The air monitoring section of the Cleveland Division of Air Quality (CDAQ) operates a network of ambient air monitors throughout Cuyahoga County. The network measures "criteria pollutants". The Environmental Protection Agency (EPA) uses six “criteria pollutants” as indicators of air quality, and has established for each of them a maximum concentration above which adverse effects on humans may occur. The threshold concentrations are known as the National Ambient Air Quality Standards and they were adopted through the 1970 Amendment to the Clean Air Act.
National Ambient Air Quality Standards
The Clean Air Act, which was last amended in 1990, requires the EPA to set National Ambient Air Quality Standards (NAAQS) for pollutants that are considered harmful to human and environmental health. There are two types of national ambient air quality standards: primary standards, which provide public health protection, and secondary standards, which provide public welfare protection.
The EPA has set NAAQS for six criteria pollutants. The standards are listed below and are subject to be reviewed and revised. Units of measure for the standards are parts per million (ppm) by volume, parts per billion (ppb) by volume, and micrograms per cubic meter of air (µg/m³).
| Pollutant | Primary / Secondary | Averaging Time | Level | Form | |
|---|---|---|---|---|---|
| Carbon Monoxide (CO) | Primary | 8 hours | 9 ppm | Not to be exceeded more than once per year | |
| 1 hour | 35 ppm | ||||
| Lead (Pb) | Primary and Secondary | Rolling 3-month average | 0.15 µg/m³ | Not to be exceeded | |
| Nitrogen Dioxide (NO₂) | Primary | 1 hour | 100 ppb | 98th percentile of 1-hour daily maximum concentrations, averaged over 3 years | |
| Primary and Secondary | 1 year | 53 ppb | Annual Mean | ||
| Ozone (O₃) | Primary and Secondary | 8 hours | 0.070 ppm | Annual fourth-highest daily maximum 8-hour concentration, averaged over 3 years | |
| Particulate Pollution (PM) | (PM₂.₅) | Primary | 1 year | 9.0 µg/m³ | Annual mean, averaged over 3 years |
| Secondary | 1 year | 15.0 µg/m³ | Annual mean, averaged over 3 years | ||
| Primary and Secondary | 24 hours | 35 µg/m³ | 98th percentile, averaged over 3 years | ||
| (PM₂10) | Primary and Secondary | 24 hours | 150 µg/m³ | Not to be exceeded more than once per year (on average over 3 years) | |
| Sulfur Dioxide (SO₂) | Primary | 1 hour | 75 ppb | 99th percentile of 1-hour daily maximum concentrations, averaged over 3 years | |
| Secondary | 1 year | 10 ppm | Not to be exceeded more than once per year | ||
U.S EPA has established standards for allowable limits of each criteria air pollutant. The averaging time (period for evaluation), level (allowable concentrations within ambient air), and form (how often the level can exceed allowable limits) are different for each pollutant. The Primary Standards protect human health and the Secondary Standards protect the environment.
The Six Criteria Pollutants
Ozone
- Made up of three oxygen atoms
- Occurs in Earth's upper atmosphere (good) and at ground-level (bad)
- Ground-level ozone is a harmful air pollutant and the main ingredient in smog
Particulate Matter
- Mixture of solid particles and liquid droplets found in the air
- Can be harmful due to the small size of the solids or droplets
- Droplets can be inhaled which may cause serious health problems
Carbon Monoxide
- Colorless, odorless gas that can be harmful when inhaled in large quantities
- Released when something is burned
- Cars, trucks and other vehicles, or machinery that burn fossil fuels are the main sources of outdoor CO pollution
Sulfur Dioxide
- Emitted to the air from the burning of fossil fuels by power plants and other industrial facilities
- Can be harmful to the human respiratory system and make it difficult to breathe
- Reacts with nitrogen dioxides, water, and other chemicals to create acid rain
Nitrogen Dioxides
- Part of a group of highly reactive gases known as nitrogen oxides (NOx)
- Primarily emitted from the burning of fuel and forms from emissions from cars, trucks, buses, off-road equipment, and power plants
- Reacts with other chemicals in the air forming particulate matter, ozone, and acid rain
Lead
- Emitted into the air from ore and metals processing and piston-engine aircraft operating on leaded aviation fuel; highest concentrations found near lead smelters
- Can negatively affect the nervous system, kidney function, immune system, reproductive and development systems, and the cardiovascular system
For more information, visit the U.S. EPA NAAQS website.
Air Monitoring Network Plan and Site Location
CDAQ Air Monitoring staff are responsible for operating air monitors at various sites throughout Cuyahoga County. The criteria used to determine the site location for monitors is specific to the type of pollutant that is being monitored. Details on CDAQs monitoring stations and the criteria used to determine their location can be found on the main AirOhio website and the Air Monitoring Network Plan links below:
Air Quality Index and Annual Reporting
The air quality index is a measurement of how good or bad the air quality is on a given day. The scale is an easy way to understand if you might need to take certain precautions if you/or a family member has existing health concerns. If the color is green, the air quality is generally accepted to be good for all populations. If the scale reaches yellow or orange, individuals with existing health concerns should be aware and modify their behavior accordingly.
The Air Quality Index is available through AirNow.gov and recorded Monday through Friday at CDAQs Hotline at (216) 664-7442.
The Northeast Ohio Areawide Coordinating Agency issues Air Quality Advisories when levels of fine particulate pollution and/or ozone are expected to exceed the health (primary) standard. You can sign up for alerts at the link below:
Northeast Ohio Areawide Coordinating Agency
The public can view real time air quality values through the Daily Parameter Report on Ohio EPAs website for most sites in Ohio. Although the information is available, it has not undergone a quality assurance process yet and it is not validated by EPA.
Daily Parameter Report on Ohio EPA
Data that has been validated is available in an Annual Report developed by Ohio EPA and can be accessed at the link below.