BANGKOK – The combination of heat and “super pollutants” is emerging as a critical threat to human health, according to experts at the Better Air Quality (BAQ) conference which ended last Friday in Bangkok.

Short-lived super pollutants – methane, black carbon, hydrofluorocarbons (HFCs), nitrous oxide and ground-level ozone – contribute to half of global warming and millions of premature deaths. 

These pollutants have a short life span, but some can be transported thousands of kilometres in days.  Meanwhile, rising heat and humidity can create dangerously high heat stress temperatures and worsen the impact of breathing polluted air. 

“From a biological pathway perspective, one hypothesis is that heat stress may increase susceptibility to the respiratory toxicity of PM2.5 (a fine particulate matter pollutant), potentially through airway dehydration, epithelial irritation, and enhanced inflammatory responses,” Steve HL Yim, a professor of environmental health at Singapore’s Nanyang Technological University, told Health Policy Watch.

Long-term exposure to black carbon already heightens the risk of cancers such as lung adenocarcinoma, commonly seen in non-smokers. Short-term exposure to black carbon may exacerbate asthma and Chronic Obstructive Pulmonary Disease (COPD or chronic lung disease), while short-term exposure to ozone may result in lung function damage.

Yim’s research shows how a global increase of just 0.1 microgram/cubic metre in black carbon (soot) concentration is associated with a 12% increase in the incidence of lung adenocarcinoma, a type of lung cancer usually associated with air pollution.

Risk for Global South

The combination of super pollutants and heat are on the rise in many parts of the world, especially in the Global South where tropical and developing nations are struggling to balance climate change adaptation while pursuing rapid development.

“The situation in Southeast Asia, South Asia and Africa is worse compared with North America and Europe,” said Yim, who is an expert member of the World Health Organisation’s (WHO) Global Air Pollution and Health Technical Advisory Group.

The risk is threefold, Yim explained. First, the emissions in the three regions are high. Second, the latest technologies take time to be transferred to the three regions. Third, there is no regulation or standard, measurement network in the three regions. 

Trans-boundary air pollution in South East Asia already causes health problems, and hot weather in these regions could create a “synergistic health effect… (that is) very serious”.

The sources of super pollutants are all around us. Black carbon comes from burning biomass and fossil fuels; methane from waste, cattle, agriculture, and industry; ozone indirectly from vehicles thanks to a chemical reaction between heat and vehicular exhaust; and HFCs from sectors such as refrigeration and air conditioning.

Tackling these pollutants can be highly effective, according to Jane Burston, CEO of the Clean Air Fund, a global philanthropy. 

“Half of the global warming that we have experienced to date is because of super pollutants,” said Burston.

“Because they don’t spend very long in the atmosphere, the quicker we can reduce them, the quicker this will impact climate change, which is why they’ve come to be known as the emergency brake on climate change.”

Burston says preventing super-pollutants could potentially avoid more than half a degree of warming by 2050 and prevent millions of premature deaths. Air pollution was linked to over eight million deaths in 2021. 

Convincing governments to act

Development and funding agencies spoke candidly, calling on governments to step up national action and regional cooperation, which can be hard given the tension between several neighbours. 

Patrick Bueker, senior technical advisor at the German Society for International Cooperation (GIZ), called for a “carrot-and-stick approach” for policymakers. The “carrot” involves demonstrating the benefits of regional co-operation in Southeast Asia, such as sharing best practices and data. Bueker suggested a new regional declaration, building on the existing Association of Southeast Asian Nations (ASEAN) agreement on transboundary haze.

The “stick” requires citizens to “push policymakers into acting on air pollution. We haven’t seen any improvement in the region,” Bueker said. 

While the effects of particulate matter (PM2.5) is well known, there is less awareness of ozone, which affects health and agricultural productivity. An informed public can “push policymakers to action”. 

Citizen science vital for air pollution

Clyde Hutchinson of the Asian Development Bank (ADB) identifies citizen science as a major opportunity, emphasising this as key to shared responsibilities: “Technology is accessible and cheap, (air pollution) sensors are cheap. We can do everything on our phone; all of us can be climate scientists now.”

Hutchinson says his role as a technology specialist of the ADB-Korea Climate Technology Hub is to “match-make” funding and technology with policy action. 

“There’s no challenge with technology or funding. So what is going wrong here? 
Why can’t we get these programs underway? And that’s part of my job. How do we match both the funding and the technology?” asked Hutchinson.

Complicated regional dynamics

The impact of open and biomass burning and fossil fuel combustion, mainly in India and Nepal, has already accelerated the melting of Himalayan glaciers. A pollution monitoring station on a Nepalese glacier at approximately 5,000 metres above sea level captured proof of this, and the culprit is black carbon.

The Indo-Gangetic Plain-Himalayan Foothills region is one of the largest, most polluted airsheds in the world, and is also in a politically sensitive neighbourhood. A key agency, the International Centre for Integrated Mountain Development (ICIMOD), working on air quality, has a difficult task as two of its member, Pakistan and Afghanistan, are engaged in conflict. 

Political co-operation remains unlikely even though ICIMOD has shepherded an air quality agreement – the Thimphu Outcome. Separately, the World Bank is providing hundreds of millions of dollars as loans across the countries. 

Despite the tensions, ICIMOD representative Parth Sarathi Mahapatra says countries “could come together voluntarily to form a cooperation platform.” 

Mahapatra, an air pollution mitigation specialist, says scientific evidence as provided from the Himalayan glacier and customising solutions from a local to the national level could encourage South Asian policy makers to act on super pollutants. Black carbon alone is affecting the richest source of freshwater, after the poles, for millions of people downstream from the glaciers. 

Against rising heat, government action can no longer afford to proceed at a glacial pace.

Image Credits: Nanyang Technological University, Chetan Bhattacharji.