Air pollution from cooking fires, tobacco a serious health hazard

VIENTIANE (Vientiane Times/ANN) - Household air pollution from both cooking fires and tobacco is highly prevalent; nearly three-quarters of all households surveyed reported exposure to smoking in the home and exposure to indoor cooking fire smoke. 

When multiple sources of exposure are evaluated together, a third of all households reported household level exposure to both secondhand smoke from tobacco and smoke from indoor cooking fires.

The high rates of combined exposure to multiple sources of indoor and outdoor smoke found in this study represent significant sources of health risks.

For example, from this sample, we recently reported that for a set of environmental risk factors (smoked tobacco, environmental tobacco smoke in an enclosed workspace, indoor cooking fire, trash fires, other outdoor communal fires), each incremental exposure added a significant 47 percent increase in the odds of tuberculosis, according to the National Adult Tobacco Survey carried out in Laos in September this year.

Health officials examined the prevalence of multiple sources of household and community sources of air pollution in a national sample of 9,043 adults enrolled in the largest national survey of adult tobacco use conducted to date in Laos.

So, for the Lao smoker who already experiences a significant 47 percent increase in the odds of tuberculosis under our model, the addition of one to four additional pollutant exposures (environmental tobacco smoke in enclosed workspace, indoor cooking fire, trash fires, other outdoor communal fires) adds another 47 percent to 188 percent increase in the odds of disease.

The study also explored the effects of exposure to multiple pollutants on respiratory health among adult males and found that combined exposure to tobacco, animal handling, cooking fires, and dust/dirt were associated with a two-fold increase in the odds of a positive chronic obstructive pulmonary diseases (COPD) screen.

A study conducted in Laos that analysed the effects of housing characteristics and activities on respiratory health among women and children aged 1 to 4 found that respiratory illness was associated with the location of fire, location of the cooking place, and smoking within the home.

Household air pollution exposure becomes an even more significant issue for adults, and children in particular, living in households located in the north of Laos where indoor cooking fire exposure is prolonged due to its dual purpose of cooking and keeping the home warm.

The evidence for major health risks associated with household air pollution from biomass fuel is growing and continues to mirror many of the risks long associated with secondhand smoke exposure, including coronary heart disease, stroke, COPD, pneumonia, and lung cancer, and negative birth outcomes such as low birth weight, prematurity, and stillbirth.

Studies in the Western Pacific Region have estimated use of biomass fuel indoors to be high, representing a high proportion of the disease burden, which only increases with the presence of smoked tobacco in the home.

One study, conducted in Laos, also demonstrated that the health effects of household air pollution and its health implications arise from a complex framework of personal behaviour, community behaviour, and the built environment.

Deputy Director of the Centre for Information and Education under the Ministry of Health, Dr Khamphithoun Somsamouth, said the findings from a large, representative national sample of Laos add to the mounting evidence associated with implicating high levels of household air pollution.

In Laos, these risks are exacerbated by the urbanisation underway within the country and surrounding nations such as China whose industries, due to fossil fuel emissions and automobile activity, are compounding the burden of outdoor air pollution.

While levels of more than 60 documented sources of household air pollution may vary from country to county, secondhand smoke consistently represents a major source of household air pollution. It is well established that there are no safe levels of exposure to secondhand smoke.

Over the past three decades, while smoking has declined in high-income countries, smoking prevalence has steadily increased in low and middle income countries (LMIC) —where currently about 80 percent of the world’s 1.1 billion smokers live. Based on global tobacco projections, exposure to secondhand smoke is increasingly compounding the profile of environmental health risks across many LMIC.

The United Nations’ 2030 Sustainable Development Goals address air pollution and call for a reduction in the mortality rate from the joint effects of household and ambient air pollution.

However, high statistical between-study variability was observed, and post-intervention levels of pollutants continued to exceed WHO guidelines. Therefore, current recommendations for the region continue to prioritise reducing the proportion of households using biomass fuel as the primary fuel.

The WHO recently launched the Clean Household Energy Solutions Toolkit, which is designed to help countries develop contextualised policies and programmes that expand clean energy access and use.

Researchers say there is a clear opportunity to enhance global health outcomes through inter-sectoral commitment at the regional level to combat air pollution, biomass burning, and tobacco consumption.

In 2019, the WHO declared air pollution as the greatest environmental risk to health. The impact of atmospheric transport of pollution from distant sources has been well established, and cross-border air pollution is becoming an increasing source of tension between countries in Asia.

 In Laos, there is a need to document and address the non-random spatial distribution of exposure at the China border. While Asian governments have in recent years signed several agreements to address cross-border air pollution, to prevent, mitigate and monitor wildfires and haze, and hold neighbouring countries accountable, monitoring and enforcement mechanisms continue be fraught with challenges. However, environmental experts report observing regional momentum and increasing political will to address transboundary pollution issues.

Within Laos, there is a need for systems research to align agricultural, air pollution, and tobacco control initiatives to improve air quality and for systems research to be embedded in decision-making processes. While health policy and health systems research tend to take the lead in these initiatives, there is a need to engage researchers and policymakers across multiple sectors.

Studies on air pollution exposure in Laos are extremely limited. Studies have evaluated indoor air pollutant concentrations in the home, and their association with housing characteristics and respiratory symptoms (via questionnaire and peak expiratory flow rate measurements) among women and children, and associations between respiratory symptoms and rates of exposure to multiple types of household and community level sources of air pollution among rural adult males.

However, there is a need for nationally representative studies that incorporate quantitative exposure data to evaluate the impact and association between air quality and respiratory disease in adults and children in Laos.