Environmental Protection Agency

Every factory, water treatment plant, and construction site that legally dumps wastewater into a river, lake, or stream has an NPDES permit. This table lists them all: where they're located, what kind of facility they are, and whether their discharge goes into a waterway that's already polluted or struggling. It's the EPA's way of tracking who's allowed to pollute and where that pollution ends up.

Every day, the EPA measures how much fine dust and pollution (PM2.5) is in the air at thousands of locations across the country. Think of it like a nationwide network of air quality sensors. For each location, you get the actual pollution level, a simple 'Air Quality Index' score that tells you if the air is good or bad, and details about where the measurement was taken. You can use this to check how clean the air is in your area right now, compare pollution levels across cities, or track whether air quality is getting better or worse over time.

A comprehensive list of every public water system in the country. If you get water from a public system, that system is in here. You'll find which agency runs it, what type of system it is, how many people it serves, and contact information. This is useful if you're researching water system coverage in your area, tracking which systems are operating, or studying the scale of Community Water Systems versus smaller systems like those at schools or campgrounds.

For decades, lead in gasoline poisoned the air we breathed. This data shows how much airborne lead EPA monitors detected at thousands of locations across the country, year by year starting in 1980. You'll see a dramatic collapse in lead levels as the government phased out leaded gas. By the 2000s, most places had virtually no airborne lead. Today, you still find pockets of elevated lead near factories and smelters, but the improvement is striking. If you're researching how successful environmental policy can be, or where lead pollution persists, this is the actual measurement record.

Lead emissions dropped by 99.99% in three decades. In 1970, on-road vehicles belched out 172,000 short tons of lead into the air each year (mostly from leaded gasoline). By 1998, that number was down to 19 short tons. This dataset shows year by year how that happened, plus emissions from other sources like factories and waste disposal. It's the EPA's official table documenting one of the biggest pollution victories in American history, and it's the specific data that researchers use when they argue that removing lead from gasoline also removed a major cause of crime.