carbon dioxide testing

Carbon Monoxide Air Quality Standard – 9 ppm

EPA Carbon Monoxide Standards

The Environmental Protection Agency (EPA) sets National Ambient Air Quality Standards (NAAQS) for carbon monoxide as part of its mandate to protect public health and the environment. Carbon monoxide is a colorless, odorless gas that can be harmful when inhaled because it interferes with the blood’s ability to carry oxygen.

Standards and Their Purpose

  • 8-hour standard: The limit of 9 parts per million (ppm) is based on a rolling average over 8 hours. This standard is particularly important for protecting individuals with chronic heart diseases, as these populations are more vulnerable to the effects of CO over longer periods of exposure.
  • 1-hour standard: The limit of 35 ppm over a 1-hour period addresses acute exposure scenarios. This standard helps to prevent significant health effects such as impaired vision and reduced brain function, which can occur at high levels of exposure, even if short-term.

Implementation and Monitoring

To ensure compliance with these standards, the EPA requires states to monitor air quality in urban areas, where CO levels are more likely to exceed health-based standards due to higher traffic volumes and other combustion sources. The monitoring data collected is used to determine if areas meet the standards or if they are in non-attainment.

Actions for Non-attainment Areas

Areas that do not meet the carbon monoxide standards must develop and implement plans to reduce CO levels. These plans often include measures to improve traffic flow, enhance public transportation options, and enforce stricter emission controls on vehicles and industrial sources.

Recent Trends and Improvements

Due to advances in emissions control technologies, especially in motor vehicle standards, levels of carbon monoxide in outdoor air have decreased significantly across the United States over the past few decades. As a result, most urban areas in the U.S. now meet the EPA’s carbon monoxide standards.

By setting and enforcing these standards, the EPA aims to minimize health risks posed by carbon monoxide exposure, contributing to the overall wellbeing of the population and the environment.

The EPA Air Quality Standard (NAAQS) for carbon monoxide is 9 parts per million. Carbon monoxide (CO) is both an asphyxiant gas and an indicator of the presence of other combustion-related vapors. Elevated levels of carbon monoxide generally result from defective combustion exhaust systems, automotive exhaust, and tobacco smoke. CO levels may vary widely from day to day and hour to hour. For premises heated with gas or oil, CO levels should always be checked during cold weather with the heating systems on to be certain that the combustion exhaust system is functioning properly. Symptoms resulting from CO exposure may include headache, dizziness, confusion, nausea and fatigue. Carbon Monoxide Air Quality Standards vary from country to country.

The EPA air quality standard for particulate matter (PM 2.5) in air is 12 micrograms per cubic meter (μg/m3).

PM stands for particulate matter (also called particle pollution): the term for a mixture of solid particles and liquid droplets found in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others are so small they can only be detected using an electron microscope.

Particle pollution includes:

EPA Air Quality Sources of PM 2.5

  • PM10 : inhalable particles, with diameters that are generally 10 micrometers and smaller; and
  • PM2.5 : fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller.
  • How small is 2.5 micrometers? Think about a single hair from your head. The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle.

These particles come in many sizes and shapes and can be made up of hundreds of different chemicals.

Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires.

Most particles form in the atmosphere as a result of complex reactions of chemicals such as sulfur dioxide and nitrogen oxides, which are pollutants emitted from power plants, industries and automobiles.

On December 14, 2012, EPA finalized an update to the National Ambient EPA Air Quality Standard for PM2.5. The annual standard was reduced from 15 μg/m3 to 12 μg/m3. The daily PM2.5 standard and standards for PM10 were retained. The revised 2012 PM standard became effective on March 18, 2013.

Please call Angstrom testing service at 516-724-4574 for more information or visit our air quality page.’s