​​​The U.S. Environmental Protection Agency (EPA) defines air pollution as the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the characteristics of the atmosphere. It can cause respiratory or other diseases, and these are important sources of morbidity and mortality. In accordance with the Clean Air Act, which is the U.S. Federal Air quality law that is intended to reduce and control air pollution nation-wide, the National Institutes of Health (NIH) Bethesda campus is classified as a major source of pollution, because it has actual or potential emissions at or above the major source threshold of any pollutants.

• ​The major source threshold for triggering Title V permitting requirements in Montgomery County is 25 tons per year for Volatile Organic Compounds (VOCs), 25 tons per year for Nitrous Oxide (NOx), 100 tons per year for any other Criteria pollutants and 25 tons per year for total Hazardous Air Pollutants (HAPs). The NIH Bethesda campus operates a five-year renewable Title V-Part 70 Operating Permit under the Code of Maryland Regulations (COMAR 26.11.03.01) because it is a major source and the actual NOx emissions from the facility are greater than the 25 tons per year major source threshold. COMAR is the official compilation of all administrative regulations issued by agencies of the state of Maryland.
• In accordance with the Title V permit requirements, the NIH Bethesda campus is required to obtaining an operating permit, operate in compliance with the permit, certify at least annually their compliance with permit requirements. Moreover, the Title V is intended to facilitate and enhance air quality planning, emission controls, compliance, and to improve existing emission inventories.
• According to EPA, the Criteria pollutants are carbon monoxide (CO), lead (Pb), nitrogen dioxide (NO₂), ozone (O₃), particulate matter (PM), and sulfur dioxide (SO₂). Also, a large number of compounds which have been determined to be hazardous are called air toxics. The NIH Bethesda campus emits greenhouse gases (GHGs) which are defined by EPA as “gases that trap heat in the atmosphere.” These include carbon dioxide, methane, and nitrous oxide. These gases are also referred to as stratospheric ozone-depleting substances and include refrigerants.
• The NIH facility has not triggered Prevention of Significant Deterioration (PSD) requirements for GHG emissions; therefore, there are no applicable GHG Clean Air Act requirements; however, because NIH Bethesda is a major source (threshold: 100,000 tons per year CO₂) for GHGs, it must quantify facility wide GHGs emissions and report them to EPA and MDE in accordance with Section 3 of the Part 70 permit.
  

DEP Points of Contact: Joseph Musa, musaj@mail.nih.gov; Trenise Trent, trenise.trent@nih.gov​