Ambient fine particulate matter (PM2.5) is the world’s leading environmental health risk factor. Reducing the PM2.5 disease burden requires specific strategies that target dominant sources across multiple spatial scales. We provide a contemporary and comprehensive evaluation of sector- and fuel-specific contributions to this disease burden across 21 regions, 204 countries, and 200 sub-national areas by integrating 24 global atmospheric chemistry-transport model sensitivity simulations, high-resolution satellite-derived PM2.5 exposure estimates, and disease-specific concentration response relationships. Globally, 1.05 (95% Confidence Interval: 0.74–1.36) million deaths were avoidable in 2017 by eliminating fossil-fuel combustion (27.3% of the total PM2.5 burden), with coal contributing to over half. Other dominant global sources included residential (0.74 [0.52–0.95] million deaths; 19.2%), industrial (0.45 [0.32–0.58] million deaths; 11.7%), and energy (0.39 [0.28–0.51] million deaths; 10.2%) sectors. Our results show that regions with large anthropogenic contributions generally had the highest attributable deaths, suggesting substantial health benefits from replacing traditional energy sources.

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Cement manufacturing contributes to the elevation of air pollutants in the atmosphere and thus impact on the nearby communities. This study assessed air quality in a major Cement Plant in Ibese Ogun State, Nigeria, through an ambient air quality monitoring and air emission dispersion modelling. Particulate Matter (PM) and gaseous pollutants were measured using portable samplers and AERMOD View was used for the emission dispersion modelling. Combustion products including SO 2 , NO, NO 2 , CO and VOCs were the gaseous pollutants detected along the complex fenceline and in the receptor environments. Pollutants measurements were undertaken at 23 locations within the fence line and receptor locations. The daily SO 2 and NO 2 Federal Ministry of Environment-Nigeria (FMEnv) limits were exceeded in ten (10) and five (5) locations along the fenceline, respectively. Particulates were detected in all the locations along the fenceline and in the communities. The cumulative gaseous pollutants resulting from simultaneous operations of all the identified plant air emission point sources are 0.01-276.13% of their respective 24-h limits along the fenceline, with 1-h SO 2 within the threshold limit at all fenceline locations, but 1-h NO X exceeds the threshold limit at all locations 16-21 times. The 24-h CO and VOCs are within their limits at all fenceline locations; however the 24-h SO 2 and NO X are breaching the limits at some locations 30-34 times (0.34-0.39% of the investigation period) and 44-87 times, respectively. Daily and Annual averaging concentrations of PM 10 was 14.32-31.54% and 4.90-52.60% of their respective limits. Process facilities are the major point sources of atmospheric emissions identified in the factory. Several fugitive emission sources were also identified during the field work. Comprehensive evaluation of the fugitive emission sources should be carried out in the cement plant for immediate attention.

Cough and sneeze droplets' interactions with indoor air of a typical hospital clinic that could be majorly found in developing African countries were studied to investigate the effectiveness of existing guidelines/protocols being adopted in the control of the widespread coronavirus disease (COVID-19) transmission. The influences of indoor air velocity, the type, size distribution, residence time in air, and trajectory of the droplets, were all considered while interrogating the effectiveness of physical distancing measures, the use of face covers, cautionary activities of the general public, and the plausibility of community spread of the SARS-CoV-2 virus through airborne transmission. Series of 3-D, coupled, discrete phase models (DPM) were implemented in the numerical studies. Based on DPM concentration maps as function of particle positions and particle residence times that were observed under different droplets release conditions, the virus-laden droplets could travel several meters away from the source of release (index patient), with smaller-sized particles staying longer in the air. The behavior of indoor air was also found to indicate complex dynamics as particle transports showed no linear dependence on air velocity.

A mixture of gases and obnoxious odours are major components of landfill emission. A dispersion modelling on air pollutants and odour emissions anticipated from a proposed Integrated Waste Management Facility was conducted considering five operating scenarios. Impacts of the predicted ground level concentrations of air pollutants (including carbon monoxide, CO; oxides of nitrogen, NO X ; sulphur dioxide, SO 2 ; particulate matter, PM and hydrocarbons, HC) and odour on ambient air quality were investigated using the 10-min 1 OU/m 3 odour limit, CH 4 Lower Explosive Limit (LEL) and the daily limits of CO, NOx, SO 2 , PM and HC. The anticipated maximum ground level concentration of emitted odour and CH 4 are 0.0040 OU/m 3 and 0.0349 ppm, respectively. Simultaneous operations of all the major components of the facility will generate the daily maximum concentrations of 7.34, 2.60, 7.31, 29.72 and 0.42 μg/m 3 , for CO, NO X , SO 2, PM and HC, respectively. Generally, the facility impacts on ambient air quality will be within the acceptable limit.

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An assessment of potential biomass resources in Nigeria for the production of methane and power generation is presented in this paper. Nigeria, as an underdeveloped and populous country, needs an uninterrupted source of energy. The country's energy problems have crippled large sectors of the economy. The percentage of people connected to the national grid is 40%. These 40% experience electricity supply failure on average 10–12 hours daily. Energy generation from municipal solid waste (MSW) is an effective MSW management strategy. Yearly waste generation has increased from 6,471 gigagrams (Gg) in 1959 to 26,600 Gg in 2015. This amount is projected to reach 36,250 Gg per year by 2030. Methane emission for 2015 was 491 Gg, and it is projected to reach 669 Gg in 2030. These values translate to 3.48 × 109 kilowatt hours (kWh) of electricity for 2015, with a projected 4.74 × 109 kWh by 2030. The revenue to be derived from the electricity that is generated could have been US$365.04 × 106 for 2015, and it is estimated that it will reach US$473.82 × 106 by 2030. It was found that methane emissions from MSW increased with time, and capturing this gas for energy production will lead to a sustainable waste management.