Anthropogenic emissions in Nigeria and implications for atmospheric ozone pollution: A view from space

E.A Marais,D.J Jacob,K Wecht,C Lerot,L Zhang,K Yu,T.P Kurosu,K Chance,B Sauvage

doi:10.1016/j.atmosenv.2014.09.055

Abstract

Nigeria has a high population density and large fossil fuel resources but very poorly managed energy infrastructure. Satellite observations of formaldehyde (HCHO) and glyoxal (CHOCHO) reveal very large sources of anthropogenic nonmethane volatile organic compounds (NMVOCs) from the Lagos megacity and oil/gas operations in the Niger Delta. This is supported by aircraft observations over Lagos and satellite observations of methane in the Niger Delta. Satellite observations of carbon monoxide (CO) and nitrogen dioxide (NO2) show large seasonal emissions from open fires in December–February (DJF). Ventilation of central Nigeria is severely restricted at that time of year, leading to very poor ozone air quality as observed from aircraft (MOZAIC) and satellite (TES). Simulations with the GEOS-Chem chemical transport model (CTM) suggest that maximum daily 8-h average (MDA8) ozone exceeds 70 ppbv over the region on a seasonal mean basis, with significant contributions from both open fires (15–20 ppbv) and fuel/industrial emissions (7–9 ppbv). The already severe ozone pollution in Nigeria could worsen in the future as a result of demographic and economic growth, although this would be offset by a decrease in open fires.

Highlights

Nigeria is Africa's most populous country (170 million people as of 2012)
We use aircraft measurements obtained during the African Monsoon Multidisciplinary Analysis (AMMA) campaign in 2006 (Hopkins et al, 2009; Redelspeger et al, 2006) and the Measurement of Ozone and Water Vapor aboard Airbus In-service Aircraft (MOZAIC) program in 2003e2004 (Marenco et al, 1998; http://www.iagos.fr/ mozaic). We interpret these data with the GEOS-Chem chemical transport model (CTM) in terms of the information they provide for Nigerian emissions and air quality
We find that carbon monoxide (CO), ethane, propane, and acetone are well simulated

Summary

Introduction

Nigeria is Africa's most populous country (170 million people as of 2012). Its population grew 60% between 1990 and 2008 and is projected to reach 0.5e1 billion people by 2100 (UN, 2013). The Nigerian economy recently surpassed South Africa as the largest on the continent (Magnowski, 2014) This rapid growth in Nigeria elicits a range of environmental concerns including air quality. We use aircraft measurements obtained during the African Monsoon Multidisciplinary Analysis (AMMA) campaign in 2006 (Hopkins et al, 2009; Redelspeger et al, 2006) and the Measurement of Ozone and Water Vapor aboard Airbus In-service Aircraft (MOZAIC) program in 2003e2004 (Marenco et al, 1998; http://www.iagos.fr/ mozaic) We interpret these data with the GEOS-Chem chemical transport model (CTM) in terms of the information they provide for Nigerian emissions and air quality

Pollution sources and transport in Nigeria

Atmospheric composition over Nigeria observed from space

Constraints on Nigerian emissions

Implications for ozone air quality

Findings

Conclusions