On 4th May 2026 a petition was filed requesting the U.S. Environmental Protection Agency (EPA) to regulate harmful aerosol (microscopic particle) emissions from commercial aviation. Every year, commercial aviation injects about 747 million pounds (339 million kilograms) of sulfur into the upper troposphere and lower stratosphere, along with other pollutants – black carbon, metallic aerosols, and ultrafine particles (UFPs). Aircraft emissions are causing atmospheric alterations. In certain conditions contrails form artificial cloud cover, rainfall patterns are disrupted and a solar dimming haze impairs visibility and reduces the availability of sunlight for the human body’s production of vitamin D, crop growth and solar panels. Sulfates and metals from aviation exhaust eventually settle on land and water, contaminating agricultural soil and watersheds. People living near airports are particularly at risk of damage to their health from higher concentrations of aviation-induced pollutants in localised ‘acute toxicity zones’, which can extend several kilometres downwind of airports. Concentrations of UFPs near airports are ‘catastrophically elevated’; an increase in particle numbers of 100-900% over the background (regional baseline) level extending 18km downwind of Los Angeles International Airport (LAX) has been documented. Every claim in the petition is derived from peer-reviewed science, government studies and EPA data. The petitioners are requesting a formal finding that emission of pollutants from civil aircraft endanger human health and welfare, binding emission and fuel standards, a public registry of aviation-related particulate emissions and mandatory contrail avoidance, with implementation to be coordinated by the FAA and Secretary of Transportation. If the EPA fails to issue a public response within 180 days the petitioners intend to seek a judicial review. Here is a link to the petition PETITION FOR RULEMAKING UNDER 5 U.S.C. § 553(e) AND CLEAN AIR ACT (CAA) § 231 REGARDING:AVIATION AEROSOL EMISSIONS, AVIATION-INDUCED CLOUDINESS (AIC) AND THE ENDANGERMENT OF PUBLIC HEALTH AND WELFARE There is also a helpful EXECUTIVE SUMMARY of the petition, translating the unavoidably complex legalese into plain English. Key people involved in the two years of work it took to develop this landmark legal action held a public webinar, see below, on the day it was submitted.