Even more shocking is his information that particulate tops the priority list of California Air Resources Board for pollution control even though in most parts the ambient concentration is close to the standards and only on rare occasions reaches the maximum level of 170 microgram to 200 microgram per cum. Compared to this the small particulate pollution in Delhi always remains 3 to 5 times the standards and in a worst case scenario it hits levels even eight times the standard.

Stark difference stands out between Delhi, reeling under severe particulate pollution load and with no firm agenda to ensure drastic cuts and California, with much lower levels of particles but more concerned about its toxic effects, facing the challenge by successfully advancing its world leadership in developing most stringent emission controls to protect public health.

"Part of the challenge for California will be to address particle pollution in conjunction with ozone air pollution. While most of our control efforts have historically focussed on reducing ozone, these strategies provide dual benefits by reducing particle pollution as well, since ozone and particles share common emission sources," said Dr Prasad in his lecture on Translating Health Concerns into Air Quality Regulations: Lessons from California. "Moreover, because nitrogen oxide (NOx) is critical to the formation of both ozone and fine particles, NOx control strategies designed for ozone also help reduce levels of fine particles" he added.

Prasad feels that the government should take the lead in shifting towards alternative fuel even in Delhi to control severe particulate pollution and to control dieseliation which is making Delhi’s air immensely more toxic.

CARB has the ‘unmistakable priority of reducing urban smog to protect public health’ and therefore has been most successful in putting in place well laid out processes to build health guidelines into air quality regulations. The most remarkable is their process of identification of toxic air contaminants (TAC) as a special target for control. "The pollutants that may cause or contribute to an increase in death or serious illness are separately identified based on scientific assessment," said Prasad.

This process shot to fame last year when diesel particles were formally designated as TAC.  Once a substance has been identified as TAC, actions to reduce risk from it are instituted. As part of this risk management CARB consults the local air districts, affected industries and the public to firm up regulatory actions to protect public from exposure from an identified TAC.

Diesel exhaust has entered the TAC designation process in 1989 and has undergone repeated reviews, elaborate process of public consultation and series’ of public workshops and scientific conferences. Despite opposition from the trucking industry and engine manufacturers the process though delayed led to final endorsement of diesel particles as TAC by the California Scientific Review Panel in 1998.

"Listing as a TAC will now begin the long process of actually controlling diesel emissions under California law," said Prasad. "Now our focus is on reducing risk from diesel particles and therefore it is our conscious decision to shift towards alternative fuel."

Commenting on how they deal with pressures from the industry Prasad said, "We never take no from industry when we propose tighter emission standards. If they say they can’t do it, we demonstrate it in our labs how to do it and only give them deadlines."

For more information contact Anumita Roychowdhury, Sandhya Sharma or Chandrachur Ghose at 6981124, 6981110, 6983394.