Effects of air pollutant parameters on respiratory diseases in Edirne

Abstract

Ambient air pollution poses a significant global public health problem and is closely associated with an increased risk of respiratory diseases. Edirne, a city in northwestern Türkiye with a population exceeding 400,000 and nearly 200,000 vehicles, faces significant air quality challenges due to anthropogenic sources such as residential heating, industrial emissions, agricultural (stubble) burning, and transportation. In Türkiye, as in many countries, there are legally established air quality standards that are established nationally and/or adapted from international legislation. Each country's limit values are set considering relevant health and environmental impacts. Türkiye's standard values are set in the "Air Quality Assessment and Management Regulation (HKDYY)". Türkiye, characterized by a rapidly expanding economy and population, hosts a wide range of commercial, social, and economic activities that contribute to its ongoing development. In addition, the ongoing intensive infrastructure and construction activities in Türkiye and the accelerated urban transformation activities due to the threat of earthquakes have led to the growth of the construction sector day by day. As a result of this growth, the capacities and numbers of mines have increased, and energy-intensive sectors with high pollution potential, such as the cement, iron, and steel sectors, have also grown. As a result of all these factors, the concentrations of particulate matter (both PM10 and PM2.5) in Türkiye frequently exceed the limit values specified in both national and international legislation. In addition, the traffic problem, which has become a major problem especially in some metropolitan cities, contributes greatly to PM10 and PM2.5 pollution, as well as to NOx pollution. Frequent forest fires in the summer months, burning of organic materials (stubble) left in the fields at the end of crop harvest, and dust transport events, especially in the spring months, from the Sahara Desert and deserts in the Arabian Peninsula, have a negative impact on air quality in Türkiye, especially regarding PM. Outdoor (ambient) air pollution is widely recognized as one of the most critical environmental risks impacting global public health. Despite significant improvements in air quality achieved by some high-income countries over recent decades, nearly 90% of the global population still resides in regions where pollutant levels exceed the air quality guidelines established by the World Health Organization (WHO). Exposure to ambient air pollution has been associated with both acute and long-term health effects. According to WHO estimates, poor air quality is responsible for approximately seven million premature deaths each year worldwide. A substantial body of epidemiological research has consistently reported strong correlations between exposure to PM10, PM2.5, and NO2 and elevated daily mortality rates, primarily resulting from respiratory illnesses, cardiovascular conditions, and certain types of cancers. This study investigates the relationship between daily average criteria air pollutants concentrations of PM10, PM2.5, NO2, and SO2 and hospital admissions for respiratory diseases including shortness of breath, cough, asthma, chronic obstructive pulmonary disease (COPD), sinusitis, bronchitis, and upper respiratory tract infections (URTI) in Edirne between March 1, 2013 and December 31, 2017 (1,767 days). In other words, for every 10 µg/m³ increase in the concentration of criteria air pollutants, the Distributed Lag Non-Linear Model (DLNM) statistically estimates the corresponding increase in hospital admissions for seven respiratory diseases. The adverse health effects of exposure to air pollutants were comprehensively examined, and the findings are expected to contribute to the more effective and efficient utilization of decision support systems in environmental and public health management. In Edirne, the concentrations of key criteria air pollutants particularly PM10, PM2.5, and SO2 have occasionally exceeded the legal threshold values defined in the National Air Quality Assessment and Management Regulation (HKDYY). PM10 has frequently surpassed the annual limit of 40 µg/m³, as stipulated by both the European Union Directive (2008/50/EC) and HKDYY. Although HKDYY does not currently specify a limit for PM2.5, the European Union has recently introduced updated standards under Regulation 2024/2881, setting the daily and annual limits at 25 µg/m³ and 10 µg/m³, respectively. These new limits are scheduled to come into effect on January 1, 2030, for all member states. Between 2013 and 2024, during the air quality assessments, it was observed that in 2021, the annual average PM10 concentration in Edirne reached 81.2 µg/m³, and the daily 24-hour limit of 50 µg/m³ was exceeded on 315 days. Throughout the analysis period, PM2.5 concentrations exceeded both the WHO's 24-hour guideline value of 15 µg/m³ and the newly established EU limit of 25 µg/m³ each year. In 2017, the annual average PM2.5 concentration in Keşan was measured at 66.2 µg/m³, with exceedances of the WHO-recommended threshold occurring on 348 days. Although NO2 levels were relatively lower, exceedances were still observed particularly in Keşan, where the annual average in 2017 was 24.7 µg/m³, and the daily limit was surpassed on 173 days. The air quality in Edirne, especially in Keşan district, was heavily polluted between 2013-2018, with high levels of SO2, PM10, and PM2.5. However, a substantial increase in natural gas usage has led to notable improvements. In Keşan, household natural gas subscription rose from 12.9% in 2014 to 78.9% in 2024, correlating strongly with a reduction in SO2 (R² = 0.96). The annual average concentration of SO2 significantly decreased from 314.5 µg/m³ in 2013 to 16.6 µg/m³ in 2023; however, it showed an upward trend in 2024, reaching 21.4 µg/m³. A similar trend was observed in PM2.5 and PM10. In 2024, the reason for the deterioration in air quality is thought to be due to households prefer cheaper and poor-quality fuels for residential heating due to the ongoing economic crisis in Türkiye. Two distinct desert dust transport events, occurring on February 1, 2015, and April 25, 2024, were analyzed using Aerosol Optical Depth (AOD) and Angstrom Exponent (AE) data obtained from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard the Aqua and Terra satellites, along with particulate matter measurements from the Edirne and Keşan Air Quality Monitoring Stations (AQMSs). A strong correlation was identified between ground-level PM10 concentrations and satellite-derived AOD values (R² = 0.99 for Edirne and R² = 0.95 for Keşan). The association between these parameters and the number of respiratory disease cases and hospital admissions observed immediately following the identified dust transport events was examined. Relatively high SO2 concentrations were detected especially in the South Marmara Region (Bursa-Bandırma-Çan) except during the winter months indicating the presence of significant industrial sources. This suggests that the source of SO2 is not solely attributable to residential heating but is also significantly influenced by industrial activities and emissions from thermal power plants. Hospital admissions for respiratory diseases were found to be significantly higher during the winter months compared to the summer months. Additionally, all air pollutant parameters, except for ozone, exhibited higher concentrations during the winter. This increase in pollution can be attributed to the use of low-calorie, poor-quality coal for heating during the winter months, as well as the use of improper burning methods. Furthermore, meteorological conditions such as high-pressure systems and temperature inversions, which are more prevalent in winter, contribute to reduced atmospheric dispersion, chemical reaction rates, and mixing height, all of which lead to higher pollution levels during this season. Poisson Generalized Linear Models (GLM) and DLNM were used to examine both the immediate and lagged effects (lag 0–9 days) of criteria air pollutants on respiratory health outcomes. The statistical analysis indicated that a 10 µg/m³ increase in pollutant concentrations was associated with significant increases in hospital admissions for specific respiratory conditions. For PM10, the increase was 16.7% for sinusitis, 9.4% for shortness of breath, and 2.2% for cough. PM2.5 was associated with a 1.8% increase in sinusitis, 1.5% in URTI, and 1.4% in shortness of breath. Increases linked to NO2 were 2.2% for shortness of breath, 1.4% for cough, and 1.4% for sinusitis. For SO2, hospital admissions rose by 1.9% for sinusitis, 1.3% for cough, and 1.2% for shortness of breath. Cumulatively, PM10 had the strongest association with shortness of breath and bronchitis; PM2.5 with sinusitis and asthma; NO2 with cough; SO2 with URTI and COPD. In conclusion, criteria air pollutants (PM10, PM2.5, NO2, and SO2) are significantly associated with increased respiratory disease incidence in Edirne, especially sinusitis and shortness of breath as well as, coughing and bronchitis. Despite natural gas adoption, economic challenges have led to increased use of lower-quality mostly coal, reversing some progress in air quality. The economic loss due to respiratory diseases is likely to be much greater than the investments required to improve air quality. In order to prevent the ongoing economic crisis from negatively affecting the quality of life of households, it is essential for governments to provide support such as natural gas subsidies which would offer significant social and environmental benefits. To mitigate the adverse health impacts of air pollution, it is crucial that governments prioritize environmental protection and invest in clean energy initiatives.