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Biomedical subjects

K Sega

Publications and source records attributed to K Sega.

15 recordsLinked to original sources
PubMed2000

Sulphates, nitrates, and chlorides in particle fractions of different size.

This paper describes a pilot study of chloride, nitrate, and sulphate content in thoracic and high-risk respirable fractions of airborne particles. Samples were collected at one measuring site in Zagreb in autumn 1998 and spring 1999. The results showed that almost total chloride, nitrate, and sulphate content was present in the respirable particle fraction. The average mass contribution of these pollutants to the particle mass amounted to 25%. Although chloride mass concentrations were quite low, the findings indicated that all pollutants originated from the same source.

Air Pollutants↗
PubMed2000

Lead, manganese, and cadmium content in PM10 and PM2.5 particle fractions--a pilot study.

This paper describes a pilot study of lead, manganese, and cadmium content in thoracic particle fraction and high-risk respirable fraction of airborne particles. Samples were collected at one measuring site in Zagreb during autumn 1998 and spring 1999. The results show that the total heavy metal contents is found in the high-risk respirable particle fraction, and point to two main pollution sources, the first for lead and manganese and the other for cadmium.

Air Pollutants↗
PubMed1999

Short-term effects of ambient nitrogen oxides on the number of emergency asthma cases in Zagreb, Croatia.

The paper describes an investigation of short-term effects of NO2 concentrations in the air on the number of emergency room visits caused by respiratory impairments, particularly asthma in adults and children. The data were collected from clinical emergency room records from July 1, 1994 to December 31, 1995. Concurrently, readings of average weekly concentrations of NO2 (microgram/m3), average weekly temperature (degree C), air pressure (kPa), and relative humidity (%) were registered. Trend and seasonality effects were estimated by the locally weighted regression (LOESS). After standardising for trend, seasonality, and meteorological conditions, the number of cases was regressed on weekly NO2 concentration, including the current and the previous week concentrations and autocorrelated residual. The weekly average NO2 concentrations were significantly associated with the number of emergency asthma cases for children and adults and with the total number of emergency respiratory cases in children, but not in adults. The results suggest that health effects of NO2 on risk groups can be detected even in moderately polluted environments. The effect is more pronounced in children.

Adult↗
PubMed1999

Air pollution studies.

The aim of this paper is to give an overview of the research in the area of air pollution, carried out exclusively at the Institute for Medical Research and Occupational Health and performed by the scientists of the Institute. For the past fifty years, air quality has been studied at work, in the ambient air of urban and industrial areas, and in various indoor environments without occupational exposure. Methods for sampling and measuring air pollutants have been introduced or developed and verified. The behaviour and the fate of air pollutants in the environment have also been investigated. Since the primary goal of the studies was to assess the extent of human exposure to air pollutants, the data were used to calculate the risk for various population groups. A dynamic model of exposure for various population groups relied on calculations of collected data, taking into account time spent in various microenvironments. This text describes the cooperation of the Institute with other institutions and agencies on the national and international level and outlines the current and prospective activities.

Air Pollution↗
PubMed1995

Total suspended particulate matter concentrations in Zagreb during the 1975-1993 period.

Daily average mass concentrations of total suspended particulate matter were measured at three sampling sites in Zagreb, and evaluated for the period April 1975-March 1993. Each sampling site represented a different town area (residential, business and administrative, industrial) with different traffic density and type of energent used for space heating. The time trends of concentration levels could, to a certain extent, be attributed to traffic flow modification in the vicinity of the sampling sites, introduction of natural gas in dwellings and degree of energy consumption influenced by the standard of living. Periodograms show a well pronounced seasonal dependence of total suspended particulate matter concentrations, with high concentrations during winters. Analysis of the results in respect to the European Community air quality limits (1) and the levels of other pollutants (SO2 and smoke) leads to the conclusion that particulates being a persistent permanent problem have become a major issue concerning ambient air pollution in Zagreb.

Air Pollutants↗
PubMed1994

Sick building syndrome--a case study in Zagreb.

Sick building syndrome was investigated in a newly built office building. Information about health complaints from the employees was obtained by means of a self-administered questionnaire. Measurements of microclimate conditions and air pollution levels confirmed that the employees' complaints were justified. Because of a high percentage of complaints, the questionnaire was evaluated by means of factor analysis. The results showed logical grouping of the complaints and/or symptoms, suggesting credibility of the answer. Factor analysis proved to be an appropriate tool for detecting and evaluating sick building syndrome.

Adult↗
PubMed1991

Different approaches to the assessment of human exposure to nitrogen dioxide.

The exposure of 15 subjects to NO2 was assessed using different approaches: (a) direct measurement of personal exposure, (b) calculation of weighted average exposure using data on time spent and concentrations measured at home, at work, in transit, and outdoors, (c) the same calculation but instead of actual concentrations, using concentrations measured in other homes in Zagreb (out of 90) situated in a district with a similar traffic density, and using the same cooking fuel. The best agreement with personal exposure was obtained for exposure under (b), but calculation with surrogate concentrations (c) also gave a fair approximation.

Air Pollutants↗
PubMedDate not supplied

Indoor concentration levels of selected pollutants and household characteristics.

As part of a large health effect-related human exposure study conducted in the city of Zagreb, Republic of Croatia (Sega and Fugas, 1987), NO2, NH3, HCHO, and settled dust concentrations were measured during winter and summer periods in the kitchens and living rooms of 90 homes throughout the city. Characteristics of households and household members were recorded and correlated with the pollutant concentration levels. The results indicate that household characteristics may be useful for predicting human exposure to air pollutants.

Adolescent↗
PubMedDate not supplied

Distributions of long-term household exposure of different population groups to nitrogen dioxide.

Exposure distributions to nitrogen dioxide in living rooms during the summer and winter were calculated for four groups of Zagreb inhabitants (high school students, university students, employed, and retired persons) using Duan's Cartesianization method. Households were classified into three categories according to fuel used for cooking and heating--electricity (or no gas use), propane-butane, and natural gas. The results showed a seasonally dependent contribution to exposure in households from outdoor sources through ventilation, while type of fuel used for heating and cooking, representing indoor pollution sources, had a predominant influence on exposure levels. Exposure distribution functions could be represented by lognormal, or summation by proportion of lognormal and normal distributions. A comparison of the results and the proposed exposure guideline value suggests that either the guideline value is too large, or a nitrogen dioxide exposure problem exists only in a small percentage of homes and is caused by the high rate of air exchange between the kitchen and living room.

Air Pollution, Indoor↗
PubMedDate not supplied

Assessment of human inhalation exposure to polycyclic aromatic hydrocarbons.

The aim of the investigation was to find a suitable approach for assessing inhalation exposure of urban inhabitants to polycyclic aromatic hydrocarbons (PAHs) in air. Personal exposure to PAHs of fifteen subjects, Zagreb inhabitants, was measured over a week in summer and again in winter. All subjects kept a diary of motion and activities and filled in a questionnaire on the characteristics of their fiat and household members. PAHs concentrations inside and outside subject's homes were simultaneously measured as were those in the working environment and in transport. Using an exposure model which takes into account the time spent by the subjects in each microenvironment and the respective concentrations measured, the inhalation exposure of each subject was calculated and compared with the directly measured personal exposure for the winter season only the summer concentrations being negligible. For a few subjects the calculated inhalation exposure deviated considerably from the one measured directly. This could be attributed to the fact that the subject spent some time in a microenvironment with significantly different PAH levels which were not included in the calculation. However, if the average results for the whole group are considered, there was no statistically significant difference between the directly measured and calculated PAH inhalation exposures. Therefore the described approach could be used for calculating average inhalation exposure to PAHs of population groups with common characteristics.

Air Pollution↗