Motor vehicles biggest source of air pollution

MANILA, Philippines - Tagged as the biggest source of polluted air, especially in Metro Manila, are motor vehicles using diesel fuel because of its toxic substance content that proves hazardous to the environment and city inhabitants.

Among the toxic chemicals and substances emitted by diesel-powered vehicles are carbon dioxide, methane, nitrous oxide, sulfur and benzene.

Their diesel exhaust produces particulate matter, a toxic air contaminant associated with lung cancer. Particulate matters are generally said to be composed of soot or carbon formed during combustion, heavy hydrocarbons condensed or absorbed on the soot, and sulfates.  

In one of his first official acts as head of the Department of Environment and Natural Resources (DENR), Secretary Ramon J. Paje issued an administrative order specifying the numerical emission limits for passenger vehicles and light-duty vehicles, and setting the limit values for vehicles fitted with direct injection type diesel engines.

Paje vowed to bring down to a healthier level the amount of smoke and dust particles suspended in the air which, he said, can be attained by improving the emission of motor vehicles that contribute at least 80 percent to the pollution level.

Aside from the toxic substances emitted by these diesel-powered buses, the situation is compounded by the horrendous traffic congestions they create since vehicle engines – no matter how clean they may be – add to the pollution load when left idling for long periods.

The program of Paje to control, if not totally eliminate air pollution in the country’s environment conforms with the objectives of Clean Air Initiatives-Asia (CAI-Asia), a multilateral endeavor formed in 2001 by the Asian Development Bank, the US-Asia Environmental Partnership and the World Bank as a flagship initiative for improved air quality.

CAI-Asia eventually evolved into the leading convenor on air quality management (AQM) through the Better Air Quality (BAQ) workshops, the largest regional gathering of AQM stakeholders in Asia.

As part of its climate change mitigation program, the ADB is helping Asia transform into low-carbon growth by promoting energy efficiency, renewable energy, shift to cleaner fuels and other low-carbon energy options; efficient transport systems; improved urban sanitation and reduction of fugitive methane emissions; and sustainable land use and forestry.