Almost half of the world's population [...] still depends on inefficient fuelsMost people living in urban areas in high income countries associate air pollution with road traffic or possibly industry. However, lack of access to clean household energy is also an important contributor to air pollution exposure. Almost half of the world's population (about 3 billion people) still depends on inefficient fuels for cooking, lighting, and household heating.
Photo: Lídia González
In such homes, an everyday task such as cooking with fuels like wood, coal, crop waste and cow dung becomes a source of high exposure to polluting particles, especially in women, who are the primary cook. The particles do not stay within the house. They travel beyond the walls making household air pollution, together with local industries and road traffic, a major source of outdoor air pollution.
The CHAI study (Cardiovascular Health effects of Air pollution in Andhra Pradesh, India) was developed to look at air pollution from outdoor and household sources in an integrated way in rural South India and link air pollution exposures to markers of cardiovascular disease.
Accurately measuring exposure to air pollution in settings like rural India is a challenge. Environments are very dusty, access to electricity is unreliable, and high temperature and humidity make measurements challenging. Temperatures reached in summer (>40ºC),
Lack of access to clean household energy is also an important contributor to air pollution exposurefor example, were a strain for the field workers and participants as well as a problem for the air pollution monitoring equipment. During a particularly hot week, we painted the black boxes protecting the sampling equipment white so they would not absorb so much heat and keep working.
Household air pollution, [...] a major source of outdoor air pollutionMany health studies are interested in the effects of several years or a lifetime of exposure to household air pollution; however, this is currently nearly impossible to measure. The growth of low-cost air quality monitors with long-lasting batteries now provide the opportunity to measure air pollution in rural settings for several weeks to months without intensive supervision.
As a PhD, I tested two potentially useful low-cost monitors (<500€) able to measure fine particulate matter and carbon monoxide and deployed them for one week in households participating in CHAI. In this real-world (compared to laboratory) environment, the monitors were very sensitive to environmental changes and often malfunctioned. In light of our results, recently published in Environmental Research, we concluded that the low-cost monitors we tested were
Women were found to spend on average 13 hours of their daytime at home [...] compared to just 9 hours for mennot yet ready to measure chronic exposures for epidemiological studies in these challenging settings. However, the technology is rapidly advancing and we can expect low-cost monitors to help get closer to the goal of unattended, long-term monitoring in the future.
Photo: Ariadna Curto
In one of the first publications from CHAI, postdoctoral researcher Margaux Sanchez analyzed the daily mobility patterns of study participants. Women were found to spend on average 13 hours of their daytime at home or within 50 meters of the home, compared to just 9 hours for men. I am now exploring whether these sex differences in mobility and time-activity patterns are also reflected in the association between outdoor air pollution at the home and blood pressure.
CHAI is providing evidence of the need to reduce air pollution exposure at multiple levelsThis association could imply a large burden of hypertension due to air pollution in India given the pervasiveness of high exposure to air pollution.
CHAI is providing evidence of the need to reduce air pollution exposure at multiple levels including ambient air pollution, household air pollution from cooking with biomass fuel, and exposures in occupational settings. These issues relate to several of the United Nations Sustainable Development Goals, including reducing illness from air pollution (Goal 3) and universal access to affordable, clean, and sustainable energy (Goal 7).