Get real
Philippine Daily Inquirer, 19 October 2012


Check it out on the Internet, folks. Liquefied petroleum gas, or LPG, is a favored motor vehicle fuel. Countries like the United States (a certain proportion of federal government cars must be fueled by LPG), the United Kingdom (the royal family’s auto fleet includes LPG-fueled cars), Australia, and Israel, provide incentives for its use, and the Philippines encourages it. Italy (1.5 million cars) and Japan (90 percent of all taxis) are probably the largest users of LPG-fueled motor vehicles, and have used them for decades.

There is a reason for this: LPG is considered “green” (i.e., it is friendly to the environment). Compared to gasoline, LPG is claimed to have 75 percent less carbon monoxide, 40 percent less nitrogen oxides, 87 percent less ozone-forming potential, 85 percent less hydrocarbons, and 10 percent less carbon dioxide. Compared to diesel, LPG is reported to have 60 percent less carbon monoxide, 90 percent less nitrogen oxides, 70 percent less ozone-forming potential, and 90 percent less particulates.

And the kicker is that it is cheaper, on a per liter basis, than either gasoline or diesel.

In other words, it is not only green, and therefore healthier, it is also lean.

Is there a downside? Yes. LPG is a less efficient fuel than either gasoline or diesel (covers less kilometers per liter). Cars manufactured for LPG use are less expensive than those manufactured for gasoline use, and conversion from gasoline to LPG adds to the cost. And finally, LPG is more flammable than its other fuel counterparts.

But the costs of conversion to LPG are quickly recovered because of the reduced fuel costs; the more the vehicle is used, the faster the cost-recovery, which is why it is particularly advantageous for taxis and other vehicles for commercial use. And the flammability disadvantage is neutralized by safety features and/or requirements of LPG equipment.

What about the health aspects? The only study I could find on the Internet on the health aspects of using LPG was a 2010 article published in The International Journal of Health Research, a peer-reviewed online journal, titled “Health Consequences of Using Liquefied Petroleum Gas (LPG) as an Alternative Car Fuel in Gaza Governorates,” by Sirdah and Rahma of the Al Azar University and the Palestinian Ministry of Health respectively.

The cross-section study was carried out between May and August 2008, using a sample size of 255, with 230 of the drivers filling out a pretested questionnaire designed to include technical and descriptive (response rate 90.2 percent) information about the cars, health characteristics, and complaints of the drivers, 98 of whom used LPG, 112 used diesel, and 20 used gasoline. The cars themselves were tested for volatile organic compounds (VOC) using a C-21 gas sensor (ECO Sensors Inc., USA) in order to quantify the amount of leakage of VOC inside the cars.

What were the results? That for all six possible complaints listed—poorer health, headaches, blurred vision, nausea, dyspnea (labored breathing), depression—the percentage of complaints were significantly higher for drivers of diesel and gasoline cars than for LPG cars. Similarly, the Mean Health Complaint Score Percentage showed that LPG drivers had a much smaller number of complaints than diesel and gasoline (highest number of complaints) drivers.

With respect to the VOC, the lowest amount was recorded in diesel-based engines, followed by LPG-based engines; gasoline based-engines showed the highest VOC score. None of the vehicles showed VOC of 50 ppm (parts per million) or higher (danger/high).

Given all the foregoing, the Philippine experience—or rather the impression that the public is given, based on a study jointly undertaken by the Department of Health (NCR) and the University of the Philippines National Poison Management and Control Center—is totally out of sync with what is happening in the rest of the world.

The study was undertaken to determine the exposure to health hazards of users of LPG vehicles versus that of users of conventional vehicles (diesel and gasoline). Conducted last February, it covered a total of 53 taxis (28 using LPG and 25 using diesel/gasoline) and 39 male drivers (26 LPG and 13 conventional). And it found that the LPG taxis had much higher levels of dangerous chemicals than their conventional counterparts.

The media reports I read and heard made no mention of the health complaints of the drivers in the survey, and since I haven’t been able to obtain a copy of the study, I don’t know if that was part of it. I haven’t a clue either as to the methodology used, or even whether it was subjected to a peer review. But since it is a UP study, I am giving it the benefit of the doubt (initially, anyway).

In the meantime, the question remains: Why should the Philippine experience be so different from the experience in other countries, which have used LPG vehicles for decades and have no health complaints?

The only answer I can think of is that the LPG taxis examined were not converted and/or maintained properly according to government regulations. Which would explain the leakages of the LPG vapor into the taxis. But even then, the leakages should have been immediately detected and fixed, unless no odorant was added to the LPG—another requirement disobeyed.

Finally, the study findings that LPG taxis had carbon monoxide levels eight times greater than found in conventional taxis is puzzling. As mentioned above, LPG has 60 percent and 75 percent less carbon monoxide than diesel and gasoline, respectively.

In any case, an explanation is in order. By the Department of Energy, or the DOH, or both.