ATP has been in awe of the 3-wheeler Rickshaw experience for a long time (see here, here and here). If you have been in a rickshaw, you will certainly remember them being really loud, – but that is not the only form of pollution they emit. Rickshaws are extremely polluting in the atmposphere, spewing out sooty smoke and toxic gases. Most rickshaws burn tons of oil in the combustion process, which sends not just oil and smoke into the air, but also large quantities of toxic metallic particles (ash) which come from components of lubricant oil.
Health effects of particulate pollution are well understood. Soot gets lodged deep inside the lungs, in the sensitive alveoli tissue, which leads to a buildup of scar tissue buildup and and eventual respiratory problems. Soot can lead to chronic bronchitis and asthma, and it has also been shown to act as a carrier of carcinogenic compounds, such as poly aromatic hydrocarbons into the body. All in all, particulate pollution from engines is really bad for our health and rickshaws are among the worst polluters in Pakistan.
But all that may be set to change now. Thanks to some governmet regulations and some other incentive schemes, it is expected that all gasoline powered (usually 2-stroke) rickshaws in Karachi will switch to CNG powered rickshaws. Similar changes are also happening across the border in India, especially in larger cities. One such CNG rickshaw was recently spotted in Karachi and pictures are shown here.
Due to the specific nature of combustion, and the fuels used, these CNG powered rickshaws are expected to emit much less black soot, carbon monoxide and unburnt hydrocarbon gases, and are hence considered much cleaner for the environment. Some new research has shown that CNG engines sometimes emit lots more nanoparticles, which are harder to detect but can be even more toxic than soot, but at least for now the visible soot and other gaseous emissions from this mode of transportation will be lower. These new rickshaws are also expected to be extremely quiet and given the price of CNG, they are also expected to be cheaper to operate.
According to a 2000 estimate, there are more than 100,000 rickshaws in Pakistan. I hope most rickshaw operators will quickly shift to the new engines. I, for one, am looking forward to a ride in one of these pretty soon.
All in all, it is a positive step forward in cleaning up our urban air, even as I worry that in a few years we will need to worry about additional emissions control technologies on these rickshaws, especially if they are not maintained properly. Operators of the previous generation of rickshaws had started to mix more than 12.5% of lubricant oil with gasoline (due to ignorance among the mechanics) even though manufacturers recommended not more than 2%. This was terrible, leading to excessive oil burning and dirtier exhaust, not to mention the extra noise.
I hope we will not repeat our mistakes, and can keep the CNG rickshaws cleaner and quitier for the next generation of rickshaw riders.
Many thanks to Jamash of Karachi Metblogs for the photograph.