Spatio-Temporal Trend Analysis of Particulate Matter and the Increments of Traffic, Urban, Industrial and Ship emission in Istanbul.
Authors: Alver Sahin Ulku 
Published: February 2023

&lt;p&gt;There are many features that affect air pollution in Istanbul such as industrial and ship emission, Saharan dust transport events, secondary aerosols from the border countries, local traffic emissions, local domestic heating emissions, road and soil dust, and dust from the construction activities. In this study the spatio-temporal variation of particulate matters (PM&lt;sub&gt;10&lt;/sub&gt; and PM&lt;sub&gt;2.5&lt;/sub&gt;) concentrations measured from 2015 to 2021 in 37 air quality measurement stations in Istanbul were studied. The main purpose of the study is to describe the trend rate of coarse and fine particles, the contribution of pollutants increament in urban, traffic, industrial and ship activity sites against the urban bacground in Istanbul.&amp;#160; Average PM&lt;sub&gt;10&lt;/sub&gt; concentration in all over the European side of Istanbul with 48.1 &amp;#181;g/m&lt;sup&gt;3&lt;/sup&gt; is higher than all over the Asian side with 37.7 &amp;#181;g/m&lt;sup&gt;3&lt;/sup&gt;. However, the average PM&lt;sub&gt;2.5&lt;/sub&gt; in both sites are the same value in 20.1 &amp;#181;g/m&lt;sup&gt;3&lt;/sup&gt;. According to the Theil-Sen trend analysis, it is clearly seen that the PM&lt;sub&gt;10&lt;/sub&gt; and PM&lt;sub&gt;2.5 &lt;/sub&gt;concentrations have significant (p&lt;0.01) negative trends with the average 6.02 % and 6.97 % in Istanbul, respectively. Contrast, the coarse fraction PM (PM&lt;sub&gt;2.5-10&lt;/sub&gt;) trends are increasing at the urban-industrial and urban-traffic, constant at the urban background and rural and decreasing urban and traffic stations (lower than PM&lt;sub&gt;2.5&lt;/sub&gt;). The highest significant industrial increments above the urban were determined for PM&lt;sub&gt;10 &lt;/sub&gt;(23.8 &amp;#181;g/m&lt;sup&gt;3&lt;/sup&gt;) and its contribution to urban is 65.5 %. It is mostly related to the industrial air quality stations which are located near the stone mining industrial area. The urban and traffic increments of PM&lt;sub&gt;2.5 &lt;/sub&gt;are 7.5 &amp;#181;g/m&lt;sup&gt;3&lt;/sup&gt; and 1.7 &amp;#181;g/m&lt;sup&gt;3&lt;/sup&gt;, these are higher than in Europe, lower than in Asia cities. The limit value of PM&lt;sub&gt;2.5&lt;/sub&gt; is not defined yet in Turkey. According to the findings in this study, although the fine particles has the decreasing trend, the secondary particulate matter can be the main contributor of fine particles in Istanbul. On the other hand the coarse fraction of particle has been constant or increasing timely. For policy implementation to improve the air quality the authorities should focus on the sources of PM which may be calculated by PMF.&lt;/p&gt;
&lt;p&gt;&lt;strong&gt;Financial support&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;This research has been supported by the Scientific and Technical Research Council of Turkey (T&amp;#220;BITAK) (grant number 115Y263, 112Y079 and 1059B191801445). Thanks to the Department of Environmental Protection and Control, Air Qaulity Management in Istanbul Metropolitan Municipality and Republic of T&amp;#252;rkiye, Ministry of Environment, Urbanization and Climate Change for their support in providing air pollutants.&lt;/p&gt;