Oatey and Studor and Toto are widely-used brands of air admittance valves so those companies may also have a small-diameter version that fits your drain line. Also Rectorseal, Pro-Vent, Irrigation King, and Wal-Rich make similar devices. Details and typical AAV installation instructions (using...
In 2013 the New York Times reported that oil odors at a farm near Tioga, Colorado were traced to a small 1/4" sized leak in an oil pipeline crossing the property. While oil companies monitor pipelines for evidence of leakage and are expected to respond promptly to any leak, some pipelin...