The relationship between air-pollution by gas flaring and lung function in Niger-Delta

The Niger-Delta region of Nigeria has witnessed over half a century of crude oil exploration and this has given rise to the environmental and health issues in the region. One of the numerous health problems not yet evaluated is the development of a lung disease. The exploration process involves mainly the flaring of associated gas found with the crude oil and this project's aim was to assess a possible relationship between the exposure to gas flaring and the development of a lung disease.

A total of 179 individuals who visited pre-selected primary healthcare centres in Nigeria for routine check-up were selected from the rest to undergo lung-function tests using a hand-spirometer. The selection of suitable subjects was achieved using the ECRHS questionnaire (ECRHS 2) and smokers as well as individuals with a previous diagnosed lung disease were excluded from taking the tests. Parameters measured were the Vital-capacity (VC), Forced expiratory volume in one second (FEV₁) as well as the Peak expiratory flow (PEF). Collated results were analysed statistically and the subjects placed in three groups according to the proximity of their homes to the gas flaring sites; group 1: subjects living 1 – 3 km away from gas flaring sites, group 2: subjects living 3.5 – 11 km away, group 3: subjects living 11 – 30 km away. 3 out of 179 results were invalid.

The mean FEV₁% in group 1 was 58.6%, in group 2: 65.9% and 72.12% in group 3. The mean Tiffeneau-index (FEV₁/FVC) was 71.45%, 75.42% and 76.29%. Comparing the groups using the Mann-Whitney test group 1 to 2 showed a p-value of > 0,01 in the FEV₁ results. Group 2 to 3 showed a p-value of 0.04 and comparing group 1 to 3 showed a p-value of > 0.01, all with respect to the FEV₁ results.

The collated results show a significant reduction of lung-function in group 1, subjects living 1 – 3 km away from gas flaring sites in comparison to groups 2 and 3. Also a significant better lung-function is recorded in subjects living as far as 11 – 30 km away from gas flaring sites in group 3). An overall review of the results shows a significant lower or decreased lung function in subjects living closer to gas flaring sites as compared to others living far away.