PM2.5 is 5.6 µg/m³ here vs 16.2 back home.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h out ≈ 5.6/22 × 0.5 = 0.1 here; 16.2/22 × 0.5 = 0.4 at home.A health-impact equivalence, not literal smoking.See how we work it out →
▼ 10.6 µg/m³ less fine-particle pollution than San Diego right now
PM2.5 is 5.8 µg/m³ here vs 16.2 back home.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h out ≈ 5.8/22 × 0.5 = 0.1 here; 16.2/22 × 0.5 = 0.4 at home.A health-impact equivalence, not literal smoking.See how we work it out →
▼ 10.4 µg/m³ less fine-particle pollution than San Diego right now
PM2.5 is 8.2 µg/m³ here vs 16.2 back home.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h out ≈ 8.2/22 × 0.5 = 0.2 here; 16.2/22 × 0.5 = 0.4 at home.A health-impact equivalence, not literal smoking.See how we work it out →
▼ 8 µg/m³ less fine-particle pollution than San Diego right now
PM2.5 is 12.4 µg/m³ here vs 16.2 back home.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h out ≈ 12.4/22 × 0.5 = 0.3 here; 16.2/22 × 0.5 = 0.4 at home.A health-impact equivalence, not literal smoking.See how we work it out →
▼ 3.8 µg/m³ less fine-particle pollution than San Diego right now
PM2.5 is 13.2 µg/m³ here vs 16.2 back home.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h out ≈ 13.2/22 × 0.5 = 0.3 here; 16.2/22 × 0.5 = 0.4 at home.A health-impact equivalence, not literal smoking.See how we work it out →
▼ 3 µg/m³ less fine-particle pollution than San Diego right now
PM2.5 is 20 µg/m³ here vs 16.2 back home.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h out ≈ 20/22 × 0.5 = 0.5 here; 16.2/22 × 0.5 = 0.4 at home.A health-impact equivalence, not literal smoking.See how we work it out →
Some particle pollutionLatest observation Jul 18, 5:00 p.m. EDT
Build-time readings shown
Air quality · San Diego
Phew. Twelve hours out here is roughlyPM2.5 here is 16.2 µg/m³.Berkeley Earth: 22 µg/m³ for 24 h ≈ 1 cigarette.12 h outside ≈ 16.2/22 × 0.5 = 0.4 cigarettes.A health-impact equivalence, not literal smoking.See how we work it out →
That is the fine-particle pollution you'd breathe standing outside all day inSan Diego right now, turned into a number your body already understands.
A health-impact equivalence, not literal smoking: Berkeley Earth puts a full day at 22 µg/m³ of PM2.5 at about one cigarette.How we work this out
Why live rankings?
Smoke plumes are patchy and move with changing winds, terrain and weather. Nearby lakefront, coastal and higher-elevation places can be much clearer than San Diego, but no direction is reliably cleaner. That is why this list is recalculated from live PM2.5 readings every hour instead of publishing a fixed escape route. If everything within three hours is smoky, the rankings will say so. Sometimes the honest answer is to stay inside with a filter running.