Earth Data School
About
Full catalog/MOD04_3K
MOD04_3K·v6.1·dataset

Haze, dust and smoke in the air (Terra, 3 km)

MODIS/Terra Aerosol 5-Min L2 Swath 3km
atmosphere NASA LAADS Level 2 active HDF-EOS
In plain English

What it measures. How much haze, dust, and smoke is in the air, mapped at a fairly fine 3-km scale so that pollution patterns over cities and towns show up clearly.

How it's made. Retrieved from the MODIS sensor on the Terra satellite using a finer-resolution version of the Dark Target aerosol method, delivered as 5-minute strips along the satellite's path.

How & where you'd use it. Designed specifically for the air-quality community to study local and regional pollution at a neighborhood-ish scale rather than just broad regions.

What's measured

ATMOSPHERE › AEROSOLS › AEROSOL BACKSCATTERATMOSPHERE › AEROSOLS › AEROSOL EXTINCTIONATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESSATMOSPHERE › AEROSOLS › AEROSOL OPTICAL DEPTH/THICKNESS › ANGSTROM EXPONENTATMOSPHERE › AEROSOLS › AEROSOL PARTICLE PROPERTIESATMOSPHERE › AEROSOLS › AEROSOL RADIANCEATMOSPHERE › AEROSOLS › CARBONACEOUS AEROSOLSATMOSPHERE › AEROSOLS › CLOUD CONDENSATION NUCLEIATMOSPHERE › AEROSOLS › DUST/ASH/SMOKEATMOSPHERE › AEROSOLS › NITRATE PARTICLESATMOSPHERE › AEROSOLS › ORGANIC PARTICLESATMOSPHERE › AEROSOLS › PARTICULATE MATTERATMOSPHERE › AEROSOLS › SULFATE PARTICLESATMOSPHERE › ATMOSPHERIC RADIATION › OPTICAL DEPTH/THICKNESS

Coverage & cadence

  • Time span2000-02-24 → ongoing
  • Measured byTerra (MODIS)
  • Processing levelLevel 2
  • Spatial extent-180, -90, 180, 90
  • FormatsHDF-EOS
  • StatusACTIVE

What you can do with it

  • Map air pollutants — NO₂, aerosols, ozone
  • Track greenhouse gases and Earth's energy budget
  • Feed weather and air-quality analysis
Official description

The new Collection 6.1 (C61) MODIS/Terra Aerosol 5 Min L2 Swath 3km (MOD04_3K) product is an improved version based on algorithm changes in Dark Target (DT) Aerosol retrieval over urban areas and uncertainty estimates for Deep Blue (DB) Aerosol retrievals. The MODIS level-2 atmospheric aerosol product provides retrieved ambient aerosol optical properties, quality assurance, and other parameters, globally over ocean and land. In Collection 5, and earlier collections, there was only one aerosol product (MOD04_L2) at 10km (at nadir) spatial resolution. Starting from C6, the Dark Target (DT) Aerosol algorithm team provided a new 3 km spatial resolution product (MOD04_3k) intended for the air quality community. The MOD04_3K product is based on the same algorithm and Look up Tables as the standard Dark Target aerosol product. Because of finer resolution, subtle differences are made in selecting pixels for retrieval and in determining QA. The only differences between the existing 10km algorithm and the new 3km algorithm are: 1) the size of the pixel-arrays defining each retrieval box ( 6x6 retrieval boxes of 36 pixels at 0.5km resolution for 3km algorithm as oppose to 20x20 retrieval boxes of 400 pixels at 0.5km resolution for 10km product); 2) the minimum percentage of "good" pixels required for a retrieval (a minimum of 5 pixels over ocean and 6 pixels over land instead of a minimum of 10 pixels over ocean or 12 pixels over land for 10km product retrieval); 3) the 10km algorithm attemptes a "poor quality" retrieval while 3km algorithm does not. Everything else is the same between two products. For more information on C6.1 changes and updates, visit the MODIS Atmosphere website at: https://modis-atmosphere.gsfc.nasa.gov/documentation/collection-61

Get the data

mod04_3k_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="MOD04_3K",
    version="6.1",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LAADS
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.