Air traffic. hazards (include lead)
Kim FortunSee this recent article about how (piston-engine) airplanes contribute to lead contamination.https://capitalandmain.com/faa-must-move-faster-to-remove-leaded-fuels-from-the-skies
And this article about how airport expansions happen (likely without much downwind input): https://www.ocregister.com/2019/04/30/orange-county-faces-balancing-act-with-john-wayne-airport-plans/