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Aeroqual and Automotive Emissions

Aeroqual and Automotive Emissions

Evolving Testing Standards

With the passage of the Clean Air Act (CAA) in 1970, the EPA began regulating nitrogen oxide (NOx) emissions from light duty vehicles. The CAA was amended in 1990, and new emission standards were set for four additional smog pollutants:

  • Non-methane organic gases (NMOG)
  • Carbon monoxide (CO)
  • Particulate matter (PM)
  • Formaldehyde (HCHO)

The amendments also gave California authority to pass its own stricter vehicle emission standards, due to its particularly worse air pollution issues. EPA must approve California’s waiver for stricter standards. States may choose to follow either the federal or California standards.

The EPA has lowered the amount of pollution light duty vehicles can emit multiple times since the first standards were set in 1970. The EPA termed the first emission standards for cars and light trucks “Tier 1” Standards, with Tier 2 and Tier 3 as subsequent updates to the standards. Nearly all cars on the road today are held to either the current Tier 3 standards or the previous Tier 2 standards.

Today, automakers choose to certify each car model to one of EPA’s smog rating standards, also known as “bins,” but the automaker’s fleet as a whole must meet a specified average. Vehicles certified to a specific bin cannot exceed the amount of pollution specified for that bin. For example, if a vehicle is certified to Bin 50, it cannot emit more than 0.05 grams of NOx + NMOG, 1.7 grams of CO, 0.003 grams of PM, and 0.004 grams of HCHO per every mile it drives*.


Emerging Technologies

It’s no secret that public and regulatory pressure have necessitated swift advancements in emissions testing technology. With California at the helm, the stage is set for the U.S. to adopt sweeping reform of car and light-duty vehicle emissions standards. Both California and Washington D.C. have legislated that all cars and light trucks sold within their jurisdiction must average more than 50 miles per gallon by 2025.

Aside from the obvious public good of lowering Greenhouse Gas (GHG) emissions related to motor vehicles, new products can lower facility operating costs while simultaneously providing greater data accuracy. Aeroqual products from CleanAir feature swappable, modular parts, fast servicing, and on-site setup and calibration.

AQM65 AQS1 Dust Sentry



* For current and proposed EPA standards, see: https://www.epa.gov/regulations-emissions-vehicles-and-engines/regulations-greenhouse-gas-emissions-passenger-cars-and and https://www.epa.gov/system/files/documents/2021-08/420r21056.pdf


EPA Light Duty Vehicle standards: https://www.epa.gov/greenvehicles/light-duty-vehicle-emissions

EPA Emissions Testing Technical Information: https://www.epa.gov/vehicle-and-fuel-emissions-testing/emissions-testing-technical-resources-national-vehicle-and-fuel

EPA Automotive Trends Report: https://www.epa.gov/automotive-trends

Grandview Research report on the emissions testing industry: https://www.grandviewresearch.com/industry-analysis/automotive-emission-test-equipment-market

Aeroqual Vehicle Pollution Monitoring: https://www.aeroqual.com/outdoor-air-quality-monitors/vehicle-pollution-monitoring