4. HEALTH CONSEQUENCES AND RISKS RELATED TO AIR POLLUTION
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4.1 Organization of monitoring activities
Subsystem I is intended for the monitoring of selected indicators of population
health and indoor/outdoor air quality. Information on population health
status is obtained from general practitioners and paediatricians in out-patient
facilities. Information on ambient air pollutant concentrations is obtained from
the network of manual and automated units operated by the public health
institutes in the cities monitored as well as from selected measuring facilities
administrated by the Czech Hydrometeorological Institute, the location of
which meets the requirements of the Monitoring System. Indoor air quality
has been monitored within Subsystem I in cooperation with selected public health institutes.
4.2 Incidence of treated acute respiratory diseases
4.2.1 Results 2004
Acute respiratory diseases (ARD) account for the highest percentage of
morbidity in children (peaking in pre-school children), and therefore the
ARD incidence is used as an important indicator of population health. Incidence
of ARD is influenced by air pollution, epidemiological situation, climatic conditions,
individual characteristics and by physician’s subjective evaluation. The
information source are medical records on the first treatment given to patients
presenting with acute respiratory disease. The basic outputs are absolute
numbers of new cases of selected diagnoses in the population monitored and
their incidence rates per 1,000 population of different age groups. The data
are entered in the system database of treated ARD acronymed MONARO. The
database is an integrated system that allows continual collection, processing
and evaluation of the data on ARD morbidity obtained from general practitioners
and paediatricians. The central database is being regularly validated to
clear possible redundant or incorrect records.
In 2004, 77 paediatricians and 41 general practitioners providing care to
a total of 178,785 patients in 25 cities took part in the ARD data collection.
The data of 2004 do not markedly differ from those from previous years
with the monthly incidence rates ranging from tens to hundreds of cases
per 1,000 population of a given age group depending on season and epidemiological
situation. In 2004, the monthly ARD incidence (excluding influenza) in children
of different age groups varied widely from 2 (Havlíčkův Brod) to 826 (Hradec
Králové) cases per 1,000 children. As in previous years, the highest ARD
morbidity was recorded in the age group 1 to 5 years. In most cities, the ARD
morbidity shows seasonal trend with a typical downward tendency in summer,
being most marked in the age group 1–5years, less marked in children aged from 6
to 14 years and least marked in adults.
Figs. 4.1a and 4.1b
show the highest and the lowest monthly ARD incidence
rates, mean monthly ARD incidence rates in 2004 and the range of the mean
monthly ARD incidence rates for 1995–2004. The mean monthly ARD incidence
rates in children aged from 1 to 14 years recorded in 2004 were mostly close
to the lower limit of the mean values range of previous years, with the
exception of the age group 1 to 5 years
(Fig. 4.1a) in Hodonín, Hradec Králové
and Šumperk (in Hradec Králové and Šumperk, the rates of 2004 are the highest
in the last decade) and the age group 6 to 14 years (Fig. 4.1b)
in Hradec Králové, Olomouc and Příbram. In 2004, the slight downward trend in ARD
morbidity (excluding influenza), affecting both upper and lower airways,
continued. A more marked decline was recorded in children aged 6 to 14 years
compared to 1–5 year-olds. A 3 % rise was recorded in the incidence of ARD
of lower airways due to higher frequency of bronchitis (increased from 7 % in 2003
to 9 % in 2004) and pneumonia (increased from 0.5 % in 2003 to 1.5 % in 2004).
As in previous years, diseases of the upper respiratory tract were responsible
for the major share in the total ARD morbidity, accounting for 75 % of the
morbidity on average (for all the monitored cities and age categories).
Influenza was the second with 10 %, followed by acute bronchitis with 9 %.
The order of the remaining diagnoses by frequency was the following: otitis
media – rhinosinusitis – mastoiditis (2.9 %), pneumonia (1.5 %) and asthma (1.2 %).
4.3 Urban air pollution
In 2004, data on air pollutant concentrations measured at 90 stations (46 stations
operated by the Public Health Institutes and 44 stations of the National
Immission Network) located in 27 cities involved in the Monitoring System
(see Tab. 3.1 and Fig. 3.1) were analyzed. For 2004, data on sulphur dioxide,
nitrogen dioxide and PM10 concentrations are available from all localities
and those on mass concentrations of selected metals (arsenic, chromium,
cadmium, manganese, nickel and lead) were provided by the stations operated
by the Public Health Institutes. Depending on automated stations, additional
data on nitrogen oxide, ozone, carbon oxide and newly also PM2.5 are variably obtained.
Concentrations of polycyclic aromatic hydrocarbons (PAHs) and volatile
organic compounds (VOCs) continue to be monitored selectively in a number
of the monitored cities.
The criteria of Government Order No. 350/2002 of August 14, 2002 as last amended
in Government Order No. 60/2004, laying down the ambient air pollution limit
values and conditions and ways of air quality monitoring, assessment, evaluation
and management, were applied to assess the recorded and calculated pollutant
concentrations. Reference values (recommended as the highest values) set by the
air hygiene working group of NIPH according to Article 45 of Act No. 86/2002
(as last amended in Act No. 92/2004) were used for pollutants with no limit
established, and the limit concentrations in force until 2002 were taken
as reference values for evaluation of the TSP fraction and sum of nitrogen oxides.
Health risks assessment was focused on carcinogenic pollutants such as
arsenic (As), nickel (Ni), benzo[a]pyrene (BaP) and benzene for which carcinogenic
risk levels have been defined. Risk levels were taken from the WHO web site
www.who.dk/air/activities/20020620-1.
4.4 Inorganic contaminants of urban air
After an extremely dry year with extreme pollution levels in 2003, long-term
trends in commonly monitored pollutants continued in 2004.
The annual arithmetic mean of sulphur dioxide (SO2) concentrations was
not higher than 14 µg/m3,
i.e. 30 % of the concentration limit (50 µg/m3) in
any of the cities monitored in 2004. This maximum value was recorded in
Karviná (Fig. 4.2a).
The limit 24-hour concentration of 125 µg/m3 was not
exceeded in any of the cities monitored.
Outdoor air ozone concentrations have been monitored in 16 cities. The
annual arithmetic means ranged between 32.6 µg/m3
and 58.3 µg/m3 (Fig. 4.2b).
24-hour concentrations exceeded 120 µg/m3 only in isolated instances (Ústí
nad Labem, Prague). In 2004, no ozone episode (exceedance of the hourly value
of 180 µg/m3) was recorded at the Public Health Service stations.
Particulate matter (PM10) concentrations in outdoor air fluctuated around
the lower limit of the concentration range of the previous years in most
cities in 2004 (Fig. 4.2c, 4.2d).
A marked decrease in PM10 concentrations
was recorded in all cities compared to extremely high concentrations established in 2003.
In 2004, the annual limit specification for PM10 (annual arithmetic mean
of 40 µg/m3 or more than 35 exceedances of the
24-hour limit of 50 µg/m3)
was exceeded in 10 of 27 cities. The 24-hour limit was exceeded more than
35 times in all monitored Prague districts but Prague 10; in Prague 5 such
exceedance was recorded for 75 days. In three cities (Kroměříž, Ostrava, Děčín)
and one Prague district (Prague 2) only the annual arithmetic means were
higher than 40 µg/m3.
The annual arithmetic means of the sum of nitrogen oxides (NOx) ranged
from 22.6 to 116.9 µg/m3 in 2004
(Fig. 4.2e). As in previous years, the level
of 80 µg/m3 (used as a comparative value) was exceeded in several Prague districts,
with the highest ever levels being recorded in Prague 2 (hot spot in Legerova
street with 116.9 µg/m3) and Prague 9 (95.5 µg/m3).
The lowest annual arithmetic mean was established in Kroměříž.
Concentrations of nitrogen dioxide (NO2) exceeded
the limit of 40 µg/m3
in Děčín (45.3 µg/m3) and several Prague districts
(Prague 1: 43.1 µg/m3,
Prague 2: 54.4 µg/m3, Prague 5 and Prague 9:
42.2 µg/m3). The highest annual
mean was found for a heavy traffic area in Prague 2 (75.9 µg/m3)
where the 24-hour value reached 179 µg/m3
in December 2004. The annual arithmetic means in
all the other cities monitored ranged from 10.6 to 37.7 µg/m3, falling below
20 µg/m3, i.e. half the limit, in eight cities
(Fig. 4.2f).
The measurement results confirm long-term low or stable concentrations
of carbon monoxide (CO). The annual levels varied between 215 and 739 µg/m3.
As in previous years, high CO levels persist in heavy traffic areas in Prague
(1,000–1,628 µg/m3) with a hot spot in Prague 8
(3,895 µg/m3).
4.4.1 Metals in suspended particulate matter
The mass concentrations of selected heavy metals were obtained by analysis
of 14-day-cumulative samples of particulate matter. Air pollution with the
elements monitored between 1995 and 2004 either shows a slightly downward
tendency (lead) or is rather stable (cadmium, chromium, arsenic), without any significant oscillations.
The annual concentrations of the metals monitored in suspended particulate
matter can be described as follows:
-
Arsenic – The annual arithmetic means of As concentrations in 2004 ranged
from 1.5E-04 µg/m3 (Hodonín)
to 4.3E-03 µg/m3 (Mělník) (Fig. 4.3a).
The measured characteristics show a long-term downtrend which is probably due to progressive
change in the fuel energy base of local and medium sources from coal to
natural gas or fuel oil. The fact that the arithmetic means decreased in
20 out of 30 monitored cities compared to those of 2003 is also indicative
of this trend. Nevertheless, slightly increased arsenic levels in 6 monitored
cities document effects of the fuel cost variation and national energy policy.
-
Cadmium – The annual concentration limit (5E-03 µg/m3) was not exceeded
in any of the cities monitored. The highest annual arithmetic mean was recorded
in Ostrava (1.81E-03 µg/m3) while the lowest one was established in Hodonín
(4E-05 µg/m3) (Fig. 4.3b).
The annual arithmetic means in most monitored cities
were lower than 1E-03 µg/m3.
-
Lead – The annual concentration limit of 5E-01 µg/m3 was not exceeded in
any of the localities monitored in 2004 (Fig. 4.3c). The highest mean annual
concentration of lead was recorded in Příbram (4.11E-02 µg/m3) and the lowest
one was found in Most (4.25E-03 µg/m3). Very good conformity between the
annual arithmetic mean and the annual geometric mean in most localities
is suggestive of relative stability and homogeneity of the concentrations
recorded, without major seasonal, climatic or other oscillations.
-
Chromium – No annual concentration limit was established for chromium.
Based on the WHO recommendation, a reference concentration of 2.5E-05 µg/m3
was determined for hexavalent chromium (Cr+VI) but cannot be used to assess
the total chromium concentration in outdoor air (variable mixture of Cr+III
plus Cr+VI with the estimated contribution of the latter varying from 10 %
to 0.001 %). The annual arithmetic mean concentrations of total chromium
ranged from 7.7E-04 µg/m3 in Hodonín to 3.72E-02 µg/m3
in Kladno. In most of the cities monitored, the level of 5E-03 µg/m3
was not exceeded (Fig. 4.3d).
-
Manganese – In 2004 the annual arithmetic means ranged from 2.84E-03 µg/m3
in Havlíčkův Brod to 4.38E-02 µg/m3 in Prague 8 except for Ústí nad Labem
with the highest annual arithmetic mean of 5.17E-01 µg/m3 attributable to
an important industrial source (Fig. 4.3e).
-
Nickel – The annual arithmetic means ranged from 6.2E-04 µg/m3 in Hodonín
to 9.4E-03 µg/m3 in Děčín. The concentration limit
(2E-02 µg/m3) was not exceeded in any of the monitored cities.
4.5 Organic contaminants of urban air
Organic air pollutants with serious health effects are among the monitored
substances. Many of them are mutagens or carcinogens which are either bound
to suspended particulate matter or present in the form of vapours. Concentrations
of these pollutants have been monitored in selected cities, mostly at one
measuring station per city; therefore the results obtained are not representative
of the situation in the given city as a whole.
4.5.1 Polycyclic aromatic hydrocarbons
In 2004, the monitoring of polycyclic aromatic hydrocarbons (PAHs) was
conducted in eight cities: Prague, Brno, Plzeň, Ústí nad Labem, Hradec Králové,
Karviná, Žďár nad Sázavou and Ostrava. The following twelve polycyclic aromatic
hydrocarbons were monitored according to US EPA TO - 13: phenanthrene, anthracene,
fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[b]fluoranthene,
benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene,
benzo[g,h,i]perylene and indeno[c,d]pyrene.
In Ostrava, only eight selected PAHs have been monitored. The ambient air
sampling was performed every sixth day.
The annual limit for benzo[a]pyrene of 1 ng/m3 was exceeded in most of
the cities monitored in 2004 (Fig. 4.5a).
The highest burden of benzo[a]pyrene
was found in Ostrava with an annual mean concentration of 6.5 ng/m3 and Karviná
with 4.5 ng/m3. In winter, mean 24-hour concentrations higher
than 20 ng/m3 were recorded at these stations on some days. The annual limit was also
markedly exceeded in Ústí nad Labem (1.7 ng/m3),
Prague 10 (1.6 ng/m3), and
Hradec Králové (1.2 ng/m3). The annual mean concentrations in Žďár nad Sázavou
and Brno were just below the limit and the lowest concentration was recorded in Plzeň.
The annual arithmetic means of benzo[a]anthracene
(Fig. 4.5a) varied widely
from 0.9 ng/m3 in Plzeň to 8.5 ng/m3
in Karviná. In contrast to previous years,
the annual reference concentration of 10 ng/m3 was not exceeded in any of
the monitored localities. In most localities contamination levels were lower
than one-third of the reference concentration, higher contamination was
recorded in Ostrava (6.7 ng/m3) and Karviná. The annual mean phenanthrene
levels did not exceed one tenth of the reference concentration (1,000 ng/m3)
in any of the cities monitored. The total annual mean PAH concentration
expressed as the sum of PAHs was highest in Karviná (Fig. 4.5a).
In the other localities 2–6 times lower values were established. The sum of PAHs
could not be calculated for Ostrava where only selected PAHs have been monitored.
The PAHs include several compounds varying in health significance; those
considered as probable carcinogens differ in health effects as well. Based
on comparison of carcinogenic effects of the concentrations measured for
different PAHs with that of benzo[a]pyrene (BaP) as one of the most toxic
and best studied carcinogenic polycyclic aromatic compounds, the carcinogenic
potential of PAHs in air may be expressed using the toxic equivalent of
benzo[a]pyrene (TEQ BaP). The following toxic equivalent factors (TEFs)
pursuant to the US EPA were used for the calculation of TEQ:
TEQ BaP conversion factors (US EPA)
PAH
|
TEF
|
PAH
|
TEF
|
PAH
|
TEF
|
Benzo[a]pyrene
|
1
|
Benzo[b]fluoranthene
|
0.1
|
Dibenz[a,h]anthracene
|
1
|
Benzo[k]fluoranthene
|
0.01
|
Benzo[a]anthracene
|
0.1
|
Indeno[c,d]pyrene
|
0.1
|
The concentration of each PAH identified in the mixture is multiplied by
the respective TEF and the sum of all products obtained is the TEQ BaP of
the PAH mixture studied.
From the very beginning of the monitoring, Ostrava and Karviná have been
among the localities at the highest carcinogenic risk from PAHs; in 2004
the highest carcinogenic potential was found in these two cities with annual
means of 9.4 ng/m3 and 7.3 ng/m3,
respectively. The values in Prague, Hradec Králové
Ústí nad Labem and Žďár nad Sázavou varied between 2 and 3 ng/m3. The mean
annual TEQ BaP values obtained in different cities between 1997 and 2004
are shown in Fig. 4.5b.
4.5.2 Volatile organic compounds
In 2004, volatile organic compounds (VOCs) in outdoor air were monitored
at 6 stations operated by the Public Health Service and 14 stations run
by the Czech Hydrometeorological Institute. At the PHS operated measuring
stations, forty-two organic compounds were monitored (pursuant to
US EPA TO - 14);
nevertheless, only twenty-three of these were taken into account
since the remaining ones were mostly present in concentrations below the
respective detection limits. Winter sampling was carried out on every sixth
day, while from April to September, outdoor air samples were collected on every
twelfth day. The stations operated by the Czech Hydrometeorological Institute
monitored benzene, toluene, ethylbenzene and sum of xylenes. The measurement
should be continuous but frequent failures occurred with the system being
newly implemented in a number of localities in 2004.
An annual concentration limit of 5.0 µg/m3 has been established for benzene
by Government Order No. 350/2002. Among other important VOCs, for which
reference concentrations have been set, are aromatic hydrocarbons (toluene,
sum of xylenes, styrene, sum of trimethylbenzenes) and chlorinated aliphatic and
aromatic hydrocarbons (trichloromethane, tetrachloromethane, trichloroethene,
tetrachloroethene, chlorobenzene, and sum of dichlorobenzenes).
In 2004, the limit for benzene was only exceeded at one station, Ostrava-Přívoz
(operated by the Czech Hydrometeorological Institute), where the annual
mean concentration reached 7.7 µg/m3. Nevertheless, since lower concentrations
were established at two other stations in Ostrava the limit was not exceeded
for Ostrava as a whole. Annual benzene concentrations close to the limit
were recorded in Prague 10 (4.1 µg/m3) and at one of the stations in Ústí
nad Labem (4.4 µg/m3). The results of four stations operated by the Czech
Hydrometeorological Institute ranged between 1.0 and 2.2 µg/m3 but could
be biased by measurement failures. Fig. 4.6a
shows annual mean concentrations of benzene
in different localities; the figures in Ústí nad Labem and Ostrava are
means from multiple measuring stations. Fig. 4.6b represents trends in annual
mean concentrations of benzene in different localities between 2000 and
2004 with the clearly highest long-term burden in Ostrava.
Any of the reference VOC concentrations was not exceeded in any of the
localities monitored. Annual mean concentrations were mostly below 25 %
of the reference VOC levels.
4.6 Assessment of exposure to major pollutants
4.6.1 Air quality index
The Air quality index (AQI) is based on the limit concentrations of the
pollutants listed in Government Order No. 350/2002 and specified in later
regulations (60/2004). The AQI takes into account annual arithmetic means
of concentrations of SO2, NO2,
particulate matter PM10, arsenic, cadmium,
nickel, lead, benzene and benzo[a]pyrene. In view of the long-term trends
and higher variability of measured concentrations of the monitored pollutants,
the method for the calculation of AQI was changed. Only concentrations higher
than 20 % of the limits established were taken into account. AQIs were calculated
for two groups of localities – group 1 comprises localities where common
pollutants, toxic metals and benzene are monitored and group 2 includes
8 localities with additional monitoring of polycyclic aromatic hydrocarbons (PAHs).
The AQI values in group 1 ranged from class 2 (acceptable atmosphere) to
class 3 (moderately polluted atmosphere) in Prague 1, Prague 2, Prague 5,
Prague 8, Prague 9, Děčín and Kroměříž. The PM10 limit was most frequently
exceeded. The AQI values are shown in Fig. 4.7a.
In group 2, Žďár nad Sázavou, Brno and Plzeň were classified into class 2,
while Ústí nad Labem, Hradec Králové and Prague 10 fell into class 3.
Higher air pollution was found in Karviná and Ostrava classified into class 4
(polluted atmosphere) similarly as in 2003. The benzo[a]pyrene and PM10
limits remained most markedly exceeded. The respective AQI values are shown
in Fig. 4.7b.
4.6.2 Exposure to ambient air pollutants
The health effects of air pollution depend on the concentration of air
pollutants and duration of human exposure. The exposure assessment is complicated
by inter- and intra-individual variability. The actual exposure of an individual
varies widely over the year and her/his lifetime with job, lifestyle and
outdoor/indoor pollutant concentrations. Pollutant concentrations change
with the environment (outdoor vs. indoor), locality (city vs. countryside,
low traffic vs. heavy traffic areas, industrial vs. non-industrial zones),
time (seasonal trends, daily variability) and climatic conditions. The
mean long-term exposure to pollutants can be expressed as potential exposure
of the population of a given locality to the mean pollutant concentration
level as the supply stratified e.g. at limit concentration intervals.
The assessment of the risk from outdoor air pollution included exposure
to sulphur dioxide as an indicator of coal incineration, nitrogen dioxide
indicative of incineration processes of other types, e.g. those associated
with gas heating and traffic, and suspended PM10 as the generally monitored
indicator of highest health significance. Population exposure to outdoor
air pollutants in the cities monitored at limit concentration intervals is
represented in Fig. 4.4.
The mean long-term exposure to sulphur dioxide is low and did not exceed
20 µg/m3, i.e. 40 % of the exposure (concentration) limit, for 99 % of the
monitored population in 2004. Since 1999, this exposure can be considered
as stable and close to the natural background exposure.
Levels of exposure to nitrogen oxides, represented by nitrogen dioxide,
remain higher and more significant. Exposure levels are rather stable in
a long-term run, but the concentration range increases; 55.9 %, 39.4 % and
1.5 % of the population monitored are long-term exposed to concentrations
below 27 µg/m3, between 27–40 µg/m3
and above the limit, respectively.
The population exposure to suspended PM10 continues to be of concern. The
criteria established by Government Order No. 350/2002 were exceeded for
72.2 % of the population monitored in 2004. Exposure may be characterized
as long-term, with slowly increasing mean values. The proportion of the population
living in the localities where the concentration limit was exceeded slightly
decreased compared to 2003.
4.6.3 Health risk assessment of carcinogens
Another possibility for air pollution assessment is health risk estimate.
Theoretical increase in cancer risk from exposure to arsenic, nickel, benzo[a]pyrene
and benzene in ambient air was calculated. The estimate was based on a linear
no-threshold dose-effect model.
Unit cancer risk (UCR)
Pollutant
|
Arsenic
|
Nickel
|
Benzo[a]pyrene
|
Benzene
|
UCR
|
1.50E-03
|
3.80E-04
|
8.70E-02
|
6.00E-6
|
Long-life exposure to particular pollutants was considered and based on
annual arithmetic mean levels for 2004 the risk estimates were calculated
for inhabitants of each city monitored. The aggregate cancer risk is the
sum of the risks from individual pollutants. The population risk, i.e. the
annual excess cancer risk to the total monitored population, was calculated
from the individual risk multiplied by the number of individuals in the
exposed population of the monitored city and divided by the life expectancy (70 years).
The results are summarized in the health risk table. For all of the assessed
pollutants, the minimum health risk, maximum health risk and mean health
risk (arithmetic mean, AVG) as well as the population risk for the cities
with measurement and for all the monitored cities are given.
Health risk 2004
Pollutant
|
Excess health risk
|
Population risk
|
Minimum
|
Mean (AVG)
|
Maximum
|
Cities with
measurement
|
Estimate for all cities
in Monitoring System
|
Arsenic
|
2.3E-07
|
3.0E-06
|
9.2E-06
|
0.119
|
0.127
|
Nickel
|
2.3E-07
|
8.2E-07
|
3.6E-06
|
0.026
|
0.036
|
Benzo[a]pyrene
|
3.3E-05
|
1.7E-04
|
5.7E-04
|
3.925
|
7.425
|
Benzene
|
4.0E-06
|
1.3E-05
|
2.9E-05
|
0.341
|
0.526
|
Total (for 3.34 million population)
|
4.411
|
8.114
|
Excess health risk for particular pollutants ranges between 10-7 and 10-4,
with the highest contribution of benzo[a]pyrene. It can be estimated that
overall exposure to four assessed pollutants could theoretically contribute
to the development of 4.4 cancer cases among 3.34 million population of
the monitored cities per year. This estimate does not include potential
effects of the four pollutants in all cities since benzo[a]pyrene has only
been followed up in eight of the monitored cities and benzene has been measured
in 17 of the monitored cities.
As the benzo[a]pyrene concentrations range from 5E-04 µg/m3
to 6.5E-03 µg/m3
in the eight monitored cities, reaching 3.8E-04 µg/m3 at the Košetice
background station, similar levels can be expected in other cities where
the monitoring of PAHs is not carried out. In case of data absence the mean
values for the monitored cities were used for the total population estimate
for all cities of the System of Monitoring. Due to this approach, the aggregate
population risk estimate almost doubled, amounting to 8.1 additional cancer
cases in 2004.
4.7 Indoor air pollution
A questionnaire survey was part of the INDOOR project focused on indoor
air quality measurement in 2003–2004. In 5 cities, i.e. Plzeň, Brno, Hradec
Králové, Karviná, and Ostrava, 1,250 dwellins (250 dwellings per city) were
randomly selected in collaboration with the Czech Statistical Office and their
users were asked to take part in a questionnaire survey.
The questionnaire included 22 questions focused on the following four data
categories: household members, daily activities, housing type and lifestyle.
The final questionnaire response rate was 56 %. The highest response rate
was achieved in Hradec Králové (78 %) while the lowest response rate (38 %) was recorded
in Plzeň. Out of 701 respondents 331 (47.2 %) consented to the subsequent
measurements and 100 out of their dwellings were randomly selected.
4.7.1 Characteristics of respondents
Data on the household member aged more than 18 years and listed in the
first place were taken into account for processing. Characteristics of respondents
are summarized in the table below.
Characteristics of respondents
Respondents
|
Distribution
|
Age
|
30–39 years
|
40–49 years
|
50–59 years
|
Other
|
18.1 %
|
22.8 %
|
21.0 %
|
38.1 %
|
Education
|
Primary
|
Secondary
|
University
|
Other
|
7.1 %
|
49.2 %
|
19.6 %
|
24.1 %
|
Economic activity
|
Employed
|
Unemployed
|
Retired
|
Other
|
54.5 %
|
3.2 %
|
31.4 %
|
10.9 %
|
When compared with the data of the Czech Statistical Office on the entire
Czech Republic (available by December 31, 2003), the study subjects showed
comparable age distribution and economic activity distribution but significantly
higher proportion of university education.
Housing characteristics
Housing
|
Distribution
|
Type
|
Apartment house
|
Family house
|
75 %
|
25 %
|
Construction material
|
Prefab
|
Bricks
|
Other
|
49.5 %
|
46.8 %
|
3.7 %
|
Floor
|
Ground floor
|
Higher floor
|
Double-floor
|
24.2 %
|
68.9 %
|
6.6 %
|
Area
|
55 to 64 m2
|
65 to 74 m2
|
74 to 100 m2
|
Other
|
12.8 %
|
24.6 %
|
38.5 %
|
24.1 %
|
Number of rooms
|
2
|
3
|
4
|
Other
|
12.7 %
|
59.4 %
|
19.8 %
|
8.5 %
|
4.7.2 Exposure factors
Daily activities: The respondents spend in their dwellings the shortest
time in summer on weekend days (12.4 h) and the longest time on winter weekend
days (17 h), see Fig. 4.8a.
Time spent to cook meals: 1–2 h (40 %) and 2–3 h (32 %) on week days. On
weekend days 2–3 h (35 %) and 3–4 h (29 %);
25 % of the households spend more than four hours to cook meals on weekend days.
Smoking habits: Smokers live in every fifth dwelling (22 %). In most dwellings
(61 %), 1 to 10 cigarettes are smoked a day.
4.7.3 Potential sources of indoor air pollution and other factors influencing
indoor air quality
Gas cookers, electric cookers or combined cookers are used by 55 %, 11 % and
33 % of households, respectively; statistically significant differences
in distribution of cooker types were found between cities (p < 0.001). The
highest proportion of gas cookers (75 %) was found in Karviná. A gas water
heater is used by 24 % of households. 90 % of households use ventilation
or a cooker hood while cooking meals.
Seven % of dwellings have plastic frame windows. Moulds around windows
are reported to appear exceptionally in 13 % of households, sometimes in 11 %
of households, permanently in 4 % of households and never in 72 % of households.
Moulds on the walls are found exceptionally in 9 % of households, sometimes
in 9 % of households and permanently in 3 % of households. As many as 79 %
of households have never seen moulds in their dwellings. Statistically
significant differences in the incidence of moulds were found between cities
(p = 0.001). The mould occurrence in dwellings
is reported in Fig. 4.8b.
Relationships between the questionnaire data and measurement results were sought for:
A. Relationships between nitrogen dioxide (NO2) levels and the use of gas appliences:
-
statistically significantly higher NO2 levels were measured in kitchens
and sitting rooms of dwellings equipped with gas or combined cookers (p = 0.013; p = 0.024);
-
slightly lower NO2 levels were found in kitchens of dwellings where ventilation
or cooker hoods are used while cooking meals. Differences at the significance
level (p = 0.054) were found between dwellings;
-
any significant effect of the gas water heater on NO2 levels was not found.
B. Relationships between the incidence of moulds and the use of plastic frame windows:
Paradoxically, the presence of moulds around windows was only found in
dwellings without plastic frame windows. Statistically significant differences
in the incidence of moulds around windows (p = 0.210) and on the walls
(p = 0.582) were not found between dwellings with and without plastic frame
windows. One of the reasons can also be the very low number of dwellings
with plastic frame windows.
C. Relationships between the incidence of moulds and characteristics of
houses and flats:
-
an apartment house compared to a family house is at nonsignificantly higher
risk for the presence of moulds (p = 0.379);
-
any effect of the construction material used on the incidence of moulds
was not found (p = 0.962);
-
the incidence of moulds is significantly higher in ground floor flats
compared to higher floor flats or double-floor flats (p = 0.048).
D. Relationships between smoking habits and indoor levels of benzene, formaldehyde
and PM10:
In contrast to what was expected, significantly higher indoor levels of
benzene attributable to smoking were not found in flats of smokers compared
to those of nonsmokers. This can be explained e.g. by more frequent and
regular ventilation in smoker flats and by the fact that nobody smoked in
the flats during the measurements. Analysis showed higher variability in
the measured pollutant levels between cities than between smoker and nonsmoker dwellings.
4.8 Partial conclusions
The data on treated acute respiratory diseases in 2004 were similar to
those obtained in previous years. The ARD incidence rates in the localities
monitored varied from several cases to hundreds of cases per 1,000 population
of a given age group. As in previous years, the highest ARD incidence was recorded
in the age group 1 to 5 years. Upper respiratory tract diseases were the
most frequent ARD to be diagnosed. In most localities, the mean annual ARD
incidence rates in children aged 1–14 recorded in 2004 were close to the
lower limit of the rate range for the past years.
Ambient air quality in the monitored cities was slightly better in 2004
compared to 2003, which was an extreme year in terms of weather and pollution.
Traffic-related air pollutants such as PM10,
NO2, benzene and benzo[a]pyrene
remain of concern. The annual PM10 limit was exceeded in 10 localities
(i.e. for 72 % of the monitored population). The benzo[a]pyrene limit is exceeded
on a long-term basis at most of the 8 measuring stations. In 2004 compared
to 2003, the benzene levels were by 30 to 40 % lower in Karviná and Ostrava
where the burden is typically the highest and remained comparable in the
other monitored localities. After the gradual increase in NO2 annual arithmetic means
between 1995 and 2003, most localities showed either lower or comparable
NO2 levels in 2004 compared to 2003 except for Děčín and heavy traffic areas in Prague.
These conclusions are in agreement with human health risk estimates for
potential carcinogens. The calculated excess risk for benzo[a]pyrene is
1.7E-04; the estimated risk to the population of the monitored cities is
7.4 new cancer cases, of these 3.1 new cancer cases are expected in the
Karviná-Ostrava region and 1.6 new cancer cases are calculated for the Prague
conurbation. The calculated excess risk for benzene in 2004 is 1.3E-05;
the estimated risk to the population is 0.5 additional cancer cases, with
the highest contribution of Ostrava (0.15). The calculated excess risk for
arsenic and nickel in 2004 is 3E-06 and 8.2E-07, respectively; the estimated
risk to the population is 0.12 and 0.03 new cancer cases, respectively.
The highest air pollution is detected in heavy industrial areas such as
Karviná, Ústí nad Labem or Liberec, and in large conurbations such as Prague,
Brno and Ostrava where the limits are exceeded for several monitored air
quality parameters. Nevertheless, due to the nation-wide increase in heavy
traffic, hot spots are found in other cities as well.
Statistical analysis of the questionnaire survey carried out within III.
phase, i.e. indoor air quality screening in dwellings of the commonest size
in the Czech Republic, revealed gas or combined cookers to be associated
with significantly higher indoor air pollution levels and the use of ventilation or
cooker hoods to have positive effect in this regard. Any effect of gas
water heaters on indoor air quality was not proved. The indoor presence of
moulds around windows and on the walls was recorded in almost 30 % of households
and was permanent in 3.7 % of instances; apartment houses compared to family
houses appeared to be at nonsignificantly higher risk for the presence of moulds
and ground floor flats compared to higher floor flats or double-floor flats
were at significantly higher risk for the presence of moulds. Residents of
22 % of dwellings are smokers, with 1 to 10 cigarettes being smoked a day
in 61 % of dwellings. Higher concentrations of benzene, formaldehyde and
PM10 were not found in smoker dwellings; this can be explained by more frequent
and regular ventilation in smoker dwellings as well as by the fact that
nobody smoked in the dwellings during the measurements.
Fig. 4.1a |
Treated acute respiratory diseases excluding influenza children
1–5 years, 1995–2004
|
Fig. 4.1b |
Treated acute respiratory diseases excluding influenza children
6–14 years, 1995–2004
|
Fig. 4.2a |
Sulphur dioxide, 1995–2004, annual arithmetic mean 2004
|
Fig. 4.2b |
Ground ozone, 1997–2004, annual arithmetic mean 2004
|
Fig. 4.2c |
Particulate matter, fraction PM10, 1995–2004,
annual arithmetic mean 2004
|
Fig. 4.2d |
Particulate matter pollution, PM10,
frequency of 24-hour limit exceedings
|
Fig. 4.2e |
Sum of nitrogen oxides, 1995–2004, annual arithmetic mean 2004
|
Fig. 4.2f |
Nitrogen dioxide, 1995–2004, annual arithmetic mean 2004
|
Fig. 4.3a |
Arsenic in particulate matter
|
Fig. 4.3b |
Cadmium in particulate matter
|
Fig. 4.3c |
Lead in particulate matter
|
Fig. 4.3d |
Chromium in particulate matter
|
Fig. 4.3e |
Manganese in particulate matter
|
Fig. 4.4 |
Distribution of the population by the potential exposure
to selected air pollutants (in intervals of the annual limit IHr)
|
Fig. 4.5a |
Polycyclic aromatic hydrocarbons (PAHs), annual arithmetic mean 2004
|
Fig. 4.5b |
Benzo[a]pyrene Toxic Equivalent TEQ (BaP) in 1997–2004
|
Fig. 4.6a |
Volatile organic compounds – Benzene, 2004
|
Fig. 4.6b |
Trend of benzene concentration levels in 2000–2004
|
Fig. 4.7a |
Air Quality Index – I.
|
Fig. 4.7b |
Air Quality Index – II.
|
Fig. 4.8a |
Proportion of daytime spent indoors
|
Fig. 4.8b |
Mould occurrence in the dwellings
|