SmogRank / Japan / Tochigi / Nasushiobara

Nasushiobara, month by month

Nasushiobara has a measured daily mean on 687 days since 28 July 2023. Its worst month was July 2025, at 53 US AQI (10.2 µg/m³), 1,223rd of 2,889 cities on that month's world ranking. Its cleanest was September 2023, at 31 US AQI (5.5 µg/m³).

Every month since 2023

2026too few days for a mean (a year needs 200)143 days measured
Jan4 daysFeb12 daysMar16 daysApr34#2,144May38#1,653Jun16 daysJul48#1,689Aug13 daysSep6 daysOct5 days
2025too few days for a mean (a year needs 256)223 days measured
Jan13 daysFeb14 daysMar21 daysApr46#1,712May19 daysJun40#1,983Jul53#1,223Aug46#1,720Sep36#1,887Oct15 daysNov12 daysDec12 days
2024too few days for a mean (a year needs 257)219 days measured
Jan6 daysFeb8 daysMar20 daysApr51#1,150May33#2,012Jun37#1,804Jul43#1,459Aug32#1,783Sep19 daysOct15 daysNov14 daysDec6 days
2023too few days for a mean (a year needs 256)102 days measured
JanFebMarAprMayJunJul4 daysAug31#1,744Sep31#1,903Oct20 daysNov14 daysDec14 days
Each square is a month's mean PM2.5 in US AQI from Nasushiobara's measured days, with its place on that month's world ranking under it. A month has a mean once 70% of its days are measured, the rule the monthly rankings use; under that, the square gives the days measured. Each square opens that month's ranking with Nasushiobara marked; each year, the year's.
Good0–50
Moderate51–100
Unhealthy for sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

25 months
MonthWhy
Oct 20265 of 12 days measured; a month needs 9. The others: 7 with readings for part of the day (a day needs 18 hours).
Sep 20266 of 30 days measured; a month needs 21. The others: 24 with readings for part of the day (a day needs 18 hours).
Aug 202613 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Jun 202616 of 30 days measured; a month needs 21. The others: 14 with under 18 hours of readings or readings that failed our checks.
Mar 202616 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Feb 202612 of 28 days measured; a month needs 20. The others: 16 with under 18 hours of readings or readings that failed our checks.
Jan 20264 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks.
Dec 202512 of 31 days measured; a month needs 22. The others: 19 with under 18 hours of readings or readings that failed our checks.
Nov 202512 of 30 days measured; a month needs 21. The others: 18 with under 18 hours of readings or readings that failed our checks.
Oct 202515 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
May 202519 of 31 days measured; a month needs 22. The others: 12 with under 18 hours of readings or readings that failed our checks.
Mar 202521 of 31 days measured; a month needs 22. The others: 10 with under 18 hours of readings or readings that failed our checks.
Feb 202514 of 28 days measured; a month needs 20. The others: 14 with under 18 hours of readings or readings that failed our checks.
Jan 202513 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks.
Dec 20246 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks.
Nov 202414 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
Oct 202415 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks.
Sep 202419 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks.
Mar 202420 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 10 with under 18 hours of readings or readings that failed our checks.
Feb 20248 of 29 days measured; a month needs 21. The others: 1 missing from OpenAQ's archive, 20 with under 18 hours of readings or readings that failed our checks.
Jan 20246 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks.
Dec 202314 of 31 days measured; a month needs 22. The others: 17 with under 18 hours of readings or readings that failed our checks.
Nov 202314 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks.
Oct 202320 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks.
Jul 20234 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.

Nasushiobara's worst months

MonthUS AQIDays measuredWorld rankEpisode
July 2025 5310.2 µg/m³26 of 311,223rdof 2,889Japan and South Korea, June and July 2025
April 2024 519.1 µg/m³26 of 301,150thof 2,520Japan and South Korea, April 2024
July 2026 488.7 µg/m³26 of 311,689thof 2,784–
August 2025 468.3 µg/m³25 of 311,720thof 2,901–
April 2025 468.2 µg/m³21 of 301,712thof 2,951–
July 2024 437.7 µg/m³28 of 311,459thof 2,566–

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.

Nasushiobara's worst days

DayUS AQIEpisode
9 Jul 2025 8628.0 µg/m³Japan and South Korea, June and July 2025
18 Apr 2024 8125.4 µg/m³Japan and South Korea, April 2024
8 Jul 2025 7924.2 µg/m³Japan and South Korea, June and July 2025
20 Apr 2025 7320.8 µg/m³–
21 May 2025 7220.4 µg/m³–
26 Mar 2025 7119.8 µg/m³–
19 Apr 2025 6818.3 µg/m³–
19 Jul 2024 6717.7 µg/m³–
7 Jul 2025 6516.7 µg/m³Japan and South Korea, June and July 2025
4 Nov 2023 6516.5 µg/m³–

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, Nasushiobara, 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/nasushiobara/history (accessed 13 Oct 2026).

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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.

Nasushiobara now: the last 24 hours, its ranks today and the last 12 months day by day.

Updated 2026-10-13 03:07 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).