outside air

I have a 90 gallon tank with a 40 gallon breeder sump. Tank is in the basement. I have a Bubble Magus Curve 7. The airline intake is connected to a 1/2" pvc pipe that runs about 35 foot and sucks air from outdoors. I have a handheld Pinpoint PH monitor. Before I tested my PH I calibrated...

Probably late for most folks, but since its just about dark here the fireworks are coming out in full force and its obvious the air quality has gone down hill fast. I have an outside airline for my skimmer and I didnt want it sucking in all of that sulfur, heavy metals, ash, etc. Those of you...