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At least 73 records · Page 4Linked to original sources
PubMed1990

[Morbidity of respiratory and cardiovascular diseases in smog conditions. Studies of 1,995 patients].

On the basis of the five-year study (1984-1988) presented herein, we have been able to demonstrate that, under conditions of smog, an increase in respiratory diseases can occur. Our results also show that cardiovascular diseases decrease simultaneously, an observation that has not so far been reported in the literature. A possible reason for this observation is, perhaps, an information effect, or an influence effect induced by warnings given in the media about the negative health-related consequences for those who leave their homes, in particular those consequences applicable to patients with cardiovascular disorders. The pathological process is traceable to a multifactorial occurrence, the temperature of the air having a decisive influence. To date, the influence of indoor pollution has not yet been clarified.

Air Pollutants↗
PubMed1980

Photochemical smog standards--practicability or purism: an evaluation of health risk in Sydney.

The photochemical smog conditions in Sydney are related to the effects on health, real and potential. Perspectives are presented with regard to the long-range goals of the World Health Organization, past and current United States Environmental Protection Agency standards, and current New South Wales prudent and actual aspirations in the short and long term. The need for practicable, rather than puritanical, goals in relation to possible adverse health effects is emphasized. The view is expressed that, while no significant ill health will be induced in current and improving atmospheric conditions, the aesthetic appearance of Sydney is unacceptable and therefore is detrimental to the feelings and well-being which are part of health.

Air Pollutants↗
PubMed1995

[Does summer smog damage the nasal mucosa and contribute to bacterial rhinitis?].

Smog in hot summers contains noxious agents resulting from the combustion of fossil fuels whose levels are highest in industrial areas. Reactions of the oxygen radical of ozone with sulfur dioxides, nitrous oxides, hydrocarbons and the water molecules of the nasal mucous membrane presumably support the formation of acids such as H2SO4 or HNO3 (from H2SO3 or HNO2 [3, 4]). Acid corrosion seems to damage the mucous membrane, leading to local erosions, bleeding, and necrotic changes. The collapsed local defense system and necrotic mucosa are an ideal culture medium for a wide spectrum of pathogenic bacteria. Main signs of tissue pathology are bleeding spots or pustules, nasal congestion, degenerative mucositis, pruritus, as well as epipharyngeal and pharyngeal irritation. Therapy is possible with topical or oral antibiotics. Prophylaxis includes avoiding touching the mucous membranes and reducing outdoor activity on hot summer days. Further clinical and scientific examination would be helpful in determining additional explanations.

Air Pollutants↗
PubMed1988

Testing of the abiotic degradation of chemicals in the atmosphere: the smog chamber approach.

Methods for measuring the hydroxyl-, ozone-, and direct photochemical reactivity of a substance in one specially designed medium size smog chamber are described. Rate coefficients for the reaction of OH with n-hexane, n-heptane, ethene, ethyne, chloroform, trichloroethene, methanol, 2-propanol, benzene, o-xylene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, p-chloroaniline, naphthalene, acenaphthene, 1,4-dichloronaphthalene, biphenyl, and fluorenone are given and discussed. An upper limit of 5 X 10(-13) cm3/sec is given for the sum penta- and hexa-chlorobiphenyls (PCB). Rate coefficients for the ozone reaction are given for beta-pinene, limonene, delta 3-carene, cineol, vinyl chloride and 1,3-butadiene. In cases where the literature data are available for comparison, the rate coefficients (kappa OH and kappa O3) reported here compare favorably with the best data reported. The direct photochemical reactivity has been shown to be measurable if the chamber is cleaned carefully. Preliminary results on benzophenone are reported. The methods described here, except that of direct photochemical reactivity, are in agreement with those proposed to OECD. Moreover, part of the Draft OECD Test Guideline (Berlin, 1987) on "Photochemical-Oxidative Degradation in the Atmosphere" is based on work described here and on closely related work in other laboratories (Becker et al., 1984).

Benzophenones↗
PubMed1981

The mutagenicity of diesel-exhaust particle extracts collected under smog-chamber conditions using the Salmonella typhimurium test system.

This study was designed to detect the effect that different environmental conditions have upon diesel-exhaust organics. In this study, diesel exhaust was injected into the Calspan smog chamber under different conditions, and the resulting particles were collected upon Pallflex glass-fiber filters. After extraction from the particles with methylene chloride, the organics were solvent exchanged to dimethyl sulfoxide and tested in the Salmonella typhimurium plate-incorporation test. Results demonstrate that the irradiation of propylene, SO2, NO and NO2 produces ozone and a mutagenic moiety. Unless another mitigating factor (e.g., ozone) was present or formed, irradiation did not alter the mutagenic response of the organics. The production or injection of ozone into chamber tended to reduce the mutagenic response of the collected organics. In summary, this study demonstrates that ambient conditions can alter the mutagenic response of diesel-exhaust organics.

Atmosphere Exposure Chambers↗
PubMed1990

Effects of photochemical smog and mineral nutrition on ponderosa pine seedlings.

Two-year-old seedlings of ponderosa pine (Pinus ponderosa Dougl. ex Laws) were exposed to ambient concentrations of photochemical smog (AA) and clean air (CA) during a single field season at Tanbark Flat of the San Gabriel Mountains in the Los Angeles Basin. The seedlings were grown in a perlite-vermiculite medium with full supply of nutrients (based on modified Hoagland solution); reduced to 50% supply of N; reduced to 50% supply of Mg; and reduced to 50% supply of N+Mg. No significant effects of air pollution exposures on injury development, stem growth and concentrations of plant pigments were determined. The seedlings in the AA treatment had decreased N concentration in current year needles compared with CA seedlings; however, the needle concentrations of other elements did not change. Reduction of N supply in the growing medium caused decreased N, P, Ca, K and chlorophyll a concentrations in needles. Stem growth of the seedlings with reduced N supply was significantly decreased as well. No changes in stem growth or chemical composition of plants with reduced Mg supply were noted. Reduction of supply of nutrients did not change responses of trees to the air pollution exposures.

Journal Article↗
PubMed2001

HPLC combined with multiple mass spectrometry (MSn): an alternative for the structure elucidation of compounds and artefacts found in smog chamber samples.

Ion trap multiple mass spectrometry combined with high-performance liquid chromatography (online HPLC-MSn) was used to identify carbonyl compounds and artefacts found in air samples of 2-3 L taken during the OH-radical reaction study of cis-3-acetyl-2,2-dimethylcyclobutylethanal (pinonal) or cis-3-acetyl-2,2-dimethylcyclobutylcarbaldehyde (nor-pinonal) in a smog chamber. Carbonyls were transformed into 2,4-dinitrophenylhydrazones. Detection of low picogram quantities was possible. Twenty-eight compounds could be identified based on the presence of structure characteristic fragments, a developed fragmentation scheme, comparison of retention times and a library of MSn spectra of selected carbonyls. Furthermore, the additional elucidation of the sub-structures of sixteen unknowns was possible. Details about the structure elucidation procedure and the formation of the observed fragments are presented.

Air Pollution↗
PubMed1975

Ozone decay in irradiated smog chambers.

Studies conducted in smog chambers show that ozone disappears significantly faster under irradiation than in the dark. A computer simulation was made to determine the cause for this accelerated O3 decay. It was found that the phenomenon can be explained by a series of chemical reactions involving O3, O1D, H2O, OH, HO2, and ultraviolet light.

Ozone↗
PubMed1971

Carbon monoxide: its role in photochemical smog formation.

The photochemistry of trace amounts of isobutene and oxides of nitrogen in an atmosphere of air was studied both in the presence and in the absence of small amounts of carbon monoxide. Carbon monoxide accelerates the reaction as measured by nitric oxide oxidation or ozone formation. This finding has relevance to photochemical smog formation.

Air↗
PubMed2006

Development of a supercritical fluid extraction-gas chromatography-mass spectrometry method for the identification of highly polar compounds in secondary organic aerosols formed from biogenic hydrocarbons in smog chamber experiments.

A new one-step method for the analysis of highly polar components of secondary organic aerosols (SOA) has been developed. This method should lead to a better understanding of SOA formation and evolution since it enables the compounds responsible for SOA formation to be identified. Since it is based on supercritical fluid extraction coupled to gas chromatography-mass spectrometry, it minimizes the analysis time and significantly enhances sensitivity, which makes it suitable for trace-level compounds, which are constituents of SOA. One of the key features of this method is the in situ derivatisation step: an online silylation allowing the measurement of highly polar, polyfunctional compounds, which is a prerequisite for the elucidation of chemical mechanisms. This paper presents the development of this analytical method and highlights its ability to address this major atmospheric issue through the analysis of SOA formed from the ozonolysis of a biogenic hydrocarbon (sabinene). Ozonolysis of sabinene was performed in a 6 m3 Teflon chamber. The aerosol components were derivatised in situ. More than thirty products, such as sabinaketone, sabinic acid and other multifunctional compounds including dicarboxylic acids and oxoacids, were measured. Nine of them were identified and quantified. The sensitivity and the linearity (0.91<R<0.98) of the method were both good and detection limits ranged from 1.2 to 6.4 ng for the investigated compounds.

Aerosols↗