by Olga BAZANOVA, journalist

Our country was the venue of international experiments "TROICA" (Transcontinental Observations into the Chemistry of the Atmosphere) carried out in 1995 to 2001 with the aim of developing methods for atmospheric observations from mobile lab platforms.

This project was initiated by Academician Georgi Golitsyn, director of the A. M. Obukhov Institute of Physics of the Atmosphere (Russian Academy of Sciences), and Paul Kruzen (Germany), Nobel prize-winner and head of the Max Planck Institute of Chemistry.

It also involved teams from the All-Russia Research Institute of Railroad Transport under its director Leonid Lisitsyn, Dr. Sc. (Technology).

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The quality of the surface, outdoor air we breathe is an essential ecological factor impacting human health, the natural environment and the economy. This is common knowledge. The principal air pollution sources are concentrated in cities and industrial zones with the highest population density. Therefore the data collected by a mobile railway laboratory (the world's only one) making a tour of such regions drew attention from the international scientific community. The very first journey undertaken by a research team from the RAS Institute of Physics of the Atmosphere (IFA) proved the high efficiency of such mobile platforms for exploring wide continental expanses. That first expedition covered thousands of miles from Moscow to Khabarovsk in the Far East, registering meteorological parameters, concentrations of ozone and nitrogen oxides in the ambient air, and the effect of solar radiation. In 1996 the "TROICA" project was joined by the Max Planck Chemistry Institute of Germany (1996), the L. Ya. Karpov Physicochemical Research Institute of Russia (1997), and the Laboratory of Climate Monitoring and Diagnostics of the United States (2001).

Our German colleagues were headed by Prof. Lelieweld (today director of the Max Planck Institute), the American - by Dr. Elkins; the research team of the L. Ya. Karpov Institute was led by A Andronov, Cand. Sc. (Phys. & Math.). The "TROICA" experiments were supervised by Dr. Yelansky of the RAS Institute of Physics of the Atmosphere.

The laboratory made six trips along the transsiberian railroad, from Moscow all the way to Khabarovsk and back. Besides, a major research program was carried out in 2000 so as to study androgenic and natural sources of methane, carbon oxide and dioxide contamination as well as organic pollutants. These studies were conducted far and wide - on the Kola Peninsula and in Russia's central regions and in the environs of Kislovodsk down south and in the mountains of the North Caucasus (in spring, as the photochemical system of the atmosphere shifts from winter to summer).

To control the condition of the atmosphere and forecast hazardous situations it is important to know the concentration of gas and aerosol impurities alongside thermodynamic, radiation and meteorological parameters, and process such data by numerical modeling methods. The railway laboratory, equipped as it was with the latest array, could well cope with this job. The lab could work nonstop in measuring a complex of essential characteristics, in contrast to solitary stations set up here and there, with their quite limited capabilities. Crossing to and from the territory thus explored and what with the different bearing of apparent wind, the mobile laboratory passed the pollution plumes coming from many sources and, therefore, roving research teams could pinpoint and evaluate such pollutants. They could compare the ecological situation in different parts of the country and, through multiple measurements, detect the change dynamics.

Every kind of transportation, power-and-heating plants and industrial enterprises discharge a large amount of nitrogen oxides (as much as 4 mln tons

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in this country) which are playing a key role in atmospheric oxidation processes. True, these compounds decompose readily and thus do not propagate far from the source; but their significant concentrations have an adverse effect on people's health. Our laboratory on wheels is a very effective means of monitoring the concentration of gases in the atmosphere. For instance, in the course of field expeditions the level of nitrogen oxide discharges was found to exceed those of dioxide. Should dioxides be in excess, they will trigger vigorous oxidation reactions in the atmosphere.

Significant concentrations of volatile organic compounds (like methanol, acetontitrile, acetaldehyde, isoprene, methanols, benzenes, toluene, etc.) are harmful to living organisms; many of these substances have a toxic, mutagenic and cancerogenic effect. Disintegrating, they form active radicals responsible for chemical processes in the atmosphere and its composition. Since no regular monitoring of such impurities was conducted here in Russia, there was scant evidence on their natural and technogenic sources, including those in vicinal states. But the mobile lab data filled this gap in part.

Thanks to this information we can now predict even emergency situations, for example, due to the accumulation of gaseous toxic substances in the environment. One such agent, trichloroacetic acid (TCA), the product of interaction among relatively inoucuous compounds, does great harm to plants: these develop an enhanced water yielding capacity against a background of lower assimilability of carbon dioxide. If present in significant concentrations in the air, this pesticide kills forests, something now observed in Central Europe. The data obtained by "TROICA" experiments will show whether this kind of disaster threatens any particular region of this country.

In 1996 "TROICA" expeditions began studying the atmospheric concentration of aerosols, their micro-physical and chemical characteristics. These disperse systems make the "optical weather" of our planet and its climate, they determine the balance of many gases, and carry chemically active and toxic agents on their particles. Therefore this line of research was among priority ones for the mobile lab. It was equipped with a computer-assisted array of instruments enabling observations in real time and hooked to Internet (this setup was developed by the Karpov Physicochemical Institute). The array includes a device for measuring a mass concentration (g/m³ ) of 0.05 - 15 μm particles (registration time, 10s and longer); it also has laser, photoelectric and electrostatic analyzers of particles in a range of 0.15 - 1 μm, 0.5 - 15 μm and 0.005 - 1 μm, respectively, as well as samplers.

Thus equipped, the wheeled lab collected data on the characteristics of aerosols over continental expanses of more than 8,000 km. It identified industrial zones and contaminations proper to them only. The concentration of pollutants in the air in the summertime was found to be between 20 - 30 μg/m³ (daylight hours) to 30 - 40μg/m³ (nighttime). In the discharge

Distribution of nitrogen oxides between Moscow and Khabarovsk.

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Distribution of fungal spores concentration along the Moscow-Vladivostok railroad.

plumes of industrial centers and cities this concentration reached 100 - 120 μg/m³ , though on days off it went down severalfold compared with regular working days. This indicator soared because of forest fires (to as much as 800 μg/m³ ). That is why, in order to assess the ecological situation in various parts of this country and pinpoint sources of aerosol pollution, soil and air samples had to be taken, with subsequent chemical analyses made under stationary conditions with the use of neutron activation and X-ray methods, electron microscopy and IF spectroscopy.

Soot particles are a very bad pollutant. Absorbing and carrying on harmful substances of technogenic origin, they are often toxic and cancerogenic, and catalyze chemical reactions in the atmosphere. Taking in solar radiation, such particles are also implicated in climate formation. The "TROICA" parties measured the concentration of this aerosol every hour while traveling up and down the transsiberian railroad and the railway lines between Murmansk and Kislovodsk. Samples were collected on quartz fiber filters and assayed for light absorption. In Russia's European part the level of soot pollution amounted to 1 - 2 μg/m³ , though this indicator was tenfold as high on railroads where diesel locomotives are employed.

Observations carried out over large expanses of this country showed starkly different distribution patterns of soot impurities due to weather and meteorological processes. The soot concentration was up with a decrease of wind velocity. Grass fires were another cause of soot particles generation.

Biological aerosols (viruses, fungous and bacterial spores, flower pollen spores and the like) are yet another hazard responsible for grave diseases in man, animals and plants. This category includes toxic agents, allergens and microorganisms causing biological impairments. Consequently, it is likewise important to identify and measure the presence of bioaerosols. Since 1996 the atmospheric monitoring of fungal spores has been done by the Department of Biology at Moscow State University. The "TROICA" research teams, well equipped with proper technology, have joined forces with the biologists. Thus pooling efforts, they could ascertain essential regularities of spores and pollen propagation along the trunk railroad line between Moscow and Vladivostok as well as the different makeup of such "bouquets" in intensive farming areas (European Russia, Tyumen) and in sparsely populated districts east of Lake Baikal.

Hothouse gases, too, act upon atmospheric processes and associated radiation, and on the chemical composition of surface air. For instance, the carbon dioxide concentration tells on the climate most of all. And carbon monoxide gives rise to ozone which, if present at high concentration, is deleterious to human health, and to the plant and animal kingdoms at large. A buildup of methane released in technogenic accidents may pose a threat of explosions.* The highest emissions of carbon dioxide were registered in the Far East, and those of carbon monoxide-in industrialized European Russia, in Eastern Siberia's south (in consequence of forest fires and combustion products carried in from China burning up farm produce wastes); enhanced concentrations of methane were also detected in the heartland of European Russia and in

* See: G. Golitsyn, "Methane and Hothouse Effect", Science in Russia, No. 6, 2002. - Ed.

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Western Siberia. Most of the methane escaped from bogs and wetlands, from industrial effluents, and garbage dumps; and some of it came from leaks attending the extraction and transportation of natural gas.

Mobile lab crews took air samples so as to assess the contribution of methane and carbon oxide in the balance of hothouse gases. Subsequent isotope analyses made at the Max Planck Institute of Chemistry (Germany) confirmed the natural cause of most of these emissions.

As a matter of fact, Russia is going to increase the production of natural gas-and it will be developing new major deposits and build more pipelines. That is why it is important to secure adequate controls over the performance of related power industries. The wheeled laboratory did a real job in pinpointing leak-proofness faults in gas pipelines and thus preventing fires and explosions. Observations were carried out with the aid of an automated array by the method of high-performance gas chromatography. As shown by expert examination, the amount of technogenic leaks of methane happened to be much lower than predicted by foreign experts.

Ozone is part of the hothouse gases. As a potent oxidizer, this gas determines the chemical composition of air, and it is toxic, too. During the 20th century the concentration of ozone doubled and attained to hazardous values in certain industrial regions; its spatial distribution, too, became more heterogeneous. The data collected by several regular, fixed stations are not sufficient for evaluating this indicator. But the mobile lab could cope quite well with this task by obtaining, for the first time ever, information on the characteristics of ozone (and precursors of this modification of oxygen) propagation over the continent, the transfer of ozone, the photochemical processes of its generation, decomposition, and so forth. The point is that the ozone concentration in the air is indicative of the dynamic transformations of temperature inversion* because it disintegrates under the respective atmospheric layer at night.

Ozone concentrations above the permissible levels received particular attention. Such excessive concentrations occur in forest and industrial fires, they also occur near high- voltage power lines, and in large cities and industrial centers given definite weather conditions. All that happens in the daytime. The roving lab monitored such phenomena, even their weak effects, with the help of high-precision calibrated instruments assisted by adequate software, and in this wise it could detect potentially dangerous sources of air pollution, predict ecologically adverse trends and their aftermath.

Ozone, if present in excessive concentrations in the surface air, may become a hazard. But the situation is different higher up, at 10 to 15 km, where the ozone layer protects living nature against the lethal short-wave

On July 3, 1999, enhanced concentrations of ozone discharged from nearby sources were registered in the Khabarovsk Territory even in early morning hours.

* Temperature inversion-an increase of temperature at higher altitudes in an atmospheric stratum instead of the expected decrease. - Ed .

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length UV solar radiation. That is why it is very important to control discharges of ozone-destroying substances, particularly, chlorofluorene carbons (freons), halons and other halogen-containing compounds. The "TROICA" research parties did their bit, too: together with their American colleagues, in 2001 they carried wide-ranging observations along the railroad line linking Moscow and Khabarovsk (over 8,000 km) and, with the aid of the four-column high-performance gas chromatography complex ACATS-IV, spotted concentrations of eleven ozone-killing substances and hothouse gases. According to subsequent calculations, Russia makes but a small contribution in the atmospheric pollution with methyl chloroform, tetrachloro-methane and freon-11; but this country contributes more of halon-1211 and freon-113, and much more, of freon-12. Now, most of this very gas escapes from old refrigerators and plants still making them.

Radioactive labels, primarily of the noble gases of radon and thoron, are very good for identification of harmful volatile impurities; rising up, such labels travel with the air and do not enter into any chemical reactions. That's why they help trace the air movement.

The mobile laboratory (a special-purpose railway car) is equipped with facilities for remote probing of the atmosphere and studying the concentration of chemically and climatically active gases all through. It thus became possible to measure the vertical distributions of ozone, nitrogen dioxide, and study the physicochemical properties of aerosols to altitudes of 45 - 50 km in areas beyond the reach of the global network of air-monitoring stations. Besides, lab research crews processed space-monitoring data on the concentration of these substances in the atmosphere, and calibrated instruments. The methods employed at ground, fixed stations proved quite good for the railway laboratory as well.

In particular, this mobile lab helped determine the extent of environmental pollution in territories adjacent to railroads. This was done by taking soil and air samples along the tracks so as to test them for the presence of aerosols. Studies made with the help of a gamma-ray radiometer cum spectrometer revealed the presence of many elements having different values of the enrichment (concentration) factor: soil particles (silicon, iron, potassium, calcium, titanium) had a factor of 10; elements of heterogeneous origin (nickel, magnesium, manganese, barium, strontium, phosphorus, zinc, lead) were close to this

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factor; and technogenic particles (cesium, sulfur, chlorine, bromine, vanadium) were above this indicator. The latter group elements are within minute fractions traveling over huge distances, far away from their source of origin.

The ground along the tracks of the transsiberian railroad was found to be badly polluted with heavy metals. At most of the railway stations the concentration of copper, nickel, zinc, vanadium and lead exceeds the permissible limit fivefold and more, and that of manganese-two- and threefold.

The rolling stock on diesel locomotive traction is likewise responsible for bad environmental pollution. Exploring a railway stretch near Petrozavodsk in Russia's northwest (where diesel locomotives are employed), the mobile lab registered a 40 fold increase in the atmospheric concentration of carbon oxides and soot compared with railways using electric locomotive traction.

But perhaps the results thus obtained might be distorted by the movement of trains traveling from the opposite direction and by the lab's own movement? Therefore adequate studies had to be made into indices on acceleration and deceleration stretches, and during stopovers. The variations were found to be quite insignificant, save for some increase in the concentration of nitrogen oxides near population centers and a higher temperature differential-negative by day and positive at night. This means that observations from the mobile platform laboratory agree with the actual condition of the atmosphere.

In 2002 and after, as the "TROICA" experiments were through, the mobile lab researchers kept up their work in Moscow, at the air monitoring station of Moscow State Univer-sity - this station donated hard- and software for the roving lab. In between regular sessions, a part of the instruments came to be employed for comprehensive studies of the ecological situation in the city of Moscow; some of the time was devoted to technical servicing, verifications and instrument calibrations. Then came nonstop measurements of concentrations of ozone in Moscow, and of nitrogen and carbon oxides, methane and aerosol concentrations; there were also measurements of meteorological and radiation parameters; this work allowed to keep tabs on the annual and circadian variability of atmospheric impurities, including the dynamics of air pollution over Moscow.

Essential data were obtained in the summer and fall of 2002 as peatbog and forest fires were on near Moscow, and as the smoke enveloped the entire megalopolis on some days. The concentration of gas impurities was often above the permissible levels, and visibility was down to 200 meters. The emission of carbon monoxide (choke-damp fumes), methane and volatile organic compounds triggered generation of other harmful substances, ozone among them.

Meanwhile, the lab car has been upgraded and fitted out with the latest of technology; its research crew has swelled its numbers, too. Today the lab can truly be called a mobile observatory, and it is bound to become the central part of the air monitoring network which will also include another two stations: the highland station at Kislovodsk and one now being set up in Eastern Siberia, 500 km away from the city of Krasnoyarsk.

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