Editing Acid rain (section)

==== Sulfur Trioxide ====
The not-to-exceed limits in the air, water, soil, or food that are recommended by regulations are often based on levels that affect animals before being modified to assist in safeguarding people. Depending on whether they employ different animal studies, have different exposure lengths (e.g., an 8-hour workday versus a 24-hour day), or for other reasons, these not-to-exceed values can vary between federal bodies.<ref name=":03"/>

The amount of sulfur dioxide that can be emitted into the atmosphere is capped by the EPA. This reduces the quantity of sulfur dioxide in the air that turns into sulfur trioxide and sulfuric acid.<ref name=":16" /> Sulfuric acid concentrations in workroom air are restricted by OSHA to 1&nbsp;mg/m<sup>3</sup>. Moreover, NIOSH advises a time-weighted average limit of 1&nbsp;mg/m<sup>3</sup>.<ref name=":03" />

When you are aware of NO<sub>2</sub> and SO<sub>3</sub> exposure, you should talk to your doctor and ask people who are around you, especially children.