Solar radiation and greenhouse gases that trap heat are the main causes of climate change. CO2 emissions – owing to the burning of fossil fuels and to industrial processes – amount to 65% of total CO2 and three-quarters of the global greenhouse gases. Recently, global emissions from all anthropogenic activities reached a record high of 45 billion tonnes, following a projected two per cent rise in burning fossil fuels, such as oil, gas and coal, a United Nations study revealed. Electricity and heat generation accounted for 42% of total greenhouse gas emissions, as reported by the International Energy Agency (IEA).

Our global energy demand, as measured by Total Primary Energy Supply (TPES), has demonstrated a 150% increase between 1971 and 2015, relying mainly on fossil fuels combustion (IEA). The drivers of the global energy demand that have increased over the past 25 years are: Urbanisation, industrial development and population growth. Ultimately, such factors are reshaping the world’s economies, straining the Earth’s resources and producing a lot of waste. As a result, the world has witnessed a serious need for future energy resources – on a global scale, driven by diversification and growth in developed countries, and in heavily populated countries and emerging economies, such as India and China. However, the energy sector stands as a main contributor of air pollution, where around 6.5 million deaths are attributed to poor air quality; the premature death rate due to this amounts to three million each year. In fact, poor indoor air quality is considered the world’s fourth-largest threat to human health, with high blood pressure, dietary risks and smoking occupying the top three ranks.

While urbanisation is sought by nearly all economies, it makes cities canyons for pollution, as they attract population, construction, traffic and extensive energy use. Urban vehicle emissions pose an additional pollution challenge, as pedestrians and vehicles co-exist in the same proximity. Globally, coal-fired power plants are used to generate two-fifths of the global electricity supply and contribute to around one-third of the global  CO2 emissions. The health and environmental impacts of coal combustion-related sulphur dioxide emissions are well pronounced, a major cause of respiratory illnesses and an originator of acid rain. Countries such as South Africa and the United States use coal for 94% and 65% of their power generation, respectively, while China and India use coal for about 70-75% of their generation. The electricity demand in China exceeded 20% use of the world’s electricity production in 2015, partly due to its 57% increase in urbanisation.

According to the United Nations, the urban population of the world has grown rapidly from 746 million in 1950 to 3.9 billion in 2014, with more than half the world’s population living in urban areas. The world’s urban population is expected to surpass six billion by 2045. Much of the expected urban growth will take place in countries of the developing regions, particularly Africa. As a result, existing infrastructures will buckle if they do not grow to meet the needs of their transportation, power generation, education and health care. Further, heavily populated cities promote degraded living conditions, which necessitate enhancing energy generation and usage, as well as enhanced urban and indoor air quality.

There is nothing comforting about the confirmation of the WHO air quality model, which states that 92% of the world’s population lives in places where air quality levels exceed WHO limits. On another count, UNICEF revealed that almost one in seven of the world’s children, 300 million, live in areas with the most toxic levels of outdoor air pollution – six or more times higher than international guidelines. So how much of the air quality degradation should be blamed on power generation, in general? In fact, in 2015, the International Energy Agency estimated the global energy-related emissions for:

• NOx to be 107 (Mt), with transport (over 50%), followed by industry (26%) and power (14%) coming after
• SO2 to be 80 (Mt), with one-third of it coming from the power sector

It is evident that the energy sector is by far the largest source of air pollution from human activity. Therefore, renewable energies are called upon to participate in the shifting process from coal-fired power plants or land-based gas turbines. Electricity generated by renewable technology played a vital role and accounted for around 90% of the growth in power generation in 2015; wind power alone produced more than half of the increase (IEA). The success of employing renewable technology is driven by falling costs and aggressive expansion in many emerging economies.

Urbanisation, industrial development and population growth are key factors for infrastructure expansion, where HVAC equipment is vital to making indoor conditions thermally comfortable. The power required to operate such equipment is generated by means of an energy mix, where land-based gas turbines are currently a dominant source of energy, used around the world for power generation. However, the growth rate of renewable technology has encouraged several countries, including India, to take a pledge to be fully renewable by 2050. The great environmental promise that renewable energy holds for cleaner climate and enhanced energy security is substantial. Particularly as building another power plant may neither be a feasible option nor the only answer to counter the increasing demand of power.

Amid all these challenges and ever-increasing demand for power, air quality has become a critical issue, irrespective of application. Considering the millions of tonnes of SO2, NOx and PM (Particulate Matter) emitted every day, filtration techniques alone, particularly conventional ones, may be unable to accommodate the increasing pollutant concentration present in the atmospheric air. In fact, if greenhouse gases have been measured for decades, why is it that HVAC systems even today have hardly incorporated air filter technologies to deal with all air pollutants at different concentration and particle size distribution?

How can we achieve progress if we allow various processes to emit a wide array of pollutants into our atmosphere and, then, seek prevention through filtration technologies? If the world is serious about making a difference with regard to enhancing air quality, our best practices must be consistent with our environmental responsibilities. Clearly, regulations alone cannot stop humans and their activities from polluting our environment. Clean Air acts and the frightening pollution death rates will neither stop polluters nor fix their processes. Filters alone will not capture all pollutants at different concentrations, so to slow down climate change we ought to initiate the change in ourselves. We need immediate actions, functional mechanisms and a ‘Marshall Plan’ to reduce emissions, fix our industrial processes and envision smarter ways to ease the pressure on our planet.

The finite sky

So before we stand and admire a landscape of a city or cities and congratulate its government for such prosperity, let’s reflect on the underlying consequences that the nation is bound to face as a result. Let’s question whether air quality was part of the urbanisation plan and a parameter in the prosperity equation or not. Why are we treating the Earth as a limitless sewer and the sky as an infinite sink where all pollution is dumped irresponsibly? How can we go back to the same sky and expect it to be clean, clear and the sole source of fresh air? Is it fair to ask how much waste we produce, compared to how many natural sources we are consuming? Prosperity should entail passing to our next generation a greener planet than the one we inherited, better indoor air quality than the one we inhaled, more efficient HVAC systems than the ones that make us thermally comfortable and re-engineered power generation technologies. Aspiring for prosperity places upon us a need for overcoming our fears and becoming fully renewable, as we become gradually independent of fossil fuels. While we are trying to renew our energy, why not renew our hearts and re-engineer our minds towards smarter production and use of energy.