Environmental Exposure: Air Quality
Air Quality and Health
Air pollution has been linked to a number of health problems, such as asthma, heart disease, and breathing problems among others.
The New Mexico Environmental Public Health Tracking Network and the National Tracking Network at CDC work closely with the Environmental Protection Agency to provide air quality data (see Collecting Air Data, below) on the EPHT Network and to better understand how air pollution affects our health. On these air quality pages you will find information and data about Ozone (O3) and Particulate Matter (PM2.5), and the kinds of problems these can cause for our health.
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Ozone and Smog
People with lung disease, children, older adults, and people who are active outdoors can be affected when ozone levels are unhealthy.
Scientists have done many studies which have linked ground-level ozone contact to a variety of problems such as:
- Airway irritation, coughing, and pain when taking a deep breath.
- Wheezing and breathing difficulties during exercise or outdoor activities.
- Inflammation of the airways.
- Aggravation of asthma and a higher chance of getting respiratory illnesses like pneumonia and bronchitis.
Ozone is a gas that you cannot see or smell. "Good" ozone occurs naturally in the sky about 10 to 30 miles above the Earth's surface. It forms a layer that protects life on Earth from the sun's harmful rays.
Ground-level ozone forms when precursor pollutants that come from cars, power plants, and other sources come in contact with each other in heat and sunlight. It is the biggest part of what we call "smog." Ground-level ozone is bad for your health and the environment.
Ground-level ozone is also called "bad" ozone because it is in the air we breathe. Many urban areas, like big cities, tend to have higher levels of bad ozone. Rural areas have bad ozone, too, because the wind carries ozone and the pollutants that form it hundreds of miles away from their original sources.
Studies have shown that being exposed to bad ozone can:
- Cause respiratory symptoms like coughing or pain when you take a deep breath.
- Make asthma worse.
- Cause lungs to get inflamed.
- Temporarily decrease the lung capacity of healthy adults.
- Repeated contact with bad ozone may permanently scar lung tissue.
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Particulate Matter (Air Pollution with Particles)
Particle pollution, or particulate matter, consists of particles that are in the air, such as dust, dirt, soot and smoke, and little drops of liquid. Some particles are large or dark enough and can be seen, like soot or smoke. Other particles are too small to be seen.
Being exposed to particle pollution for more than a year is linked to heart and lung problems such as:
- Breathing problems.
- Reduced lung function.
- Chronic bronchitis.
- Heart disease.
These problems may lead to more hospital stays, more emergency department visits, and even early death. Sensitive people such as older adults, people with diseases like asthma or congestive heart disease, and children are more likely to be affected by contact with PM2.5 (particle pollution).
Being exposed to particle pollution for short periods of time, like hours or a few days, can:
- Make lung disease worse.
- Cause asthma attacks.
- Cause bronchitis.
- Make it easier for people to get respiratory infections.
In people with heart disease, short-term contact with PM2.5 has been linked to heart attacks and irregular heartbeat. Short-term exposure has also been linked with early deaths, usually in people who already have a serious health problem such as lung or heart disease.
Healthy children and adults usually do not have serious problems from short-term exposure to particle pollution. They may have minor problems, like a scratchy throat or scratchy eyes, when particle levels are elevated.
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Collecting Air Data
Ambient Air Quality Monitoring in the United States: Monitoring Networks
Federal, state, local, and tribal air agencies operate and maintain a wide variety of ambient monitoring systems across the United States. Many of these systems serve multiple environmental objectives. At a basic level, they let us know how clean or polluted the air is, help us track progress in reducing air pollution, and inform the public about air quality in their communities through the Air Quality Index (AQI). EPA provides guidance to help these groups understand the quality of the data produced by these networks. The data from these monitors are used to characterize the status of the nation's air quality and the trends across the United States.
Since the 1970s, State and Local Ambient Monitoring Stations (SLAMS) have represented the majority of all criteria pollutant monitoring across the nation. At one point, over 5,000 monitors at approximately 3,000 sites were maintained as part of the SLAMS network.
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Air Quality System Database
The Air Quality System (AQS) database contains ambient air pollution data. The data are collected by EPA, state, local, and tribal air pollution control agencies. There are thousands of monitoring stations across the United States. AQS also contains meteorological data, information about each monitoring station such as its location and its operator, and data quality assurance and quality control information. State and local agencies are required to submit their air quality monitoring data into AQS by the end of the quarter following the quarter in which the data were collected. This ensures timely submission of these data for use by state, local, and tribal agencies, EPA, and the public.
The Air Quality System (AQS) is important because it helps EPA and others to:
- Assess air quality.
- Assist in determining which areas of the country are meeting air quality standards.
- Evaluate state plans for controlling air pollution.
- Perform modeling for permit review analysis.
- Perform other air quality analyses such as trend analysis and health effect studies.
AQS information is also used to prepare reports for Congress, which is required by the Clean Air Act.
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Advantages and Limitations of the Air Quality Monitoring and Reporting System
Air quality data are required to assess public health impacts caused by poor air quality, determine whether an area is meeting the standards, and evaluate changes in air quality as a result of state implementation plans. The challenge is to get measurements of air quality in time and space that are useful for Environmental Public Health Tracking activities.
The advantage of using ambient data from EPA, state, and local monitoring networks for comparison with health outcomes is that these measurements of pollution concentrations are the best characterization of the concentration of a given pollutant at a given time and location. Furthermore, the data are supported by a comprehensive quality assurance program, ensuring good data of known quality. One disadvantage of using the ambient monitoring data is that there are a limited number of monitors that can be sited and maintained. This limitation creates gaps in temporal and spatial coverage for a complete assessment of air pollution exposure needed to assess health outcomes. This spatial and temporal ‘misalignment’ between air quality monitoring data and health outcomes is influenced by the following key factors:
- The living or working locations (microenvironments) where a person spends their time is not co-located with an air quality monitor.
- Time(s)/date(s) when a patient experiences a health outcome/symptom (e.g., asthma attack) not coinciding with time(s)/date(s) when an air quality monitor records ambient concentrations of a pollutant high enough to affect the symptom (e.g., asthma attack during a high PM2.5 day).
To compare/correlate ambient concentrations with acute health effects, daily local air quality data are needed. Spatial gaps exist in the air quality monitoring network, especially in rural areas, since the air quality monitoring network is designed to focus on measurement of pollutant concentrations in high population density areas.
Temporal limits also exist. PM2.5 monitors generally collect samples only once every three days, due in part to the time and costs involved in collecting and analyzing the samples. However, monitors that can automatically collect, analyze, and report PM2.5 measurements on an hourly basis have been introduced over the past several years. These monitors are available in most of the major metropolitan areas. Ozone is monitored daily, but mostly during the ozone season (the warmer months, approximately April through October), and year-long data would be extremely useful to evaluate whether ozone is a factor in health outcomes during the non-ozone seasons.
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