LowEmissionAsphalt-136pg-WhitePaper-May2023

P a g e | 6 However, CO 2 in excessive levels is the leading greenhouse gas , 5 and affects the planet’s climate. NO 2 is the primary precursor to photochemical smog ( air pollution ), 6 helping supply nitrogen to plants, but in excess amounts is toxic to all animals, including humans. We will be spending much time on both CO 2 and NO 2 throughout this report. Both are necessary for sustaining all life on Earth, obviously. But increased human activities are creating imbalances. Our transportation system is now the key source for both climate and pollutive impacts from excess atmospheric carbon and nitrogen loading. Action is required! Photochemical Smog Comes from Traffic 7 Knowledge has resulted in a global understanding of the need to manage, reduce, and even reverse emission accumulations from all facets of human activity, including, if not especially, in the transportation sector. How effectively and pragmatically we go about it will matter greatly. 5 photochemical smog : air pollution containing ozone and other reactive chemical compounds formed by the action of sunlight on nitrogen oxides and hydrocarbons, especially those in automobile exhaust. 6 greenhouse gas is any gas that has the property of absorbing infrared radiation (net heat energy) emitted from Earth’s surface and reradiating it back to Earth’s surface. 7 85% of global air pollution comes from burning fossil fuels; 70% from vehicles, Clean Air Fund, www.cleanairfund.org .