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San Bernardino, California, ranked as the dirtiest city in the United States in LawnStarter’s 2025 study. That result may surprise readers expecting a much larger city, but it depends on what “dirtiest” means: LawnStarter combined pollution, living conditions, waste infrastructure and resident opinions rather than measuring sidewalk litter alone.
Why San Bernardino ranked first
LawnStarter gave San Bernardino an overall score of 55.34 out of 100 in its 2025 ranking. The city also tied for the worst median Air Quality Index in the ranking, at 97, and 75% of its surveyed residents were dissatisfied with pollution, according to the outlet’s reported figures.
A secondary article published in June 2026 says San Bernardino was also first in a newer LawnStarter ranking. That account does not provide the original 2026 methodology in full, so the clearest detailed explanation of the result is LawnStarter’s 2025 report.
What LawnStarter means by “dirtiest”
The ranking is a proprietary composite index, not an official federal designation or a direct count of trash on streets. LawnStarter assessed 20 metrics in four weighted categories:
#1 Best Overall
- Know your air – An Alexa air quality monitor that makes it easy to understand what’s in your indoor air.
- Track and measure – Our indoor air quality monitor keeps tabs on 5 key factors: particulate matter (PM 2.5), volatile organic compounds (VOCs), carbon monoxide (CO), humidity, and temperature.
- Stay informed – Get an indication of current indoor air quality from the color-coded LED, and detailed information and an easy-to-understand air quality score in the Alexa app.
- Real-time alerts - Get notifications on your phone or announcements on Echo devices when Alexa detects poor indoor air quality.
- Automate climate control - Enable Routines to turn on or off your compatible Alexa devices, such as air purifiers, dehumidifiers, and fans, when the indoor air quality sensors detect changes.
- Pollution
- Inadequate living conditions
- Inadequate waste infrastructure
- Resident dissatisfaction
It assigned each city an overall score out of 100; the highest score ranked “Dirtiest” and the lowest “Least Dirty.” The result therefore combines environmental conditions, housing and infrastructure indicators, and residents’ opinions. It should not be read as a claim that every San Bernardino neighborhood looks the same, or that the city has the most visible litter under every definition of cleanliness.
Which cities were included, and how current is the data?
LawnStarter says it collected data for the 500 largest U.S. cities and retained 303 in the final 2025 sample. It excluded 197 cities that lacked sufficient data in at least one category. The methodology lists sources including AARP, the CDC, County Health Rankings & Roadmaps, the EPA, Numbeo and other LawnStarter studies.
Rank #2
- 【16-in-1 Air Quality Monitor Indoor】Experience the ultimate indoor air quality monitoring with our 16-in-1 Air Quality Monitor, offering real-time detection of 9 key parameters including CO2, PM2.5, PM1.0, PM10, HCHO, TVOC, Temperature, Humidity, AQI, and Time. With 7 distinct AQI alert buzzers, this air quality tester ensures your family breathes with ease.(*Note: "16-in-1" refers to the combination of 9 key detectable parameters and 7 types of AQI alert buzzers.)
- 【Crystal Clear 7-inch Large Display】Enjoy a 7-inch LED display for sharp, clear air quality readings. Provides an instant, comprehensive view of your indoor air without navigating through menus, with three brightness settings for any lighting condition
- 【External High-Precision Sensors with 0.001 Accuracy】Equipped with advanced external high-precision sensors, this device delivers unmatched accuracy (0.001 units) by directly sampling the air. Its innovative multi-sensor array and enhanced airflow design detect even the slightest environmental changes, allowing for instant response and optimal safety. (*Note: Avoid touching the sensors or exposing them to perfumes/strong odors to maintain accuracy.)
- 【Real-Time AQI Alert Buzzers】Our air quality monitor provides real-time monitoring and alerts for pollutants like CO2, PM2.5, PM1.0, PM10, HCHO, TVOC, Temperature, Humidity, and AQI, with 7 distinct alert functions. Stay informed with clear alerts and rest easy with a mute button to silence alarms. Your health and comfort are our priority. Toggle between Fahrenheit and Celsius instantly with a double-press of the "Power" button on this air quality detector.
- 【Up to 8 Hours of Runtime & Flexible USB-C Charging】 Enjoy up to 8 hours of continuous air quality monitoring on a full charge. The USB-C charging interface offers flexible power options and is compatible with widely available USB-C cables, while the included AC adapter provides convenient charging at home. Designed for effortless monitoring wherever you need it—from bedrooms and living spaces to your car and beyond.
Not every measure refers to the year the ranking was published. For example, LawnStarter says the water-quality-violation measure uses the last reported year available, 2023. A ranking’s edition year and its underlying data years are not necessarily the same.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why another list might name Baltimore
There is no single standardized measure of a “dirtiest” city, so different lists can produce different winners. In April 2025, The Economic Times reported that a separate HouseFresh study placed Baltimore first based on sanitation-related complaints per 100,000 residents. That is a narrower complaint-based measure, not a direct rival to LawnStarter’s 20-metric composite.
Rank #3
- High Accuracy & Fast Refresh Data: With this smart sensor, the PM2.5 accuracy is ±15 µg/m³ while temperature and humidity accuracies are ±0.54°F and ±3%RH.The two-second correction data feature shows the latest changes in PM2.5, temperature, and humidity.Keep sensor clear for accurate detection.
- Multifunctional Air Quality Detector: The GoveeLife Air Quality Monitor conveniently measures 3 important indexes for indoor air quality, including PM2.5, temperature, and humidity.
- Switchable Display: Press the top button for the clock & PM2.5 display. Long press for 2 seconds to switch to bright screen mode & night mode. The LED indicator displays 4 levels of ambient air quality. 2.4G Wi-Fi is required to display the time.
- Connect with GoveeHome Appliances: Set your target air quality and link with your other GoveeHome smart appliances. GoveeLife air purifiers, humidifiers, and space heaters will turn on and off automatically when the indoor air quality changes.
- H5106 needs to be connected to a power source and supports GoveeLife devices: Smart Air Purifiers - H7126, H7120, H7124, H712C, H7122, H7123; Humidifiers - H7140; Fans - H7100, H7102
To make a useful comparison, check who published each list, its edition year, the outcome it measures, the factors and weights it uses, the cities included, and the dates of the underlying data. Scores from indexes measuring different things should not be treated as if they were on one shared scale.
Quick Recap
Rank #4
- 【16-In-1 Comprehensive Air Quality Tracking】
- 【Easy Single-Tap Operation with Adjustable Audio Prompt】
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