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نوع مقاله : مقالات پژوهشی

نویسندگان

1 کارشناس ارشد، گروه مهندسی عمران-محیط زیست(آلودگی هوا)، دانشکده محیط زیست، دانشگاه تهران، تهران، ایران.

2 استادیار، گروه مهندسی محیط زیست_ آلودگی هوا، دانشکده محیط زیست، دانشگاه تهران، تهران، ایران.

3 دستیار پژوهشی، دانشکده محیط زیست، دانشگاه تهران، تهران، ایران.

چکیده

زمینه و هدف: توسعه شهرنشینی همواره با آلودگی هوا همراه بوده است. از جمله این آلاینده­ها، ترکیبات آلی فرار شامل بنزن، تولوئن، اتیل بنزن و زایلن (BTEX) می‌باشند. مطالعه حاضر با هدف اندازه­گیری غلظت این ترکیبات در فضای باز شهر تهران انجام شد.
مواد و روش­ ها: در این مطالعه برای اندازه‌گیری غلظت BTEX در 46 ایستگاه در زمستان و بهار سال 1394 و همچنین 19 ایستگاه در خرداد ماه سال 1382 از قوانین مؤسسه ملی ایمنی و بهداشت شغلی (NIOSH) استفاده شد. آماده­سازی نمونه و استخراج آلاینده­ها به وسیله حلال دی ­­سولفید کربن انجام شد. تجزیه نمونه­ها توسط دستگاه گاز کروماتوگرافی و تحلیل داده­ها با استفاده از نرم ­افزار آماری 16، SPSS  انجام گرفت.
یافته­ ها: در سال 1382، آلودگی­های ناشی از BTEX مشاهده شده در مناطق شرق، مرکز و جنوب شهر تهران بیشتر و متوسط غلظت این ترکیبات​​ 238، 130، 118 و ppb 69 بود. نسبت بنزن به تولوئن 0/8تا 3/2 بود که نشان دهنده کیفیت پایین بنزین است. در سال 1394، غلظت BTEX در منطقه 19 (در جنوب شهر تهران) بالاتر از مناطق شرقی و مرکزی که در مناطق ترافیک با توسعه گسترده در حمل و نقل عمومی واقع شده‌اند، بود.
نتیجه ­گیری: دلیل کاهش غلظت BTEX به مقدار مجاز آن، بهبود کیفیت بنزین، تجدید خودروهای شخصی و توسعه مترو و حمل و نقل عمومی تا سال 1394 در این مناطق می­باشد. در این سال غلظت متوسط این ترکیبات به ترتیب ​​ 5/3، 9/2، 1/5 و ppb 2/6 و نسبت بنزن به تولوئن 0/39 تا 0/76 بود که این نوسان نقش قابل توجه تردد خودروها در آلودگی ناشی از ترکیبات BTEX را نشان می‌دهد.

کلیدواژه‌ها

عنوان مقاله [English]

Experimental study of benzene, toluene, ethylbenzene and xylene (BTEX) concentrations in the air pollution of Tehran, Iran.

نویسندگان [English]

  • faezeh borhani 1
  • Mohsen Mirmohammadi 2
  • Alireza Aslemand 3

1 M.SC. Department of Civil Engineering-Environmental Engineering (Air Pollution), Faculty of Environment, Tehran University, Tehran, Iran.

2 Assistant Professor, Department of Environmental Engineering- Air Pollution, Faculty of Environment, University of Tehran, Tehran, Iran.

3 Research Assistant, Faculty of Environment, Tehran University, Tehran, Iran.

چکیده [English]

Back ground: Urbanization and development has always been led to air pollution. Volatile organic compounds such as benzene, toluene, ethylbenzene, and xylene (BTEX) are known as one of the most important groups of air pollutants. The present study aims to measureand investigate the outdoor concentrations of BTEX in Tehran, Iran.
Methods and Materials: The National Institute for Occupational Safety and Health (NIOSH)'s methods were applied to measure the concentrations of BTEX in winter and spring of 2015 at 46 stations as well as in July 2003 at 19 stations. Sample preparation and extraction were accomplished by CS2 solvent. Sample and data analysis were performed by Gas Chromathography (GC) and SPSS-16 software respectively.
Results: In 2003, The BTEX pollutants were more observed in the eastern, central and southern zones of Tehran, respectively. The average concentrations of BTEX were 238, 130, 69 and 118 ppb, respectively. The benzene to toluene (B/T) ratios were between 0.8 to 3.2, which indicated the poor quality of gasoline. In 2015, the BTEX concentrations in District 19 (south of Tehran) were higher than eastern and central regions, which located in traffic zones with extensive development in public transportations.
Conclusions: Improvement of gasoline quality, renewal of private cars and development of subway and public transportation till 2015 can be considered as the most important factors in decreasingBTEX concentrations  to allowable amounts. During this year, thehe average concentrations of BTEX were 5.3 ppb, 9.2 ppb, 1.5 ppb and 2.6 ppb, respectively. The B/T ratio was fluctuated between 0.39 to 0.76, which depicted the remarkable role of vehicle traffic in BTEX pollution.

کلیدواژه‌ها [English]

  • Tehran air pollution
  • BTEX
  • Ambient measurement
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