Environmental Engineering Reference
In-Depth Information
and spatial dynamics of ozone production in the Istanbul area by measurement and
modeling. In this project Istanbul urban plume was modeled using MM5 meteoro-
logical model and CMAQ chemistry and transport model.
2. Materials and Methods
2.1. Area of investigation
The city of Istanbul is in the inner most domains situated at 41°N and 29°E. The
Bosporus channel separates the European part from its counterpart in Asia Minor.
The total area of the two parts of the city is about 5,712 km
2
. In the framework of
this study of a COST 728 Action, three air quality stations are operated on the
Asian side of the city measuring hourly ozone and NOx concentrations. Kandilli
air quality station (125 m asl) is situated above the Bosporus and is located at the
Kandilli Observatory garden. There are no major emission sources within a few
kilometers. Kandilli is considered as a semi-rural surrounding of Istanbul. Büyükada
air quality station (200 m asl) is situated at the crest of Prince Island of Istanbul.
There are no emissions sources including motor vehicles in the island. It's about
20 km south of the mainland. Büyükada is considered as representative for the
background station of Istanbul. Finally, a traffic station is operated on a busy
motorway on the Asian side of the city, which is also in the vicinity of various
residential and industrial activities.
2.2. Model description
Hourly ozone and NOx measurements are used in order to determine high ozone
days in İstanbul. Data, common from all three stations goes back to January, 2008.
Although the measurements showed that the ozone concentrations were below the
national limit of 240 μgm
−3
, for the air quality modeling purpose, a 5-day episodic
period was chosen, where the ozone concentrations made the maximums in both
station
(Fig. 1)
.
2.2.1. Meteorological modeling
The PSU/NCAR Mesoscale Modeling System (MM5) is a non-hydrostatic and
limited area model. The MM5 is designed to predict the meteorological fields. In
this study, the meteorological fields were generated using MM5 V3.7 mesoscale
meteorological model. Three nested domains were used to reach a horizontal
resolution of 2 km in the İstanbul area (
Fig. 2):
199 × 175 grids of 30 km resolution
covering Europe, 181 × 202 grids of 10 km resolution covering the Balkan area,
and finally, 136 × 111 grids of 2 km resolution covering the Istanbul area
(Fig. 1)
.
The vertical resolution of the model covered 37 sigma levels. The meteorological
data was obtained from NCEP on 1° resolution for a 10-day period, starting from
