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Why Air Quality Specialists Should Measure for Sulfur Dioxide (SO2) in Homes & Offices

Application Note #AQ-14-825

What is Sulfur Dioxide? (SO2)

Sulfur Dioxide (SO2) is a highly reactive gas that is part of a larger group of sulfur oxides or SOx gases. According to the U.S. Environmental Protection Agency, the largest sources of SO2 emissions are due to “fossil fuel combustion at power plants (73%) and other industrial facilities (20%)”. Although residents in homes and offices at or near the “fenceline” of power plants and industrial facilities are most at risk of SO2 exposure, the toxic gas can be leaked within any building. Common sources of SO2 in homes or offices can include tobacco smoke, improperly vented gas appliances, oil furnaces, kerosene heaters, wood or coal stoves, automobile exhaust from attached garages and malfunctioning chimneys.

Adverse Health Effects of Sulfur Dioxide (SO2) Exposure

According to the Occupational Safety and Health Administration (OSHA), the permissible exposure limit for SO2 in homes and offices should not exceed 5 ppm (13 mg/m3) over an 8-hour period1. However, SO2 levels as low as 0.25 ppm have been shown to cause respiratory discomfort in vulnerable populations such as asthmatics and those with respiratory concerns2. Exposure to SO2 can lead to a variety of negative health issues. At low concentrations, SO2 can cause irritation of the nose and throat, difficulty breathing, and respiratory distress. Long term exposure to even low levels of sulfur dioxide can cause lung function to deteriorate, aggravate existing heart disease and increase complications for people with asthma. Exposure to high levels of SO2 can be life threatening even during short term exposure.


Concentration Effects
< 0.1 PPM: Good Should have minimal health effects or occupant complaints
0.1 to < 5 PPM: Marginal Could produce some negative health effects among vulnerable populations, including asthmatics and others with respiratory issues
5 PPM and Higher: Poor Likely to cause serious health effects or discomfort among all populations

SO2 Monitoring Solution

AQ EXPERT and AQ PRO Indoor Air Quality Monitors

The measurement of the concentration of SO2 commonly found in indoor environments can be performed using the E Instruments AQ EXPERT portable IAQ monitor and the AQ PRO handheld IAQ monitor. These specialized monitoring instruments utilize the latest sensor technology that allow air quality analysts, environmental safety companies, laboratory technicians, etc., to quickly and accurately monitor the levels of dangerous SO2 present in the breathing environ- ments of homes, office building, laboratories, or industrial facilities. These monitors include software with real-time continues data logging, wireless Bluetooth compatibility, and can be customized to monitor up to 11 different parameters relevant to indoor air quality.

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