Pollution from stubble burning significantly reduced lung function and was particularly harmful to women in rural Punjab, says one of the largest studies of its kind in India, correlating the effect of air pollution on health.
The study was conducted in six villages of Patiala, Punjab and spanned two phases: The first was in October 2018 and again the following summer from March to April 2019 and the second phase was undertaken in the same villages during late Oct-Nov, 2018. The latter is the period when crop burning peaks and the two timeframes were considered to measure the change in air quality during both periods. Close to 3,600 participants, from 10-60 years of age were included in the study.
While the links between particulate matter pollution and respiratory health are widely documented, there have been limited studies in India that have clearly linked the impact of poor air on lung health.
High PM2.5 levels
It emerged from the study that the concentrations of PM2.5, the category of unburnt carbon particles considered most harmful to respiratory health, was found to increase more than twice between the two phases, from 100 g/m3 to 250 g/m3. Incidentally these are around 10-15 times the WHO prescribed air quality standards though the permissible standards by India’s Central Pollution Control Board (CPCB) are higher.
More symptoms
During the crop residue burning period, a two to three-fold increase was noted in most of the respiratory symptoms including wheezing, breathlessness on exertion, cough in morning, cough at night, skin rashes, runny nose or itchiness of eyes etc. across all age groups (10-60 years). The highest number of respiratory complaints were reported by the elderly population (>40-60) and the lowest in the younger age group(>10-18) during crop burning period, the study’s authors note.
There was decline in lung function with increase in PM2.5 concentration across all age groups even after controlling for several other exposure variables, such the influence of cooking fuel, ventilation, distance from road etc. The authors reported a 10-14% decline in lung function in men and nearly 15-18% decline in women across all age categories.
The study, authored by researchers at The Energy Resources Institute (TERI), Delhi has contributions from experts from All India Institute of Medical Sciences (AIIMS), Delhi, and the Punjab Agricultural University. The findings, which have not been peer reviewed as yet, appear on the website of the CPCB, which has supported the study.
