Air pollution is a threat to food security and livelihood especially in developing countries like Uganda where there's high dependence on crop cultivation and animal rearing for food source as well as an economic activity. 

Air pollutants such as ozone, nitrogen oxides and sulphur dioxide have both direct and indirect adverse effects on animal and crop yields.

Directly, air pollutants cause visible injury to plants and also alter metabolic processes when they enter through stomata.

For instance, Ozone, a pollutant formed due to subsequent reactions of primary air pollutants like nitrogen oxide and volatile organic compounds in the atmosphere, inhibits carbon fixation in leaves which lowers photosynthesis rate. Ozone also accelerates leaf senescence and inhibits pollen tube growth.

Soot, which is released from burning of wood fuel and in exhaust gas, is opaque and therefore reduces light available to plants. It also clogs leaf stomata, thereby preventing transpiration and plant breathing which decreases plant productivity.

Sulphur dioxide causes bleaching in plant leaves, turning them yellow which reduces photosynthesis and further decreases crop yields. 

Indirectly, air pollutants such as sulphur dioxide contribute to acid rain, which destroys the protective waxy layer in leaves, chlorophyll in the plant and causes soil acidification. Soil acidification decreases availability of nutrients and prevents proper nitrogen fixation in the soil. All these decrease the plant productivity and can cause it's death.

Consequently, air pollution causes a decline in the crop yields which further reduces food available to both livestock and humans, therefore heightening mortality rates through increased starvation.

References

1. Ozone Research and Vegetative impacts by Ray Knighton.

2. Soil acidity

https://agriculture.vic.gov.au/farm-management/soil/soil-acidity

3. What Is Acid Rain: Tips For Safeguarding Plants From Acid Rain Damage 

Https://www.gardeningknowhow.com/plant-problems/environmental/acid-rain-damage.htm

2. Want to feed the world? Tackle pollution from ozone and soot

https://theconversation.com/want-to-feed-the-world-tackle-pollution-from-ozone-and-soot-33761

Image source: Wikimedia Commons