Spatial distribution of health risks associated with PM2.5 in turkey and iran using satellite and ground observations

Abstract

Industrialization, has been increasing air pollution. In recent decades, the most industrialized and populated cities began to investigate this issue and estimating the cost of health effects for the governments. These researches reasoned the goverments to make new legislation and standards which eventually reduced the air pollution and health effects of it afterward. New York, Paris, London, Seoul and Istanbul are successful examples of these practices. Iran and Turkey, have almost the same population of 80 million individuals. Such large populations make a high demand in energy production, as some days in winter of 2017, Iran natural gas consumption reached the EU consumption. On the other hand, gasoline consumption in Iran is around 100 ML/d and in Turkey is 68ML/d. Meanwhile, climate change is a serious concern in both countries, which is one of the reasons for dust events in the region. Ambient PM is the sixth Global Burdon of Disease risk factor responsible for premature death of 4.1M individuals in 2016. Studies on PM health effects, playing the key role in policymaking. To observe and analyze the air pollution trend, ground measurement data is needed. This study, used the very recently published Iran nationwide ground measurements from the years 2015 to 2017. Since the population in both countries are high and spatially distributed, the number of ground measurement stations are not enough. Thus, spatially more complete remote sensing data was also used in this study. Although PM remote sensing, is still under developments since the instruments only measure AOD and not PM directly. To convert AOD to PM, researchers mostly use GEOS (Goddard Earth Observing System) chemical transport model which first used in 2011 by. For satellite retrievals, dataset V4.GL.02 is chosen in this thesis. This product obtained from three different instruments and with Geos-Chem transport model converted to PM2.5. The product has dust and sea-salt removed version which implied to have a better compare with ground measurements, as there are a lot of sand events happening in the region especially in Iran which might mask the anthropogenic sources of PM2.5. In addition, dust and sea-salt included version was also used to compare total PM2.5 concentrations in both countries. Initial ground data analysis of Turkey showed that out of 42 available PM2.5 stations, 41 stations have reported concentrations above WHO guideline and 45% of stations stand out of European Environment Agency's standard. Edirne Kesan, Sakarya Hendek and Erzurum Tashan are the PM2.5 stations with annual averages more than 50 mg/m3 all the time, which is 5 times higher than WHO guidelines. It was observed that populated cities in both countries such as Ankara, Istanbul, Tehran, Isfahan, Mashhad are experiencing high concentrations due to traffic and domestic energy consumption. Although in cities like Igdir in northeast Turkey, Zabol in southeast Iran or Khuzestan province which are having high concentrations without being populated. The reason for a high PM2.5 profile in Khuzestan province is dust events, as well as in Zabol. Also in southwest Iran is the oil refineries zone of the country, which is responsible for anthropogenic PM2.5 emissions mostly. To calculate the exposure and health effects of PM2.5 and PM10, three methodologies exist. The first methodology uses systematic review and meta-analysis oriented exposure-response function, which is based on hundreds of global researches and oriented by meta-analysis. In the second method, AirQ+, a software from WHO can be used to estimate the short-term and long-term adverse health effects of ambient PM. AirQ+ uses life-tables technique and stand on risk estimates oriented from cohort studies. Third method which is mainly used in this thesis is using concentration-response functions from a study in the US and exposure-dose functions to calculate mortality associated with PM2.5. The correlation between PM2.5 ground measurements and satellite retrievals was investigated. In general, the correlation was low due to the version of the satellite used for this study which is dust and sea-salt removed, and also the fact that ground stations measure one point and that value is considered as the region/province's average concentration. Therefore when all compositions PM2.5 satellite product used, only for this purpose, the correlations improved. In this study, a high resolution population dataset from European Commission has been used. In order to input this dataset in the function, the resolution reduced to 1000m×1000m to match the PM2.5 satellite product resolution. To estimate the mortality attributable with PM2.5, three different causes has been calculated by implying the cause-specific mortality rates for Iran and Turkey from WHO. Firstly, baseline mortality rate for three different causes as: all causes, ischemic heart disease, and lung cancer for Turkey and Iran in 2016 has been calculated. The concentration-response factor for each mortality cause and its upper and lower boundaries, separately obtained from one of the most cited studies in United States. All the datasets such as satellite derived and ground based observations, population, concentration-response factor and baseline mortality rate has been used as inputs for the function which is most commonly used in dose-response and concentration-response estimations. The calculations were performed with ArcGIS spatial analyst tools beside Excel and Google Earth Pro. The mortality attributable with PM2.5, has been calculated based on both ground observations and satellite-derived separately, on district and province level for both countries. In result of satellite-derived based calculations, Istanbul with 6297 deaths, Ankara with 3636 deaths, Izmir with 2254 deaths, Bursa with 1930 deaths, Mersin with 1131 deaths, and Konya with 1116 deaths caused by all causes and attributed to PM2.5 in the year 2016. These provinces had the highest mortalities in Turkey. In Iran, Tehran with 6724 deaths, East Azerbaijan with 2587 deaths, Alborz with 2456 deaths, Khuzestan with 2325 deaths, Mazandaran with 2322 deaths and Gilan with 2250 deaths caused by all causes and attributed to PM2.5 in the year 2016. These provinces were under the most in Iran. To sum up, 36967 deaths attributable with anthropogenic PM2.5 was estimated for Turkey, and 34491 deaths attributable with anthropogenic PM2.5 was estimated for Iran in 2016. However, these numbers increase significantly by implying the ground observation PM2.5 concentrations. In Turkey, the results based on ground observations were as 10529 deaths in Istanbul, 4094 deaths in Ankara, 2570 deaths in Bursa and 1233 deaths in Erzurum by all causes attributable with PM2.5. In Iran though, Tehran with 12383 deaths, Razavi Khorasan with 5376, Khuzestan with 4990 deaths, and Isfahan with 4 601 deaths are the most at risk provinces of Iran. The other studied mortality cause in this thesis, was ischemic heart diseases. By using the specific concentration-response factors used for ischemic heart disease, and its upper and lower boundaries, mortalities estimated separately based on satellite derived PM2.5 and ground observations. By using satellite derived PM2.5 in Turkey, Istanbul with 5200 deaths, Ankara with 2893, Izmir with 2893 deaths caused by ischemic heart diseases attributable with PM2.5 are the most at risk provinces. In Iran, 5541 deaths, East Azerbaijan 2056 deaths, and in Alborz 2003 deaths have been estimated caused by ischemic heart diseases. As in ground measured PM2.5, dust and sea-salt is included, concentrations are higher and thus, estimated mortalities increased. In Turkey, Istanbul with 14165 deaths, Ankara with 5416 deaths, Bursa with 3433 deaths, and Erzurum with 1257 deaths having the most mortalities estimated. In Iran, Tehran with 12383 deaths, Razavi Khorasan with 5376 deaths, and Khuzestan with 1483 deaths estimated as the most at risk provinces. In total, 2817 deaths in Iran estimated with satellite-derived PM2.5, caused by ischemic heart diseases attributable with PM2.5. In Turkey, 30240 deaths in total have estimated caused by ischemic heart disease attributable with PM2.5. By using ground observations, 25525 deaths estimated in Turkey and 3866 deaths in Iran. The ground observation based calculation only contributes to the provinces which PM2.5 had been measured in the year 2016. The third investigated cause, was lung cancer. The reported mortalities by WHO showing higher deaths in Turkey than Iran. Therefore, it affected the baseline mortality rate and estimation's difference of two countries. In Turkey, 5591 deaths in total and 669 deaths in Iran estimated by using satellite-derived PM2.5, caused by lung cancer and attributed to PM2.5. Although, by using ground measurements total mortality in Turkey changes to 5883 deaths and 776 deaths in Iran. The calculated results, were relevant to what was reported by State of Global Air. However, results in comparison with the report, results are higher than global reports for Turkey. Eventually, the risk distribution maps for both countries were produced. Maps were showing central Turkey (Aksaray, Ankara, Konya, Kirsehir) are at high risk, as well as Izmir, Igdir, Mardin, Batman, and Bursa. In Iran, from West Azerbaijan in the northwest, to Tehran in north-center of the country, very high-risk estimations were observed. In south Iran, Khuzestan province observed with high-risk estimations.