Hobbies And Interests
Home  >> Science & Nature >> Science

Normal SO2 Levels in Air

Sulfur dioxide, also known as SO2, is one of six major pollutants that are considered criteria pollutants. The EPA sets standards for maximum levels of sulfur dioxide for primary exposure, which is regarding short time close exposure, and secondary exposure, which is longer exposure. While there is no "normal" level of SO2, efforts are made to keep SO2 levels as low as possible.
  1. Health Concerns

    • SO2 has major health concerns for the young, elderly and asthmatics. Exposures to sulfur dioxide has been linked to respiratory illness, bronchoconstriction and increased asthma symptoms. The EPA also shows a correlation between the concentration and short-term exposure to SO2 with emergency and hospital visits regarding respiratory-related systems. Sulfides, which are other sulfur compounds, are also major components of acid rain.

    Emissions

    • Sulfur oxide is released into the atmosphere by many different industries. The largest producer of SO2 emissions are power plants that burn fossil fuels, accounting for 73 percent of all SO2 emissions. Other industrial facilities account for 20 percent of SO2 emissions. Other activities that release SO2 include mining metal ore and transportation such as railroads and shipping, which burn fuels with high concentrations of sulfur.

    National Standards

    • The EPA has set both primary and secondary standards for emissions. Primary standards, which were established in June 2010, are 75 parts per billion of SO2 over a one-hour time frame, and new monitors for measuring SO2 must be in place no later that January 2013 in highly populated urban areas. The EPA deems short-term exposure as the greatest health risk to the public. Secondary standards are 0.5 parts per million over a three-hour time frame. Secondary standards are due for review by the EPA in 2012, so these numbers may change.

    Trends

    • The EPA closely monitors and updates requirements for all criteria pollutants. This process has provided positive results. Since 1990, the level of SO2 released in the atmosphere has dropped significantly. The national standard for annual SO2 levels is 30 parts per billion. In no year has the annual level exceeded the national standard, and in that time frame, the level of SO2 has dropped 65 percent based on information from 1990 to 2009 from more than 250 sites around the country.


https://www.htfbw.com © Hobbies And Interests