Quantification and health impact assessment of polycyclic aromatic hydrocarbons (PAHs) emissions from crop residue combustion.

Emission of Polycyclic Aromatic Hydrocarbon compounds from combustion of crop residue was investigated. Crop residues comprising maize cobs, maize husks, rice husks and bean chaff were burnt in a furnace at a temperature of 400 °C and the emissions from the combustion process were characterized using standard methods. Health risk through inhalation was assessed using toxic equivalent factors and excess lifetime cancer risk. The results showed the detection of 16 PAH compound which included: Benzo[ghi]perylene, Naphthalene, Acenaphthene, Anthracene, Phenanthrene, Fluorene, Fluoranthene, Acenaphthylene, Pyrene, Benzo[a]anthracene, Dibenzo[a,h]anthracene, Benzo[b]fluoranthene, Chrysene, Benzo[a]pyrene, Indene[1,2,3-cd]pyrene and Benzo[k]fluoranthene. Benzo[b]fluoranthene had highest mean concentration of 1.30 µg/mg while Dibenzo[a,h]anthracene had the lowest mean concentration of 0.01 µg/mg. It was also revealed that the toxicity of PAHs was due to the presence of Benzo[b]fluoranthene for all the samples except for sample 4 for which the main contribution to toxicity was emission from benzo(a)pyrene, while the cancer risk assessment estimated to be 1.2 × 10-1 was far above the acceptable carcinogenic risk limit of 1 × 10-6. This study concluded that, more efforts are needed to reduce emission of PAHs from the combustion of crop residues into the ambient air otherwise, human health could be under threat especially if exposed for a long period.

Evaluation of emission indices and air quality implications of liquefied petroleum gas burners.

Major cities in Nigeria has adopted the use of liquefied petroleum gas (LPG) as their main source for domestic cooking, however, this adoption led to different designs of LPG burners in Nigeria market. The emission indices of these burners and their air quality implications are yet to be ascertain. To solve these problems and fill the data gap, laboratory analysis were carried out on 16 conventional LPG burner heads identified in Nigeria market. The emission factors for Carbon monoxide (CO), Oxide of Nitrogen (NOx), Carbon dioxide (CO2), Hydrocarbons (HC) and sulphur dioxide (SO2) on the basis of useful energy delivered were 0.123-21.784 g/MJd, 1.973-32.943 g/MJd, 73.819-147.639 g/MJd, 4.069-171.643 g/MJd and 0-0.1644 g/MJd while the emission rates were 0.000238-0.1125 g/s, 0.0071-0.2 g/s, 0.1083-0.7 g/s, 0.0117-1.2583 g/s and 0-0.000194 g/s respectively. It was observed that results from the study were within the International Organization for Standardization, International Workshop Agreement 11 and World Health Organization indoor air quality guidelines for human protection.