SmogRank / Japan / Nara / Hōryūji
Hōryūji, month by month
Hōryūji has a measured daily mean on 1,141 days since 28 July 2023. Its worst month was April 2024, at 58 US AQI (13.1 µg/m³), 583rd of 2,520 cities on that month's world ranking. Its cleanest was August 2023, at 32 US AQI (5.7 µg/m³). 2025 averaged 54 US AQI (10.9 µg/m³), against 51 US AQI (9.1 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Months without a mean, and why
1 month
| Month | Why |
|---|---|
| Jul 2023 | 4 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Hōryūji's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| April 2024 | 5813.1 µg/m³ | 583rdof 2,520 | Japan and South Korea, April 2024 |
| July 2025 | 5813.0 µg/m³ | 639thof 2,889 | Japan and South Korea, June and July 2025 |
| April 2025 | 5812.8 µg/m³ | 677thof 2,951 | – |
| February 2026 | 5712.3 µg/m³ | 990thof 2,866 | – |
| July 2026 | 5712.3 µg/m³ | 843rdof 2,784 | – |
| March 2025 | 5712.1 µg/m³ | 1,229thof 2,862 | Japan and South Korea, March 2025 Japan and South Korea, February and March 2025 |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Hōryūji's worst days
| Day | US AQI | Episode |
|---|---|---|
| 18 Apr 2024 | 15055.4 µg/m³ | Japan and South Korea, April 2024 |
| 4 Jul 2025 | 12043.1 µg/m³ | Japan and South Korea, June and July 2025 |
| 5 Jul 2025 | 9633.4 µg/m³ | Japan and South Korea, June and July 2025 |
| 3 Jul 2025 | 9331.5 µg/m³ | Japan and South Korea, June and July 2025 |
| 26 Mar 2025 | 9331.4 µg/m³ | Japan and South Korea, March 2025 |
| 1 Feb 2025 | 9029.8 µg/m³ | Japan and South Korea, 31 January to 1 February 2025 |
| 31 Jan 2025 | 8929.5 µg/m³ | Japan and South Korea, 31 January to 1 February 2025 |
| 17 Apr 2024 | 8929.3 µg/m³ | Japan and South Korea, April 2024 |
| 2 Mar 2025 | 8527.1 µg/m³ | Japan and South Korea, February and March 2025 |
| 2 Jul 2025 | 8426.9 µg/m³ | Japan and South Korea, June and July 2025 |
Daily means, the highest since 28 Jul 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Hōryūji, Japan, 28 Jul 2023 – 12 Oct 2026. Monitor data from Ministry of the Environment Air Pollutant Wide Area Monitoring System via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/jp/horyuji/history (accessed 12 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Hōryūji now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 20:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).