Harris County, TX

ZIP 77503

In ZIP 77503, 7 of the 12 things we check have at least one part graded D or F.

• Drinking water: City Of Pasadena meets every EPA legal limit; 11 contaminants are above health goals, led by pfos at 2.6× California’s Public Health Goal.
• Nearest Superfund site: Patrick Bayou, 3.4 miles away (3 within 10 miles).
• Largest share of modeled toxic air from industry: Equistar Chemicals Bayport Chemicals Plant (46%), mostly ethylene oxide.
• Fine particles (PM2.5) average 9.7 µg/m³; the WHO guideline is 5 and the EPA annual standard is 9.
• About 38,374 kg of agricultural pesticides are applied in the county each year.

Grades for ZIP 77503

• Superfund sites nearbyD to F
• Factories and industrial sitesA to F
• Oil and gas wellsD
• Parks and nature nearbyC to F
• Air qualityF
• Drinking water qualityC
• Pesticide useA to B
• Neighborhood health statusA to D
• Past wildfire impactsA
• Past flood impactsC
• Noise levelsA to D
• Radiation signalsB

Based on 11 census tracts · compiled October 25, 2026 · how each grade works and its sources

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