is known as Petrol-line, and uses plastic jointing technology called
electrofusion, originally developed by British Gas and enhanced by Durapipe
of Cannock for the special needs of petrol stations.

Two sections of pipe are connected using a polythene ring which contains
a heating coil. When a current is passed through the coil from a portable
control unit, the heat generated causes the surrounding material to melt
in an expanding pool, until it touches the pipe surface, which melts and
forms a fused joint. Unlike welding, electrofusion can be carried out in
any weather and in confined spaces.

Petrol-line is made from a high-density plastic, designed for the petrol
lines which fill the main underground storage tanks, and for the vapour
recovery lines which run separately from the tanks to the filling tankers
so that petrol vapour is not discharged into the air during filling.

What I really needed was a tiny, portable, battery-powered hard disc
drive – not that such a device existed. But now it does. In the past year,
an American hard disc manufacturer, has perfected a 2.5 inch hard disc drive
and Jilutech has bundled it into a small black box complete with a rechargeable
battery and necessary electronics. The whole thing measures 12.5 centimetres
square and 4 centimetres deep, about the size of a personal stereo.

The Jilutech Drive 25 plugs into the back of any PC and is very easy
to set up. It comes in storage capacities ranging from 21 megabytes to a
huge 130 megabytes. The 21 megabyte version costs ÂŁ295, and takes
a lot of the pain out of backing up and transferring copious amounts of
data. It is also a useful addition to any laptop computer without a hard
disc drive.

*Jilutech, 23 Metro Centre, Brittania Way, Park Royal, London NW10 7PE.
Tel: 081 965-9494.

Ecology is now a highly quantitative subject, based on huge sets of
field data. Plant species, for example, tend to cluster in particular groups
with the exact composition and density of species varying according to geography
and environmental influences. Changes in these groupings can provide a great
deal of information about the environment and how to manage it.

Quantitative ecologists use a statistical tool called multivariate analysis
to help them to understand species groups and to detect even subtle changes
in their composition. VESPAN is a piece of software designed to store, process,
analyse and display prodigious amounts of field data.

It was written by Andrew Malloch, a senior lecturer in ecology at the
University of Lancaster. Malloch has a strong interest in computing and
has been deeply involved in the Nature Conservancy Council’s National Vegetation
Classification (NVC) programme and developed VESPAN to process 15 years’
of field data from the NVC.

VESPAN incorporates some existing programs for multivariate analysis
and adds its own modules to edit the data and map it on a national grid
reference system. There is also an expert system module called MATCH, built
from ecological databases. It mathematically compares field data with diagnostic
data held in the database, and assigns the collected data to the kinds of
species communities nearest to it.

MATCH has been used extensively for the NVC and has taken a lot of the
drudgery out of plant community analyses. MATCH is also being used at Lancaster
to monitor community changes that may arise from global warming. Although
VESPAN and MATCH were developed for vegetation analyses, they have been
used, for example, by entomologists and aquatic ecologists.

VESPAN and MATCH will run on IBM-compatible machines. The software supports
a maths co-processor, which greatly speeds up analyses. The basic, 16-bit
version of VESPAN costs ÂŁ100, with an enhanced 32-bit version at
ÂŁ150. Malloch can also supply VESPAN as source code (at ÂŁ100),
or in Fortran for a mainframe computer. MATCH costs ÂŁ100, with discounts
for educational users.

Rick Gould is an environmental scientist and computer modeller.

* Biological Sciences, University of Lancaster, Lancaster LA1 3BG. Tel:
0524 65201.

Most scientists and technologists use a personal computer and a telephone
system. Connect the two using a modem and some communications software,
and you can link up to thousands of computers worldwide.

Once connected in this way, you can send electronic messages and even
whole files to host computers from where they are downloaded by the intended
recipient. People can send you messages, too. This is electronic mail (e-mail),
and very rapid and efficient it is. For example, one contributor to New
ĐÓ°ÉÔ­´´ based in Oregon sends his articles electronically. This takes
seconds, unlike the post, and editors do not have to retype the copy.

You also have instant access to hundreds of scientific and technical
databases, 24 hours a day from anywhere, as long as you have a phone line.
But how do you get connected? Some online networks and information services
are prohibitively expensive and complex.

Fortunately, there are two electronic services that are both relatively
inexpensive and easy to access and use: CompuServe Information Services
(CIS) and Compulink Information Exchange (CIX). As a scientist, researcher
and writer, I find them useful and they do, despite some similarities, offer
different services.

CIX is claimed to be the largest cyber-conferencing system in Europe.
You enrol electronically and, once registered, receive a manual and join
an online tutorial. Having become au fait with the system – which does
not take long – CIX users can send e-mail to other members of CIX, and communicate
with thousands of sites and users worldwide. You can reach anybody who has
access to the standard Unix to Unix Copy (UUCP) network, including those
on CIS, Joint Academic Network (Janet) and most educational establishments.

But CIX’s trump card is its system of conferencing. Groups of users
link up to discuss a common interest. They are easy to join and anybody
can set one up. Many deal with computers – several of the conferences provide
online help groups, which are supported by hardware and software companies,
such as WordPerfect and Hayes. Other current conferences include the science
of signs, robotics and automation in libraries. There is even a conference
for disgruntled biologists.

CIX is very informal, having been set up by a group of young computer
enthusiasts based in London. But the service is excellent and the system
(based on Sequent mainframes) reliable.

CompuServe has an altogether different feel. It began in the US in 1979
and has its central computer in Ohio. CIS claims to be the largest information
network in the world – it has more than 850 000 registered users, and has
recently become established in Britain and Australasia. CIS has e-mail facilities
similar to those of CIX but it does not have CIX’s flexible and informal
conferencing set-up, concentrating its resources instead on providing information.

Once logged onto CIS and registered electronically, you receive a manual,
windows-based communications software, and access to more information than
my home town (population 50 000) could read in a lifetime. You obtain information
by joining a forum. Like CIX, CIS is supported by most computer companies,
so has forums acting as help lines. Other forums provide information on
the weather, news, financial services, consumer goods and travel. You can
even buy airline tickets via CIS. The drawback is that its services are
biased towards the US, but that is changing rapidly.

Apart from e-mail facilities, CompuServe’s greatest strength for scientists
and technologists is its access to databases, more than 800 of them. Services
such as Dialog and Data Star, reached through IQuest, give you access to
anything from Agrochemicals to Zinc, Lead and Cadmium Abstracts, pulling
information from millions of journals. IQuest also gives access to up-to-the-minute
information through a link with NewsNet. The Businesswire service carries
news releases from research institutions in the US among other things and
is updated every 15 minutes. And there is much more.

Now the costs. You pay ÂŁ15 to register as a CIX user, while online
charges are ÂŁ3.10 an hour at the peak rate and ÂŁ2 an hour cheap
rate. There is a minimum monthly charge of ÂŁ6.25 for individuals using
credit cards, and ÂŁ15 for corporate users to cover extra monthly
billing and credit.

In Britain, CIS costs ÂŁ19.95 to join, which includes the communications
software, manual and $25 usage credit. Online charges depend on the speed
of your modem: for 2400 baud they are $12.50 an hour and $22.50 an hour
for connection at 9600 baud. There are also communication surcharges, varying
according to which local telephone network you use to log on. In Britain,
they are $8 an hour at the peak rate and $4.50 at the cheap rate when
using BT DialPlus nodes. For users in London, access is through CompuServe’s
own node, a mere 30c an hour at the cheap rate. Some services (such as IQuest)
have their own access surcharges. To all this, you have to add the telephone
charges, which can be crushing. The costs can mount up swiftly if you get
carried away and lose track of the time you spend on the line.

The trick is to minimise online time. Fortunately this can be done using
an Off Line Reader (OLR). This is software that automates logging on, logging
off and the transfer of information. For example, you can download a conference
or forum, then read it offline at your leisure. An OLR will also help you
to write your contribution offline, and then send it to the network quickly.

Both CIX and CIS have OLRs available as shareware – called Matrix (for
CIX) and Tapcis (for CIS). These can be downloaded. However, I have found
the best OLR is a package called Tele-Pathy produced by Ashmount Research,
a company specialising in this kind of software. There are versions of TelePathy
for both CIX and CIS, and Ashmount Research is currently working on a version
for mainframes. Though TelePathy costs ÂŁ45, it quickly pays for itself.
You can reduce your phone bills and online time by 90 per cent. So, if you
just want connectivity and conference facilities, register with CIX. For
information, I would recommend CIS. I use both. Just watch those phone bills.

CIX, Suite 2, The Sanctuary, Oakhill Grove, Surbiton, Surrey, KT6 6DU.
Tel: 081-390 8446. CompuServe, 15-16 Lower Park Row, P. O. Box 676, Bristol
BS99 1YN. Tel: 0800 289458 (in Britain) or +44 272 255111 (from outside
Britain). Ashmount Research, 67 Shelton Street, Covent Garden, London WC₂H
9HE. Tel: 071-240 4460.

Rick Gould is a computer scientist and writer.

The researchers, led by David Bradley and Derek Seward from Lancaster
University’s Department of Engineering, began by interviewing and observing
people who worked on excavators. This information was used to program a
computer. ‘The plan was to mimic the subtle behaviour of digger operators,’
says Seward, ‘bearing in mind that a machine would have a different way
of doing things than a human being.’

The excavator has an on-board computer which controls the hydraulics
and bucket and will be guided by a laser beam pointed horizontally above
the ground. The beam will be a reference point to derive coordinates for
the length, depth, width and tilt of the trench.

The robot excavator will be able to dig to greater precision than skilled
human operators, who can usually dig to within 10 centimetres of specifications.
It will also enhance safety: when used in hazardous environments, such as
digging up leaking gas pipes, the excavator can be operated remotely. The
project was sponsored by JCB, a British company which makes excavators.

The researchers are now experimenting with other sensors – such as metal
detectors – so that the excavator will avoid crushing buried cables and
pipes. This could save the British construction industry some of the ÂŁ75
million lost each year through hitting buried objects.

The work was carried out in 14 universities and 4 research centres,
including the Institute of Terrestrial Ecology (ITE). The programme was
designed to investigate areas such as how pollution damages plants; interactions
between pollutants and other environmental factors; the fertilising power
of nitrogen oxides; and plant protection.

The most surprising results emerged from the interactions between environmental
stresses. For example, the ITE and the University of Edinburgh examined
the combined effects of wind, low temperature, acid mist and raised ozone
levels on Norway spruce. Such conditions are common in upland areas of Europe.
They found that these conditions left the trees more susceptible to frost
damage than those not exposed to air pollutants. The temperature at which
50 per cent of branches suffered frost damage rose by 6.6 °C in the
polluted conditions.

Another study, carried out jointly by the University of Lancaster and
Imperial College, London, examined the responses of common tree aphids,
feeding on conifers, to a variety of pollutants. The results show that both
nitrogen dioxide and sulphur dioxide significantly increase growth rates
of Elatobium abietinum feeding on sitka spruce, and of Schizolachnus pineti
feeding on Scots pine.

Further studies at Imperial College demonstrated that cereal aphids
grow faster when feeding on cereals exposed to raised, though not abnormal,
levels of ozone. The researchers, led by Nigel Bell, discovered that ozone
increases the concentration of soluble nitrogen compounds in the sap of
cereals, which benefits the aphids.

The Special Topic Programme also pioneered research into damage caused
by interactions between ozone, sulphur dioxide and fungal pathogens. Noresh
Magan and Mark Smith at the Cranfield Institute of Technology, near Bedford,
examined the effects of air pollution on two spruce needle fungi – Lophodermium
piceae and Rhizosphacra kalkhoffii – which are associated with premature
ageing and death of the needles. They found that the fungi were more abundant
on trees in highly polluted sites than on those in areas with low pollution.
Work done at National Power’s research centre at Liphook in Hampshire confirmed
that more fungi colonised trees exposed to sulphur dioxide.

But the story turned out to have another chapter. When pesticide was
used to kill the aphids, the abundance of fungi on spruce needles began
to fall. It seems that the aphids were transporting the fungi from one tree
to another. So, pollutants such as sulphur oxides not only increase the
population of the aphids which transport fungi between trees, but also encourage
the growth of the fungi themselves.

Despite the importance of the results produced by the research programme,
a question mark hangs over its future. Soon after National Power and PowerGen
were privatised they decided to pull out of air pollution research (This
Week, 13 July). It is feared within the NERC that without support from PowerGen
and National Power most of the planned research in this field will have
to be cut, unless more outside help can be found.