Microalgae consist of a group of highly diverse and fast-growing microorganisms, capable of photoautotrophy, heterotrophy, and mixotrophy. They can be cultivated on non-fertile land with unit CO2 fixation capacity 10–50 times higher than terrestrial plants.
NASA is currently planning human spaceflight missions with longer durations than ever before. Closed-loop technologies, specifically photosynthetic algal photobioreactors, can offer multiple functions such as air revitalization (CO2 absorption and O2 provision) and thermal control with less launch mass and volume for long-duration flights.
Biological CO2 fixation depends on the tolerance of selected strains to high temperatures and the amount of CO2 present in flue gas, together with SOx and NOx.
Odour control systems do not give overall success unless the entire facility is properly enclosed and maintained, especially for the densely populated area like Hong Kong.
Increased concentrations of PM2·5 and traffic-related air pollution within metropolitan areas, in ranges commonly encountered worldwide, are associated with progression in coronary calcification, consistent with acceleration of atherosclerosis. This study supports the case for global efforts of pollution reduction in prevention of cardiovascular diseases.
The combined direct and indirect CO2 metabolic sources, estimated at 3.1 GtC/year, have increased 7 fold since pre-industrial times and are predicted to continue to rise over the 21st century.