Black Carbon

Description

Context

Black Carbon has a significant adverse effect on human health and leads to premature mortality, says a new study by Department of Science and Technology.

Note: The health effects in terms of mortality due to BC aerosol exposure have never been evaluated in India.

Findings

Indo-Gangetic Plain, experiences very high aerosol loading and trace gas concentrations throughout the year due to prevalence of a subsidence zone (sudden sinking of the Earth's surface).
The region observed decadal increasing trends both in Aerosol Optical Depth and Black Carbon aerosols.
From 2009 to 2016, correlation between daily all-cause mortality and ambient air quality establish that there is a clear impact of BC aerosols, NO2 and, PM2.5 exposure.
The effect of pollutants was more prominent for males, age group 5-44 and, in winter.
The adverse effect of air pollutants was not limited to current day of exposure but can extend as high as up to 5 days (Lag effect).
Mortality rises linearly with an increase in air pollutants level.

Significance of the study

The study could help in the estimation of future burden of mortality associated with air pollutants more accurately.
Inclusion of Black Carbon as a potential health hazard provides a background for more such studies of effects of air pollutants on health.
This will help government and policy-makers for better planning to mitigate the adversity associated with changing climate-air pollution-health nexus.

Aerosol

An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas.
Aerosols can be natural or anthropogenic.
Examples of natural aerosols are fog or mist, dust, forest exudates and geyser steam.
Examples of anthropogenic aerosols are particulate air pollutants and smoke.

Black Carbon

Chemically, black carbon (BC) is a component of fine particulate matter (PM ≤ 2.5 µm).
It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass.
Black carbon is a climate forcing agent contributing to global warming.
It warms the Earth by absorbing sunlight and heating the atmosphere and by reducing albedo when deposited on snow and ice (direct effects) and indirectly by interaction with clouds.
Black carbon stays in the atmosphere for only several days to weeks
The IPCC have posited that reducing black carbon is one of the easiest ways to slow down short term global warming.

Aerosol Optical Depth

Aerosol Optical Depth (AOD) is the measure of aerosols (e.g., urban haze, smoke. particles, desert dust, sea salt) distributed within a column of air from the Earth's surface to the top of the atmosphere.