A Modelling Study of Road Traffic Contributions to Ambient PM2.5 Concentrations in Lagos

As the fastest growing city in Africa, Lagos experiences extremely high levels of air pollution. While there are many sources of air pollution in Lagos, road traffic has been widely reported as the most prominent. Due to a dearth of studies on modelling of pollutant dispersions from vehicular emissions, this study adapted the OSCAR System to model the contributions of road traffic to ambient concentrations of PM2.5 in the megacity. The model was evaluated by comparing its predicted PM2.5 concentrations with the observed concentrations in the study area. This comparison was carried out using a number of conventional statistical parameters: model bias, normalised mean square error, fractional bias, correlation coefficient (R) and factor of 2 analysis (F2). The evaluation showed aggregate R and F2 values of 0.66 and 0.80 respectively. This implies a good level of agreement between the measured and the predicted PM2.5 concentrations. For November 2018, the model predicted mean traffic increment of 28.1µg/m3 (37.2%) - 29.3 µg/m3 (38.2%) along the Mile 12 – Ikorodu road. However, the predicted increment around the Expressway (a busier road) was 36.5 µg/m3 (43.5%). The Ikorodu -Mile 12 road is a very important traffic corridor in the Lagos Metropolitan Area – being the pioneering route for the government’s Bus Rapid Transit scheme. A scenario analysis carried out in this study shows that under a fixed meteorological condition, traffic contributions (to ambient concentrations of PM2.5) would increase by a factor of 7 (from November 2010 to November 2018) near the Ikorodu road. Further, it reveals that cars are the highest emitters of PM2.5 along the Ikorodu road. Hence, the government’s “Non- Motorised Transport (NMT)” policy could enhance reduction of PM2.5 emission along the Ikorodu road

Prevalence and Prognostic Features of ECG Abnormalities in Acute Stroke: Findings From the SIREN Study Among Africans

Background Africa has a growing burden of stroke with associated high morbidity and a 3-year fatality rate of 84%. Cardiac disease contributes to stroke occurrence and outcomes, but the precise relationship of abnormalities as noted on a cheap and widely available test, the electrocardiogram (ECG), and acute stroke outcomes have not been previously characterized in Africans. Objectives The study assessed the prevalence and prognoses of various ECG abnormalities among African acute stroke patients encountered in a multisite, cross-national epidemiologic study. Methods We included 890 patients from Nigeria and Ghana with acute stroke who had 12-lead ECG recording within first 24 h of admission and stroke classified based on brain computed tomography scan or magnetic resonance imaging. Stroke severity at baseline was assessed using the Stroke Levity Scale (SLS), whereas 1-month outcome was assessed using the modified Rankin Scale (mRS). Results Patients\u27 mean age was 58.4 ± 13.4 years, 490 were men (55%) and 400 were women (45%), 65.5% had ischemic stroke, and 85.4% had at least 1 ECG abnormality. Women were significantly more likely to have atrial fibrillation, or left ventricular hypertrophy with or without strain pattern. Compared to ischemic stroke patients, hemorrhagic stroke patients were less likely to have atrial fibrillation (1.0% vs. 6.7%; p = 0.002), but more likely to have left ventricular hypertrophy (64.4% vs. 51.4%; p = 0.004). Odds of severe disability or death at 1 month were higher with severe stroke (AOR: 2.25; 95% confidence interval: 1.44 to 3.50), or atrial enlargement (AOR: 1.45; 95% confidence interval: 1.04 to 2.02). Conclusions About 4 in 5 acute stroke patients in this African cohort had evidence of a baseline ECG abnormality, but presence of any atrial enlargement was the only independent ECG predictor of death or disability