Is cancer in Phuket's air?

PHUKET: Phuket needs to clamp down on diesel-belching vehicles. Tanyaluk Sakoot investigates.

Friday 13 July 2012, 11:24AM

One of the more depressing sights on Phuket’s roads is tour buses filled with happy tourists admiring the scenery on their way to another souvenir shop or to view the sunset that is unique to Laem Phrom Thep.

Behind, out of their view as the bus labours up another of Phuket’s steep inclines, motorists drive through a reeking black fog of diesel fumes belching from the back end of the bus.

It’s not just buses, but trucks, too, and ancient pick-up trucks.

It used to be thought that diesel emissions, though smelly, were less harmful than gasoline fumes.

Diesel also has the advantages that it is simpler to refine from raw oil, and is really quite hard to ignite, making it safer than gasoline – one reason that it is the first option for military vehicles, which will not explode when hit by gunfire from the enemy.

But in June, diesel’s already faltering reputation as a “cleaner” fuel was shattered when the International Agency for Research on Cancer (IARC), an affiliate of the World Health Organisation (WHO), based in Lyon, France, announced that diesel exhaust is a carcinogen.

In a press release dated June 12, the WHO announced, “The scientific evidence was reviewed thoroughly by the [diesel emissions] working group and overall it was concluded that there was sufficient evidence in humans for the carcinogenicity of diesel exhaust.

“The Working Group found that diesel exhaust is a cause of lung cancer (sufficient evidence) and also noted a positive association (limited evidence) with an increased risk of bladder cancer (Group 1).”

Group 1 is a list of substances that the WHO regards as having definite links to cancer.
The experts, who said their decision was unanimous and based on “compelling” scientific evidence, urged people worldwide to reduce their exposure to diesel fumes as much as possible.

The downgrade to Group 1 puts diesel exhaust fumes in the same risk category as such poisonous substances as asbestos, arsenic, mustard gas, alcohol and tobacco.

Dr Christopher Portier, Chairman of the IARC working Group, stated that “The scientific evidence was compelling and the Working Group’s conclusion was unanimous: diesel engine exhaust causes lung cancer in humans.”

Dr Portier continued: “Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide.”

Cancer killed 7.6 million people worldwide in 2008, the most recent year for which the WHO has full data. Lung cancer was the most deadly type, accounting for 18 per cent of cancer deaths.

“In addition,” he said, “Existing fuels and vehicles without modifications [to reduce emissions] will take many years to be replaced, particularly in less developed countries, where regulatory measures are currently also less stringent.”

In Phuket, however, the reaction to the news from the IARC has been less than urgent. The Natural Resources and Environment Department’s Phuket Office monitors air quality in Phuket.

The AQI ranks a score of 0-50 as “good”. Scores between 50 and 100 are ranked as “moderate”. Above 100, and air quality has reached a point where it “affects health”. Between 200 and 300 it has “a great effect on health”.

The index tops out at 500. Any score between 300 and the maximum ranks as “dangerous”.

On Wednesday this week, Phuket’s AQI, as measured at the Provincial Public Health Office in Phuket Town, was 36, which ranks in the cleanest band. The recent rain will undoubtedly have helped to keep the number low.

A Public Health official told The Phuket News that pollution from diesel transportation “rarely harms anyone in Phuket because the geography is open-air and it is an island”.

Buses and large trucks must be inspected by the Transport Department twice a year before being issued permits to be on the road. Any that fail emissions tests do not get a permit renewal until they have been repaired and have passed the test.

In between, however, there are no checks, so vehicles continue to belch diesel fumes – now confirmed as carcinogenic – into Phuket’s proverbially crystal blue skies.