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Black carbon and ozone have a direct impact on growth and their build up is of particular relevance to agriculture. Black carbon alters the quality and nature of solar radiation reaching the ground. Recent studies show that the aerosols in the ABC reduce the amount of sunlight reaching the Earth's surface by as much as 10 to 15%, and enhance atmospheric solar heating by as much as 50%.

Black carbon accounts for significant amounts of SLCPs and dielsel engines are a prime source, it alters the quality and nature of solar radiation reaching the ground.

Wheat production in India is concentrated in the northern states of Uttar Pradesh, Haryana and the Punjab, known as the Indo-Gangetic Plains. This area is subject to a dramatic annual buildup of pullutants known as the Atmospheric Brown Cloud (ABC) before the monsoon. This coincides with the peak grain filling period for wheat so that at a critical time in the crops development the pollution levels are at their highest. This gives rise to a dramatic surface dimming of 7 - 10%. Researchers concluded that wheat yields were 36% lower in 2010 than they would have been in the abscence of climate and SLCP emissions. Rice yields were reduced by 20%. In determining the contribution of SLCPs alone wheat yields were reduced by 19%.

This equates to over 24 million tons of wheat: around four times India's wheat imports. Mitigation of SLCP emissions in India would have an important impact on food security both domestically and internationally. The researchers concluded that imapcts of SLCPs would be just as large in China.

source: Recent climate and air pollution impacts on Indian agriculture - Burney & Ramanathan 2014