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At least 91 records · Page 5Linked to original sources
PubMed1985

Peroxybenzoylnitrate: measurements in smog chambers and in urban air.

Peroxybenzoylnitrate (PBzN, C6H5C(O)OONO2), a photochemical atmospheric pollutant and powerful eye irritant, was detected at greater than or equal to 10 ng following aqueous alkaline hydrolysis to benzoate ion and analysis by ion chromatography with ultraviolet detection. Method validation studies and studies of potential interferents including benzaldehyde and benzoic acid are described, together with applications to PBzN measurements in environmental chamber atmospheres and in ambient air.

Air Pollutants↗
PubMed2004

Killer smog of London, 50 years on: particle properties and oxidative capacity.

Total suspended particulate (TSP) samples collected on glass fibre filters in London before (1955) and after (1958-1974) the Clean Air Act was examined for physicochemical characteristics and oxidative capacity. High-resolution microscopy identified most of the material as soot with smelter spheres, fly ash (FA), sodium chloride and calcium sulphate particles. Image analysis (IA) was used to show that most of the soot aggregates were less than 1 microm in size and contained chains of individual particles of 10-50 nm. Speed mapping of large agglomerates of the historic particles confirmed that the samples were enriched with soot probably derived from a sulphur-rich coal called nutty slack which was used extensively at this time. Inductively coupled plasma-mass spectrometry (ICP-MS) was used to examine elemental composition. Meaningful quantitation of certain elements (Mg, Al and Zn) proved impossible because they were in high quantities in the glass fibre filters. However, high quantities of Fe>Pb>Cu>Mn>V>As were detected which may explain in part the bioreactivity of the samples. Using a simple in vitro test of oxidative capacity (plasmid assay), one historic particulate sample (1958) showed three times the activity of a modern-day diesel exhaust particle (DEP) sample but ten times less activity than a modern-day urban ambient particle collection. Such studies are continuing to link particle physicochemical properties and bioreactivity with a wider range of the samples collected between 1955 and 74 and how such historic samples compare with present-day London ambient particles.

Air Pollutants↗
PubMed1992

The effect of ozone associated with summertime photochemical smog on the frequency of asthma visits to hospital emergency departments.

A retrospective study using ambient ozone, temperature, and other environmental variables and their effect on the frequency of hospital visits for asthma was conducted in New Jersey, an area that often exceeds the allowable national standard for ozone. Data on emergency department visits for asthma, bronchitis, and finger wounds (a nonrespiratory control) were analyzed for the period May through August for 1988 and 1989. Asthma visits were correlated with temperature while the correlation between asthma visits and ozone concentration was nonsignificant. However, when temperature was controlled for in a multiple regression analysis, a highly significant relationship between asthma visits and ozone concentration was identified. Between 13 and 15% of the variability of the asthma visits was explained in the regression model by temperature and ambient ozone levels. This association, when compared to similar studies in Canada, shows the contribution of ozone to asthma admissions to be stronger in areas with higher ozone concentrations. Thus, among regions with periodic accumulations of ozone in the ambient atmosphere, an exposure-response relationship may be discernible. This supports the need to attain air quality standards for ozone to protect individuals in the general population from the adverse health effects caused by ambient ozone exposure.

Asthma↗
PubMed1997

Simple laboratory-made system for the determination of C2-C7 hydrocarbons relevant to photochemical smog pollution.

A simple gas chromatographic system suitable for determining volatile organic compounds from C2 to C7 in air is described. It consists of a capillary cold trap filled with graphitic carbon, a thermodesorbing device, a capillary gas chromatograph equipped with an alumina column and a flame ionization detector. Dry, as well as humid, air samples can be analysed with our system. Up to 2-1 samples of air can be enriched on our trapping device by using Nafion membranes for removing water. Direct analysis of air samples is possible by enriching 250 ml on the carbon trap. The recovery, sensitivity and linearity of our system have been checked with standard mixtures and real samples. The performances have been compared with those afforded by a commercially available instrument exploiting a different enrichment procedure. The results obtained show that our analyser can be successfully applied to determinations of C2 to C7 hydrocarbons present in air samples at levels of 0.01 ppb (v/v).

Air Pollutants↗
PubMed1954

SMOG.

Explore the source record for details and available documents.

Air Pollution↗
PubMed1970

A lesson from the smog capital of the world.

The history of air pollution control in the Los Angeles area shows a gradual transfer of authority from city and county to state and federal government. The relative role of the various levels of government is discussed. Regional control will become increasingly important with standards set or approved by state and federal authorities. Progress is noted in the control of both stationary and moving sources, but long-range planning of the development of our urban complex with an overriding regard for its effect on the environment is needed if the technological innovations are to keep pace with the demands of an ever-increasing population.

Air Pollution↗