Air pollution causes infertility as well as birth complications, emerging research goes to show

Air pollution does not only cause premature deaths but also affects fertility and the birth process, growing scientific evidence suggests. Multiple studies have linked air pollution with infertility, birth complications, increased birth defects in the offspring and stillbirths. Evidence also suggests that air pollution may affect semen quality.

A pregnant woman’s exposure to every 10-μg/m3 increase in PM 2.5 could result in a four-gram decline in the baby’s birth-weight, according to a 2018 study conducted in Chennai and its surrounding districts involving 1,285 pregnant women. PM 2.5 are fine particulate matter found in the air with a diameter of 2.5 micrometres or less and are known to pose the greatest risk to human beings. On average, Delhi’s PM 2.5 measures between 100 and 180 10-μg/m3, over 10 times the standards set by the World Health Organization (WHO).

"The median estimate in birth-weight is a 72-gram increase, which means that you can expect somewhere around 70- to 80-gram increase in the newborn’s birth weight if they [pregnant women] lived in cleaner area,” said Kalpana Balakrishnan, associate dean (research) at the SRU-ICMR Centre for Advanced Research on Air Quality, Climate and Health, Sri Ramachandra Institute of Higher Education and Research, Chennai.

India’s environment minister Prakash Javadekar, in December 2019, denied in parliament any link between air pollution and premature deaths, which contradicts the government’s own 2018 study. But growing scientific evidence paints a contrasting, more troubling picture. "There is substantial literature suggesting poor air quality is associated with adverse reproductive health," said Pauline Mendola, a senior investigator in the epidemiology branch of the Division of Intramural Population Health Research at the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Since the mixtures of specific pollutants vary over time and location, people with different levels of exposure to air pollution are affected variously, Mendola said. "So, the global picture, particularly for fine particles or traffic-related pollutants, suggests increased risk but individual studies have some variability," she added.

Government diluting air pollution norms

Indians breathe some of the world’s most toxic air and the country is home to 15 of the 20 most polluted cities in the world, according to a study released in March 2019 by the NGO Greenpeace. By breathing clean air alone, Indians would live 1.7 years longer, on average, found a December 2018 study led by the Indian Council of Medical Research (ICMR). Around 91 percent of premature deaths linked to air pollution have been in low- and middle-income countries, according to the WHO. Just by ensuring cleaner air, countries can reduce their burden of stroke, heart disease, lung cancer and respiratory diseases, it said.

India’s power industry, led by its largest producer National Thermal Power Corporation (NTPC), is pushing to water down the norms for lethal nitrous oxide (NOx) emissions, an IndiaSpend investigation found. Long-term exposure to these emissions affect the development of embryos and cause life-threatening bone-marrow depression in adults. The NTPC is suggesting that norms for new plants commissioned after 2017 be diluted from 100 milligram per cubic metre (or mg/Nm3 where ‘N’ refers to standard temperature and pressure) to 450 mg/Nm3. The government is already in the process of diluting the norms for power plants that came up between 2003 and 2016--from 300 mg/Nm3 to 450 mg/Nm3, a central government affidavit to the apex court shows.

While Javadekar attacked the opposition for creating a “fear psychosis among people”, he was rebuked by WHO officials. The world body wished that air pollution did not kill people, “but it unfortunately does”, said WHO’s public health director Maria Neira, speaking to a journalist from The Times of India.

Shortage of funds, limited research

Research on the links between air pollution and public health is limited in India due to the shortage of funds, according to experts. “In India many researchers have done correlation between indoor air pollution and health,” said Ajay Nagpure, head of air pollution in the Sustainable Cities programme at the World Resources Institute, India.

"We don’t have India-specific concentration-response function--which is the relationship between health and the exposure (to air pollution)."

This lack of data is the reason why the air pollution-public health link is questioned, as Javadekar did in parliament. The quality of data needed to conduct a long-term study has only improved in the past decade or so in India but is now comparable to the best in the world, said experts.

"One needs to conduct long-term population studies,” said Nagpure. “Some institutions are carrying them out but the health data will take another three to four years."

The country already has enough global evidence to act on, said Kalpana Balakrishnan of Sri Ramachandra Institute of Higher Education and Research, who is helming a study on the health impacts of Delhi’s air pollution that is expected to take two years. “When the long-term studies happen in India we expect the numbers to be quite comparable with the global pool of evidence,” she said. “But we do have enough information to start acting on the primary sources to lower the PM 2.5 exposure.”

3 in 4 Indians breathe toxic air

In 2017, nearly 77 percent Indians were exposed to PM 2.5 at annual levels above 40 μg/m3--the recommended limit by India’s National Ambient Air Quality Standards, a lax standard compared to WHO’s 10 μg/m3.

“Household emissions (from cooking, heating and kerosene lighting) contribute maximum to the ambient PM 2.5 in India,” said Sagnik Dey, associate professor, Centre for Atmospheric Science, Indian Institute of Technology, Delhi, who co-authored a study on air pollution in India that was published in the May 2019 edition of the journal PNAS (Proceedings of the National Academy of Sciences, US).

PM 2.5 particles measure roughly 1/30th of a human hair and can cause irritation to patients with asthma, respiratory inflammation and even lung cancer, according to studies.

“The fact that 77 percent of India's population does not live in areas that meet Indian standard should be an eye-opener for everyone,” said Dey. “The most critical region is the Indo-Gangetic basin where 70 percent of the Indian population lives and (where) the annual PM 2.5 is more than double the Indian standard.”

The exposure to PM 2.5 was the highest in the state of Delhi, followed by the other north Indian states of Uttar Pradesh, Bihar and Haryana.

The implications of this level of air pollution for Indians are dire, it was found.

Cleaning up India’s toxic air

In 2017, India saw 6,70,000 deaths due to outdoor air pollution and another 4,80,000 deaths due to household air pollution, according to the 2018 ICMR study. One in eight deaths in India in 2017 was due to air pollution--the leading risk factor for death in India and second only to maternal and child malnutrition.

India already has a National Clean Air Programme in 102 cities that is set to expand to more cities in 2020. The programme links nodal research institutions with state pollution authorities so they can access the latest scientific technology and expertise to reduce pollution.

The Centre has also asked cities to draw up individual plans to combat air pollution and has sanctioned Rs 10 crore each to those with a population above 1 million, Javadekar told the parliament on December 6, 2019. But experts believe meeting India’s air quality standards should not be the goal. “We should not be complacent meeting the Indian air quality standard, which is four times higher than the WHO standard,” said Dey. “Today, if we see AQI (air quality index) in the moderate range, people feel very happy.”

For ideas, India only has to look east. China improved its air by 32 percent in some cities by reducing emissions from coal plants and shifting from coal to natural gas.

“The scientific community can greatly accelerate air quality actions by engaging in studies that help assess the efficacy of interventions,” said Kalpana Balakrishnan. The ubiquity of air pollution sources makes it impossible to act everywhere, she added.

“It is imperative that actions be prioritised,” suggested Balakrishnan who is currently leading the Household Air Pollution Intervention Network trial in Tamil Nadu with funding from the National Institute of Health, the primary public health and biomedical research agency of the US government. “For this, one can adopt strategic epidemiological approaches to add to the strength of the evidence while at the same time inform policy makers on where best to invest resources.”

The solutions are already with the policymakers, according to WHO’s Neira. “The question here is how many lungs or losing quality of life or even losing our brainpower are you ready to accept,” she said in an interview to IndiaSpend in September 2019.

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