A SURVEY ON VARIATIONS OF BTEX AND OZONE FORMATION POTENTIAL IN YAZD CITY AND MAPPING WITH GIS

Today use of unleaded gasoline is increasing in the world which contains abundant amount of aromatic organic carcinogenic compounds. This study aims to monitor the temporal and spatial concentration of BTEX volatile organic compounds and ozone formation potential (OFP) in the air of Yazd city.
This research was carried out at different hours of the morning and evening in the early fall of 2015. Sampling and measurement of benzene - toluene was done according to1501 NIOSH guidelines using active sampling and GC-FID. GIS software was used for zoning.
The mean concentration of BTEX in the early morning hours was 130 and 659 (μg / m3) and late in the morning was 159 and 830 (μg / m3), respectively, which indicates an increase in emissions in the last hour’s morning. Also, Toluene to benzene ratio (T / B) obtained 1.3 to 2.1 and 1.2 to 3, which represents benzene and toluene emissions caused by traffic. T/B, xylene to benzene (X/B) and xylene to ethyl benzene (X/EB) Ratio ranges were obtained 1.2 to 2.1, 1 to 4 and 2 to 6.
In this study, spatial analysis by GIS software showed the center and south parts of Yazd more polluted than the north part. Also, spatial variations of BTEX and OFP concentrations were more, but the temporal trend obtained less values and Spearman good correlation (0.01> P and 0.89