Journal of Geophysical Research: Atmospheres

Cover image for Vol. 122 Issue 24

Impact Factor: 3.454

ISI Journal Citation Reports © Ranking: 2016: 20/85 (Meteorology & Atmospheric Sciences)

Online ISSN: 2169-8996

Associated Title(s): Journal of Geophysical Research

Asian emissions contribute to air pollution in western United States

As Asian countries develop, they are emitting more ozone precursors that pollute surface level air. Many studies have documented this pollution being carried by air currents to the western United States. To learn more about the mechanisms that transport air pollution across the ocean and determine the effects of Asian air pollution on air quality in the western United States, Lin et al. (2012) analyzed in situ and satellite measurements from May to June 2010 using a global high-resolution climate chemistry model. They quantified the contribution of Asian pollution to surface ozone levels in both densely populated regions such as the Los Angeles area and rural areas such as national parks. They found that Asian pollution contributes as much as 20% of total ozone during springtime pollution episodes in western U.S. surface air. Current guidelines from the Environmental Protection Agency dictate that surface level air should have no more than 75 parts per billion per hour average by volume of ozone. Although local pollution plays a large role on days when that standard is not met in Southern California, the authors estimate that 53% of the instances where that limit was exceeded would not have occurred without the contribution from Asian air pollution. The researchers also found that an index based on satellite observations of Asian pollution plumes could serve as a qualitative early warning indicator, with a lead time of 1-3 days, of Asian pollution influence on western U.S. air quality.

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