- Biogas sources
The World Health Organisation (WHO) reports that in 2012 around 7 million deaths were the result of exposure to air pollution – equating to one in eight global deaths annually. These findings verify that air pollution is now the world’s largest single environmental health hazard.
Life threatening health risks associated with air pollution include heart disease, stroke, upper respiratory disease, and lung cancer. Nearly 88% of the premature deaths attributed to air pollution occurred in low and middle income countries, with the highest mortality rates occurring in Western Pacific and South East Asia regions. 
A 2013 study found air pollution to be the fifth largest killer in India, for instance, causing more than 600,000 premature deaths. This is six times higher than those reported in 2000.  In New Delhi alone, three-quarters of the deadly smog is produced by the city’s 7.2 million vehicles, with 1400 new cars being added to the road daily. 
Within the city, levels of PM 10 (particulate matter that is 10 micrometers in size), have continually risen to 400 micrograms per cubic meter in the past few months. That alone is four times New Delhi’s legal limit of 100 micrograms per cubic meter, and shockingly above the World Health Organization's recommended limit of 20.  WHO estimate that 3.7 million deaths in 2012 were caused by cardiovascular and respiratory disease linked to PM10 exposure. 
Elsewhere, the situation in China has become so extreme that the Chinese government have gone to lengths to keep their citizens informed of the dangers of air pollution. On days when heavy smog and high levels of PM 2.5 particles are present (which are even smaller than PM 10 and therefore considered more dangerous) municipal authorities issue health alerts which advice schools and businesses to close. Citizens are now able to access their smart phones to check for hourly readings.
Recent months have seen much speculation surrounding whether Beijing or New Delhi has the most severe smog, with the Centre for Science and Environment in India reporting that when Beijing’s PM 2.5 reading crossed the 500 mark for the first time this year on January 15, New Delhi had already recorded eight days at higher levels. 
Of course, it isn’t only Asia that needs to concentrate on escalating air pollution issues. The number of global deaths linked to air pollution in 2012 was higher than the 1.7 million AIDs related fatalities in 2011 and the 660,000 deaths from malaria in 2010 .
In the United States the nation’s air quality deteriorated in 2010-2012, with more than 147.6 million people, 47% of the population, now living in areas where the pollution levels are frequently reaching dangerous peaks. 
The ‘Air Quality in Europe – 2013 Report’ estimates that between 2009 and 2011, up to 96 % of European city dwellers were exposed to fine particulate matter (PM2.5) at concentrations above WHO guidelines. 
Closer to home, residents in the South of England and London were urged to stay indoors in April as air pollution levels reached the highest on record in the country, with cities left blanketed in a layer of Saharan dust. Domestic air pollution, combined with dust coming across from the Sahara on low south easterly winds caused thick smog to cover London, resulting in public outcry, with some London schools banning outdoor play to limit their children’s exposure. 
Road transport is a major source of global air pollution damaging the environment, health and quality of life for urban populations. WHO estimate that by reducing particulate matter pollution (PM10) from 70 to 20 micrograms per cubic metre air pollution-related deaths can be cut by around 15%. 
Biomethane produced from the decomposition of organic waste through anaerobic activity has the lowest greenhouse gas emissions of any biofuel and offers more than 90% reduction in particulate matter emissions. By replacing diesel with biomethane, Gazasia is playing an important role in reducing air pollution and improving public health.