SmogRank / Romania / Sălaj County / Zalău

Zalău, month by month

Zalău has a measured daily mean on 266 days since 19 December 2025. Its worst month was January 2026, at 91 US AQI (30.7 µg/m³), 171st of 2,617 cities on that month's world ranking. Its cleanest was July 2026, at 28 US AQI (5.1 µg/m³).

Every month since 2025

202655 so far253 days measured807th of 2,793 in the world
Jan91#171Feb61#815Mar62#865Apr48#1,321May29#2,220Jun32#1,981Jul28#2,581Aug37#2,212Sep38#1,365Oct8 days
2025too few days for a mean (a year needs 256)13 days measured
JanFebMarAprMayJunJulAugSepOctNovDec13 days
Each square is a month's mean PM2.5 in US AQI from Zalău'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 Zalău marked; each year, the year's.
Good0–50
Moderate51–100
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

2 months
MonthWhy
Oct 20268 of 12 days measured; a month needs 9. The others: 1 with no readings from the monitor, 3 with readings for part of the day (a day needs 18 hours).
Dec 202513 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.

Zalău's worst months

MonthUS AQIDays measuredWorld rankEpisode
January 2026 9130.7 µg/m³29 of 31171stof 2,617Europe, January and February 2026
March 2026 6214.8 µg/m³28 of 31865thof 2,971Europe, 1 to 12 March 2026
February 2026 6114.4 µg/m³27 of 28815thof 2,866Europe, January and February 2026
April 2026 488.7 µg/m³28 of 301,321stof 2,941–
September 2026 386.8 µg/m³27 of 301,365thof 2,981–
August 2026 376.7 µg/m³25 of 312,212thof 2,896–

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.

Zalău's worst days

DayUS AQIEpisode
20 Jan 2026 16879.3 µg/m³Europe, January and February 2026
15 Jan 2026 15257.0 µg/m³Europe, January and February 2026
19 Dec 2025 15156.1 µg/m³–
13 Jan 2026 14453.1 µg/m³Europe, January and February 2026
20 Dec 2025 13348.3 µg/m³–
19 Jan 2026 13047.4 µg/m³Europe, January and February 2026
22 Jan 2026 12545.2 µg/m³Europe, January and February 2026
14 Jan 2026 11440.9 µg/m³Europe, January and February 2026
21 Dec 2025 11340.5 µg/m³–
23 Jan 2026 10838.2 µg/m³Europe, January and February 2026

Daily means, the highest since 19 Dec 2025; 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, Zalău, Romania, 19 Dec 2025 – 10 Oct 2026. Monitor data from EEA, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/ro/zalau/history (accessed 12 Oct 2026).

Download chart (PNG)

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.

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

Updated 2026-10-12 21:07 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).