The health effects of air pollution are complicated by the combination of indoor and outdoor exposures in India. This has led to a pressing public health burden, according to Kalpana Balakrishnan, Ph.D.
As director of the World Health Organization (WHO) Collaborating Centre for Research and Training in Occupational and Environmental Health, she emphasized the need for evidence-based actions to address these issues. Balakrishnan spoke April 5 as part of the NIEHS Keystone Science Lecture Seminar series.
“The ubiquity of air pollution exposure in India is unmistakable,” she said. “Anyone who has traveled there doesn’t need to be convinced that it is a serious public health problem.”
Indoor air in India may be polluted by smoke from traditional cookstoves, which are typically powered by solid fuels such as wood and biomass. Outdoor air pollution sources include vehicle exhaust, industrial emissions, such as those from power plants, and others.
Risk and exposure distributions
According to Balakrishnan, air pollution ranks second among the top risk factors contributing to the total years lost due to ill-health, disability, or early death. She said that respiratory and cardiovascular diseases play a major role in the total disease burden attributable to air pollution.
Recent evidence suggests that air quality is poorer in some northern states than in the rest of India. “These findings will help us prioritize methods to address air quality issues in different regions across India,” said Balakrishnan. The collaborating center she leads is in the state of Tamil Nadu, along the southeast coast of the country.
Strengthening evidence, engaging stakeholders
“Results from empirical studies are needed to move from evidence to action,” she said. “The heart of moving towards actionable policies requires not only solid evidence, but also that stakeholders be in constant communication with each other.”
“Dr. Balakrishnan continues to work with politicians and many other stakeholders to improve the quality of life in India,” said Srikanth (Sri) Nadadur, Ph.D., a program director in the NIEHS Exposure, Response, and Technology Branch.
Balakrishnan is an active member of the Indo-US Communities of Researchers, which is an informal group led by Nadadur to explore collaborative research opportunities to address air quality health issues in India. Nadadur, who hosted the talk, completed a 90-day assignment in New Delhi as a U.S. Embassy Fellow in 2015.
Short-term health effects
Balakrishnan and colleagues launched the Tamil Nadu Air Pollution and Health Effects (TAPHE) cohort study in 2010. The study provides evidence for policymakers on the short-term health effects of combined household and outdoor air pollution, as well as on exposure-response relationships, she said. Researchers recruited both rural and urban participants.
TAPHE has two arms — one focused on adults and respiratory symptoms, and the other focused on pregnant mothers and birth outcomes. In February, Balakrishnan and colleagues reported that an increase in fine particulate matter, an indicator of indoor air pollution, was associated with lower birth weight in the TAPHE cohort. Similar results were found for outdoor air pollution exposure.
Interventions for household air pollution
Scientists are exploring the most effective cookstove technologies for improving household air quality. Because liquified petroleum gas (LPG) stoves are an efficient and user-friendly alternative, Balakrishnan and colleagues are providing LPG stoves to a subset of TAPHE study participants.
This intervention trial is part of a larger, multicountry study called the Household Air Pollution Intervention Network Trial (HAPIN; see sidebar). Nadadur pointed out that the researchers are connecting to the Indian government’s ongoing effort to assist rural households in switching to LPG stoves.
“Preliminary findings thus far have shown that the LPG stove is a promising intervention for reducing personal exposure to household air pollution,” said Balakrishnan. “Moving forward, we plan to develop an implementation framework to scale-up and enhance LPG use among pregnant women, who continue to be a vulnerable population in India.”
Citation: Balakrishnan K, Ghosh S, Thangavel G, Sambandam S, Mukhopadhyay K, Puttaswamy N, Sadasivam A, Ramaswamy P, Johnson P, Kuppuswamy R, Natesan D, Maheshwari U, Natarajan A, Rajendran G, Ramasami R, Madhav S, Manivannan S, Nargunanadan S, Natarajan S, Saidam S, Chakraborty M, Balakrishnan L, Thanasekaraan V. 2018. Exposures to fine particulate matter (PM2.5) and birthweight in a rural-urban, mother-child cohort in Tamil Nadu, India. Environ Res 161:524–531.
(Kenda Freeman is a research and communication specialist for MDB, Inc., a contractor for the NIEHS Division of Extramural Research and Training.)