4. RESULTS OF SUBSYSTEM 1: HEALTH CONSEQUENCES AND RISKS RELATED TO AIR POLLUTION

4.1 Organization of monitoring activities

The Subsystem is intended for monitoring selected indicators of population health and air quality. Information on population health status is obtained from general practitioners and pediatricians in out-patient facilities (acute respiratory diseases) and from parents of selected groups of children (allergy and indoor air quality), in part from routine records and in part through questionnaire investigation.

Information on ambient air pollutant concentrations is obtained from the network of manual and automated units operated by the Public Health Centres of the cities monitored and from selected measuring facilities supervised by the Czech Hydrometeorological Institute (ČHMÚ), the location of which meet the requirements of the Monitoring System.

During 2000, thanks to regular audits of the central database MONARO, some redundant records were corrected and validated. All data given below come from the validated database.

4.2 Incidence of treated acute respiratory diseases

The incidence of treated acute respiratory diseases (ARD) has been monitored in selected cities for the sixth year. Last year, the basic statistical analysis of the first five-year period data was performed (for more details, see the Summary Report 1999). The source of information are medical records on the first treatment given to patients with acute respiratory disease. In 2000, 75 pediatricians and 45 general practitioners providing care to a total of 186 500 patients of 25 cities took part in data collection. The data obtained are expressed as the incidence rates, i.e. the numbers of new cases per 1000 persons of monitored population or population group.

The results of 2000 do not markedly differ from those of previous years. Fig. 4.1a to 4.1c show the highest, lowest and mean monthly ARD incidence rates of 2000 and the range of the mean monthly ARD incidence rates for all years of monitoring. With some exceptions, the mean monthly ARD incidence rates of 2000 were close to the lower limit of the range presented for all age categories. The monthly ARD incidence rates in children up to 15 years of age varied widely from 11 cases per 1000 citizen (Příbram) to 489 cases per 1000 citizen (Hradec Králové). The highest rate of ARD cases treated in 2000 was recorded for the age group 1 to 5 years again. The monthly ARD incidence rates of 2000 show typical seasonality with summer decreases.

The monthly incidence rates of the lower respiratory tract diseases (bronchitis and pneumonia) in children up to 15 years of age varied in different cities from 0 (mostly in summer) to 117 (Plzeň). These diseases, the incidence of which may be influenced by some air pollutants such as nitrogen oxides account for very different percentages of the total ARD morbidity in different cities. The percentage range for these is from 2 to 17 %. A high total ARD incidence does not always mean high incidence rates of pneumonia and bronchitis (e.g. in Liberec). In contrast, high incidence rates of lower respiratory tract diseases were recorded in some cities with relatively low total ARD incidence rates (Svitavy). A high total ARD incidence rate with a high incidence rate of pneumonia was found in Plzeň.

The monitoring of six ARD diagnostic groups showed the same distribution within the total ARD incidence as in previous years. The most frequent ARD for all age categories and monitored cities are those of the upper respiratory diseases, accounting annually for 75 % of the ARD morbidity on average. Influenza is the second (12 %) and inflammation of the lower respiratory tract follows (9.5 %). The order of the remaining diagnoses monitored according to their frequency is as follows: otitis media - rhinosinusitis - mastoiditis (2 %), pneumonia (0.9 %), and asthma (0.4 %).

4.3 Prevalence of allergic diseases in children

In 2000, the prevalence rates of allegric diseases in the population of 17-year-olds were investigated in 16 cities. The questionnaire of 1999 was used (case-control study, data obtained from medical records and parents) with additional information on the lifestyles as indicated directly by the 17-year-olds. The objective was to obtain information not only on the prevalence rates of allergic diseases in the adolescent population but also on some factors of family and personal histories, type of housing and lifestyle. A part of the respondents were addressed repeatedly (in 1996 for the first time at the age of 13 years). A total of 1801 adolescents, 50.5 % of males, were investigated. The questionnaire returnability was over 90 %.

The results are described using frequency analysis and the hypothesis of congruence between the percentages of the categories in the contingency table assessed by the test of independence c 2. The tests were performed at a 5 % level of significance. The linkage relation is described by the odds ratio (OR) between the population exposed to a factor and that non-exposed. The OR values are adjusted for the sex, district and family history. The levels of significance are indicated the following way: * p < 0.05, ** p < 0.01, *** p < 0.001.

The life-long prevalence of allergic diseases in 17-year-olds is 23.2 % with a slight predominance in males. The most frequent diagnosis for this age is pollinosis (Fig. 4.2a). Within four years the frequency of allergy increased by 8 %. The beginning of the allergic diseases mostly dates back to the school age. Interesting is the information on the prevalence of symptoms suggestive of the presence of bronchial hyperreactivity and asthma. In the population studied, wheezing breath associated with infection is reported in 15 % of the total number of studied 17-year-olds, in 27 % of allergic individuals and in 12 % of adolescent without allergy. Even more alarming is the presence of this symptom with no association with respiratory infections, i.e. in 6 % of the total number of studied 17-year-olds, 3.8 % of non-allergic healthy adolescents. Asthma was diagnosed in one third of the children reporting this symptom only. As many as 23.5 % of adolescents are followed up for a chronic disease other than allergy. The most frequent reasons for the follow up at this age are poor eyesight (defective accommodation and refraction) and diseases of the musculoskeletal system (Fig. 4.2b).

The impact of the following perinatal abnormalities on the future development of allergy and their interference were taken into consideration: at risk pregnancy, smoking during pregnancy, premature delivery, complicated delivery, resuscitation at birth, low birth weight and therapy at maternity hospital.

The last part of the questionnaire was focused on some lifestyle factors. The admitted smoking prevalence is 26 %. The obesity prevalence rates are 14.7 % in males and 9.2 % in females. Most prone to obesity are those who either never did any sport or started doing sport within last two years. No sport activities were recorded for 20 % of children and the same proportion of this population show long-term health problems affecting mainly the musculoskeletal system (subjective data). Better lifestyle features were reported by secondary school students (grammar and vocational schools) compared to apprentices.

4.4 Ambient air pollution

In 2000, ambient air pollutant concentrations were measured in 27 cities (Table 3.1 and Fig. 3.1).

The following modifications were made to the monitoring activities:

In 2000, sulphur dioxide (manual stations performed measurements during the heating season only), sum of nitrogen oxides, particulate matter (TSP and/or PM10 fraction), and mass concentrations of selected metals (arsenic, chromium, cadmium, manganese, nickel and lead) in particulate matter samples were monitored in all cities of the Monitoring System. In some of them, concentrations of other metals (beryllium, copper, mercury, vanadium and zinc) in particulate matter, carbon oxide, ozone, nitrogen monoxide and nitrogen dioxide continue to be monitored selectively.

4.4.1 Pollutants monitored in most cities under the Monitoring System

In 2000, the long-term trend in development of some commonly monitored pollutants continued.

The derived recommended annual concentration of PM10 (30 µg/m3) was exceeded in 11 of the cities monitored (Prague 10 - 46.9, Prague 1 - 39.2, Karviná - 39.1, Ostrava - 37.7, Prague 5 - 37.6, Ústí nad Labem - 36.1, Prague 9 - 35.6, Prague 4 - 33.7, Olomouc - 31.3, Prague 6 - 30.8 and Prague 2 - 30.6 µg/m3). The annual arithmetic mean ranges from 20 to 30 µg/m3 (Fig. 4.3e and 4.3f) in all other cities monitored except Most with about 18 µg/m3.

4.4.2 Selectively monitored pollutants

The monitoring of the substances, which, under opportune conditions, may be responsible for the formation of photochemical reaction products in the atmosphere, i.e. nitrogen monoxide, nitrogen dioxide, ozone and organic substances (Fig. 4.3i to 4.3l, 4.3o and 4.3p), continues to be of concern.

4.4.3 Metals in particulate matter

The mass concentrations of the metals under long-time monitoring were obtained by analyses of 14-day cumulative samples of particulate matter. The results can be summarized as follows:

4.5 Assessment of exposure to major pollutants

4.5.1 Air quality index

The air quality index (AQI) was based on the recorded concentrations of SO2, NOx, TSP and PM10. The air quality was satisfactory (class II) in over one half of 35 localities and Prague monitored districts, moderate air pollution was found in 15 of them (class III), including Prague 5 with borderline levels between classes III and IV (polluted air), see Fig. 4.4.

4.5.2 Exposure to pollutants from the ambient air

The degree of pollution can also be expressed as the potential exposure of the population of a given locality to a certain pollutant concentration level. The mean long-term exposure to major pollutants, the annual limits (IHr) for which are set, is characterized in such a manner. The result reflects the proportion of the total population of a monitored city that is exposed to a certain concentration level of pollutants in the ambient air (Fig. 4.5). The non-measured Šumperk locality (0.9 % of the population under monitoring) was also included in the calculation of the proportion of the population exposed.

4.6 Mobile measuring system

In 2000, the data files obtained in the first phase of the mobile system operation in Prague, continued to be updated. Measurements were performed in twenty localities in Prague. Relationships between the first-phase data files and those updated in 2000 were tested by statistical analysis. The objectives were as follows:

The mobile system of the National Institute of Public Health was audited by the Czech Institute for Accreditation in December 2000 for measurement of concentrations of sulphur dioxide, carbon oxide, ozone, TSP and PM10, nitrogen monoxide, nitrogen dioxide and some meteorologic parameters of ambient air quality (pressure, temperature, relative humidity). The mobile system activities were also focused on good operation of the QA/QC system, namely on the transmission of the correct data to the measuring network operated by the Public Health Service in different regions. These activities are parallel to those of the calibration laboratory of the National Institute of Public Health.

4.7 Indoor environment quality

From 1999 to 2001, 120 dwellings randomly selected from those inhabited by questionnaire respondents who gave their consent (the questionnaire investigation was performed in 1999, see the Summary Report, 1999) were measured within the indoor environment monitoring focused on description and assessment of chemical, physical and biological factors of the indoor environment and major lifestyle aspects. The objectives of the Project are to determine and to describe exposure to pollutants from the indoor environment in children. The population of preschool children attending nursery schools was monitored. The indoor air sampling was performed in the children’s room and kitchen; the season was taken into account (heating season from November to February and non-heating season from May to August). The following parameters were monitored:

Comprehensive analysis of the pollutant concentrations in the indoor air in agreement with the objectives set is a long-term process. Based on the description of the data measured in children’s rooms and kitchens in the period of 1999 to 2001, the following can be submitted:

A particular part of the project was an associated study focused on description of the pollutant concentration variability in the indoor air within a day and week. Since the pollutant concentrations have been measured in the interval between 3 p.m. and 8 p.m., the intention was to test whether this time interval was representative of the whole day as the exposure assessment is based on the mean total burden. The daily and weekly concentration profiles were measured in ten dwellings during the heating and non-heating seasons. The variability of the indoor air quality parameters monitored was evaluated and the significance of the measuring interval used was considered with reference to the total burden.

Statistical analysis confirmed that the concentrations measured in the interval between 3 p.m. and 8 p.m. on weekdays are either characteristic of the mean levels or slightly higher in some cases. In addition, significant relationships were found between nitrogen dioxide concentrations in the children’s room and those in the kitchen, which is indicative of the pollutant transmission within the dwelling.

4.8 Partial conclusions

The incidence rate of treated acute respiratory diseases (ARD) is similar as in previous years. The monthly ARD incidence in children varied widely and showed typical seasonality with a decrease in summer in most monitored cities. With some exceptions, the mean monthly ARD incidence was close to the lower limit of the range recorded for all years of monitoring. The mean proportion of lower respiratory tract diseases was 10.4 % of the total treated ARD incidence, ranging from 5 to 17 % in different cities.

The questionnaire investigation of a sample of 1801 17-year-olds of 16 cities revealed a 23 % prevalence of allergic diseases in this age group. The most frequent diagnosis is pollinosis. A high frequency of wheezing breath in non-allergic children with a cold and high prevalence of smoking were found, even in asthmatics. The children investigated repeatedly (for the first time in 1996 at the age of 13 years) showed an increase in allergic diseases rate by 8 %. Case history data were used to find out possible risk factors. Apart from those already identified (allergy in the family, frequent respiratory morbidity in the early childhood), the significance of some perinatal abnormalities and selected factors related to the living conditions in the babyhood was found with reference to the future development of allergic diseases.

The mean annual concentrations of sulphur dioxide did not exceed 15 µg/m3 in any of the monitored localities. Nitrogen oxide pollution slightly decreased, nevertheless, as in 1998 and 1999, in Prague 5, Prague 8 and in Děčín the limit mean value was exceeded. A higher burden with carbon monoxide in the ambient air persists in the Prague conurbation. Significant is particulate matter pollution, fractions TSP and PM10. Nowhere did the annual arithmetical mean exceed the limits either set or recommended for the metals monitored.

Benzo(a)pyrene remains of the highest concern among the polynucleus aromatic hydrocarbons, its maximum admissible concentration recommended was exceeded in all localities monitored. The maximum admissible concentration for benzo(a)anthracene was exceeded in three localities. The carcinogenic potential of polynucleus aromatic hydrocarbons in Ostrava is twice higher that in Karviná and six times higher that in Prague, Plzeň, Ústí nad Labem and Hradec Králové. The recommended maximum admissible concentrations of VOCs, i.e. benzene, toluene, sum of xylenes, styrene and trimethylbenzene, have been exceeded only exceptionally.

The annual index of air quality, remains relatively stable. Potential exposure to concentrations exceeding the exposure limits was found in 1.7 % of the monitored population, namely for the sum of nitrogen oxides, the concentrations of which, after a marked deterioration between 1994 and 1995, have been stable. The population is exposed (indiscriminately) to the highest mean concentration levels of particulate matter. As much as 90 % of the population monitored are exposed to mean annual PM10 concentrations over 20 µg/m3.

In 2000, the data sets obtained in the first phase of measurements of the mobile system in Prague continued to be updated. Comparison of the trends of the pollutants monitored between 1994 to 1996 and 2000 revealed the following: a statistically significant marked decrease in sulphur dioxide concentrations, a less marked statistically significant decrease in carbon monoxide concentrations, nitrogen dioxide and nitrogen monoxide, a statistically significant increase in ozone concentrations. No statistically significant shift of mean concentrations of the sum of nitrogen oxides and nitrogen monoxide-nitrogen dioxide ratio was found.

The indoor air parameters were measured in 120 dwellings from 1999 to 2001. The significance of exposure to nitrogen dioxide, benzene, formaldehyde and microclimatic factors was confirmed. Exposure to TSP and PM10 is also significant. The associated study confirmed that the concentrations measured in the interval between 3 p.m. and 8 p.m. on weekdays are either characteristic of the mean levels or slightly higher in some cases. In addition, significant relationships were found between nitrogen dioxide concentrations in the children’s room and those in the kitchen, which is indicative of the pollutant transmission within the dwelling.

Fig. 4.1a Acute respiratory diseases excluding influenza - children 1–5 years, 1995–2000
Fig. 4.1b Acute respiratory diseases excluding influenza - children 6–14 years, 1995–2000
Fig. 4.1c Acute respiratory diseases excluding influenza - adults, 1995–2000
Fig. 4.1d Selected diagnostic groups proportion on treated ARD illness rate (all age groups)
Fig. 4.2a Allergic diseases structure in the 17-year-old population set
Fig. 4.2b Selected causes of long-term medical follow up of the 17-year-old children (excluding allergy)
Fig. 4.3a Sulphur dioxide pollution - annual arithmetic mean, 2000
Fig. 4.3b Concentration range of sulphur dioxide - annual arithmetic mean, 1991–2000
Fig. 4.3c Particulate matter pollution, TSP - annual arithmetic mean, 2000
Fig. 4.3d Concentration range of particulate matter (TSP) - annual arithmetic mean, 1991–2000
Fig. 4.3e Particulate matter pollution, fraction PM10 - annual arithmetic mean, 2000
Fig. 4.3f Concentration range of particulate matter, fraction PM10 - annual arithmetic mean, 1991–2000
Fig. 4.3g Sum of nitrogen oxides pollution - annual arithmetic mean, 2000
Fig. 4.3h Concentration range of nitrogen oxides - annual arithmetic mean, 1991–2000
Fig. 4.3i Nitrogen monoxide pollution - annual arithmetic mean, 2000
Fig. 4.3j Concentration range of nitrogen monoxide - annual arithmetic mean, 1995–2000
Fig. 4.3k Nitrogen dioxide pollution - annual arithmetic mean, 2000
Fig. 4.3l Concentration range of nitrogen dioxide - annual arithmetic mean, 1995–2000
Fig. 4.3m Carbon monoxide pollution - annual arithmetic mean, 2000
Fig. 4.3n Concentration range of carbon monoxide - annual arithmetic mean, 1995–2000
Fig. 4.3o Ozone pollution - annual arithmetic mean and 95th percentile of daily concentration, 2000
Fig. 4.3p Concentration range of ozone - annual arithmetic mean, 1995–2000
Fig. 4.4 Annual Air quality index (AQI), 1995–2000
Fig. 4.5 Distribution of the population according to the potential exposure to selected pollutants (in intervals of the annual limit rate IHr), 1995–2000
Fig. 4.6a Polyaromatic hydrocarbons (PAHs) pollution annual arithmetic mean of PAHs sum and toxic equivalent TEQ (BaP), 2000
Fig. 4.6b Concentration of selected PAHs - annual arithmetic mean, 2000
Fig. 4.6c Concentration of volatile organic compounds (VOCs) - annual arithmetic mean, 2000
Fig. 4.7a Arsenic in particulate matter - annual arithmetic mean, 1991–2000
Fig. 4.7b Cadmium in particulate matter - annual arithmetic mean, 1991–2000
Fig. 4.7c Chromium in particulate matter - annual arithmetic mean, 1991–2000
Fig. 4.7d Nickel in particulate matter - annual arithmetic mean, 1991–2000
Fig. 4.7e Lead in particulate matter - annual arithmetic mean, 1991–2000
Fig. 4.7f Manganese in particulate matter - annual arithmetic mean, 1991–2000
Fig. 4.8a Distribution of dwellings according to relative humidity
Fig. 4.8b Distribution of dwellings according to NO2 concentration
Fig. 4.8c Distribution of dwellings according to formaldehyde concentration
Fig. 4.8d Distribution of dwellings according to benzene concentration

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