Ambient air refers to the atmospheric air in its natural state, not contaminated by air-borne pollutants. It is typically composed of 78% nitrogen and 21% oxygen, with the remaining 1% made up of a combination of carbon, helium, methane, argon, and hydrogen. Ambient air quality criteria or standards are concentrations of pollutants in the air, and typically refer to outdoor air. Poor ambient air quality occurs when pollutants reach high enough concentrations to affect human health and/or the environment. Urban outdoor air pollution is a more specific term referring to the ambient air pollution experienced by populations living in urban areas, typically in or around cities.
The World Health Organization (WHO) defines ambient air pollution as potentially harmful pollutants emitted by industries, households, cars, and trucks-air-quality-and-health). Most sources of outdoor air pollution are well beyond the control of individuals and require concerted action by local, national, and regional level policy-makers working in sectors like energy, transport, waste management, urban planning, and agriculture-air-quality-and-health).
Reducing the health effects from ambient air pollution requires action by public authorities at the national, regional, and even international levels. Individuals can contribute to improving air quality by choosing cleaner options for transport, energy use, energy production, and waste disposal. Improving air quality should be an important consideration in policy planning across different economic sectors.
In summary, ambient air is the natural state of atmospheric air, not contaminated by air-borne pollutants. Poor ambient air quality occurs when pollutants reach high enough concentrations to affect human health and/or the environment. It is a major environmental health problem affecting everyone in low-, middle-, and high-income countries.
