AIR POLLUTION – MONITORING MODELLING AND HEALTH

Air Pollution in Mega Cities: A Case Study of Istanbul 107
evaluated the highest ozone concentrations in Istanbul. They observed in summer periods
having sunny days and maximum temperatures above 25 °C, and the episodes were mainly
characterized by south-westerly surface winds during the day and north-easterly surface
winds during the night. A modeling study conducted by Im et al. (2011a) showed that a
NO x -sensitive ozone chemistry is more pronounced in the northern parts of the city that are
characterized by forested areas with high biogenic VOC emissions. Furthermore, the high
anthropogenic NO x emissions in the urban parts leads to response of ozone more to changes
in NO x , agreeing with the findings of Im et al. (2008).
400
Kadıkoy
O 3
( g/m 3 )
300
200
100
0
2001 2002 2003 2004 2005
400
Sarachane
O 3
( g/m 3 )
300
200
100
0
2001 2002 2003 2004 2005
Fig. 17. Daily peak ozone concentrations measured in Aksaray (Sarachane) and Kadikoy.
Furthermore, an assessment of the wind field simulations for a case study in explaining the
ozone formation mechanism over Istanbul is performed by Anteplioglu et al., 2003. In this
study, meteorological conditions favorable for high ozone concentrations appear when
Istanbul and the surrounding region are dominated by an anticyclonic pressure system.
During the ozone favorable days, south and south-westerly winds with low wind speed
influence Istanbul. In addition to the examining of the available monitoring air quality data
in the city, surface ozone concentrations and NO, NO 2 were measured first time at three
different sites one is on the island (Prince’s Island or Büyükada) as background site; semi
urban site, Kandilli just over the Bosphorus and as a nearby major high way site (Goztepe
DMO). Figures 18a,b and 19a,b present the time serious of the data for the major high way
and background stations (Incecik et al., 2010). The assessment of meteorological variables
has shown that the production and destruction of the surface ozone was highly related to
temperature and wind speeds. In urban and rural areas emissions of NO decrease ozone
concentrations in the absence of solar radiation due to the reaction O 3 , NO, NO 2 and NO x .
Conversely, O 3 concentrations show comparatively less diurnal variability in rural areas due
to the absence of high NO x emission sources.