Introduction

Air pollution refers to contamination of the indoor and outdoor environment on the part of any chemical, physical, or biological agent that alters the natural features of the atmosphere. Common sources of air pollution include household combustion devices, motor vehicles, industrial facilities, and forest fires. Pollutants of particular concern to public health include particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide. Both outdoor and indoor air pollution can cause potentially fatal respiratory and other diseases (WHO 2013a).

Ambient (outdoor) air pollution has been linked to adverse health outcomes since the first half of the twentieth century (ATS 1996; Varol and Çağlayan 2017). Ambient air pollution in both urban and rural areas was estimated to result in 4.2 million premature deaths worldwide annually in 2016 (WHO 2018). World Health Organization (WHO) data show that nine out of 10 people breathe air containing high levels of pollutants. The major sources of outdoor pollution include motor vehicles, power generation, building heating systems, agriculture/waste incineration, and industry (WHO 2020a). A report in the Lancet showed that pollution in air, water, and soil, and in the workplace is linked to 16% of global deaths. Most of these deaths are the result of non-communicable diseases, such as heart disease, stroke, lung cancer, and chronic obstructive pulmonary disease (COPD) (Landrigan et al. 2018).

Energy policy and the use of fossil fuels are the other major causes of outdoor air pollution. Although ambient air pollution affects both developed and developing countries; the greatest burden is incurred by low- and middle-income countries (WHO 2018). Outdoor air pollution is also a major threat to human health and the climate. Human activities representing major sources of outdoor air pollution include fuel combustion from motor vehicles (cars and heavy duty vehicles), heat and power generation (such as oil- and coal-fired power plants and boilers), industrial facilities (such as manufacturing plants, mines, and oil refineries), municipal and agricultural waste sites and waste incineration/burning, and residential cooking, heating, and lighting with polluting fuels (WHO 2018).

Ninety-one percent of the world population is exposed to key air pollutant levels that exceed WHO guideline limits. The WHO recently announced that outdoor air pollution had been classified as carcinogenic to humans (group 1) and is associated with an increased risk of bladder cancer. The WHO also announced that particulate matter (PM), a major component of outdoor air pollution, had also been classified as carcinogenic to humans (WHO 2020b). PM is a common air pollutant that consists of a mixture of solid and liquid particles suspended in the air. PM10 and PM2.5 mean the mass concentration of particles with a diameter of less than 10 μm and of particles with a diameter of less than 2.5 μm, respectively (WHO Europe 2013).

Outdoor air pollution causes 36% of deaths from lung cancer, 34% of deaths from stroke, and 27% of deaths from heart disease. This has led ambient air pollution to be described as “the invisible killer” (WHO 2020c). Current estimates suggest that premature mortality caused by air pollution exposure will double by 2050 (Lelieveld et al. 2015). However, the impacts of ambient air pollution are not limited to these (ÇMO 2019; RCAP 2020). A close, quantitative relationship exists between exposure to high concentrations of small particulates (PM10 and PM2.5) and increased mortality or morbidity, both daily and over the course of time. Average life expectancy is estimated to be 8.6 months lower than it would otherwise be because of exposure to PM from human sources. In addition to PM, exposure to ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2) also results in severe risks to human health. Ozone is particularly implicated in asthma-related morbidity and mortality, while NO2 and SO2 may also be involved in asthma, bronchial symptoms, lung inflammation, and reduced lung function. SO2 can affect the respiratory system and pulmonary functions and causes irritation of the eyes. Inflammation of the respiratory tract leads to coughing, mucus secretion, exacerbation of asthma and chronic bronchitis, and increased susceptibility to respiratory tract infections. Larger numbers of hospital admissions due to cardiac disease and mortality are observed on days with higher SO2 levels (WHO 2013b).

Air pollution is a major challenge for Turkey. Eight of the 10 cities with the poorest air quality in Europe are in Turkey (HEAL 2017). The European Environment Agency estimates that 97.2% of the urban population is exposed to unhealthy levels of PM10 in the whole world. The province of Tekirdağ borders on the megacity of Istanbul in the European part of the country. The city itself has a population of approximately 1.5 million and stands approximately 100 km from Greece and Bulgaria. Süleymanpaşa, where this study was conducted, has a population of approximately 200,000 and constitutes the center of the city. The purposes of this study were to compare air quality values in Süleymanpaşa with WHO air quality thresholds, to examine the association with mortality, and to calculate the mortality attributed to air pollution.

Methods

The research was performed as an ecological study and included 2016 data.

Tekirdağ constitutes the western border of İstanbul and the northern border of the Marmara Sea. Süleymanpaşa is the biggest district of Tekirdağ. Although agriculture is the main economic activity of Süleymanpaşa and also service industry is important, it is also known as a city of tourism and university education. The population size of Süleymanpaşa is 937,910 in 2016.

Air quality data were obtained from a website established by the Ministry of Environment and Urbanization (MEU) to monitor air quality (MoEU 2020). In line with current legislation, air quality index (AQI) calculation in Turkey is based on five basic pollutants, PM10, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3). AQI evaluation is color coded with six colors ranging from green (good, AQI: 0–50) to brown (dangerous, AQI: 301–500). Critical 1-h, 8-h, 24-h, and annual threshold values for each pollutant have also been given as a legal requirement (MoEU 2020). Air quality is monitored at two different stations in Süleymanpaşa, Tekirdağ (Fig. 1). However, deficiencies are observed in the station data, with measurements either not being performed or not being shared on numerous occasions during the course of the year. Under the relevant ministerial regulations, in order for the data from a particular station to be capable of sound use in the assessment of air pollution, monitoring station must have produced data on at least 75% of days in the year concerned. Since the days when measurements were taken at the stations in the city were compatible with that criterion, they are reliable for use in the analysis in the present study. The first station stands at a location where traffic pollution can be evaluated, and it measures PM10, SO2, NO2, NO, NOX, and CO parameters. The second station stands at a location where pollution deriving from domestic heating can be evaluated, and it measures only PM10 and SO2 parameters. The study analyses were therefore based on PM10 and SO2 parameters.

Fig.1
figure 1

Air quality monitoring stations in Süleymanpaşa, Tekirdağ. 1: Measuring station in heavy traffic area. 2: Measuring station in residential area

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Mortality data were acquired from a website established by the Ministry of Health for the purpose of documenting all deaths in Turkey (MoH 2020). All deaths, except those involving external injury and poisoning, or the deaths of Süleymanpaşa residents which occurred outside the Süleymanpaşa District were included in the study. Population data for age groups for use in statistical analyses were obtained from the Address Based Population Registration System database (TurkStat 2016).

Statistical analyses were performed using descriptive analysis, Pearson correlation, and linear regression analysis. The data from the two stations were employed separately, together with the mean PM10 and SO2 values from both stations.

The number of deaths attributed to air pollution was calculated with AirQ+ software. AirQ+ methodology developed by the WHO Regional Office for Europe for calculating the health burden and impacts of air pollution on any specific population was used to determine preventable deaths due to ambient air pollution. In this methodology, based on 95% confidence intervals for the relative risk coefficient, the lowest and highest estimates are obtained for deaths attributed to air pollution.

AirQ+ software uses a crude mortality rate calculated using deaths over the age of 30, excluding external injury and poisoning deaths, and the population aged over 30, together with PM2.5 levels, a more significant pollutant for monitoring air pollution in terms of health effects. However, PM2.5 levels are not measured by the MEU at all stations in Turkey. In this study, therefore, as proposed in the AirQ+ software, PM2.5 levels were calculated by multiplying the PM10 levels for Tekirdağ by the conversion coefficient 0.66327 specified for Turkey. PM2.5 was calculated through conversion of the mean values for PM10 data using the appropriate coefficient.

The requisite ethical approvals were obtained for the study.

Results

Mean ± standard deviation (SD) of total SO2 and PM10 values was 33.1 ± 41.8 (median: 11.3) μg/m3 and 86.6 ± 34.7 (median: 81.2) μg/m3, respectively. Measurements were not taken on several occasions in both stations (Table 1).

Table 1 Air quality index values in Süleymanpaşa
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The threshold value set for SO2 under the Turkish national air quality standards in 2016 and the WHO 24-h threshold value are 200 μg/m3 and 20 μg/m3, respectively. The 24-h threshold value for the European Union (EU) for PM10 is the same as the WHO limit, while that for SO2 is 125 μg/m3. The threshold value set for PM10 under the Turkey national air quality standards in 2016 and the WHO 24-h threshold value are 80 μg/m3 and 50 μg/m3, respectively. Twenty-four-hour SO2 measurements in the study region, with its intensive motor traffic, exceeded the national and WHO threshold values on 5 days and 143 days, while PM10 values exceeded those limits on 239 days and 331 days, respectively (Figs. 2 and 3). Twenty-four-hour SO2 measurements in the station located close to residential areas exceeded the WHO limit on only 124 days, while 24-h PM10 values exceeded the national and WHO limits on 97 days and 243 days, respectively (Figs. 2 and 3). In total, 24-h SO2 measurements exceeded the WHO threshold on 128 days, while 24-h PM10 measurements exceeded national and WHO thresholds on 160 days and 278 days, respectively (Table 1). The Turkish national air quality standards in 2016 and the WHO and EU annual threshold values for SO2 were the same at 20 μg/m3. Turkish national air quality standards in 2016 and the WHO and EU annual limits for PM10 were 52 μg/m3, 20 μg/m3, and 40 μg/m3, respectively.

Fig. 2
figure 2

SO2/24-h mean values for the heavy traffic and residential areas in Süleymanpaşa, Tekirdağ

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Fig. 3
figure 3

PM10/24-h mean for the heavy traffic and residential area values in Süleymanpaşa, Tekirdağ

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Mean 24-h values of SO2 for heavy traffic area and residential areas were 38.6 ± 51.1 (median: 12.15) μg/m3 and 26.6 ± 35.9 (median: 7.52) μg/m3, respectively (Table 1), while mean 24-h values of PM10 for heavy traffic and residential areas were 102.0 ± 39.7 (median: 94.5) μg/m3 and 71.0 ± 31.1 (median: 65.1) μg/m3, respectively (Table 1, Fig. 2). Daily mean values for PM10 and SO2 in heavy traffic and residential areas of Süleymanpaşa, together with EU and WHO thresholds, are shown in Figs. 1 and 2, respectively.

Positive, linear correlation was observed between PM10 and SO2 levels in the region with heavy traffic density (p < 0.001, r = 0.37) and in the region containing residential areas (p < 0.001, r = 0.23).

In 2016, a total of 1901 deaths meeting the specified criteria occurred. Males represented 56.4% of these, and the mean age of these cases was 71.3 ± 17.3 years. Distributions of total SO2 and PM10 pollution levels and deaths in the city by months are shown in Fig. 4.

Fig. 4
figure 4

Total 24-h SO2 and PM10 values (mean of the heavy traffic and residential areas) and numbers of deaths by months in Süleymanpaşa, Tekirdağ

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Correlation was observed between numbers of deaths and SO2 levels in the heavy traffic area (p = 0.023, r = 0.12), but none in terms of any other pollutant or localization (p > 0.05). At multivariate analysis, a linear regression equation was constructed between SO2 levels in the area with heavy traffic and numbers of deaths in the city (R = 0.122, R2 = 0.02, p = 0.023, DW is 1.870) (Table 2, Fig. 5).

Table 2 The linear relation between deaths and SO2 and PM10 levels in Süleymanpaşa, Tekirdağ
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Fig. 5
figure 5

The linear relation between deaths and SO2 levels in the heavy traffic region

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The basic indicator used to calculate the air pollution-related disease burden and mortality rate worldwide is PM2.5. AirQ+ software and PM2.5 were also employed in the present study. However, since PM2.5 is not routinely measured at air quality measurement stations in the province of Tekirdağ, similar to other stations in Turkey, deaths attributed to air quality were calculated by converting PM10 into PM2.5.

The number of individuals in the 30+ age group in Süleymanpaşa, Tekirdağ, in 2016 was 111,282. The number of deaths in individuals aged over 30, and the number of deaths in residents in Tekirdağ apart from accidents in that year was 1062. A mean PM2.5 concentration of 63.65 was calculated from conversion of mean PM10 concentrations obtained from the air pollution measurement stations. According to AirQ+ calculation, the number of deaths attributable to air pollution in the province of Tekirdağ in 2016 was 461 (95% confidence interval (CI) 316–585). In other words, 25.2% of deaths excluding accidents in the 30+ age group were caused by air pollution, with 415 in 100,000 deaths being attributable to air pollution (Table 3).

Table 3 Deaths attributed to air pollution in Süleymanpaşa in the province of Tekirdağ in 2016
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Discussion

Air pollution is an important health risk factor in Europe and the rest of the world. Outdoor air pollution is a major environmental health problem affecting the populations of low-, middle-, and high-income countries. Outdoor air pollution in both cities and rural areas was estimated to cause 4.2 million premature deaths and to contribute to 7.6% of all deaths, in 2016. This mortality is due to exposure to small particulate matter of 2.5 μm or less in diameter (PM2.5), which causes cardiovascular and respiratory diseases and cancers.

The WHO and the EU have published various guidelines on the subject of air quality. Compared with WHO guideline values (WHO 2006) and EU threshold values (EC 2020), Tekirdağ Province appears to be particularly challenged in terms of air quality values, and particularly PM10 (Table 1). PM10 and SO2 values measured in the city exceeded WHO and EU guideline values, both separately and in total, on hundreds of days (Table 1, Figs. 2 and 3). In addition, threshold values for PM10 and SO2 in Turkish national regulations are higher than those in the WHO and EU guidelines. Turkish air quality threshold values were based on adaptation to EU regulations, and a gradual transition was adopted for that purpose. Although the city’s air quality values in the year when this study was performed were compatible with the national legislation, they still far exceeded limits set by the WHO and the EU. The study findings also suggest that the city’s air quality values also exceeded the values specified in the national regulations for 2016. For example, the threshold limits specified in Turkish domestic legislation was exceeded for PM10 on 239 days and for SO2 on 5 days (Table 1). In addition, as set out in Appendix 1 of the Air Quality Evaluation and Management Directive published in Turkey on 6 June 2008 (No. 26898), the mean 24-h limit value for PM10 is 50 μg/m3, and this must not be exceeded on more than 35 occasions a year. However, our study findings show that this was exceeded on many more days. This value is equivalent to the WHO threshold value for PM10 and exceeded 331 times at the station in the heavy traffic region and 243 times at the station in the residential area (Table 1). Mean annual PM10 and SO2 values measured in the city are far above the mean annual values set by the WHO and the EU. For example, based on the WHO annual guideline values, PM10 values in the heavy traffic area were approximately five times higher, and they are 3.5 times in the residential area exposed to heating-related pollution. Similarly, SO2 levels are 1.95 and 1.35 times higher, respectively.

Studies of the global disease burden show that air pollution is one of the two main global risk factors for health (IHME 2014). The majority of deaths attributable to air pollution exposure result from acute ischemic/thrombotic cardiovascular events. In addition to excess mortality, air pollution is also linked to significant decreases in healthy life years and in employee productivity (Brook et al. 2017; Newby et al. 2015; Zivin and Neidell 2018). Lower respiratory tract infections and COPD are the most common diseases attributed to air pollution. Particulate matter in the outdoor air is implicated in 27.5% of all deaths due to lower respiratory tract infections and in 26.8% of those caused by COPD (RFC 2017). Studies have shown that PM2.5 is a more potent risk factor than PM10 in terms of adverse health impacts of long-term exposure and premature mortality (WHO 2016a). From that perspective, PM pollution is of particular importance in terms of public health. Particulate matter also exhibits broad effects on the respiratory system, the cardiovascular system, and the neurological system. Ambient air pollution contributed to 7.6% of all deaths in 2016 (WHO 2016b). Particulate matter in the ambient environment has been linked to 27.5% of all lower respiratory tract infections and 26.8% of deaths associated with COPD (SCOR 2018). Since we were unable to access data for causes of deaths in the present study, we were only able to perform general analyses based on total mortality rates. In addition, examination of the data shows that pollution is much more intensive in the winter months. SO2 pollution is particularly pronounced in winter. While transport-derived pollution is always present in the city, its density also increases in winter. SO2 levels decrease rapidly from May onward and remain low until October. Since particulate matter contains numerous pollutants, it does not exhibit the same sharp decline as SO2 but, nevertheless, decreases in summer (Fig. 3). This appears to be directly associated with coal used for domestic heating in particular. Although this is also a fossil fuel, new residences in the city have switched to natural gas. However, coal is still widely used in several parts of the city. In addition, the government also provides coal aid for poorer sections of society. The coal dispatched for that purpose is generally of low quality. In terms of vehicular traffic, the city has few roads but large numbers of vehicles and has no rail-based public transportation system. The city is also growing in population and experiencing high levels of immigration. Although the city stands by the sea, air circulation in terms of construction and planning is insufficient, and residents of the city are only newly becoming acquainted with alternative modes of transport such as the bicycle.

While the health effects of air pollution emerge in association with exposure, there is no safe threshold at which no health impact will be seen. In addition, studies from Europe and the USA estimate a concentration range at which adverse health impacts are seen for PM2.5 of 3–5 μg/m3. A mean annual long-term limit concentration value of 10 μg/m3 was selected for PM2.5. This value represents the lower threshold of the range at which significant effects on survival are observed in the American Cancer Society (ACS) study. All these studies reported powerful associations between long-term exposure to PM2.5 and mortality (Daniels et al. 2000; Pope 2000; WHO Europe 2005). Studies have also shown that every increase of 10 μg/m3 in PM10 may be associated with a 0.7% increase in cardiovascular system–related health problems and a 1.4% increase in respiratory health problems (Perez et al. 2015). In addition, a study from 2019 including almost 60 million deaths from 652 cities in 24 countries concluded that an increase of 10 μg per cubic meter in the mean values over the current and previous days was associated with increases of 0.44% in daily all-cause mortality, 0.36% in daily cardiovascular mortality, and 0.47% in daily respiratory mortality. The corresponding increases in daily mortality for the same change in PM2.5 concentrations were 0.68%, 0.55%, and 0.74%, respectively. These associations remained significant even after adjustment for gaseous pollutants. Associations were stronger in locations with lower annual mean PM concentrations and higher annual average temperatures. Effectively, every 20 μg/m3 rise in PM10/2.5 levels increases mortality by 1% (Liu et al. 2019). Guo et al. (2018) reported that an increase of 10 μg/m3 in the 8-day moving average concentrations of PM10, PM2.5, and SO2 corresponded to increases of 0.18% (95% CI 0.10%, 0.26%), 0.21% (95% CI 0.11%, 0.31%), and 0.16% (95% CI 0.04%, 0.30%), respectively, in daily mortality (Guo et al. 2018). In the light of the above figures, air pollution in the province of Süleymanpaşa exceeded WHO guideline values throughout nearly the entire year (Table 1, Figs. 2 and 3). For example, the mean PM10 value of the two stations exceeded WHO 24-h PM10 values on 278 days, and every 10 μg/m3 increase on these days may be regarded as being responsible for 0.44% of mortality on those days. However, the studies cited above involved very large populations. The fact is that the present study was conducted in a relatively small city and the relatively small number of deaths makes it more difficult to perform such a calculation.

SO2, another pollutant parameter employed that was used to evaluate the air quality index, may emerge in primary form with the use of fossil fuel or, secondarily, through a series of meteorological reactions. In terms of health impacts, the polluting effects of SO2 are reported to act more quickly, with findings and symptoms in the human body also appearing more rapidly. For example, acute health problems such as rhinitis and conjunctivitis are reported to appear first following acute exposure to intense SO2 pollutions, followed by an increase in mortality, similar to PM (Sunyer et al. 1996). In addition, acute symptoms of exposure to high-dose SO2 include flare-ups in diseases against a background of asthma and COPD, increased hospital presentations, admissions and lengths of stay, and mortality (Auturp 2010; Atkinson et al. 2014; Bellander et al. 2001; Boman et al. 2003; DeViries et al. 2017; Keles et al. 1999; Lee et al. 1999; Venners et al. 2003). In the present study, SO2 pollution associated with heavy traffic was found to be linked to deaths over the year, with the mortality rate increasing in line with traffic-related SO2 pollution. The possibility of the relationship determined at multivariate analysis being causal is consistent with the previous literature (Table 2, Fig. 4).

The most important sources of PM2.5, whose preventable deaths we calculated in the present study, are human activity-related heating, transportation, industry, and electricity production. Since PM2.5 can reach the deepest parts of the lungs and enters directly into the circulation system, it represents a greater health risk than the relatively larger PM10 and is used as the main indicator of the air pollution-related disease burden and for calculating mortality rates worldwide. It is still difficult to being together sufficient and confirmed data concerning air pollution in Turkey. For example, since PM2.5 is not measured at the stations where the present study was performed, WHO PM10 to PM2.5 conversion coefficients were used on AirQ+. According to the available evidence, Turkey is one of those European countries with high air pollution–related early mortality rates. According to the latest figures, 28,924 individuals in Turkey in 2010 died prematurely due to exposure to PM and ozone in the ambient environment (OECD 2014). In addition according to a study by the Health and Environment Alliance (HEAL), pollution from coal-powered thermal stations that are still in operation in Turkey leads to at least 2876 premature deaths every year (HEAL 2015). According to the Black Report prepared by the Right to Clean Air Platform in 2018, the PM2.5 level in the province of Tekirdağ was 40 μg/m3, and the number of deaths attributed to air pollution in 2017 was 824 (554–1062); mortality attributed to air pollution was 16.5%, and the incidence of mortality attributed to air pollution was 129.7 per 100,000 (RCAP 2019). Approximately 25% of the deaths in our study were attributed to air pollution, and the preventable deaths attributed to air pollution is 415 in 100,000. This is due to our study being based on measurement data for Süleymanpaşa where the measurement stations are located. Since the mortality data in the Black Report were calculated from mortality data in the entire province of Tekirdağ, the risk ascribed to air pollution in the Black Report may have been lower than in reality. In addition, as previously described, air pollution in the city center of Tekirdağ derives more from fossil fuel use for transport and heating, and the city’s geographical location, its receipt of migration and unplanned growth, and the industrial districts in the north and the coal-fired power stations in the south-west may also have contributed to pollution of the ambient atmosphere. However, air pollution and its effect on mortality and the disease burden can be reversed with public health policies. A new directive that entered into force in Launceston, Australia, in 2001 improved air quality by producing a 38% decrease in PM10 dust. This measure, in turn, resulted in a 17.9% decrease in cardiovascular diseases and a 22.8% decrease in respiratory diseases, while the total death rate fell by 11.4% (Johnston et al. 2013). In addition, a research project involving 25 European cities showed that compliance with the WHO PM2.5 concentration of 10 μg/m3 increased the mean life expectancy of individuals of 30 or more by up to 22 months (Pascal et al. 2013).

Study limitations

  1. 1.

    This is an ecological study. The relations it identifies may not be causal, and the results cannot be generalized. We endeavored to minimize this limitation by the use of multivariate analyses and the AirQ+ method.

  2. 2.

    Exposure to PM2.5 is regarded as a proxy marker in calculating the health effects of air pollution. PM2.5 levels are therefore estimated based on PM10 measurements for locations where measurements cannot be performed. The WHO states that PM2.5 concentrations not determined by measurements are calculated using national conversion factors (the PM2.5/PM10 ratio), and that if national conversion factors are unavailable, regional data obtained from mean nation-specific conversion factors should be used. The WHO also emphasizes that the PM2.5/PM10 conversion factor can vary depending on settlement (generally between 0.4 and 0.8), that a PM2.5 value based on PM10 concentrations may deviate from the true value, and that the converted value should only be employed as an approximation. We attempted to minimize this limitation by providing standardization of interpretation and comparability through the use of the conversion coefficient specified for Turkey by the WHO.

  3. 3.

    Problems are encountered in obtaining data for the country as a whole. Mortality data in the present study were obtained numerically, but no data was shared concerning causes of death. We were able to reach only death numbers because it is not permitted to access detailed death statistics. The analyses in the study were therefore based solely on total mortality data.

Conclusion

The study findings show that air quality in the city lags far below WHO standards. Turkey’s legal threshold PM10 and SO2 values are far higher than those of the WHO. However, the values in Tekirdağ exceeded the national threshold values on many occasions over the year. No data were also recorded for some days. The numbers of deaths are shown to be related to the levels of SO2 in the residential area. The slightest increase in sources of pollution in the city, or even maintenance of the existing status quo, is unacceptable, and urgent policies now need to be adopted. We therefore recommend that fossil fuel use for heating in the city first be limited, followed by work toward a transition to renewable energy. Public transportation and vehicles running on renewable energy can be encouraged and incentivized. In addition to improving cities’ air quality, public health measures introduced for that purpose have also been shown to reduce morbidity and mortality among residents. For example, the ban on coal burning introduced in Dublin, Eire, in the 1990s resulted in a 71% in black smoke dust in the air and a 34% decrease in sulfur dioxide. This reduced the incidence of cardiovascular diseases in the city by 7% and that of respiratory diseases by 13%, together with an 8% decrease in the total death rate (Clancy et al. 2002).

Based on these findings, since there is no national threshold value or regulation for PM2.5, the pollutant most responsible for air pollution-based health problems in Turkey, we recommend that PM2.5 be included among the air quality index evaluation criteria by means of amendment to the existing legislation, that a national threshold limit for PM2.5 be determined, and that measurements in the province of Tekirdağ be initiated as a matter of urgency.

Air pollution is a major environmental risk to health. By reducing the pollutant levels or by reducing air pollution, countries can reduce their burden of disease. Considering the positive contribution to the health of residents of the air pollution–lowering public health measures described in the “Discussion” section, local government, ministries, and the academic world need to collaborate on the establishment of decision-making mechanisms through scientific routes and methods. Alternative energy sources should be adopted in order to reduce heating-related pollution, fossil fuels should be abandoned over the long term, while the quality of the cold used and/or distributed needs to be supervised in the short term. Creating alternative means of transportation and vehicles in the city in order to reduce traffic-related pollution may also be important in terms of facilitating access to vehicles operating with renewable energy.

Well-designed studies are now needed to explain the relationship between air pollution and mortality.