Dear Satybrata Mohapatra

Absolutely correct answer given by Mr. Mauchael ,The metropolitan city are most polluted City. e.g. New Delhi.Implications - The instance of urban pollution is rising on a global scale, which has driven up the concern for consumers that are making the push back into metropolitan hubs. Larger-than-life exhibitions focused on air purification are transitioning the concern for air quality from a niche matter to a topic of concern for those of all income brackets and not just those of the upper echelon. Air quality in major cities across the globe is taking a hit to alarming levels due to large scale industrialization without respecting emission norms. Considering this for healthy life (safe and clean air) what can be the best possible and technologically viable alternative for large scale purification of contaminated air? There are reasonably good research activities....but some collective and major initiatives are needed for a better future...suggestions.

1.      Urban farming firm ‘GrowUp’ lets you raise fish and grow plants easily in your backyard with the GrowUp Box. The box is made of an upcycled shipping container and has two levels.

2.      ‘Bubbles’ is an air quality architecture concept from Orproject Architects that addresses the poor air quality in many of the world’s major cities.

3.      This ingenious solution to construction pollution tackles an important eco issue while also promoting a Peru university.

4.    This large living wall in London, in fact it’s the biggest in the city, is meant to prevent flooding. Designed by Gary Grant of Green Roof.

5.      Phytokinetic, designed by landscaper Marc Granen, turns the condensation from air conditioning into water irrigation for this bus rooftop garden.

6. The population is the major pollutant.

7. Cycling is the best way.

Please find attached herewith Link & file.

Regards,

Prem Baboo

Research LATEST STEPS TAKEN TO CONTROL AIR POLLUTION IN METROPOLITAN CITY

Plant a few more trees and motivate others to do the same.. ;) ;) 

Dear Satyabrata,

I don't know what you mean by purification. If you mean removing particulate contaminants from air in an enclosure, I think the best would be to use nanoporous membranes at the windows of the enclosure and have the air inside at a slightly higher pressure. It is more difficult to remove gaseous contaminants and you have to use specific adsorbents for specific gases. Does this help?

Controlling air pressure is a bulky job! Electrostatic precipitation can help for clean air in restricted areas. For laboratory clean air, Laminar Flow benches are available

commercially . 

I agree with you Michael and Alokmay da...and its time to follow these simple and effective changes in life style...but such changes may take more time as people look for comfortable life....its a choice...either change life style or be ready to wear mask all the time to breathe safe air...

But, we can improve the quality of air confined within an enclosed small area using air purifiers...nanoporous membranes, efficient adsorbents....but its a tougher job when it comes to improving air quality of a much larger area that too if the contaminated air contains smaller toxic gas molecules....it looks bit difficult and challenging but some easier way out for large scale air purification must come soon....before bad air quality suffocates the young.....

Wish that our young scientists come out with practical solutions as desired

Reduce emission of noxious gases in the environment and increase tree cover. 

University of Engineering and Technology (UTEC), Peru  has developed air-purifying billboard and installed near a construction zone in Lima, a city that's famous for having the worst air quality in all of South America. The billboard works by combining polluted air with water, using basic thermodynamic principles to actively dissolve the pollutants (such as bacteria, dust and germs) in water to release fresh air. It is claimed that the billboard filtered around 500,000 cubic meters of air within one week. Pl refer following threads for various devices claiming to purify air in various ways;-

http://www.gizmag.com/utecs-air-purifying-billboard-installed-at-lima/31931/].

http://www.trendhunter.com/trends/hyper-filter-skyscraper

http://www.ecofriend.com/what-s-next-outdoor-air-purification-systems.html

http://www.wired.com/2015/09/tower-purifies-million-cubic-feet-air-hour/

If purification of air means slowing down economic activity then even people in developed countries will become adverse to the environmental movement, leave aside those in developing and underdeveloped countries. We cannot think of that when millions live in the most miserable conditions and rightfully demand a decent life.

for large scla, i think that the electrostatic precipitation is the best tecnnologie for particles filtration but we can find some problems using ESPs like the particles recovery, so in my recent article i work on a new ESP configuration.

As long as I can control what I breathe , I would be able to arrest the impact. The real need is to arrest mal effects on individual health. we can design air purifying masks who filter the particulates, absorb the noxious gases and rejuvenate / re hydrate the air .at economic cost. That can control mass scale pollution effects.