Elevated Air Pollution Concentrations Research Articles

Air pollution potential in Buenos Aires city, Argentina

A study of the climatology of ventilation properties of the atmosphere in Buenos Aires city has been carried out. From routinely available observational data, the daytime stability conditions and related ventilation factors and airflow characteristics are obtained and studied. In all cases, the seasonal and annual behaviour is analysed. The frequencies of occurrence of daytime reduced ventilation factors are important, being 55% over the whole year and, respectively, 67% and 44% in the cold and warm periods. The prevailing daytime atmospheric stability conditions are near neutral, slightly unstable and unstable. The most frequent daytime wind directions occur in the north-southeast sector and during the cold period are mainly associated with the smallest ventilation factor ranges. The results obtained suggest that, during the cold season, conditions for elevated air pollution concentrations occur with high probability in the atmosphere of Buenos Aires city.

Assessing health effects of air pollution

Exposure to elevated concentrations of ambient air pollutants causes adverse human health effects. Two modes or methods of study are generally relied on to quantify the relationships between pollutants and specific effects. These are: human clinical experiments and epidemiological (or community exposure) studies. (Animal toxicological studies can be used to indicate the existence of an effect, but not the rate of the effect in humans.) Each method has limitations as a basis for quantifying the level of adverse effects anticipated in a given human population as a result of exposure. Consequently, care must be taken in deciding which studies are appropriate for assessment of health impacts in a population. Some limitations are inherent in the method. Epidemiological studies, for example, depend on adequate community monitoring and the ability to associate a cohort with ambient data. Clinical studies often do not represent the complex mix of pollutants in the atmosphere. Consequently, construction of dose/exposure-response functions is challenging. Another common complication in quantifying expected health impacts of a pollutant mix is lack of adequate ambient monitoring data coupled with little or no knowledge of a population's time and activity profiles. This paper summarizes the difficulties inherent in constructing estimates of health effects in populationsliving in densely populated and polluted areas and suggests approaches to making initial limited estimates. An example of the level of effort required to conduct a sophisticated study, using relatively rich databases, is given based on work done in the Southern California region.

Reexamination of London, England, mortality in relation to exposure to acidic aerosols during 1963-1972 winters.

Air pollution epidemiology since the 1950s has been able to demonstrate that increases in daily mortality in London, England, were associated with elevated concentrations of index air pollutants, i.e., British Smoke (BS) and sulfur dioxide (SO2). In this work, we reanalyze that portion of the 1958-1972 winter mortality-pollution record for which daily direct acid aerosol measurements were made at a central site in London (St. Bartholomew's Medical College). The purposes of these exploratory analyses are to examine the dataset for indications of a relationship between acid aerosol pollution and human mortality and to compare any noted associations with those for other pollution variables. It is found that the log of acid aerosol concentrations is more strongly associated with raw total mortality in bivariate analyses than is BS or SO2, despite the fact that acid data are available from only one central site (versus seven disperse sites for BS and SO2). The logarithmic nature of the exposure side of the H2SO4-mortality relationship implies a saturation model of pollution effects, possibly due to multiday pollution harvesting influences on a susceptible subpopulation. Moreover, mortality-pollution cross-correlation analyses indicate that mortality effects usually follow pollution in time, supporting a causal relationship between the two. The apparent advantage of H2SO4 over BS in predicting total raw mortality is consistent with the hypothesis that it is the portion of particulate mass of greater health significance and may also allow the development of London mortality results which are more easily transferable to other environments than is the case for existing BS results.

Reexamination of London, England, Mortality in Relation to Exposure to Acidic Aerosols during 1963-1972 Winters

Air pollution epidemiology since the 1950s has been able to demonstrate that increases in daily mortality in London, England, were associated with elevated concentrations of index air pollutants, i.e., British Smoke (BS) and sulfur dioxide (SO2). In this work, we reanalyze that portion of the 1958-1972 winter mortality-pollution record for which daily direct acid aerosol measurements were made at a central site in London (St. Bartholomew's Medical College). The purposes of these exploratory analyses are to examine the dataset for indications of a relationship between acid aerosol pollution and human mortality and to compare any noted associations with those for other pollution variables. It is found that the log of acid aerosol concentrations is more strongly associated with raw total mortality in bivariate analyses than is BS or SO2, despite the fact that acid data are available from only one central site (versus seven disperse sites for BS and SO2). The logarithmic nature of the exposure side of the H2SO4-mortality relationship implies a saturation model of pollution effects, possibly due to multiday pollution harvesting influences on a susceptible subpopulation. Moreover, mortality-pollution cross-correlation analyses indicate that mortality effects usually follow pollution in time, supporting a causal relationship between the two. The apparent advantage of H2SO4 over BS in predicting total raw mortality is consistent with the hypothesis that it is the portion of particulate mass of greater health significance and may also allow the development of London mortality results which are more easily transferable to other environments than is the case for existing BS results.