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Citing Polluting Vehicles Using Roadside Sensors
Makarand writes "A regional southern Californian law will
soon allow installation of
roadside sensors to measure pollutants from tailpipes
as vehicles accelerate.
The sensors would then activate a camera to photograph the license plates of vehicles whose emissions are too high and the owner would be notified to bring his vehicle for a smog check.
This would ensure that if a vehicle has developed a problem and become a polluter, the owner cannot wait till the next smog check date to fix the problem. The plan is to have these sensors in place by year 2010. As of now, the state depends on the mandatory vehicle smog checks and the Highway Patrol and travelers to report smoking vehicles."
To my limited knowledge, spectroscopy is the method of choice of measuring pollution in exhaust of plants.
AFAIK, a LASER directed on the chute and measuring the reflected spectrum deliver accurate data on various gases (CO,SO2...)
The external factors you have named maybe unpredictable, but are measurable and the systematical errors and statistical errors stemming from them can be measured and accounted for.
I may be wrong, I only remember it from something I've heard 5-10 years ago.
In that case, please enlighten me.
The report was something along this line:
Before such systems, govermental agencies checking the exhaust of plants had to build up an apparatus at the site (at the exhaust). The arrival of the agency at the site gave the operator the signal change the settings, so that they pass the inspection, which usually operated at a cheaper and less cleaner moed.
The (at that time) new system fitted into a van. They just had to drive some hundred meters near to the chute, with a line-of-sight, pointed the LASER at the exhaust and read the print-out, which listed the PPM of the pollutants.
"Between strong and weak, between rich and poor [...], it is freedom which oppresses and the law which sets free"
You are absolutely and totally correct- except that plants don't move, and emissions from plants travel at a fixed distance and usually a fixed speed between the source of the emissions and the sensor. On the road, there is no such guarantee, and the sensor- and the emission source- is subject to orders of magnitude more variability and much more environmental exposure, and hence a great deal more likelihood of false reports.
Now, if the spectroscopic sensor were embedded in the tailpipe or mounted on the bumper pointed at the tailpipe, that would work well- but civil libertarians would (probably justifiably) be up in arms over such heavy-handed law enforcement.
Eventually, this system will probably work for cars- I doubt by 2010, but eventually. However, until it's reliable and prevents innocent, law-abiding drivers from being unfairly targeted, I don't think it's proper or fair to implement it.
We tried this several years ago in Arizona. They had vans they rolled out with equipment on the entrances to the freeway system. As you rolled over a wire, a sensor would take a sniff and snap your photo. I think that the policy was to only issue a demand for inspection after 12 of these tests were failed. I haven't seen the vans around in some time (the last couple of years). If I had to guess why, I'd say it was probably because they weren't very effective or accurate.