Wet deposition of hydrocarbons in the city of Tehran-Iran

Air pollution in the city of Tehran has been a major problem for the past three decades. The direct effects of hydrocarbon contaminants in the air are particularly important such as their carcinogenic, mutagenic, and teratogenic effects which can be transported to other environments via dry and wet deposition. In the present study, rainwater samples were collected and analyzed for 16 polycyclic aromatic hydrocarbons (PAHs), benzene, toluene, ethyl benzene, and xylene (BTEX) as well as fuel fingerprints in two ranges of gasoline (C5–C11) and diesel fuel (C12–C20) using a gas chromatograph equipped with a flame ionization detector (GC/FID). Mean concentrations of ∑16 PAHs varied between 372 and 527 µg/L and for BTEX was between 87 and 188 µg/L with maximum of 36 µg/L for toluene. Both gasoline range hydrocarbons (GRH) and diesel range hydrocarbons (DRH) were also present in the collected rainwater at concentrations of 190 and 950 µg/L, respectively. Hydrocarbon transports from air to soil were determined in this wet deposition. Average hydrocarbon transportation for ∑PAHs, BTEX, GRH, and DRH was 2,747, 627, 1,152, and 5,733 µg/m2, respectively

Analisis Kefektifan Pembelajaran Luring dengan Metode Resitasi di Masa Pandemi Covid- 19 pada Siswa SMP Negeri Nunufafi Kabupaten Timor Tengah Utara

Penelitian ini bertujuan untuk mengetahui keefektifan pembelajaran luring (luar jaringan) dengan menggunakan metode resitasi di masa pandemi covid-19 pada siswa SMPN Nunufafi. Jenis penelitian ini adalah mixed methods gabungan antara penelitian kualitatif dan kuantitatif. Populasi penelitian adalah seluruh siswa kelas VIII SMPN Nunufafi tahun ajaran 2020/2021. Sampel dalam penelitian ini adalah siswa kelas VIII B SMPN Nunufafi berjumlah 18 orang. Teknik pengumpulan data menggunakan diperoleh dari nilai pretest dan posttest dan datanya diperoleh langsung dari siswa sebagai subyek berupa hasil tes belajar siswa serta kuisioner. Hasil Uji hipotesis, menunjukkan pembelajaran luring dengan metode resitasi efektif digunakan selama masa pandemik, hal ini diketahui dari analisis data menggunakan uji t  bahwa t hitung > t tabel yaitu 6,27 > 2,04. Sedangkan respon siswa terkait pembelajaran luring dengan metode resitasi menjelaskan bahwa tingkat keefektifan pembelajaran luring melalui metode resitasi, indikator yang rata-ratanya paling tinggi adalah pemberian tugas dan penerapan pembelajaran luring saat pandemi covid-19 dengan memperoleh hasil 100% kualifikasi efektifan 100%, sedangkan indikator yang rata-ratanya paling rendah adalah hasil pembelajaran dengan perolehan hasil 50% dengan kualifikasi keefektifan kurang baik

GIS ASSESSMENT OF THE PM₁₀, PM_2.5 AND PM_1.0 CONCENTRATIONS IN URBAN AREA OF TEHRAN IN WARM AND COLD SEASONS

In recent years, atmospheric models, such as GIS, are used for environmental analysis and the related management for supporting the environmental decision makers in different countries. In this study, concentrations of PM10, PM2.5 and PM1.0 are found in urban areas of Tehran in warm and cold seasons and the data applied in the related modelling, using Arc-GIS. For this purpose, samples were collected from 42 sites in an 18 km2 region located in the west and central parts of Tehran. The mean concentrations of PM1.0, PM2.5 and PM10 are found to be 13.14 μg/m3, 22.67 μg/m3 and 95.72 μg/m3 in the warm season; and 50.12 μg/m3, 70.72 μg/m3 and 193.86 μg/m3 in the cold season respectively. In this paper, with the aid of GIS, concentrations of the suspended particles were measured in 22 major hospitals, the patients in which are in contact with these pollutants. It was found the concentrations of the suspended particles were much higher in the cold season

Aerosol Size Segregated of Tehran's Atmosphere in Iran

Tehran is located in a valley at the foot of the Alborz Mountains in northern Iran (35 degrees latitude north). Urban expansion in Tehran resulted from a high rate of population growth and rural-urban migration combined with a strong tradition of centralization in the capital. Airborne particulate of Tehran's atmosphere was fractionated in a 6-stage high-volume cascade Impactor. The first objective was to measurement of PM in twenty sites in Tehran areas. Other objectives were to obtain detailed measurements of aerosol size distribution in Tehran's atmosphere during the 2004 at five sites. In all samples the PM is high for stage 6 (< 0.49 μm). In Enghelab station mean of PM value (< 0.49 μ) is 260.97 μg/m3. The highest PM (10-7 μm) concentration is found 115.12 μg/m3 at the Enghelab station. And the highest PM (3-1.5 μm) was found 40.5μg/m3 at the Baseej site