London Air Research Articles

The incidence of increased pollen concentrations during rainfall in the air of London

Data from a Burkard volumetric sampler in a densely built-up area of North-central London, England are used to investigate the effects of rainfall on pollen concentrtions over four years. Pollen counts generally decreased with rainfall, although several episodes of increased pollen concentration have been recorded in London following the onset of precipitation.

Concentrations of particulate and gaseous polycyclic aromatic hydrocarbons in London air following a reduction in the lead content of petrol in the United Kingdom

The environmental importance of tropospheric polycyclic aromatic hydrocarbons (PAH) is reviewed. The impact of reducing lead on airborne PAH is indicated and the importance of monitoring both particulate and gaseous-phase PAH is demonstrated. A Brief description of a sampling regime performed from 1985 to 1987 is given. Sampling of 18 PAH was performed and particulate lead concentrations at the kerbside were measured concurrently. Measurements indicate that there is a pronounced seasonality in PAH concentrations and in the distribution of PAH between particulate and gaseous phases. On average, 47% of the PAH measured were in the gaseous phase, indicating the importance of measuring the volatile fraction. The dominance of the common variation of each PAH was also investigated using principal components analysis. An uneven spread of data prior to and following the reduction in lead content, hindered a thorough examination of the effect of this change on PAH concentrations. However, they appeared to indicate only a small change in PAH concentration and this was linked to an increase in aromatic content of the petrol, which was much less than expected.

Diurnal variation of pollen concentration in the air of north-central london

Abstract Pollen concentrations recorded during three years sampling in north-central London have shown distinctive diurnal variations. This paper identifies these patterns for three pollen taxa and attempts to account for the variations observed. The diurnal variations identified are interpreted in relation to meteorological conditions, pollen source area and phenological patterns of pollen release. A hypothesis of pollen dispersal to the sampling site is suggested.

Characterization and reconstruction of historical London, England, acidic aerosol concentrations.

Several past studies of the historical London air pollution record have reported an association between daily mortality and British Smoke levels. However, this pollution index does not give direct information on particulate mass or its chemical composition. A more specific particulate matter index, aerosol acidity, was measured at a site in central London, and daily data are available for the period 1963-1972. British Smoke and SO2 were also measured at the same site. Also, meteorological parameters were routinely measured at a nearby British Meteorological Office. Thus, daily fluctuation of the acidic aerosols was characterized in terms of other environmental parameters. Each of the other parameters analyzed seems necessary, but not sufficient to explain a high level of acidic aerosol. Overall, about half of the variance of log-transformed daily fluctuations of acidic aerosols can be explained by a combination of parameters including SO2 and British Smoke concentrations, temperature, ventilation by wind, and humidity. The rest of the variance cannot be explained by the parameters included in this analysis. Potential factors responsible for this unique variance would be variations in the availability of basic gases to cause neutralization and variation in the availability of catalytic metal salts. Because the acidic aerosol has a unique component of variation, it may be possible to distinguish health effects due to this specific pollutant from other available pollution indices or environmental factors.

Old Parr: or how old is old?

In 1635, the noted physician Sir William Harvey performed an autopsy on the body of Thomas Parr who was reported to have been 152 years old. Although there is little evidence to support Parr's age, historians agree that he had indeed reached an advanced age and was probably a centenarian. In his writings, Dr. Harvey left an interesting account of the autopsy, presenting a detailed description of the condition of Parr's body. He concluded that Parr's simple, active life-style probably contributed to his longevity and that the rich diet and polluted air of London probably contributed to his demise.

Indirect effects of air pollutants: Changes in plant/parasite interactions

The impact of air pollutants on plant/parasite-interactions has been investigated. It could be demonstrated that fumigation of Vicia faba L. with 0·15 ppm SO 2 (400 μg m −3) or 0·2 ppm NO 2 (400 μg m −3) during 7 days caused changes in plant metabolism which resulted in higher growth rates of the aphid Aphis fabae Scop. feeding on these plants. Fumigation of V. faba with 0·085 ppm O 3 during 2 or 3 days, however, caused decreased aphid growth on fumigated plants. That result could be reversed by higher O 3 concentrations or through the presence of NO x during O 3 fumigation. Ambient air comprising a mixture of pollutant gases had a strong enhancing effect on aphid performance. Thus, the growth of A. fabae on field bean plants was significantly higher in ambient summertime. London air than in charcoal-filtered air. Similarly, the growth of Macrosiphon rosae L. on rose bushes ( Rosa sp., cv. Nina Weibull) was improved in ambient summertime Munich air; the increase in growth rate averaged about 20%.

Safety Topics

REFLECTING widespread concern over the maintenance and where possible, the improvement of safety standards, the annual report of the Civil Aviation Authority (CAA) makes these topics a central theme. The progress made in recent years towards improving the safety of air traffic control (ATC) has been maintained, in particular the number of public transport aircraft involved in risk‐bearing airmisses fell from 45 in 1977 to 16 in 1985 and remained at that level in 1986. Because traffic levels continued to rise in the latter two years, however, this represents a small improvement from 2.9 per 100,000 hours flown in 1985 to 2.8 in 1986. The comparable figure for 1977 was 11.3. In the accompanying illustration is the three‐year moving average of civil aircraft in risk‐bearing airmisses within UK airspace. Some £125 million has been spent over the last five years on re‐equipping the system, including new radars, new navigational aids and new landing systems. New computer equipment, incorporating for the first time a conflict alert capability, has also been installed at the Oceanic ATC Centre at Prestwick. Over the next five years, £200 million is intended to be spent on more radar improvements and upgrading facilities at the London Air Traffic Control Centre (LATCC) at West Drayton as well as the installation of a new central computer for which detailed design studies are well under way.

Air pollution increases Aphis fabae pest potential

Many observations have been made of increased population densities of herbivorous insects in areas subject to air pollution1–3. However, in the absence of experimental investigations, the significance of most of these observations is not clear and any underlying causal mechanisms remain obscure. The only published studies designed to investigate experimentally the impact of pollutants on plant–herbivore systems involve fumigations with either hydrogen fluoride (HF)4 or sulphur dioxide (SO2)5,6 of Phaseolus vulgaris and Glycine max plants, infested with the Mexican bean beetle, Epilachna varivestis: in general the results showed that HF reduced beetle performance whereas SO2 stimulated it, but the relative importance of direct and indirect effects of the pollutants was not elucidated. We show here stimulatory effects of SO2 and NO2 and ambient London air on the growth of the black bean aphid, Aphis fabae, and demonstrate that these have been mediated entirely via the host plant.

Long term trends in London fog

The frequency, and weekly and seasonal distribution of London fog may be obtained from non-instrumental observations which stretch back into the seventeenth century. Despite difficulties due to differences in individual observer's definitions of fog and perceptual bias, a coherent picture emerges. The fogs of the late seventeenth century have a surprisingly high frequency (20 per year) and a rather unusual seasonal distribution that may arise from the Little Ice Age climate. The eighteenth and early nineteenth century seems to have been a period with a relatively low frequency of fogs (about 10 per year), but most of the nineteenth century exhibits a dramatic rise in the incidence of fogs which rose to nearly 70 per year by the 1890's. These changes were followed by an equally dramatic reduction in fog frequency throughout the present century. These trends are attributable to changes in the distribution and strength of London's air pollution sources. The weekly distribution of fogs shows no really pronounced “Sunday-effect” which might implicate domestic sources for the pollution, despite contemporary comment on this phenomenon. The yellow colour and proverbial celebrity of London fog is also discussed.

Ethylene dibromide in urban air

Ethylene dibromide (EDB) has recently been reported by the National Cancer Institute U.S.A., to be a potential carcinogen. Its commercial use is predominantly as a scavenging agent for lead in petrol. A procedure has been developed for the rapid sampling of ethylene dibromide in ambient air followed by analysis using gas chromatography with an electron capture detector. Ambient levels in London air were found to be in the range 0.001–0.17 μg m −3 and on a garage forecourt levels of 1.2 and 1.8 μg m −3 were determined. Ethylene dibromide was also measured in car exhaust and a calculation is included relating levels of organic lead to those of ethylene dibromide.

Parallelism of atmospheric electrical potential and mortality in London air pollution episodes.

Atmospheric electrical potential (E) was evaluated statistically with smoke and sulfur dioxide as a predictor of excess mortality during the London air pollution episodes of the 1950s. E, as a surrogate of respirable aerosols, in combination with SO2 proved to be a better predictor of excess episode mortality than smoke.

The Operation of Light Aircraft

An informal discussion on the operation of light aircraft took place at a meeting of the Technical Committee of the Institute in London on 21 April 1976. A personal view expressed by Mr. F. S. Stringer and comments by Mr. C. Powell and Professor A. N. Black are printed below.Recent technical press disclosures have highlighted C.A.A. concern that the London Air Traffic Zone is being entered by unauthorized light aircraft, the infringements varying from minor boundary incursions to major crossings of the area. The pilots involved vary in experience, and in most if not all cases have been flying under VFR rules and out of radio contact with Air Traffic Control. It seems very probable that these pilots are lost, or at least very unsure of their position; the topographical relation of charts to places on the ground is becoming increasingly difficult to interpret due to the complexity of built-up areas, especially around the T.M.A.s. Not all aircraft carry VOR or ADF and the map and DR are the main navigational aids; some pilots are reluctant to call for radar assistance for a variety of reasons.

London air pollution, 1500–1900

Documentary evidence for the changes in the air pollutant levels and climate of London are compared with the results obtained from a simple single box model for the annual mean SO 2 and particulate levels in the London air. Sulphur dioxide reaches a maximum of nearly 200 μg m −3 in a plateau that stretches from 1690–1880. Particulate concentrations show a peak at the end of the 19th century.

Changing pattern in concentrations of polycyclic aromatic hydrocarbons in the air of Central London

The concentrations of polycyclic aromatic hydrocarbons have been measured in Central London and the levels of some of these have declined markedly. For example the concentration of 3:4-benzpyrene has fallen to about one-tenth of the level found 25 years ago. By using selected ratios of polycyclic aromatic hydrocarbons it has been shown that the contribution to the air of the 3:4-benzpyrene from coal burning sources has declined; at one roof-top site about one-fifth to one-quarter of the total benzpyrene found there now probably comes from the traffic sources.

Elevated ozone levels in the air of Central London.

AMONG the reactions of primary pollutants with one another and with substances naturally present in air, the reactions induced by light are particularly important. The occurrence of such reactions is related to the accumulation of strongly oxidizing species, particularly ozone1, which occurs naturally in the atmosphere to the extent of 20–50 p.p.b. during daylight2,3. Ozone can be detected by smell by sensitive individuals at 100 p.p.b.4, which value is a suitable threshold for an air quality evaluation, having been proposed as an air quality standard in the USA5.

Organochlorine Pesticides in Rainwater in the British Isles

PREVIOUS studies of the presence of the persistent organochlorine pesticides in the atmospheric environment of this country1–3 have all indicated the need for more comprehensive surveys. The first of these studies by Wheatley and Hardman1 was confined to rainwater collected in the rural area of Wellesbourne, in Warwickshire. Subsequent studies by the Laboratory of the Government Chemist were concerned with the examination of rainwater2 and air3 collected chiefly in the central London area. These three studies showed that, in the areas concerned, the atmospheric environment contained small amounts of BHC, dieldrin and DDT; rainwater collected in these areas contained concentrations of up to 400 parts/1012 of these compounds and their breakdown products. The higher levels for DDT found in London rainwater, compared with that from Wellesbourne, were attributed to London air having a higher content of particulate matter, chiefly carbon particles, for which DDT has an affinity. Dieldrin probably also shows this affinity but to a lesser extent.

Natural History of Chronic Bronchitis in Working Men.

s1 May 1968Natural History of Chronic Bronchitis in Working Men.Charles M. Fletcher, M.D., F.R.C.P., Cecily M. Tinker, M.R.C.P., I. David Hill, B.SC., Frank S. Speizer, M.D.Charles M. Fletcher, M.D., F.R.C.P.Search for more papers by this author, Cecily M. Tinker, M.R.C.P.Search for more papers by this author, I. David Hill, B.SC.Search for more papers by this author, Frank S. Speizer, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-68-5-1185_3 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptThe study was designed to test the hypothesis that in the development of chronic airway obstruction mucous hypersecretion encourages bronchial infection which causes bronchiolar damage, or emphysema, or both. Biennial measurements of sputum volume, respiratory illness frequency, and forced expiratory volume (FEV) were made on 905 working men in West London from 1961 through 1966. Mean sputum volume declined steadily, perhaps owing to reduction in London's air pollution. It declined most steeply in men who stopped smoking. Chest illnesses had little effect. Only one new case of simple bronchitis appeared. Illness frequency increased with increasing sputum volume and decreasing FEV... This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: London, PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics 1 May 1968Volume 68, Issue 5Page: 1185-1186KeywordsAir pollutionBronchitisChronic bronchitisEmphysemaForced expiratory volumePulmonary diseasesSputumThorax Issue Published: 1 May 1968 PDF DownloadLoading ...

Some measurements of carbon monoxide in the air of London.

Some measurements of carbon monoxide in the air of London.

POSTABORTAL OLIGURIA

Renal insufficiency as a complication of pregnancy, and particularly of abortion, has long attracted serious consideration. At necropsy the organs of fatal cases in this group are found with morphologic features in common; and there is a constant relationship between the clinical syndrome and these structural changes. Comparison of this relationship with that resulting from other causes has made possible a more complete explanation of postabortal oliguria. Bywaters and Beall¹in 1941 activated interest in the clinical-pathologic picture which followed crush injuries sustained in the London air raids. The triad of crushing injury, subsequent renal failure and histopathologic alterations in the kidneys focused the attention of clinicians and pathologists on this disease entity, which they called the crush syndrome. The onset of symptoms 2 follows in the wake of crushing trauma or other precipitating factors with or without evidence of shock. Nausea, vomiting, malaise and abdominal pain are usually

British Food Journal Volume 49 Issue 1 1947

British Food Journal Volume 49 Issue 1 1947