LIVE • 2026-10-09

Highest O3 cities right now

Top 30 cities ranked by current O3 concentration across all 217 tracked locations. Refreshes every 30 minutes. The highest O3 right now is in Sao Paulo, Brazil at 215.0 ppb. WHO 2021 8-hour guideline: 100 μg/m³ (~50 ppb).

#1
215.0 ppb

BR

Sao Paulo

149
AQI
PM2.5
15.9μg
PM10
16.2μg
O3
215.0ppb
Unhealthy for Sensitive Groups
#2
182.0 ppb

BR

Rio de Janeiro

81
AQI
PM2.5
18.0μg
PM10
19.6μg
O3
182.0ppb
Moderate
#3
177.0 ppb

IN

Mumbai

158
AQI
PM2.5
50.9μg
PM10
60.5μg
O3
177.0ppb
Unhealthy
#4
174.0 ppb

NG

Lagos

139
AQI
PM2.5
23.8μg
PM10
32.5μg
O3
174.0ppb
Unhealthy for Sensitive Groups
#5
157.0 ppb

TH

Hua Hin

195
AQI
PM2.5
17.8μg
PM10
18.0μg
O3
157.0ppb
Unhealthy
#6
154.0 ppb

SG

Singapore

198
AQI
PM2.5
61.7μg
PM10
69.2μg
O3
154.0ppb
Unhealthy
#7
141.0 ppb

QA

Doha

118
AQI
PM2.5
35.6μg
PM10
61.0μg
O3
141.0ppb
Unhealthy for Sensitive Groups
#8
136.0 ppb

CD

Kinshasa

107
AQI
PM2.5
44.6μg
PM10
46.4μg
O3
136.0ppb
Unhealthy for Sensitive Groups
#9
133.0 ppb

CN

Qingdao

96
AQI
PM2.5
20.9μg
PM10
33.2μg
O3
133.0ppb
Moderate
#10
133.0 ppb

BR

Belo Horizonte

53
AQI
PM2.5
7.4μg
PM10
8.7μg
O3
133.0ppb
Moderate
#11
133.0 ppb

BR

Brasilia

52
AQI
PM2.5
5.5μg
PM10
6.0μg
O3
133.0ppb
Moderate
#12
132.0 ppb

TH

Koh Samui

122
AQI
PM2.5
8.0μg
PM10
10.3μg
O3
132.0ppb
Unhealthy for Sensitive Groups
#13
129.0 ppb

AE

Abu Dhabi

116
AQI
PM2.5
41.8μg
PM10
56.2μg
O3
129.0ppb
Unhealthy for Sensitive Groups
#14
127.0 ppb

ZA

Johannesburg

85
AQI
PM2.5
9.9μg
PM10
10.1μg
O3
127.0ppb
Moderate
#15
119.0 ppb

NP

Pokhara

78
AQI
PM2.5
13.2μg
PM10
14.8μg
O3
119.0ppb
Moderate
#16
118.0 ppb

CO

Medellin

38
AQI
PM2.5
4.6μg
PM10
4.6μg
O3
118.0ppb
Good
#17
115.0 ppb

IN

Kolkata

210
AQI
PM2.5
156.0μg
PM10
163.4μg
O3
115.0ppb
Very Unhealthy
#18
114.0 ppb

OM

Muscat

73
AQI
PM2.5
30.4μg
PM10
69.4μg
O3
114.0ppb
Moderate
#19
113.0 ppb

BR

Manaus

144
AQI
PM2.5
27.8μg
PM10
30.0μg
O3
113.0ppb
Unhealthy for Sensitive Groups
#20
103.0 ppb

US

Houston

59
AQI
PM2.5
11.6μg
PM10
12.0μg
O3
103.0ppb
Moderate
#21
100.0 ppb

LB

Beirut

88
AQI
PM2.5
26.8μg
PM10
38.1μg
O3
100.0ppb
Moderate
#22
99.0 ppb

EG

Cairo

62
AQI
PM2.5
11.5μg
PM10
18.5μg
O3
99.0ppb
Moderate
#23
96.0 ppb

MA

Casablanca

52
AQI
PM2.5
8.9μg
PM10
14.3μg
O3
96.0ppb
Moderate
#24
95.0 ppb

SN

Dakar

100
AQI
PM2.5
33.5μg
PM10
94.8μg
O3
95.0ppb
Moderate
#25
95.0 ppb

US

San Antonio

55
AQI
PM2.5
11.2μg
PM10
11.2μg
O3
95.0ppb
Moderate
#26
93.0 ppb

IL

Tel Aviv

53
AQI
PM2.5
9.4μg
PM10
15.4μg
O3
93.0ppb
Moderate
#27
91.0 ppb

IN

Delhi

158
AQI
PM2.5
60.3μg
PM10
161.6μg
O3
91.0ppb
Unhealthy
#28
91.0 ppb

JO

Amman

70
AQI
PM2.5
16.7μg
PM10
28.4μg
O3
91.0ppb
Moderate
#29
90.0 ppb

BD

Dhaka

156
AQI
PM2.5
34.9μg
PM10
37.8μg
O3
90.0ppb
Unhealthy
#30
90.0 ppb

ZW

Harare

65
AQI
PM2.5
6.0μg
PM10
6.9μg
O3
90.0ppb
Moderate

About O3

See the full O3 guide for sources, health effects, and mitigation. Or jump back to overall most polluted cities ranked by US EPA Air Quality Index.

See also: highest PM2.5 · highest PM10 · highest NO2