Breaking the PM2.5 cycle

Thailand is notorious for its ad hoc responses to recurring and foreseeable problems— from seasonal flooding and drought to fatal road accidents during holidays. In recent years, dangerously unhealthy smog caused by fine dust particles known as PM2.5 has become another predictable threat that has drawn some recent “long-term” measures from the government, though these appear to be too broad.

With the arrival of the cool season, Bangkok and provinces across the North, the Northeast and Central Plains are suffering another dose of toxic air. The situation has improved somewhat in the capital over the past few days, but don’t be fooled: we can expect air quality to get worse, much worse, over the next few months.

Vehicle exhaust gas, forest fires, burning of crop stubble and industrial emissions are the known causes of PM2.5, particulate matter with a diameter of less than 2.5 micrometres which is hazardous to human health.

In response, the government has come up with directives ranging from efforts to get old polluting cars off the road to the promotion of “cleaner” biodiesel. But it has left two crucial issues unaddressed. These are the Pollution Control Department’s (PCD) woefully misnamed “safe” threshold of PM2.5 — set at a 24-hour average of 50μg/m³ — and the lack of practical solutions to deal with industrial emissions and outdoor burning.

The PCD’s “safe” level is twice as high as the World Health Organisation (WHO)’s 25 μg/m³ threshold. PCD director-general Pralong Dumrongthai has ignored calls to adopt the WHO standard, instead insisting that the current threshold is safe enough for Thailand. Setting it at 25μg/m³ could cause public panic, he said.

Under the government’s national plan to combat PM2.5, approved on Oct 1, the safe threshold will be lowered to 37.5μg/m³ by 2022 or 2024. Why must we wait that long to acknowledge that the Thai standard is dangerously out of step with the international limit? And why doesn’t the PCD adopt the WHO-recommended safe level now?

Adopting the strictest safety standard would improve public knowledge of air pollution levels and give us the power, when necessary, to protect ourselves with face mask or by limiting our time spent outdoors. At the same time, it would jolt state agencies out of their complacency and force them to adopt effective measures to reduce PM2.5 in the air.

Required urgently is a measure to deal with fieldburning on corn and sugarcane farms, which takes place from late January to April. So far, the government has issued orders and tightened enforcement of laws to deter and punish farmers from open burning.

However, farmers have been offered no cost-effective alternatives to burning off stubble to prepare land for planting, so the practice continues unabated. Machines to clear crop residues are one such alternative, but most farmers can’t afford them. This is where the government could step in, subsidising the purchase of such machines and/or backing development of other technologies to help clear crop stubble.

Emissions from industrial activity also needs urgent attention. The Industry Ministry’s 2006 regulation is lax because it only requires factories to monitor and report emissions of all dust, not specifically PM2.5. The government must require firms to measure and report their emissions of PM2.5.

Tackling the most hazardous form of air pollution effectively will take time. Still, the government should begin by employing targeted and practical measures. Otherwise seasonal toxic air will become just another recurring “Thai” problem.