Characterization of emissions from diesel backup generators in Cambodia

Özet

This study provided a comprehensive emission characterization of the diesel backup generators commonly used in the commercial sector in Cambodia using the hood experiment method. Two backup generators were selected and referred to as E1 (small size, 18.4 kW) and E2 (larger size, 92 kW). The monitoring parameters included particulate matter (PM), 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs, separately in PM and gas phase), and inorganic gases (CO, CO2, SOx and NOx). The PM compositions of element carbon (EC) and organic carbon (OC), PAHs, water-soluble inorganic ions, and elements were characterized to develop the source emission profile. The emission factors (EFs) were higher for E1 (smaller engine) as compared to E2 for all monitored parameters except for NOx. PM EFs were 2.03 ± 0.18 g kg−1 for E1 and 1.05 ± 0.01 g kg−1 for E2. Total 16 PAHs EFs, about 86% were in gas phase, were 2.0 ± 0.03 mg kg−1 for E1 and 1.03 ± 0.03 for E2. The obtained PM profile showed significant components in the descending order of OC, EC, soluble ions, elements and PAHs. The smaller engine also had higher PAHs toxicity in term of BaPeq, mainly because of more heavy PAHs found in the PM phase. The PAH concentration profiles and the diagnostic ratios obtained in this study were in the range of the literature reported values for diesel engines and could be useful for PAH source identification. The annual emissions of diesel backup generators used in the commercial sector in Cambodia were estimated for 2015 which showed the largest emission share from Phnom Penh followed by Siem Reap.