Review of 184 studies links air pollution to heart disease and other ailments, not just lung problems

The Centre for Research on Energy and Clean Air (CREA) has reviewed 184 health studies conducted over more than 40 years to understand the impact of air pollution in India. The review comes as pollution and the Air Quality Index (AQI) remain in the news during the festival season.

Of the studies reviewed, 164, or 91.8 per cent, recorded at least one adverse health association with exposure to air pollution. The organisation says 44 of 46 government-funded studies and 77 of 81 government-linked studies also found adverse health associations.

According to CREA, the effects of very poor air are not limited to respiratory diseases. Heart disease, blood disorders, mental and neurocognitive disorders, metabolic disorders, sleep problems, eye diseases, pregnancy complications and low birth weight are also possible. Studies on rural populations too showed a link between poor health and air quality.

Dr Manoj Kumar, an air quality analyst at CREA, said: "Many of the studies reviewed were government-linked or government-funded, and they too found adverse health outcomes. These findings show that people's exposure to air pollution and the associated health risks need to be reduced. The National Ambient Air Quality Standards (NAAQS) of India also need to be revised. These standards came into force 17 years ago, and the changes were long overdue. Emission standards for industries and power plants should also be tightened."

According to the CREA review, 99 studies found both positive and null results, while 63 studies had only positive results. In many of these, exposures such as household biomass or solid fuel, cooking smoke, traffic-related pollution and particulate matter were linked to reduced lung function, respiratory symptoms, asthma, TB and other respiratory complications.

Some studies found that pollutants such as PM2.5, PM10, CO, NO2 and SO2 have a major effect on respiratory health, while in others the effect did not appear as significant. Of the 184 studies, 42 related only to Indian states. Most of these were conducted in Delhi and Punjab, followed by Maharashtra and Uttar Pradesh.

The organisation found that research on the physical effects of air quality has grown in recent years, although most studies are based on ambient air quality data.