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The most common airborne algae are recognized as a community of acroalgae, and their morphological attributes and dimensions arc associated to an average aerodynamic structure, called idcal airborne algae. The principal atmospheric factors producing the dispersion and viability of alga are briefly introduced. For the first time. in a systematic and consequent way. preprocessors of atmospheric parameters are used in aerobiology. The research indicates, at least statistically. that the synthesis of specific parameters in preprocessors is of a greater relevance for the dispersion of algae (and physically equivalent particles) than each onc of the mctcorological paramcters by themselves. This synthesis introduces a theoretical -practical level of elaboration that allows a greater deepness of analysis. In this case, the adequate preprocessors of atmosphcric movements are the turbulent kinetic energy and the evaporation. Another fundarncntal factor is the atmosphcric pollution. In the southern metropolitan area of hlexico City the ozone rcpresents an acccptable index of the lcvcls of pollution limiting the viability of airborne algae. Under the assumption of a (steady) given supply of algae, a possible model of concentrations of algae in thc atmosphere is constructed based on statistical considerations, aimed to predictions of thosc concentrations. There is a tremendous variety of sporulated organisms in the air. It is known that they have taken evolutionary advantage of the atmospheric turbulence as a medium of dispersion and thus, they can be isolated from the air. In fact, their life cycles are associated to the seasonal variations of the meteorological conditions of their environment, and even the morphological characteristics of their units of dispersion are an adaptive response to this transport option.It has been demonstrated that even non-sporulated organisms can utilize the air as a medium of transport in an efficient way. The benefits of this ability for those species are subject of still open speculations, although it is clear that a great adaptive value can result from the ability of the cells of some species of microorganisms to be airborne any time, without waiting for some specific stage of their life cycle.The microorganisms here considered are the microalgae. After this first contribution, neither Sokoloff nor anybody else carried on with research in this area in Mexico. In the eighties a dramatic interest in air pollutants and in the search for causal agents of allergic and respiratory illness took place. It was then that research in aerobiology was undertaken again in Mexico.The first study where one of the authors (Roy-Ocotla) collaborated, was principally of exploration, and it was aimed to' the search of allergenic algae polluting Mexico City's air (Rosas et al. 1987). The founding arose more questions than answers. It was demonstrated that airborne algae were present in samples of the city's atmosphere in trace concentrations, often absent in the samples. In the research group was not known how ...

Southwest metropolitan Mexico City (SWMMC) inhabitants have been exposed several hours per day for the last 6 years to photochemical smog, ozone being the most important oxidant pollutant. Subjects exposed to the SWMMC atmosphere develop several histopathological changes in their nasal mucosa: dysplasia is the most significant, affecting 78.72% of adult individuals within 60 or more days of residence in SWMMC. This study was originally designed to explore whether chemical intervention could modify nasal dysplasia, as determined by nasal cytology, in a defined adult population. In a placebo-controlled, randomized, double-blind trial, 177 healthy male subjects were divided into 5 groups to whom 5000 IU of vitamin A, 100 IU of vitamin E, a combination of vitamins A and E (5000 IU + 100 IU), 16 mg of beta-carotene, or placebo were administered daily for 4 months. Sixteen clinical and cytological variables were monitored. No effect on dysplasia was seen at the end of the 4-month trial; however, an apparent reversibility as well as progression of the dysplastic nasal lesions and high correlation coefficients between dysplasia and nasal cytology of polymorphonuclear leukocytes (PMNs; 0.85), squamous metaplasia (SM; 0.50), and nasal mucosa atrophy (NMA; 0.41) were found. A mathematical theoretical nasal dysplasia (tD) predictor equation for SWMMC adult male inhabitants is proposed (tD = 0.85 delta PMNs + 0.50 delta SM + 0.41 delta NMA + 0.98), in which PMNs are the best single dysplasia predictor, and all variables are independent.(ABSTRACT TRUNCATED AT 250 WORDS)

Southwest metropolitan Mexico City (SWMMC) inhabitants have been exposed several hours per day for the last 6 years to photochemical smog, ozone being the most important oxidant pollutant. Subjects exposed to the SWMMC atmosphere develop several histopathological changes in their nasal mucosa: dysplasia is the most significant, affecting 78.72% of adult individuals within 60 or more days of residence in SWMMC. This study was originally designed to explore whether chemical intervention could modify nasal dysplasia, as determined by nasal cytology, in a defined adult population. In a placebo-controlled, randomized, double-blind trial, 177 healthy male subjects were divided into 5 groups to whom 5000 IU of vitamin A, 100 IU of vitamin E, a combination of vitamins A and E (5000 IU + 100 IU), 16 mg of beta-carotene, or placebo were administered daily for 4 months. Sixteen clinical and cytological variables were monitored. No effect on dysplasia was seen at the end of the 4-month trial; however, an apparent reversibility as well as progression of the dysplastic nasal lesions and high correlation coefficients between dysplasia and nasal cytology of polymorphonuclear leukocytes (PMNs; 0.85), squamous metaplasia (SM; 0.50), and nasal mucosa atrophy (NMA; 0.41) were found. A mathematical theoretical nasal dysplasia (tD) predictor equation for SWMMC adult male inhabitants is proposed (tD = 0.85 delta PMNs + 0.50 delta SM + 0.41 delta NMA + 0.98), in which PMNs are the best single dysplasia predictor, and all variables are independent.(ABSTRACT TRUNCATED AT 250 WORDS)