Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues. Our student Ross Mazur makes this connection here…

The news article entitled To Curb China’s Haze, Air Pollution, Use Water as was headlined by ScienceDaily summarized the technical article Water Spray Geoengineering to Clean air Pollution for Mitigating Haze in China’s Cities published by the journal Environmental Chemistry Letters in mid-November of 2013. This study pertains to the field of WRE because of its connection to water distribution and treatment. The method described in the article is a proposed urban tropospheric air pollution control technology using water sprayed into the air to adsorb particulates and dissolve gaseous pollutants. The new article’s author mentions that the using sprayers on the top of buildings and other high elevation features would to generate “precipitation” which would collect pollutants as described. The technology is described as being environmentally safe and “if well designed” has the potential to require minimal inputs if the faux-precipitation is harvested and sprayed on a regular basis to remove the pollutants. In general I think we should be very wary of geoengineering technologies which affect a very large scale change for a few reasons. When large scale changes occur, numerous unintended side-effects occur (an example of a possible one in this scenario would be incomplete harvesting of this pollutant-laden precipitation leading to contamination of drinking water sources). Even if this technology works remarkably well in a small scale, characteristics of many chemical engineering systems do not scale linearly or predictably, which could lead to wasted resources and capital (if the system does not preform to the intended standards). I also think the author underplays the required capital to operate a system such as this. Pumping large volumes of water to the top of skyscrapers and mountains (with significant pressure head once at the top to be able to spray a considerable distance) would be costly and energy intensive. One aspect of the proposed technology is the water harvesting aspect.

This technology is one with substantial implications (both beneficial and harmful) because of the way it is a large resource and energy user, and because of the way in which it has the potential to remove airborne pollutants on a large scale. If a large amount of water had to be diverted from a major river which could pose as a substantial source of conflict. Also, the technology would likely require either the bulking up of or construction of entirely new additional water treatment infrastructure, which would be expensive and a potential conflict for use of public capital. As is described in the Environmental Chemistry Letters article, that the air pollution problem in China’s “megacities is sourced from the economic growth they have experienced over the past three decades leading to a massively inflated industrial sector, Yu (2013). They also describe the way that the system would be designed so that the precipitation would have physical characteristics desirable for collection of an optimal amount of gaseous and particulate pollution, Yu (2013).

Figure 1 – Air pollution sourced from dense cities in China visible from space as it blows off-land. Implementing the proposed geoengineering technology could reduce air pollution. (Photo sourced from http://eoimages.gsfc.nasa.gov/images/imagerecords/40000/40557/China_TMO_2009275.jpg )

Figure 1 – Air pollution sourced from dense cities in China visible from space as it blows off-land.
Implementing the proposed geoengineering technology could reduce air pollution. (Photo sourced from
http://eoimages.gsfc.nasa.gov/images/imagerecords/40000/40557/China_TMO_2009275.jpg )

Figure 2 – Graphics of the proposed sprayer systems on structures of great elevation. (photo sourced from Yu (2013)).

Figure 2 – Graphics of the proposed sprayer systems on structures of great elevation. (photo sourced from Yu (2013)).

References:

1. Robert Delaney. AMA Citation Style; American Medical Association Manual of Style 9th Edition. Long Island University Post. November 8 2006. http://www2.liu.edu/cwis/cwp/library/workshop/citama.htm. Accessed January 13th 2014.

2. ScienceDaily Writer. To Curb China’s Haze, Air Pollution, Use Water. ScienceDaily. 2014 January 6. http://www.sciencedaily.com/releases/2014/01/140106133253.htm. Accessed January 13th, 2014.

3. Shaocai Yu. Water Spray Geoengineering to Clean Air Pollution for Migrating Haze in China’s Cities. Environmental Chemistry Letters. 2013; 10.1007/s10311-013-0444. Available at: http://download.springer.com/static/pdf/793/art%253A10.1007%252Fs10311-013-0444-0.pdf auth66=1389841809_7f8ef1796ecfcc7ec6a0e5981e9f6c79&ext=.pdf. Accessed January 13th, 2014.

 

 

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