SmogRank / United States / Illinois / Niles

Niles, month by month

Niles has a measured daily mean on 127 days since 31 January 2026. Its worst month was March 2026, at 55 US AQI (11.4 µg/m³), 1,520th of 3,285 cities on that month's world ranking. Its cleanest was September 2026, at 44 US AQI (8.0 µg/m³).

Every month since 2026

2026too few days for a mean (a year needs 200)127 days measured
Jan1 dayFeb18 daysMar55#1,520Apr3 daysMay9 daysJun7 daysJul12 daysAug16 daysSep44#1,044Oct40#1,680
Each square is a month's mean PM2.5 in US AQI from Niles'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 Niles marked; each year, the year's. A dashed square is the running month, so far.
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

7 months
MonthWhy
Aug 202616 of 31 days measured; a month needs 22. The others: 15 with under 18 hours of readings or readings that failed our checks.
Jul 202612 of 31 days measured; a month needs 22. The others: 9 with readings for part of the day (a day needs 18 hours), 10 with under 18 hours of readings or readings that failed our checks.
Jun 20267 of 30 days measured; a month needs 21. The others: 1 with no readings from the monitors, 22 with readings for part of the day (a day needs 18 hours).
May 20269 of 31 days measured; a month needs 22. The others: 20 with readings for part of the day (a day needs 18 hours), 2 with under 18 hours of readings or readings that failed our checks.
Apr 20263 of 30 days measured; a month needs 21. The others: 23 with readings for part of the day (a day needs 18 hours), 4 with under 18 hours of readings or readings that failed our checks.
Feb 202618 of 28 days measured; a month needs 20. The others: 7 with readings for part of the day (a day needs 18 hours), 3 with under 18 hours of readings or readings that failed our checks.
Jan 20261 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.

Niles's worst months

MonthUS AQIDays measuredWorld rank
March 2026 5511.4 µg/m³23 of 311,520thof 3,285
September 2026 448.0 µg/m³27 of 301,044thof 3,347

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.

Niles's worst days

DayUS AQI
16 Jul 2026 277202.0 µg/m³
15 Feb 2026 9432.0 µg/m³
4 Mar 2026 8527.4 µg/m³
19 Mar 2026 7622.7 µg/m³
18 Jul 2026 7522.1 µg/m³
2 Feb 2026 7421.3 µg/m³
9 Feb 2026 7421.3 µg/m³
14 Feb 2026 7321.1 µg/m³
20 Mar 2026 7220.4 µg/m³
17 Feb 2026 7119.9 µg/m³

Daily means, the highest since 31 Jan 2026; 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, Niles, United States, 31 Jan 2026 – 12 Oct 2026. Monitor data from Clarity and AirGradient via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/us/niles/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.

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

Updated 2026-10-13 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).